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And Selection in Relation to Sex 


Auth'orof -THE ORIGIN OF SPECIES," etc., etc ' 


printed from the Second English Edition, 
Revised and Augmented 


A. L. BURT COMPANY, ^ ^ ^ ^ ^ 

>>)' n ^ to -> 


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troduced and four of the old drawings have been replaced 
by better ones, done from life by Mr.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

I may take this opportunity of remarking that my critics 
frequently assume that I attribute all changes of corporeal 
structure and mental power exclusively to the natural se- 
lection of such variations as are often called spontaneous; 
whereas, even in the first edition of the '* Origin of 
Species," I distinctly stated that great weight muet l;)e at- 


tributed to the inherited effects of use and disuse, with re- 
spect both to the body and mind. I also attributed some 
amount of modification to the direct and prolonged action 
of changed conditions of life. Some allowance, too, must 
be made for occasional reversions of structure; nor must we 
forget what I have called "correlated^' growth, meaning 
thereby that various parts of the organization are in some 
unknown manner so connected, that when one part varies 
so do others; and if variations in the one are accumulated 
by selection other parts will be modified. Again, it has 
been said by several critics that when I found that many 
details of structure in man could not be explained through 
natural selection, I invented sexual selection; I gave, how- 
ever, a tolerably clear sketch of this principle in the first 
edition of the " Origin of Species, '^ and I there stated that 
it was applicable to man. This subject of sexual selection 
has been treated at full length in the present work, simply 
because an opportunity was here first afforded me. I have 
been struck with the likeness of many of the half -favorable 
criticisms on sexual selection, with those which appeared 
at first on natural selection; such as, that it would explain 
some few details, but certainly was not applicable to the 
extent to which I have employed it. My conviction of the 
power of sexual selection remains unshaken ; but it is 
probable, or almost certain, that several of my conclusions 
will hereafter be found erroneous; this can hardly fail to 
be the case in the first treatment of a subject. When 
naturalists have become familiar with the idea of sexual 
selection, it will, as I believe, be much more largely ac- 
cepted; and it has already been fully and favorably re- 
ceived by several capable judges. 

Down, Bbckenham, Kent, September, 1874 


Intboduction 1 



The Evidence of the Descent of Man from Some Lower Form. . 5 

On the Manner of Development of Man from Some Lower Form 29 


Comparison of the Mental Powers of Man and the Lower 

Animals 73 


Comparison of the Mental Powers of Man and the Lower 

Animals — continued 110 


On the Development of the Intellectual and Moral Faculties 

During Primeval and Civilized Times 144 

On the Affinities and Genealogy of Man • 166 

On the Races of Man 189 





Principles of Sexual Selection 234 


Secondary Sexual Characters in the Lower Classes of tlie Ani- 
mal Kingdom 294 

Secondary Sexual Characters of Insects 311 

Insects, continued — Order Lepidoptera. Butterflies and Moths. 348 


Secondary Sexual Characters of Fishes, Amphibians, and 

peptiles 375 

Secondary Sexual Characters of Birds 407 

Birds — cantinued , 459 

'Biix^&—contimied , 505 

'BudiQ— concluded 528 

Secondary Sexual Characters of Mammals 570 




Secondary Sexual Characters of Mammals — continued 600 



Secondary Sexual Characters of Man ^ 634 

Secondary Sexual Characters of M.SiJi-— continued 668 

General Summary and Conclusion 693 

Supplemental Note ,. 709 

Index •••.. •••• 715 





The nature of the following work will be best understood 
by a brief account of how it came to be written. During 
many years I collected notes on the origin or descent of 
man, without any intention of publishing on the subject, 
but rather with the determination not to publish, as I 
thought that I should thus only add to the prejudices 
against my views. It seemed to me sufficient to indicate, 
in the first edition of my '' Origin of Species, ^^ that by this 
work " light would be thrown on the origin of man and his 
history;" and this implies that man must be included with 
other organic beings in any general conclusion respecting 
his manner of appearance on this earth. Now the case 
wears a wholly different aspect. When a naturalist like 
Carl Vogt ventures 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 independ- 
ante 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; and this es- 
pecially 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 honored chiefs in natural science, many un- 
fortunately are still opposed to evolution in every form. 

In consequence of the views now adopted by most natu- 
ralists, and which will ultimately, as in every other case, be 


followed by others who are not scientific, I have been led to 
put together my notes, so as to see how far the general con- 
clusions arrived at in my former works were applicable to 
man. This seemed all the more desirable, as I had never 
deliberately applied these views to a species taken singly. 
When we confine our attention to any one form, we are de- 
prived of the weighty arguments derived from the nature 
of the affinities which connect together whole groups of 
organisms — their geographical distribution in past and pres- 
ent times, and their geological succession. The homologi- 
cal structure, embryological development, and rudimentary 
organs of a species remain to be considered, whether it be 
man or any other animal, to which our attention may be 
directed; but these great classes of facts afford, as it ap- 
pears to me, ample and conclusive evidence in favor of the 
principle of gradual evolution. The strong support derived 
from the other arguments should, however, always be kept 
before the mind. 

The sole object of this work is to consider, firstly, 
whether man, like every other species, is descended from 
some pre-existing form; secondly, the manner of his devel- 
opment; and thirdly, the value of the differences 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 sub- 
ject which has been fully discussed in many valuable works. 
The high antiquity of man has recently been demonstrated 
by the labors of a host of eminent men, beginning with M. 
Boucher de Perthes; and this is the indispensable basis for 
understanding his origin. I shall, therefore, take this 
conclusion for granted, and may refer my readers to the 
admirable treatises of Sir Charles Lyell, Sir John Lubbock, 
and others. Nor shall I have occasion to do more than to 
allude to the amount of difference between man and the 
anthropomorphous apes; for Prof. Huxley, in the opinion 
of most competent judges, has conclusively shown that in 
every visible character man differs less from the higher 
apes than these do from the lower members of the same 
order of Primates. 

This work contains hardly any original facts in regard 
to man; but as the conclusions at which I arrived, after 
drawing up a rough draft, appeared to me interesting, I 
thought that they might interest others. It has often and 


confidently been asserted that man's origin can never be 
known: but ignorance more frequently begets confidence 
than does knowledge: it is those who know little, and not 
those who know much, who so positively assert that this or 
that problem will never be solved by science. The con- 
clusion that man is the co-descendant with other species of 
some ancient, lower, and extinct form, is not in any degree 
new. Lamarck long ago came to this conclusion, which 
has lately been maintained by several eminent naturalists 
and philosophers; for instance, by Wallace, Huxley, Lyell, 
Vogt, Lubbock, Biichner, Rolle, etc.,* and especially by 
Hackel. This last naturalist, besides his great work, 
^^Generelle Morphologic" (1866), has recently (1868, 
with a second edition in 1870), published his " Naturliche 
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 com- 
pleted it. Almost all the conclusions at which I have 
arrived I ttnd confirmed by this naturalist, whose knowl- 
edge on many points is much fuller than mine. Wherever 
I have added any fact or view from Prof. HackeFs writ- 
ings, I give his authority in the text; other statements I 
leave as they originally stood in my manuscript, occasion- 
ally giving in the footnotes references to his works, as a 
confirmation of the more doubtful or interesting points. 

During many years it has seemed to me highly probable 
that sexual selection has played an important part in 
diiferentiating the races of man; but in my " Origin 
of Species" (first edition) 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 

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


subject in full detail.* Consequently, the second pai^t of 
the present work, treating of sexual selection, has extended 
to an inordinate length, compared with the first part; but 
this could not be avoided. 

I had intended adding to the present volume an essay on 
the expression of the various emotions by man and the 
lower animals. My attention was called to this subject 
many years ago by Sir Charles BelFs admirable worJc. 
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 re- 
serve my essay for separate publication. 

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





Nature of the evidence bearing on tlie 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, etc. — 
The bearing of these three great classes of facts on the origin of 

He who wishes to decide whether man is the modified 
descendant of some pre-existing form, would probably first 
inquire 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. Again, 
are the variations the result, as far as our ignorance permits 
us to Judge, of the same general causes, and are they 
governed by the same general laws, as in the case of other 
organisms; for instance, by correlation, the inherited effects 
of use and disuse, etc. ? Is man subject to similar malcon- 
formations, the result of arrested development, of reduplica- 
tion of parts, etc. , and does he display in any of his anoma- 
lies reversion to some former and ancient type of structure? 
It might also naturally be inquired whether man, like so 
many other animals, has given rise to varieties and sub- 
races, differing but slightly from each other, or to races 
differing so much that they must be classed as doubtful 
species? How are such races distributed over the world; 
and how, when crossed, do they react on each other in the 
first and succeeding generations? And so with many other 


The inquirer 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 conse- 
quently 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 one another, so that some finally 
become extinct ? We shall see that all these questions, as 
indeed is obvious in respect to most of them, n^aist be an- 
swered in the affirmative, in the same manner as with the 
lower animals. But the several considerations just referred 
to may be conveniently deferred for a time : and we will 
first see how far the bodily structure of man shows traces, 
more or less plain, of his descent from some lower form. 
In succeeding chapters the mental powers of man, in com- 
parison with those of the lower animals, will be considered. 

The Bodily Structure of Man. — It is notorious that man 
is constructed on the same general type or model as 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 vis- 
cera. The brain, the most important of all the organs, 
follows the same law, as shown by Huxley and other anato- 
mists. Bischoff,* who is a hostile witness, admits that every 
chief fissure and fold in the brain of man has its analogy 
in that of the orang ; but he adds that at no period of de- 
velopment do their brains perfectly agree ; nor could per- 
fect agreement be expected, for otherwise their mental pow- 
ers would have been the same. Vulpianf remarks : " Les 
differences reelles qui existent entre Tencephale de Fhomme 
et celui des singes superieurs, sont bein minimes. II ne 
faut pas se faire d^illu6ions d cet egard. L^homme est bein 
plus pres des singes anthropomorphes par les caracteres 
anatomiques de son cerveau que ceux-ci ne le sont non seul- 
ement des autres mammif ^res, mais meme de certains quad- 
rumanes, des guenons et des macaques. ''' But it would be 

* " Grossliirnwindungen des Mensclien," 1868, s. 96. Tlie con- 
clusions of this author, as well as those of Gratiolet and Aeby, con- 
cerning the brain, will be discussed by Prof. Huxley in the Appendix 
alluded to in the Preface to this edition. 

f "Lee. sur la Phys.," 1866, p. 890, as quoted by M. Dally, 
" t'Ordre des Primates et le Transformisme," 1868, p. 39. 


superfluous here to give further details on the correspond- 
ence between man and the higher mammels 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 structure, by which 
this correspondence or relationship is well shown. 

Man is liable to receive from the lower animals, and 
to communicate to them, certain diseases, as hydrophobia, 
variola, the glanders, syphilis, cholera, herpes, etc. ;* and 
this fact proves the close similarity f of their tissues and 
blood, both in minute structure and composition, far more 
plainly than does their comparison under the best micro- 
scope, or by the aid of the best chemical analysis. Mon- 
keys are liable to many of the same non-contagious diseases 
as we are; thus Kengger,! who carefully observed for a loug 
time the Cehus Azarce in its native land, found it liable to 
catarrh, with the usual symptoms, and which, when often 
recurrent, led to consumption. These monkeys suffered 
also from apoplexy, inflammation of the bowels, and cata- 
ract in the eye. The younger ones when shedding their 
milk-teeth often died from fever. Medicines produced the 
same effect on them as on us. Many kinds of m'onkeys 
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 
Afi-ica 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 

* Dr. W. Lauder Lindsay has treated this subject at some length 
in the "Journal of Mental Science," July, 1871; and in the "Edin- 
burgh Veterinary Review," July, 1858. 

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

X " Naturgeschichte der Saugethiere von Paraguay," 1830, s. 50. 

§ The same tastes are common to some animals much lower in the 
scale. Mr, A. Nichols informs me that he kept in Queensland, in 
Australia, three individuals of the Phaseolarctus cinereus ; and that, 
without having been taught in any way, they acquired a strong tast© 
Iqx rum aad smoking tobacco. 


this state; and he gives a laughable account of their behav- 
ior 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 dis- 
gust, but relished the juice of lemons.* An American 
monkey, an Ateles, after getting drunk on brandy, would 
never touch it again, and thus was wiser than many men. 
These trifling facts prove how similar the nerves of taste 
must De in monkeys and man, and how similarly their whole 
nervous system is affected. 

Man is infested with internal parasites, sometimes causing 
fatal effects; and is plagued by external parasites, all of 
which belong to the same genera or families as those infest- 
ing other mammals, and in the case of scabies to the same 
species, f Man is subject, like other mammals, birds, and 
even insects, J to that mysterious law, which causes certain 
normal processes, such as gestation, as well as the matura- 
tion and duration of various diseases, to follow lunar periods. 
His wounds are repaired by the same process of healing; 
and the stumps left after the amputation of his limbs, es- 
pecially during an early embryonic period, occasionally 
possess some power of regeneration, as in the lowest 
animals. § 

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, | to 

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

f Dr. W. Lauder Lindsay, "Edinburgh Veterinary Review," July, 
1858, p. 13. 

X With respect to insects see Dr. Lay cock " On a General Law of 
Vital Periodicity," *' British Association," 1842. Dr. Macculloch, 
" Silliman's North American Journal of Science," vol. xvii, p. 305, 
has seen a dog suffering from tertian ague. Hereafter I shall return 
to this subject. 

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

\ Mares e diversis generibus Quadrumanorum sine dubio dignos- 
cunt feminas humanas a maribus, Primum, credo, odoratu, postea 
aspectu. Mr. Youatt, qui diu in Hortis Zoologicis (Bestiariis) medi- 
cus animalium erat, vir in rebus observandis cautus et sagax, hoo 
mihi certissime probavit, et curatores ejusdem loci et alii e ministris 
COttfirmaverunt. Sir Andrew Smith et Brehm notabant idem in Cyno* 


the birtli and nurturing of the young. Monkeys are born 
in almost as helpless a condition as our own infants; and in 
certain genera the young differ fully as much in appearance 
from the adults, as do our children from their full-grown 
parents.* It has been urged by some writers, as an import- 
ant 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 coun- 
tries the difference is not great, for the orang is believed 
not to be adult till the age of from ten to fifteen years. \ 
Man differs from woman in size, bodily strength, hairiness, 
etc., as well as in mind, in the same manner as do the two 
sexes of many mammals. So that the correspondence in 
general structure, in the minute structure of the tissues, in 
chemical composition and in constitution, between man and 
the higher animals, especially the anthropomorphous apes, 
is extremely close. 

Em'bryo7iic 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 distin- 
guished from that of other members of the vertebrate king- 
dom. 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 (/, g, fig. 1), marking their former posi- 
tion. 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 fundamental form," It is, says Prof. Huxley,]; 

ceplialo. Illustrissimus Cuvier etiam narrat multa de liac re, qua 
ut opinor, niliil turpius potest indicari inter omnia liominibus et 
Quadrumanis communia. Narrat enim Cynocephalum quendam in 
f urorem incidere aspectu feminarum aliquarum, sed nequaquam ac- 
cendi tanto furore ab omnibus. Semper eligebat juniores, et dignos- 
cebat in turba, et advocabat voce gestuque. 

*This remark is made with respect to Cynocephalus and tlie 
antbropomorplious apes by Geoffrey Saint-Hilaire and F. Cuvier, 
" Hist. Nat. des Manimiferes," tom.i, 1824. 

f Huxley, «* Man's Place in Nature." 1863, p. 34. 

Jlbid., p. 67. 


*' quite in the later stages of development ttiat the young 
human being presents marked differences from the young 
ape, while the latter departs as much from the dog in its 
developments as the man does. Startling as this last asser- 
tion may appear to be, it is demonstrably true/* 

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

After the foregoing statements made by such high 
authorities, it would be superfluous on my part to give a 
number of borrowed details, showing that the embryo of 
man closely resembles that of other mammals. It may, 
however, be added, that the human embryo likewise resem- 
bles certain low forms when adult in various points of 
structure. For instance, the heart at first exists as a simple 
pulsating vessel ; the excreta are voided through a cloacal 
passage ; and the os coccyx projects like a true tail, ^' ex- 
tending considerably beyond the rudimentary legs.^'^f In 
the embryos of all air-breathing vertebrates, certain glands, 
called the corpora Wolffiana, correspond with, and act 
like the kidneys of mature fishes. | Even at a later 
embryonic period, some striking resemblances between 
man and the lower animals may be observed. Bischofl 
says that " the convolutions of the brain in a human foetus 
at the end of the seventh month reach about the same 
stage of development as in a baboon when adult. "§ 
The great toe, -as Prof. Owen remarks, || " which forms 
the fulcrum when standing or walking, is perhaps 

*The human embryo (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 
BischofE, " Entwicklungsgeschichte des Hunde-Eies," 1845, tab. xi, 
fig. 42 B. This drawing is five times magnified, the embryo being 
twenty five days old. The internal viscer; have been omitted, and 
the uterine appendages in both drawings removed. I was directed 
to these figures by Prof. Huxley, from whose work, " Man's Place in 
Nature," the idea of giving them was taken. Hackel has also given 
analogous drawings in his " Schopfungsgeschichte." 

f Prof. Wyman in ** Proc. of American Acad, of Sciences," vol, iv, 
1860, p. 17. 

X Owen, " Anatomy of Vertebrates," vol. i, p. 533. 

§ " Die Qrosshirnwindungen des Menschen." 1868, s. 95. 

I ** Anatomy of Vertebrates," vol. ii, p. 553. 



Fiff. 1. Upper figure human embryo, from Ecker. 
^ *'*' » £j.Qj^ BischofE. 

Lower figure that of a dog. 

a. Pore-brain, cerebral hemispberes, 

b'. Mid-brain, corpora quadrigemina. 

c. Hind-brain, cerebellum, medulla 

d. Eye. 
I, £ar. 

/. First visceral arch. 
Q. Second visceral arch. 
H. Vertebral columns and muscles 
in process of development. 
i Ajiterior j. extremities. 
K. Posterior ) 
L. Tail or os coccyx. 


the most characteristic peculiarity in the human stmct- 
ure;" but in an embryo, about an inch in length, Prof. 
Wyman* found '' that the great toe was shorter than the 
others; and, instead of being parallel to them, projected at 
an angle from the side of the foot, thus corresponding with 
the permanent condition of this part in the quadrumana/^ 
I will conclude with a quotation from Huxley, f who after 
asking, does man originate in a different way from a dog, 
bird, frog, or fish? says, ''the reply is not doubtful for a 
moment; without question, the mode of origin, and the 
early stages of the development of man, are identical with 
those of the animals immediately below him in the scale: 
without a doubt in these respects he is far nearer to apes 
than the apes are to the dog/' 

Rudiments, — This subject, though not intrinsically mpre 
important than the two last, will for several reasons be 
treated here more fully. X Not one of the higher animals 
can be named which does not bear some part in a rudi- 
mentary 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 mamm^ of male quadrupeds, or the incisor teeth of 
ruminants, which never cut through the gums; or they are 
of such slight service to their present possessors, that we 
can hardly suppose that they were developed under the 
conditions which now exist. Organs in this latter state are not 
strictly rudimentary, but they are tending in this direction. 
Nascent organs, on the other hand, though not fully devel- 
oped, are of high service to their possessors, and are capa- 
ble of further development. Rudimentary organs are 
eminently variable; and this is partly intelligible, as they 
are useless, or nearly useless, and consequently are no 

* "Proc. Soc. Nat. Hist.," Boston 1863, vol. ix, p. 185. 

f "Man's Place in Nature," p, 65. 

:j:I had written a rough copy of this chapter before reading- a valu- 
able paper, " Caratteri rudimentali in ordine all' origine dell' uomo'* 
(" Annuario della Soc. d. Nat.," Modena, 1867, p. 81), by G. Canes- 
trini, to which paper I am considerably indebted. Hackel has given 
admirable discussions on this whole subject, under the title of Dys- 
teleology, in his " Generelle Morphologie" and ' ' SchOpf ungsge- 


longer subjected to natural selection. They often become 
wholly suppressed. When this occurs, they are neverthe- 
less liable to occasional reappearance through reversion — a 
circumstance well worthy of attention. 

The chief agents in causing organs to become rudiment- 
ary seem to have been disuse at that period of life when 
the organ is chiefly used (and this is generally during matu- 
rity), and also inheritance at a corresponding period of life. 
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 alterna- 
tions of pressure, or from becoming in any way less habitu- 
ally active. Eudiments, however, may occur in one sex 
of those parts which are normally present in the other sex; 
and such rudiments, as we shall hereafter see, have often 
originated in a way distinct from those here referred to. 
In some cases, organs have been reduced by means of nat- 
ural selection, from having become injurious to the species 
under changed habits of life. The process of reduction is 
probably often aided through the two principles of com- 
pensation and economy of growth; bnt the later stages of 
reduction, after disuse has done all that can fairly be at- 
tributed to it, and when the saving to be effected by the 
economy of growth would be very small,* are difficult to 
understand. The final and complete suppression of a part, 
already useless and much reduced in size, in which case 
neither compensation nor economy come into play, is 
perhaps intelligible by the aid of the hypothesis of pangene- 
sis. But as the whole subject of rudimentary organs has 
been discussed and illustrated in my former works, f I need 
here say no more on this head. 

Eudiments of various muscles have been observed in 
many parts of the human body ;J and not a few muscles, 

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

\ " Variation of Animals and Plants under Domestication," vol. ii, 
pp. 317 and 397. See also "Origin of Species." 

X For instance M Richard (** Annales des Sciences Nat., 3d 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 froro 
time to time in a more or less rudimentary conditioa, * 


which are regularly present in some of the lower animals, 
can occasionally be detected in man in a greatly reduced con- 
dition. Every one must have noticed the power which many 
animals, especially horses, possess of moving or twitching 
their skin ; and this is effected by the panniculus carnosus. 
Remnants of this muscle in an efficient state are found in 
various parts of our bodies ; for instance, the muscle on the 
forehead, by which the eyebrows are raised. The platysma 
myoides, which is well developed on the neck, belongs to 
this system. Prof. Turner, of Edinburgh, has occa- 
sionally detected, as he informs me, muscular fasciculi in 
five different situations, namely in the axillae, near the 
scapulae, etc., all of which must be referred to the system 
of the panniculus. He has also shown* that the musculus 
sternalis or sternalis irutorum, which is not an extension 
of the rectus ahdominalis, but is closely allied to ih.Q pan- 
niculus, occurred in the proportion of about three per cent, 
in upwards of 600 bodies ; he adds, that this muscle affords 
'* an excellent illustration of the statement that occasional 
and rudimentary structures are especially liable to variation 
in 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 the family, 
could, when a youth, pitch several heavy books from his 
head by the movement of the scalp alone ; and he won 
wagers by performing this feat. His father, uncle, grand- 
father, and his three children possess the same power to the 
3ame 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 persistent 
may be the transmission of an absolutely useless faculty, 
probably derived from our remote semi-human progenitors; 

*Prof. W Turaer, " Proc. Royal Soc. Edinburgh," 1866-67, p. 65. 


since many monkeys have, and frequently use the power, 
of largely moving tlieir scalps up and down. * 

The extrinsic muscles which serve to move the external 
ear, and the intrinsic muscles which move the different 
parts, are in a rudimentary condition in man, and they all 
belong to the system of the pa?iuicuhis ; they are also vari- 
able in development, or at least in function. I have seen 
one man who could draw the whole ear forward; other men 
can draw it upward; another who could draw it backward;! 
and from what one of these persons told me, it is probable 
that most of us, by often touching our ears, and thus 
directing our attention toward them, could recover some 
power of movement by repeated trials. The power of erect- 
ing and directing the shell of the ears to the various points 
of the compass, is no doubt of the highest service to many 
animals, as they thus perceive the direction of danger; but 
I have never heard, on sufficient evidence, of a man who 
possessed this power, the one which might be of use to him. 
The whole external shell may be considered a rudiment, to- 
gether with the various folds and prominences (helix and 
anti-helix, tragus, and anti-tragus, etc.) which in the lower 
animals strengthen and support the ear when erect, with- 
out 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,J after 
collecting all the known evidence on this head, concludes 
that the external shell is of no distinct use. The ears of 
the chimpanzee and orang are curiously like those of man, 
and the proper muscles are likewise but very slightly 
developed. § I am also assured by the keepers in the 
Zoological Gardens that these animals never move or erect 
their ears; so that they are in an equally rudimentary condi- 
tion with those of man, as far as function is concerned. 

* See my *• Expression of tlie Emotions in Man and Animals," 1872, 
p. 144. 

f Canestrini quotes Hyrtl. ("Annuario della Soc. dei Naturalisti," 
Modena, 1867, p. 97) to the same effect. 

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

SProf. A. Macalister, "Annals and Mag. of Nat. History," voL 
vii, 1871, p. 342, 


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 satisfied with this view, 
that owing to their arboreal habits and great strength they 
were but little exposed to danger, and so during a length- 
ened period moved their ears but little, and thus gradually 
lost the power of moving them. This would be a parallel 
case with that of those large and heavy birds, which, from 
inhabiting oceanic islands, have not been exposed to the 
attacks of beasts of prey, and have consequently lost the 
power of using their wings for flight. The inability to 
move the ears in man and several apes is, however, partly 
compensated by the freedom with which they can move the 
head in a horizontal plane, so as to catch sounds from all 
directions. It has been asserted that the ear of man alone 
possesses a lobule; but "a rudiment of it is found in the 
gorilla;"* and, as I hear from Prof. Preyer, it is not rarely 
absent in the negro. 

The celebrated sculptor, Mr. Woolner, informs me of 
one little peculiarity in the external ear, which he has often 
observed both in men and women, and of which he per- 
ceived the full significance. His attention was first called 
to the subject while at work on his figure of Puck, to 
which he had given pointed ears. He was thus led to ex- 
amine the ears of various monkeys, and subsequently more 
carefully those of man. The peculiarity consists in a little 
blunt point, projecting from the inwardly folded margin, 
or helix. When present, it is developed at birth, and, ac- 
cording to Prof. Ludwig Meyer, more frequently in man 
than in woman. Mr. Woolner made an exact model of one 
such case, and sent me the accompanying drawing. (Fig. 2. ) 
These points not only project inward toward the center of 
the ear, but often a little outward from its plane, so as to be 
visible when the head is viewed from directly in front or 
behind. They are variable in size, and somewhat in position, 
standing either a little higher or lower ; and they sometimes 
occur on one ear and not on the other. They are not con- 
fined to mankind, for I observed a case in one of the spider- 
monkeys (Ateles Beehebuth) in our Zoological Gardens; 
and Mr. E. Kay Lankester informs me of another case in a 
chimpanzee in the gardens at Hamburg. The helix ob- 

*Mr. St. George Mivart, "Elementary Anatomy," 1873, p. 390. 


viously consists of the extreme margin of the ear folded 
inward ; and this folding appears to be in some manner 
connected with the whole external ear being permanently 
pressed backward. In many monkeys, which do not stand 
high in the order, as baboons and some species of Macacus,* 
the upper portion of the ear is slightly pointed, and the 
margin is not at all folded inward ; but if the margin were, 
to be thus folded, a slight point would necessarily project 
inward toward the center, and probably a little outward 
from the plane of the ear ; and this I believe to be their 
origin in many cases. On the other hand. Prof. L. Meyer, 
in an able paper recently published,! maintains that the 
whole case is one of mere variability; 
and that the projections are not real 
ones, but are due to the internal 
cartilage on each side of the points 
not having been fully developed. I 
am quite ready to admit that this is 
the correct explanation in many in- 
stances, as in those figured by Prof. 
Meyer, in which there are several 
minute points, or the whole margin 
is sinuous. I have myself seen, 
through the kindness of Dr. L. Down, 
the ear of a microcephalous idiot, 
on which there is a projection on the 
outside of the helix, and not on the 
inward folded edge, so that this point 
can have no relation to a former apex 
of the ear. Nevertheless in some 
cases, my original view, that the points are vestiges of the tips 
of formerly erect and pointed ears, still seems to me probable. 
I think so from the frequency of their occurrence, and from the 
general correspondence in position with that of the tip of a 
pointed ear. In one case, of which a photograph has been 
Bent me, the projection is so large, that supposing, in ac- 
cordance with Prof. Meyer's view, the ear to be made per- 

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

f Ueber das Darwin'sche Spitzolur. "Archiv fur Path. Anat. und 
Phys./' 1871, p. 485. 

Fig. 2. Human Ear, mod- 
eled and drawn X>y Mr. 

o. The projecting point. 


feet by the equal development of the cartilage throughout 
the whole extent of the margin, it would have covered fully 
one-third of the whole ear. Two cases have been commu- 
nicated to me, one in North America and the other in 
England, in which the upper margin is not at all folded 
inward, but is pointed, so that it closely resembles the 
pointed ear of an ordinary quadruped in outline. In one 
of these cases, which was that of a young child, the father 
compared the ear with the drawing which I have given* of 

Mg. 8. Foetus x)f an Orang. Exact copy of a photograph, showing 
the form of the ear- at this early age. 

the ear of a monkey, the Cynopitliecus niger, and says that 
their outlines are closely similar. If, in these two cases, 
the margin had been folded inward in the normal manner, 
an inward projection must have been formed. I may add 
that in two other cases the outline still remains somewhat 
pointed, although the margin of the upper part of the ear 
is normally folded inward — in one of them, however, very 
narrowly. The above wood-cut (Fig. 3) is an accurate 
copy of a photograph of the foetus of an orang (kindly sent 
me by Dr. Nitsche), in which it may be seen how different 
the pointed outline of the ear is at this period from its 
adult condition, when it bears a close general resemblance 

*" Tlie Expression of the Emotions/* p. 136. . • 


to that of man. It is evident that the folding over of the 
tip of such an ear, unless it changed greatly during its 
further development, would give rise to a point projecting 
inward. On the whole, it still seems to me probable that 
the points in question are in some cases, both in man and 
apes, vestiges of a former condition. 

The nictitating membrane, or third eyelid, with its ac- 
cessory muscles and other structures, is especially well 
developed in, birds, and is of much functional importance 
to them, as it can be rapidly drawn across the whole eye- 
ball. It is found in some reptiles and amphibians, and in 
certain fishes, as in sharks. It is fairly well developed in 
the two lower divisions of the mammalian series, namely, 
in the monotremata and marsupials, 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 ad- 
mitted by all anatomists, as a mere rudiment, called the 
semilunar fold.* 

The sense of smell is of the highest importance to the 
greater number of mammals — to some, as the ruminants, in 
warning them of danger; to others, as the carnivora, in 
finding their prey; to others, again, as the wild boar, for 
both purposes combined. But the sense of smell is of 
extremely slight service, if any, even to the dark colored 
races of men, in whom it is much more highly developed 
than in the white and civilized races, f Nevertheless it 
does not warn them of danger, nor guide them to their 

*Miiller's ** Elements of Pliysiology," Eng. translat., 1842, vol. ii, 
p. 1117. Owen, ** Anatomy of Vertebrates," vol. iii, p. 260; ibid, on 
tlie Walrus, **Proc. Zoolog. Soc," NovemlDer 8, 1854. See also R. 
Knox, "Great Artists and Anatomists," p. 106. This rudiment ap- 
parently is somewhat larger in Negroes and Australians than in Euro- 
peans, see Carl Vogt, " Lectures on Man," Eng. translat., p. 129. 

f The account given by Humboldt of the power of smell possessed 
by the natives of South America is well known, and has been con- 
firmed by others o M. Houzeau(" Etudes sur les Facultes Mentales," 
etc., torn, i, 1872, p. 91) asserts that he repeatedly made experiments, 
and proved that Negroes and Indians could recognize persons in the 
dark by their odor. Dr. W. Ogle has made some curious observa- 
tions on the connection between the power of smell and the coloring 
matter of the mucous membrane of the olfactory region, as well as of 
the skin of the body. I have, therefore, spoken in the text of the 
dark colored races having a finer sense of smell than the white races. 
See his paper, " Medico-Chirurgical Transactions," London, vol. liii, 
1870, p. 276. 


food; nor does it prevent the Esquimaux from sleeping in 
the most fetid atmosphere, nor many savages from eating 
half -putrid meat. In Europeans the power differs greatly 
in different individuals, as I am assured by an eminent 
naturalist who possesses this sense highly developed, and 
who has attended to the subject. Those who believe in the 
principle of gradual evolution will not readily admit that 
the sense of smell in its present state was originally acquired 
by man as he now exists. He inherits the j)ower 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. In those animals which 
have this sense highly developed, such as dogs and horses, 
the recollection of persons and of places is strongly associ- 
ated with their odor; and we can thus perhaps understand 
how it is, as Dr. Maudsley has truly remarked,* that the 
sense of smell in man *^is singularly effective in recalling 
vividly the ideas and images of forgotten scenes and places." 

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

I am informed by Sir James Paget that often several 
members of a family have a few hairs in their eyebrows 
much longer than the others; so that even this slight 

* " The Physiology and Pathology of Mind," 2d edit., 1868, p. 134. 

f Eschricht, Ueber die Richtung der Haare am menschlichen K6r- 
per, "Miiller's Archiv fur Anat. und Phys.," 1837, s. 47. I shall 
often have to refer to this very curious paper. 

J Paget, ** Lectures on Surgical Pathology," 1853, vol. i, p. 71. 


peculiarity seems to be inherited. These hairs, too, seem 
to have their representatives; for in the chimpanzee, and in 
certain species of Macacus, there are scattered hairs of con- 
siderable length rising from the naked skin above the eyes, 
and corresponding to our eyebrows; similar long hairs pro- 
ject from the hairy covering of the superciliary ridges in 
some baboons. 

The fine wool-like hair, or so-called lanugo, with which 
the human foetus during the sixth month is thickly cov- 
ered, offers a more curious case. It is first developed, dur- 
ing the fifth month, on the eyebrows and face, and espe- 
cially round the mouth, where it is much longer than that 
on the head. A mustache of this kind was observed by 
Eschricht* on a female foetus; but this is not so surprising 
a circumstance as it may at first appear, 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 varia- 
bility. The whole surface, including even the forehead 
and ears, is thus thickly clothed; but it is a significant fact 
that the palms of the hands and the soles of the feet are 
quite naked, like the inferior surfaces of all four extremi- 
ties in most of the lower animals. As this can hardly be 
an accidental coincidence, the woolly covering of the foetus 
probably represents the first permanent coat of hair in those 
mammals which are born hairy. Three or four cases have 
been recorded of persons born with their whole bodies and 
faces thickly covered wdth fine long hairs; and this strange 
condition is strongly inherited, and is correlated with an 
abnormal condition of the teeth, f Prof. Alex. Brandt in- 
forms me that he has compared the hair from the face of a 
man thus characterized, aged thirty-five, with the lanugo 
of a foetus, and finds it quite similar in texture; therefore, 
as he remarks, the case may be attributed to an arrest of 
development in the hair, together with its continued 
growth. Many delicate children, as I have been assured 
by a surgeon to a hospital for children, have their backs 

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

f See my "Variation of Animals and Plants under Domestication," 
vol. ii, p. S27. Prof. Alex. Brandt has recently sent me an additional 
case of a father and son, born in Russia, with tJbese peculiarities. I 
nave received drawings of both from Patis* 


covered by rather long silky hairs; and such cases probably 
come under the same head. 

It appears as if the posterior molar or wisdom teeth were 
tending to become rudimentary in the more civilized 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 eminent 
dentists. They are also much more liable to vary, both in 
structure and in the period of their development, than the 
other teeth.* 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, f 
Prof. Schaaffhausen accounts for this difference between 
the races by '^ the posterior dental portion of the jaw being 
always shortened "in those that are civilized, J and this 
shortening may, I presume, be attributed to civilized men 
habitually feeding on soft, cooked food, and thus using 
their jaws less. I am informed by Mr. Brace that it is 
becoming quite a common 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 caecum. The caecum is a branch or diver- 
ticulum of the intestine, ending in a cul-de-sac, and is ex- 
tremely long in many of the lower vegetable-feeding mam- 

* Dr. Webb, ** Teeth in Man and the Anthropoid Apes," as quote 1 
by Dr. C. Carter Blake in "Anthropological Review," July, 1867. 
p. 299. 

f Owen, ** Anatomy of Vertebrates. ** vol. iii, pp. 320, 321 and 325. 

j ** On the Primitive Form of the Skull," Eng. translat. in" Anthrop- 
ological Review," Oct. 1868, p. 426. 

§ Prof. Montegazza writes to me from Florence, that he has lately 
been studying the last molar teeth in the different races of man, and 
has come to the same conclusion as that given in my text, viz. : that 
in the higher or dTtlized races they are on the road toward atrophy 
or eUmint^QQt 

HmnMENTS. 23 

mals. In the marsupial koala it is actually more than 
thrice as long as the whole hody.* It is sometimes produced 
into a long gradually tapering point, and is sometimes con- 
stricted in parts. It appears as if, in consequence of 
changed diet or habits, the caecum had become much short- 
ened 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 f 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 flattened solid expansion. In the orang 
this appendage is long and convoluted : in man it arises 
from the end of the short caecum, and is commonly from 
four to five inches in length, being only about the third of 
an inch in diameter. Not only is it useless, but it is some- 
times the cause of death, of which fact I have lately heard 
two instances : this is due to small hard bodies, such as 
seeds, entering the passage, and causing inflammation. J 

In some of the lower Quadrumana, in the Lemuridae and 
Carnivora, -as well as in many marsupials, there is a pas- 
sage near the lower end of the humerus, called the supra- 
condyloid foramen, through which the great nerve of the 
fore limb and often the great artery pass. Now in the 
humerus of man, there is generally a trace of this passage, 
which is sometimes fairly well developed, being formed by 
a depending hook-like process of bone, completed by a band 
of ligament. Dr.. Struthers,§ who has closely attended to 
the subject, has now shown that this peculiarity is some- 
times inherited, as it has occurred in a father, and in no less 

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

t " Annuario della Soc. d. Nat.," Modena, 1867, p. 94. 

JM. C. Martins ("De I'lTnite Organique," in "Revue d6s Deux 
Mondes," June 15, 1863, p. 16), and Hackel ("Generelle Morpholo- 
gie," B. ii, s. 278), liave botli remarked on the singular fact of this 
rudiment sometimes causing death. 

§ With respect to inheritance, see Dr. Struthers in the *• Lancet," 
Feb. 15, 1873, and another important paper, ibid., Jan. 34, 1863, p. 
83. Dr. Knox, as I am informed, was the first anatomist who drew 
attention to this peculiar structure in man ; see his ' ' G^reat Artists 
and Anatomists," p. 63. See also an important meijioir on thitj pro- 
cess by Dr. Gruber, in the " Bulletin de I'Acad. Imp. de S^. Patera- 
bourg," torn, xii, 1867, p, 448- 


than four out of his seven children. When present, the 
great nerve invariably passes through it ; and this clearly 
indicates that it is the homologue and rudiment of the 
supra-condyloid foramen of the lower animals. Prof. 
Turner estimates, as he informs me, that it occurs in about 
one per cent, of recent skeletons. But if the occasional 
development of this structure in man is, as seems probable, 
due to reversion, it is a return to a very ancient state of 
things, because in the higher Quadrumana it is absent. 

There is another foramen or perforation in the humerus, 
occasionally present in man, which may be called the inter- 
condyloid. This occurs, but not constantly, in various an- 
thropoid and other apes,* and likewise in many of the lower 
animals. It is remarkable that this perforation seems to 
have been present in man much more frequently during 
ancient times than recently. Mr. Buskf 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 ' Oimetiere du Sud,' at Paris; and in the 
Grotto of Orrony, the contents of which are referred to the 
Bronze period, as many as eight humeri out of thirty-two 
were perforated ; but this extraordinary proportion, he 
thinks, might be due to the cavern having been a sort of 
'family vault. ^ Again, M. D upon t found thirty per cent, 
of perforated bones in the caves of the Valley of the Lesse, 
belonging to the Reindeer period; while M. Leguay, in a 
sort of dolmen at Argenteuil, observed twenty-five per cent, 
to be perforated; and M. Pruner-Bey found twenty-six per 
cent, in the same condition in bones from Vaureal. Nor 
should it be left unnoticed that M. Pruner-Bey states that 
this condition is common in Guanche skeletons.^' It is an 
interesting fact that ancient races, in this and several other 
cases, more frequently present structures which resemble 
those of the lower animals than do the modern. One chief 
cause seems to be that the ancient races stand somewhat 

*Mr. St. George Mivart, *' Transact. Pliil. Soc," 1867, p. 310. 

f " On tlie Caves of Gibraltar," "Transact. Internat. Congress of 
Prehist. Arch." Third Session, 1869, p. 159. Prof. Wyman has lately 
shown (Fourth Annual Report, Peabody Museum, 1871, p. 20), thai 
this perforation is present in thirty-one per cent, of some human re- 
mains from ancient mounds in the Western United States, and in 
Florida. It frequently occurs in the negro. 


nearer in the long line of descent to their remote animal- 
like progenitors. 

In man, the os coccyx, together with certain other verte- 
bra3 hereafter to be described, though f unctionless as a tail, 
plainly represent this part in other vertebrate animals. At 
an early embryonic period it is free, and projects beyond 
the lower extremities; as may be seen in the drawing (Fig. 
1) of a human embryo. Even after birth it has been known, 
in certain rare and anomalous cases,* to form a small ex- 
ternal rudiment of a tail. The os coccyx is short, usually 
including only four vertebrge, all anchylosed together; and 
these are in a rudimentary condition, for they consist, with 
the exception of the basal one, of the centrum alone, f 
They are furnished with some small muscles; one of which, 
as I am informed by Prof. Turner, has been expressly de- 
scribed by Theile as a rudimentary repetition of the exten- 
sor of the tail, a muscle which is so largely developed in 
many mammals. 

The spinal cord in man extends only as far downward as 
the last dorsal or first lumbar vertebra; but a thread-like 
structure (the filum terminale) runs down the axis of the 
sacral part of the spinal canal, and even along the back of 
the coccygeal bones. The upper part of this filament, as 
Prof. Turner informs me, is 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 ves- 
tige of so important a structure as the spinal cord, though 
no longer inclosed within a bony canal. The following 
fact, for which I am also indebted to Prof. Turner, 
shows how closely the os coccyx corresponds with the 
true tail in the lower animals: Luschka has recently dis- 
covered at the extremity of the coccygeal bones a very pe- 
culiar convoluted body, which is continuous with the mid- 
dle sacral artery; and this discovery led Krause and Meyer 

* Quatrefages lias lately collected the evidence on this subject. 
"Revue des Cours Scienti'fiques," 1867-1868, p. 625. In 1840 Fleisch- 
mann exhibited a human foetus bearing' a free tail, which, as is not 
always the case, included vertebral bodies; and this tail was critically 
examined by the many anatomists present at the meeting of natural- 
ists at Erlangen (see Marshall in ' ' Niederlandischen Archiv f iir Zoolo- 
gie," December, 1871). 

t Owen, " On the Nature of Limbs," 1849, p. 114. 


to examine the tail of a monkey (Macacus), and of a cat, 
in both of which they found a similarly convoluted body, 
though not at the extremity. 

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

The bearing of the three great classes of facts now given 
is unmistakable. But it Avould be superfluous fully to recap- 
itulate the line of argument given in detail in my " Origin 
of Species. ^^ The homological construction of the whole 

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

fSee, on this subject, Owen, "Anatomy of Vertebrates," vol. iii, 
np. 675, 676, 706. 


frame in the members of the same class is intelligible, if we 
admit their descent from a common progenitor, together 
with their subsequent adaptation to diversified conditions. 
On any other view, the similarity of pattern between the 
hand of a man or monkey, the foot of a horse, the flipper 
of a seal, the wing of a bat, etc., is utterly inexplicable.* 
It is no scientific explanation to assert that they have all 
been formed on the same ideal plan. With respect to de- 
velopment, we can clearly understand, on the principle of 
variations supervening at a rather late embryonic period, 
and being inherited at a corresponding period, how it is 
that the embryos of wonderfully different forms should still 
retain, more or less perfectly, the structure of their common 
progenitor. No other explanation has ever been given of 
the marvelous fact that the embryos of a man, dog, seal, 
bat, reptile, etc., can at first hardly be distinguished from 
each other. In order to understand the existence of rudi- 
mentary organs, we have only to suppose that a former pro- 
genitor 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 superfluous part, aided by the other means pre- 
viously indicated. 

* Prof. Bianconi, in a recently published work, illustrated by ad- 
mirable engravings (" La Tbeorie Darwinienne et la creation dite in- 
dependante," 1874), endeavors to sliow that homological structures, 
in the above and other cases, can be fully explained on mechanical 
principles, in accordance with their uses. No one has shown so well, 
how admirably such structures are adapted for their final purpose ; 
and this adaptation can, as I believe, be explained through natural 
selection. In considering the wing of a bat, he brings forward (p. 
218) what appears to me (to use Auguste Comte's words) a mere met- 
aphysical principle, namely, the preservation ' ' in its integrity of the 
mammalian nature of the animal." In only a few cases does he dis- 
cuss rudiments, and then only those parts which are partially 
rudimentary, such as the little hoofs of the pig and ox, which do not 
touch the ground ; these he shows clearly to be of service to the ani- 
mal. It is unfortunate that he did not consider such cases as the 
minute teeth, which never cut through the jaw in the ox, or the 
mammae of male quadrupeds, or the wings of certain beetles, existing 
under the soldered wing-covers, or the vestiges of the pistil and 
stamens in various flowers, and many other such cases. Although I 
greatly admire Prof. Bianconi's work, yet the belief now held by 
most naturalists seems to me left unshaken, that homological struct- 
ures are inexplicable on the principle of mere adaptation. 


Thus we can understand how it has come to pass that 
man and all other vertebrate animals have been con- 
structed 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 structure, and that of 
all the animals around us, is a mere snare laid to entrap our 
judgment. This conclusion is greatly strengthened, if we 
look to the members of the whole animal series, and con- 
sider the evidence derived from their affinities or classifica- 
tion, their geographical distribution and geological succes- 
sion. It is only our natural prejudice, and that arrogance 
which made our forefathers declare that they were de- 
scended from demi-gods, which leads us to demur to 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. 




Variability of body and mind in man — Inheritance — Causes of varia- 
bility — Laws of variation the same in man as in the lower ani- 
mals — Direct action of the conditions of life — Effects of the 
increased use and disuse of parts — Arrested development — 
Reversion — Correlated variation — Rate of increase — Checks to 
increase — Natural selection — Man the most dominant animal in 
the world — Importance of his 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. 

It is manifest that man is now subject to much variabil- 
ity. No two individuals of the same race are quite alike. 
We may compare millions of faces, and each will be dis- 
tinct. There is an equally great amount of diversity in the 
proportions and dimensions of the various parts of the body; 
the length of the legs being one of the most variable points.* 
Although in some quarters of the world an elongated skull, 
and in other quarters a short skull prevails, yet there is 
great diversity of shape even within the limits of the same 
race, as with the aborigines of America and South Australia 
— the latter a race " probably as pure and homogeneous in 
blood, customs, and language as any in existence" — and 
even with the inhabitants of so confined an area as the 
Sandwich Islands, f An eminent dentist assures me that 

* ' ' Investigations in Military and Anthropolog. Statistics of Ameri- 
can Soldiers," by B. A. Gould, 1869, p. 256. 

f With respect to the ** Cranial forms of the American Aborigines," 
see Dr. Aitken Meigs in "Proc. Acad. Nat. Sci.," Philadelphia, May, 
1868. On the Australians, see Huxley, in Lyell's "Antiquity of 
Man," 1863, p. 87. On the Sandwich Islanders, Prof. J. Wyman, 
*• Observations on Crania," Boston, 1868, p. 18. 


there is nearly as much diversity in the teeth as in the feat- 
ures. The chief arteries so frequently run in abnormal 
courses, that it has been found useful for surgical purposes 
to calculate from 1040 corpses how often each course pre- 
vails.* The muscles are eminently variable : thus those of 
the foot were found by Prof. Turner f not to be strictly 
alike in any two out of fifty bodies ; and in some the de- 
viations were considerable. He adds, that the power of 
performing the appropriate movements must have been 
modified in accordance with the several deviations. Mr. 
J. Wood has recorded J the occurrence of 295 muscular 
variations in thirty-six subjects, and in another set of the 
same number no less than 558 variations, those occurring 
on both sides of the body being only reckoned as one. In 
the last set, not one body out of the thirty-six was ^' found 
totally wanting in departures from the standard descrip- 
tions of the muscular system given in anatomical text 
books." A single body presented the extraordinary num- 
ber of twenty-five distinct abnormalities. The same mus- 
cle sometimes varies in many ways : thus Prof. Macalister 
describes § no less than twenty distinct .variations in the 
palmaris accessorius. 

The famous old anatomist, Wolff, || insists that the inter- 
nal viscera are more variable than the external parts: Nulla 
particula est qum no7i aliter et aliter in aliis se liabeat 
ho7ninibus. 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, 
etc., as of the human face divine, sounds strange in our 

The variability or diversity of the mental faculties in 
men of the same race, not to mention the greater differ- 
ences between the men of distinct races, is so notorious that 
not a word need here be caid. So it is with the lower ani- 
mals. All who have had charge of menageries admit this 
fact, and we see it plainly in our dogs and other domestic 

* "Anatomy of the Arteries," by R. Quain. Preface, vol. i, 1844. 
f "Transact. Royal Soc. Edinburgh," vol. xxiv, pp. 175, 189. 
t*'Proc. Royal Soc," 1867, p. 544; also 1868, pp. 483, 524. There 
is a previous paper, 1866, p. 229. 

§"Proc. R. Irish Academy," vol. x, 1868, p. 141. 
1 " Act. Acad. St. Petersburg," 1778, part ii, p. 217. 


animals. Brehm especially insists that each individual 
monkey of those which he kept tame 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 remarkable for intelli- 
gence. Rengger, also, insists on the diversity in the vari- 
ous 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.* 

I have elsewhere f so fully discussed the subject of In- 
heritance, that I need here add hardly any thing. 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 ani- 
mals; though the facts are copious enough with respect to 
the latter. So in regard to mental qualities, their trans- 
mission is manifest in our dogs, horses, and other domestic 
animals. Besides special tastes and habits, general intelli- 
gence, courage, bad and good temper, etc., are certainly 
transmitted. With man we see similar facts in almost 
every family ; and we now know, through the admirable 
labors of Mr. GaltonJ that genius which implies a wonder- 
fully complex combination of high faculties, tends to be 
inherited; and, on the other hand, it is too certain that in- 
sanity and deteriorated mental powers likewise run in 

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 stand in some relation to the conditions 
to which each species has been exposed during several gen- 
erations. Domesticated animals vary more than those in a 
state of nature; and this is apparently due to the diversified 
and changing nature of the conditions to which they have 
been subjected. In this respect the different races of man 

* Brehm, " Thierleben," B. i, s. 58, 87. tlengger, " Saugetliiere 
von Paraguay," s. 57. 

f ' ' Variation of Animals and Plants under Domestication," vol. ii, 
cLiap. xii. 

t" Hereditary Genius: an Inquiry into its Laws and Conse- 
quences," 1869. 


resemble domesticated animals, and so do the individuals 
of the same race, when inhabiting a very wide area, like 
that of America. We see the influence of diversified con- 
ditions in the more civilized nations; for the members be- 
longing to different grades of rank, and following different 
occupations, present a greater range of character than do 
the members of barbarous nations. But the uniformity of 
savages has often been exaggerated, and in some cases can 
hardly be said to exist.* It is, nevertheless, an error to 
speak of man, even if we look only to the conditions to 
which he has been exposed, as '^'^far more domesticated ''f 
than any other animal. Some savage races, such as the 
Australians, are not exposed to more diversified conditions 
than are many species which have a wide range. In an- 
other and much more important respect, man differs widely 
from any strictly domesticated animal; for his breeding has 
never long been controlled, either by methodical or uncon- 
scious selection. No race or body of men has been so com- 
pletely subjugated by other men, as that certain individuals 
should be preserved, and thus unconsciously selected, from 
somehow excelling in utility to their masters. Nor have 
certain 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 methodical selection; 
for it is asserted that many tall men were reared in the 
villages inhabited by the grenadiers and their tall wives. 
In Sparta, also,, a form of selection was followed, for it was 
enacted that all children should be examined shortly after 
birth; the well-formed and vigorous being preserved, the 
others left to perish. | 

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

f Blumenbach, •* Treatises on Anthropolog.," Eug. translat., 1865, 
p. 205. 

ifMitford's "History of Greece," vol. i, p. 282. It appears also 
from a passage in Xenophon's "Memorabilia," B. ii, 4 (to which my 
attention has been called by the Rev. J. N. Hoare), that it was a well 
recognized principle with the Greeks, that men ought to select their 
wives with a view to the health and vigor of their children. The 


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 Pol3^nesians, have very wide ranges. It 
is a well-known law that widely ranging species are much 
more variable than species with restricted ranges; and the 
variability of man may with mere truth be compared with 
that of widely ranging species, than with that of domesti- 
cated animals. 

Not only does variability appear to be in(Juced in man 
and the lower animals by the same general causes, but in 
both the same parts of the body are affected in a closely 
analogous manner. This has been proved in such full de- 
tail by Godron and Quatrefages, that I need here only refer 
to their works.* Monstrosities, which graduate into slight 
variations, are likewise so similar in man and the lower 
animals, that the same classification and the same terms 
can be used for both, as has been shown by Isidore Geoffrey 
St.-Hilaire.f In my work on the variation of domestic 
animals, I have attempted to arrange in a rude fashion the 
laws of variation under the following heads : The direct 
and definite action of changed conditions, as exhibited by 

Grecian poet, Tlieognis, who lived 550 B.C., clearly saw how import- 
ant selection, if carefully applied, would be for the improvement of 
mankind. He saw, likewise, that wealth often checks the proper 
action of sexual selection. He thus writes : 

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

*Godron, "De I'Espece," 1859, tom. ii, livre 3. Quatrefages, 
"Unite de I'Espece Humaine," 1861. Also Lectures on Anthropol- 
og.y. given in the " Revue des Cours Scientifiques," 1866-1868. 

f " Hist. Gen. et Part, des Anomalies de I'Organisation," in three 
volumes, tom. i, 183^. 


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 variability of multiple 
parts. Compensation of growth ; but of this law I have 
found no good instance in the case of man. The effects of 
the mechanical pressure of one part on another; as of the 
pelvis on the cranium of the infant in the womb. Arrests 
of development, leading to the diminution or suppression 
of parts. The reappearance of long-lost characters through 
reversion. And lastly, correlated variation. And these 
so-called laws apply equally to man and the lower animals ; 
and most of them even to plants. It would be superfluous 
here to discuss all of them; * but several are so important, 
that they must be treated at considerable length. 

The Direct and Definite Action of Changed Conditions. — 
This is a most perplexing subject. It cannot be denied 
that changed conditions produce some, and occasionally 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 favor of this conclusion; and valid reasons 
may be urged on the other side, at least as far as the in- 
numerable structures are concerned which are adapted for 
special ends. There can, however, be no doubt that 
changed conditions induce an almost indefinite amount of 
fluctuating variability, by which the whole organization is 
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 were recorded, f 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, 

*I have fully discussed tliese laws in my "Variation of Animals 
and Plants under Domestication," vol. ii, chap, xxii and xxiii. M. J. 
P. Durand has lately (1868) published a valuable essay ** De I'lnfiu- 
ence des Milieux," etc. He lays much stress, in the case of plants, 
on the nature of the soil. 

f "Investigations in Military and Anthrop. Statistics/' etc., 1869, 
by B. A. Gould, pp. 93, 107, 136, 131, 134. 


which indicates the ancestry, seem to exert a marked in- 
fluence on the stature." For instance, it is established, 
" that residence in the Western States, during the years of 
growth, tends to produce increase of stature." On the 
other hand, it is certain that with sailors, their life delays 
growth, as shown ^^'^by the great difference between the 
statures of soldiers and sailors at the ages of seventeen and 
eighteen years." Mr. B. A. Gould endeavored to ascertain! 
the nature of the influences which thus act on stature; but 
he arrived only at negative results, namely, that they did 
not relate to climate, the elevation of the land, soil, nor 
even '^^in any controlling degree" to the abundance or the 
need of the comforts of life. This latter conclusion is 
directly opposed to that arrived at by Villerme, from the 
statistics of the height of the conscripts in different parts 
of France. When we compare the differences in stature 
between the Polynesian chiefs and the lower orders within 
the same islands, or between the inhabitants of the fertile 
volcanic and low ban en coral islands of the same ocean,* 
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 influence stature. 
But the preceding statements show 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 vigor, "f 

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 influ- 
ence, inasmuch as the lungs and kidneys are brought into 

*For tlie Polynesians, see Pricliard's "Physical Hist, of Man- 
kind," vol. V, 1847, pp. 145, 283. Also Godron, "De I'Espece," torn, 
ii, p. 289. There is also a remarkable difference in appearance be- 
tween the closely allied Hindoos inhabiting the Upper Ganges and 
Bengal ; see Elphinstone's " History of India," vol. i, p. 824. 

t " Memoirs, Anthropolog. Soc." vol. iii, 1867-69, pp. 561, 065, 


activity under a low temperature, and the liver and skin 
under a high one. * It was formerly thought that the color 
of the skin and the character of the hair were determined 
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 we treat of the different races of mankind. 
With our domestic animals there are grounds for believing 
that cold and damp directly affect the growth of the hair; 
but I have not met with any evidence on this head in the 
case of man. 

Effects of the Increased Use and Disuse of Parts. — It is 
M^ell known that use strengthens the muscles in the individ- 
ual, 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 kid- 
ney ceases to act from disease, the other increases in size, 
and does double work. Bones increase not only in thick- 
ness, but in length, from carrying a greater weight, f Dif- 
ferent occupations, habitually followed, lead to changed 
proportions in various parts of the body. Thus it was as- 
certained by the United States Commission;!; that the legs 
of the sailors employed in the late war were longer by 0.217 
of an inch than those of the soldiers, though the sailors 
were on an average shorter men ; while their arms were 
shorter by 1.09 of an inch, and therefore, out of proportion, 
shorter in relation to their lesser heiglit. This shortness of 
the arms is apparently due to their greater use, and is an 
unexpected result: but sailors chiefly use their arms in pull- 
ing, and not in supporting weights. With sailors, the girth 
of the neck and the depth of the instep are greater, while 

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

f I have given authorities for these several statements in my 
"Variation of Animals under Domestication," vol. ii, pp. 297-800 
Dr. Jaeger, "Ueber das Langenwachsthum der Knochen," " Jenais 
chen Zeitschrift," B. v, Heft. i. 

X " Investigations," etc. By B. A. Gould, 1869, p. 233. 


the circumference of the chest, waist, and hips is less than 
in soldiers. 

Whether the several foregoing modifications would be- 
come hereditary, if the same habits of life were followed 
during many generations, is not known, but it is probable. 
Kengger* 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 extremi- 
ties motionless. Other writers have come to a similar con- 
clusion in analogous cases. According to Cranz,f 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 
himself, though he lost his father in childhood/' But in 
this case it is mental aptitude, quite as much as bodily 
structure, which appears to be inherited. It is asserted 
that the hands of English laborers are at birth larger than 
those of the gentry. X From the correlation which exists, 
at least in some cases, § between the de^'elopment of the ex- 
tremities and of the jaws, it is possible that in those classes 
which do not labor much with their hands and feet, the 
jaws would be reduced in size from this cause. That they 
are generally smaller in refined and civilized men than in 
hard-working men or savages, is certain. But with savages, 
as Mr. Herbert Spencer || has remarked, the greater use of 
the jaws in chewing coarse, uncooked food, would act in a 
direct manner on the masticatory muscles, and on the bones 
to which they are attached. In infants, long before birth, 
the skin on the soles of the feet is thicker than on any other 
part of the body ;^ and it can hardly be doubted that this is 
due to the inherited effects of pressure during a long series 
of generations. 

It is familiar to every one that watchmakers and engrav- 
ers are liable to be short-sighted, while men living much 
out of doors, and especially savages, are generally long- 

* *' Saugethiere von Paraguay," 1830, s. 4. 

f "History of Greenland," Eng. translat., 1767, vol. i, p. 230. 

X "Intermarriage." By Alex. Walker, 1838, p. 377. 

§ *' The Variation of Animals under Domestication," vol. I, p. 173. 

\ "Principles of Biology," vol. i, p. 455. 

Tf Paget, " Lectures on Surgical Pathology," vol, ii, 1853, p. 309. 


sighted.* Short-sight and long-sight certainly tend to 
be inherited, f The inferiority of Europeans, in comparison 
with savages, in eyesight and in the other senses, is no 
doubt the accumulated and transmitted effect of lessened 
use during many generations ; for Rengger X states that he 
has repeatedly observed Europeans, who had been brought 
up and spent their whole lives with the wild Indians, who 
nevertheless did not equal them in the sharpness of their 
senses. The same naturalist observes that the cavities in 
the skull for the reception of the several sense-organs are 
larger in the American aborigines than in Europeans ; and 
this probably indicates a corresponding difference in the 
dimensions of the organs themselves. Blumenbach has 
also remarked on the large size of the nasal cavities in the 
skulls of the American aborigines, and connects this fact 
with their remarkably acute power of smell. The Mon- 
golians of the plains of Northern Asia, according to Pallas, 
have wonderfully perfect senses; and Prichard believes that 
the great breadth of their skulls across the zygomas follows 
from their highly developed sense-organs. § 

The Quechua Indians inhabit the lofty plateaux of Peru; 
and Alcide d^Orbigny states || that, from continually breath- 
ing a highly rarefied atmosphere, they have acquired chests 
and lungs of extraordinary dimensions. The cells, also, of 
the lungs are larger and more numerous than in Europeans. 

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

f " The Variation of Animals under Domestication," vol. i, p. 8. 

X " 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," etc. , 1822, 
p. 404) on this same subject. M. Giraud-Teulon has recently col- 
lected (" Revue des Cours Scientifiques," 1870, p. 625) a large and 
valuable body of evidence proving that the cause of short-sight, 
•* Ceat le travail assidu, de pres." 

% Prichard, " Phys. Hist, of Mankind," on the authority of Blum- 
enbach, vol. i, 1851» p. 311 ; for the statement by Pallas, vol. iv, 
1844, p. 407. 

I Quoted by Prichard, •* Researches into the Phys. Hist, of Man- 
tod," VOL 7, j>. 463. 


These observations have been doubted ; but Mr. D. Forbes 
carefully measured many Aymaras, an allied race, living at 
the height of between 10,000 and 15,000 feet ; and he in- 
forms me * that they differ conspicuously from the men of 
all other races seen by him in the circumference and length 
of their bodies. In his table of measurements, the stature 
of each man is taken at 1,000, and the other measurements 
are reduced to this standard. It is here seen that the ex- 
tended 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 peculiarity, 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 ; while in two Europeans, measured at the same 
time, the femora to the tibiae were as 244 to 230 ; and in 
three Negroes as 258 to 241. The humerus is likewise 
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 compensa- 
tion 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 

These men are so thoroughly acclimatized 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 survived during two genera- 
tions : and he observed that they still inherited their char- 
acteristic peculiarities. But it was manifest, even without 
measurement, that these peculiarities had all decreased ; 
and on measurement, their bodies were found not to be so 
much elongated as those of the men on the high plateau ; 
while their femora had become somewhat lengthened, as 
had their tibiag, although in a less degree. The actual 
measurements may be seen by consulting Mr. Forbes' 
memoir. From these observations, there can, I think, be 
no doubt that residence during many generations at a great 

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


elevation tends, both directly and indirectly, to induce in- 
herited modifications in the proportions of the body.* 

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

Arrests of Developmejit. — There is a difference between 
arrested development and arrested growth, for parts in the 
former state continue to grow while still retaining their 
early condition. Various monstrosities come under this 
head; and some, as a cleft-palate, are known to be occa- 
sionally inherited. It will suffice for our purpose to refer 
to the arrested brain-development of microcephalous idiots, 
as described in Vogt's memoir, f 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 pro- 
gnathous to an '' eff ray a7if degree; so that these idiots 
somewhat resemble the lower types of mankind. Their in- 
telligence, 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 ac- 
tive, continually gambolling and jumping about, and mak- 
ing grimaces. They often ascend stairs on all-fours; and 
are curiously fond of climbing up furniture or trees. We 
are thus reminded of the delight shown by almost all boys 
in climbing trees; and this again reminds us how lambs 
and kids, originally alpine animals, delight to frisk on any 
hillock, however small. Idiots also resemble the lower 

*Dr. WilckensC'Landwirtliscliaft. Woclienblatt," No. 10, 
has lately published an interesting Essay showing how domestic ani- 
mals, which live in mountainous regions, have their frames modified. 

f'Memoire sur les Microcephales/' 1867, pp. 50, 125, 169, 171, 


animals in some other respects; thus several cases are re- 
corded of their carefully smelling every mouthful of food 
before eating it. One idiot is described as often using his 
mouth in aid of his hands while hunting for lice. They 
are often filthy in their habits, and have no sense of de- 
cency; and several cases have been published of their bodies 
being remarkably hairy.* 

Reversion. — Many of the cases to be here given, might 
have been introduced under tlie last heading. When a 
structure is arrested in its development, but still continues 
growing, until it closely resembles a corresponding struct- 
ure in some lower and adult member of the same group, it 
may in one sense be considered as a case of reversion. The 
lower members in a group give us some idea how the com- 
mon progenitor was probably constructed; and it is hardly 
credible that a complex part, arrested at an early phase of 
embryonic development, should go on growing so as ulti- 
mately to perform its proper function, unless it had ac- 
quired such power during some earlier state of existence, 
when the present exceptional or arrested structure was 
normal. The simple brain of a microcephalous idiot, in 
as far as it resembles that of an ape, may in this sense be 
said to offer a case of reversion, f There are other cases 

* Prof. Laycock sums up the character of brute-like idiots by call- 
ing them thermd ; "Journal of Mental Science," July, 1863. Dr. 
Scott ("The Deaf and Dumb," 2d edit., 1870, p. 10) has often ob- 
served the imbecile smelling their food. See, on this same subject, 
and on the hairiness of idiots. Dr. Maudsley, "Body and Mind," 
1870, pp. 46-51. Pinel has also given a striking case of hairiness iu 
an idiot. 

f 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 effi- 
cient mammae occurred in the inguinal region of a woman, the daugh- 
ter of another woman with supernumerary mammee. But I now find 
(see, for instance, Prof. Preyer, " Der Kampf um das Dasein," 1869, 
s. 45) that mammcB erraticm occur in other situations, as on the back, 
in the armpit, and on the thigh; the mammae in this latter instance 
having given so much milk that the child was thus nourished. The 
probability that the additional mammae are due to reversion is thus 
much weakened ; nevertheless, it still seems to me probable, because 
two pairs are often found symmetrically on the breast ; and of this I 
myself have received information in several cases. It is well known 


which come more strictly under our present head of rever- 
sion. 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 normally present in the 
human embryo, they become abnormally developed, al- 
though in a manner which is normal in the lower members 
of the group. These remarks will be rendered clearer by 
the following illustrations. 

tliat some Lemurs normally have two pairs of mammae on the breast. 
Five cases have been recorded of the presence of more than a pair of 
mammae (of course rudimentary) in the male sex of mankind ; see 
*' Journal of Anat arW Physiology," 1873, p. 56, for a case given by 
Dr. Handyside, in which two brothers exhibited this peculiarity ; see 
also a paper by Dr. Bartels, in " Reichert's and du Bois-Reymond's 
Archiv.," 1872, p. 304. In one of the cases alluded toby Dr. Bartels, 
a man bore five mammae, one being medial and placed above the 
navel ; Meckel von Hemsbach thinks that this latter case is illus- 
trated by a medial mammae occurring in certain Cheiroptera. On the 
whole, we may well doubt if additional mammae would ever have 
been developed in both sexes of mankind, had not his early progeni- 
tors been provided with more than a single pair. In the above work 
(vol. ii, p. 12), I also attributed, though with much hesitation, the 
frequent cases of poly dactyl ism in men and various animals to rever- 
sion. I was partly led to this through Prof. Owen's statement, that 
some of the Ichthyopterygia possess more than five digits, and there- 
fore, as I supposed, had retained a primordial condition ; but Prof. 
Gegenbaur (" Jenaischen Zeitschrift," B. v. Heft. 3, s. 341), disputes 
Owen's conclusion. On the other hand, according to the opinion 
lately advanced by Dr. Giinther, on the paddle of Ceratodus, which 
is provided with articulated bony rays on both sides of a central 
chain of bones, there seems no great difiiculty in admitting that six 
or more digits on one side, or on both sides, might reappear through 
reversion. I am informed by Dr. Zouteveen that there is a case on 
record of a man having twenty-four fingers and twenty-four toes ! I 
was chiefly led to the conclusion that the presence of supernumerary 
digits might be due to reversion from the fact that such digits, not 
only are strongly inherited, but, as I then believed, had the power of 
regrowth after amputation, like the normal digits of the lower verte- 
brata. But I have explained in the second edition of my Variation 
under Domestication why I now place little reliance on the recorded 
cases of such regrowth. Nevertheless it deserves notice, inasmuch 
as arrested development and reversion are intimately related pro- 
cesses ; that various structures in an embryonic or arrested condition, 
such as a cleft palate, bifid uterus, etc., are frequently accompanied 
by polydactylism. This has been strongly insisted on by Meckel and 
Isidore Geoff roy St.-Hilaire. But at present it is the safest course to 
give up altogether the idea that there is any relation between the de- 
velopment of supernumerary digits and reversion to some lowly or- 
ganized progonitor of man. ^ 


In various mammals the uterus graduates from a double 
organ with two distinct orifices and two passages, as in the 
marsupials, into a single organ, which is in no way double 
except from having a slight internal fold, as in the higher 
apes and man. The rodents exhibit a perfect series of gra- 
dations 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. Farre, "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 mid- 
dle portion or body exists, the cornua remain ununited. As 
the development of the uterus proceeds, the two cornua be- 
come 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 in ani- 
mals as high up in the scale as the lower apes and lemurs. 

Now in women, anomalous cases are not very infrequent, 
in which the mature uterus is furnished with cornua, or is 
partially divided into two organs; and such cases, according 
to Owen, repeat " the grade of concentrative development," 
attained by certain rodents. Here perhaps we have an in- 
stance 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 per- 
forming the proper office of gestation. In other and rarer 
cases, two distinct uterine cavities are formed, each having 
its proper orifice and passage.* No such stage is passed 
through during the ordinary development of the embryo ; 
and it is difficult to believe, though perhaps not impossible, 
that the two simple, minute, primitive tubes should know 
how (if such an expression may be used) to grow into two 
distinct uteri, each with a well-constructed orifice and pas- 
sage, and each furnished with numerous muscles, nerves, 
glands and vessels, if they had not formerly passed through 
a similar course of development, as in the case of existing 
marsupials. No one will pretend that so perfect a struct- 
ure as the abnormal double uterus in woman could be the 
result of mere chance. But the principal of reversion, by 

* See Dr. A. Farre's well-known article in the '* Cyclopaedia of 
Anatomy and Physiology," vol. v, 1859, p. 642. Owen, "Anatomy 
of Vertebrates," vol. iii, 1868, p. 687. I'rof. Turner, in " Edinburgh 
Medical Journal," Feb., 1865- 


which a long-lost structure is called back into existence, 
might serve as the guide for its full development, even after 
the lapse of an enormous interval of time. 

Prof. Canestrini, after discussing the foregoing and 
various analogous cases, arrives at the same conclusion as 
that just given. He adduces another instance, in the case 
of the malar bone,* which, in some of the Quadrumana 
and other mammals, normally consists of two portions. 
This is its condition in the human foetus when two months 
old ; and through arrested development, it sometimes 
remains thus in man when adult, more especially in the 
lower prognathous races. Hence Canestrini concludes that 
some ancient progenitor of man must have had this bone 
normally divided into two portions, which afterward be- 
came 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 distinct suture. This suture occasionally 
persists more or less distinctly in man after maturity ; and 
more frequently in ancient than in recent crania, especially, 
as Canestrini has observed, in those exhumed from the 
Drift, and belonging to the brachycephalic type. Here 
again he comes to the same conclusion as in the analogous 
case of the malar bones. In this, and other instances 
presently to be given, the cause of ancient races approach- 
ing the lower animals in certain characters more frequently 
than do the modern races, appears to be, that the latter 
stand at a somewhat greater distance in the long line of 
descent from their early semi-human progenitors. 

*"Annuario della Soc, dei Naturalist! in Modena," 1867, p. 83. 
Prof. Canestrini gives extracts on this subject from various authori- 
ties. Laurillard remarks, that as he has found a complete similarity 
in the form, proportions, and connection of the two malar bones in 
several human subjects and in certain apes, he cannot consider this 
disposition of the parts as simply accidental. Another paper on this 
same anomaly has been published by Dr. Saviotti in the " Gazzetta 
delle Cliniche," Turin, 1871, where he says that traces of the division 
may be detected in about two per cent, of adult skulls ; he also re- 
marks that it more frequently occurs in prognathous skulls, not of 
the Aryan race, than in otliers. See also G. Delorenzi on the same 
subject ; " Tre nuovi casi d'anomalia dell' osso malare," Torino, 1872. 
Also, E. Morselli, " Sopra una rara anomalia dell' osso malare," 
Modena, 1872. Still more recently Gruber has written a pamphlet 
on the division of this bone. I give these references because a re- 
viewer, without any grounds or scruples, has thrown doubts on mj 


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

In man, the canine teeth are perfectly efficient instruments 
for mastication. But their true canine character, as Owenf 
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 ex- 
pressed 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 col- 
lection of human skulls some may be found, as Hackel;]; 
observes, with the canine teeth projecting considerably be- 
yond the others in the same manner as in the anthropomor- 
phous apes, but in a less degree. In these cases, open 
spaces between the teeth in the one jaw are left for the re- 
ception of the canines of the opposite jaw. An interspace 
of this kind in a Kaffir skull, figured by Wagner, is sur- 
prisingly wide.§ Considering how few are the ancient 
skulls which have been examined, compared to recent 
skulls, it is an interesting fact that in at least three cases 

* A whole series of cases is given by Isid. Geoffroy St.-Hilaire, 
" Hist, des Anomalies," torn, iii, p. 437. A reviewer (" Journal of 
Anat. and Physiology," 1871, p. 366) blames me much for not having 
discussed the numerous cases, which have been recorded, of various 
parts arrested in their development. He says that, according to my 
theory, " every transient condition of an organ, during its develop- 
ment, is not only a means to an end, but once was an end in itself." 
This does not seem to me necessarily to hold good. Why should not 
variation occur during an early period of development, having no 
relation to reversion ; yet such variations might be preserved and ac- 
cumulated, if in any way serviceable, for instance, in shortening and 
simplifying the course of development ? And again, why should not 
injurious abnormalities, such as atrophied or hypertrophied parts, 
which have no relation to a former state of existence, occur at an 
early period, as well as during maturity ? 

+ "Anatomy of Vertebrates," vol. iii, 1868, p. 323. 

X " Generelle Morphologie," 1866, B. ii, s. civ. 

§ Carl Vogt's " Lectures on Man," En^. translat., 1864, p. 151. 


the canines project largely ; and in the Naulette jaw they 
are spoken of as enormous.* 

Of the anthropomorphous apes the males alone have their 
canines fully developed ; but in the female gorilla, and in 
a less degree in the female orang, these teeth project con- 
siderably beyond the others ; therefore the fact, of which I 
have been assured, that women sometimes have considerably 
projecting canines, is no serious objection to the belief that 
their occasional great development in man is a case of re- 
version to an ape-like progenitor. He who rejects with 
scorn the belief that the shape of his own canines, and their 
occasional great development in other men, are due to our 
early forefathers having been provided with these formidable 
weapons, will probably reveal, by sneering, the line of his 
descent. For though he no longer intends, nor has the 
power, to use these teeth as weapons, he will unconsciously 
retract his '^ snarling muscles " (thus named by Sir 0. Bell), \ 
so as to expose them ready for action, like a dog prepared 
to fight. 

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

Mr. J. Wood, in his valuable series of papers, § has mi- 

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

t " The Anatomy of Expression," 1844, pp. 110, 131. 

:j: Quoted by Prof. Canestrini in the ** Annuario," etc., 1867, p. 90. 

§ These papers deserve careful study by any one who desires to 
learn how frequently our muscles vary, and in varying come to re- 
semble those of the Quadrumana. The following references relate 
to the few points touched on in my text : "Proc. Royal Soc," vol, 
xiv, 1865, pp. 379-384 ; vol. xv, 1866, pp. 241, 242 ; vol. xv, 1867, p. 
044 ; vol. :$vi, 1868, p. 524. 1 may ii©j:© add that Dr. Murie and Mr 


nufcely described a vast number of muscular variations in 
man, which resemble normal structures in the lower ani- 
mals. The muscles which closely resemble those regularly 
present in our nearest allies^, the Quadrumana, are too 
numerous to be here even specified. In a single male sub- 
ject, 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 daviculce/' such as is 
found in all kinds of apes, and which is said to occur in 
about one out of sixty human subjects.* Again, this man 
had " a special abductor of the metatarsal bone of the fifth 
digit, such as Prof. Huxley and Mr. Flower have shown to 
exist uniformly in the higher and lower apes.^^ I will give 
only two additional cases; the acromio-hasilar muscle is 
found in all mammals below man, and seems to be correl- 
ated with a quadrupedal gait,f and it occurs in about one 
out of sixty human subjects. In the lower extremities Mr. 
Bradley J found an abductor ossis metatarsi quinti in both 
feet of man; this muscle had not up to that time been re- 
corded in mankind, but is always present in the anthropo- 
morphous apes. The muscles of the hands and arms — parts 
which are so eminently characteristic of man — are extremely 
liable to vary, so as to resemble the corresponding muscles 
in the lower animals. § Such resemblances are either perfect 
or imperfect; yet in the latter case they are manifestly of a 
transitional nature. Certain variations are more common 
in man, and others in woman, without our being able to 
assign any reason. Mr. Wood, after describing numerous 

St. George Mivart have shown in their Memoir on the Lemuroidea 
("Transact. Zoolog. Soc," vol. vii, 1869, p. 96), how extraordinarily- 
variable some of the muscles are in these animals, the lowest 
members of the Primates. Gradations, also, in the muscles leading 
to structures found in animals still lower in the scale, are numerous 
In the Lemuroidea. 

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

f Mr. Champneys in "Journal of Anat. and Phys.," November. 
1871, p. 178. 

X " Journal of Anat. and Phys.," May, 1872, p. 421, 
§Prof. Macalister (ibid., p. 121) has tabulated his observations, 
and finds that muscular abnormalities are most frequent in the fore- 
arms, secondly, in the face, thirdly, in the foot, etc. 


variations, makes the following pregnant remark: ''Notable 
departures from the ordinary type of the muscular struct- 
ures 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 an- 

That this unknown factor is reversion to a former state 
of existence may be admitted as in the highest degree 
probable, f It is quite incredible that a man should through 
mere accident abnormally resemble certain apes in no less 
than seven of his muscles, if there had been no genetic con- 
nection between them. On the other hand, if man is de- 
scended from some ape-like creature, no valid reason can 
be assigned why certain muscles should not suddenly reap- 
pear after an interval of many thousand generations, in the 
same manner as with horses, asses, and mules, dark col- 
ored stripes suddenly reappear on the legs, and shoulders, 
after an interval of hundreds, or more probably of thous- 
ands of generations. 

These various cases of reversion are so closely related to 
those of rudimentary organs given in the first chapter, that 
many of them might have been indifferently introduced either 
there or here. Thus a human uterus furnished with cornua 

*Tbe Rev. Dr, HauglitoD, after giving (" Proc. R. Irisli Academy," 
June 27, 1864, p. 715) a remarkable case of variation in tlie human 
flexor pollicis longus, adds: "This remarkable example shows that 
man may sometimes possess the arrangement of tendons of thumb 
and fingers characteristic of the macaque ; but whether such a case 
should be regarded as a macaque passing upward into a man, or a 
man passing downward into a macaque, or as a congenital freak of 
nature, I cannot undertake to say." It is satisfactory to hear so 
capable an anatomist, and so embittered an opponent of evolutionism, 
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 relations to the same muscle in the Quadrumana. 

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


may be said to represent, in a rudimentary condition, the 
same organ in its normal state in certain mammals. Some 
parts which are rudimentary in man, as the os coccyx in 
both sexes, and the mammae in the male sex, are always 
present; while others, such as the supra-condyloid foramen, 
only occasionally appear, and therefore might have been in- 
troduced under the head of reversion. These several rever- 
sionary structures, as well as the strictly rudimentary ones, 
reveal the descent of man from some lower form in an 
unmistakable 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 gov- 
erned by some earlier developed part. Various monstrosi- 
ties, as I. Geoffrey repeatedly insists, are thus intimately 
connected. Homologous structures are particularly liable to 
change together, as we see on the opposite sides of the body, 
and in the upper and lower extremities. Meckel long ago 
remarked, that when the muscles of the arm depart from 
their proper type, they almost always imitate those of the 
leg; and so, conversely, with the muscles of the legs. The 
organs of sight and hearing, the teeth and hair, the color 
of the skin and of the hair, color and constitution, are 
more or less correlated.* Prof. Schaaffhausen first drew 
attention to the relation apparently existing between a mus- 
cular frame and the strongly pronounced supra-orbital 
ridges, which are so characteristic of the lower races of man. 

Besides the variations which can be grouped with more 
or less probability under the foregoing heads, there is a 
large class of variations which may be provisionally called 
spontaneous, for to our ignorance, they appear to arise 
without any exciting cause. It can, however, be shown 
that such variations, whether consisting of slight individ- 
ual differences, or of strongly marked and abrupt devi- 
ations of structure, depend much more on the constitu- 
tion of the organism than on the nature of the conditions 
to which it has been subjected, f 

*The authorities for these several statements are given in my 
"Variation of Animals under Domestication," vol, ii, pp. 320-335. 

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


Rate of hicrease. — Civilized populations have been 
known under favorable conditions, as in the United States, 
to double their numbers in twenty-five years ; and, accord- 
ing to a calculation, by Euler, this might occur in a little 
over twelve years.* At the former rate, the present popu- 
lation of the United States (thirty millions), would in 657 
years cover the whole terraqueous globe so thickly, that 
four men would have to stand on each square yard of sur- 
face. 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 subsistence is easy, and there is plenty of room. If 
such means were suddenly doubled in Great Britain, our 
number would be quickly doubled. With civilized nations 
this primary check acts chiefly by restraining marriages. 
The greater death-rate of infants in the poorest classes is 
also very important; as well as the greater mortality, from 
various diseases, of the inhabitants of crowded and miser- 
able houses at all ages. The efl'ects of severe epidemics 
and wars are soon counterbalanced, and more than counter- 
balanced in nations placed under favorable conditions. 
Emigration also comes in aid as a temporary check, but 
with the extremely poor classes, not to any great extent. 

There is reason to suspect, as Malthus has remarked, that 
the reproductive power is actually less in barbarous, 
than in civilized races. We knoAV 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 during a long time ; but it 
is highly probable that savages, who often suffer much 
hardship, and who do not obtain so much nutritious food 
as civilized men, would be actually less prolific. I have 
shown in a former work,f that all our domesticated quad- 
rupeds and birds, and all our cultivated plants, are more 

fertile than the corresponding species m a state of nature. 

» — ■ ' — 

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

f " Variation of Animals and Plants under DomcBtication," vol. ii, 
pp. 111-113, 163. 


It is no valid objection to this conclusion that animals sud- 
denly supplied with an excess of food, or when grown very 
fat, and that most plants on sudden removal from very 
poor to very rich soil, are rendered more or less sterile. We 
might, therefore, expect that civilized men, who in one 
sense are highly domesticated, would be more prolific than 
wild men. It is also probable that the increased fertility of 
civilized nations would become, as with our domestic 
animals, an inherited character : it is at least known that 
with mankind a tendency to produce twins runs in families.* 
Notwithstanding that savages appear to be less prolific 
than civilized people, they would no doubt rapidly increase 
if their numbers were not by some means rigidly kept down. 
The Santali, or hill-tribes of India, have recently afforded 
a good illustration of this fact ; for, as shown by Mr. 
Hunter, f they have increased 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 subsistence occasionally 
limits their number in a much more direct manner than 
with civilized people, for all tribes periodically suffer from 
severe famines. At such times savages are forced to devour 
much bad food, and their health can hardly fail to be 
injured. Many accounts have been published of their pro- 
truding stomachs and emaciated limbs after and during 
famines. They are then, also, compelled to wander much, 
and, as I was assured in Australia, their infants perish in 
large numbers. As famines are periodical, depending 
chiefly on extreme seasons, all tribes must fluctuate in 
number. They cannot steadily and regularly increase, as 
there is no artificial increase in the supply of food. Sav- 
ages, when hard pressed, encroach on each other^s- terri- 
tories, and war is the result ; but they are indeed almost 

*Mr. Sedgwick, "British and Foreign Medico-CMrurg. Review," 
July, 1863, p. 170. 
f "The Annals of Rural Bengal," by W. W. Hunter, 1868, p. 259. 


always at war with their neighbors. They are liable to 
many accidents on land and water in their search for food ; 
and in some countries they suffer much from the largei 
beasts of prey. Even in India^ districts have been depop- 
ulated by the ravages of tigers. 

Malthus has discussed these several checks, but he does 
not lay stress enough on what is probably the most import- 
ant 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. McLennan* has shown, 
on a still more extensive scale. These practices appear to 
have originated in savages recognizing the difficulty, or 
rather the impossibility of supporting all the infants that 
are born. Licentiousness may also be added to the forego- 
ing checks; but this does not follow from failing means of 
subsistence; though there is reason to believe that in some 
cases (as in Japan) it has been intentionally encouraged as 
a means of keeping down the population. 

If we look back to an extremely remote epoch, before 
man had arrived at the dignity of manhood, he would have 
been guided more by instinct and less by reason than are 
the lowest savages at the present time. Our early semi- 
human progenitors would not have practiced infanticide or 
polyandry; for the instincts of the lower animals are never 
so perverted f as to lead them regularly to destroy their own 
offspring, or to be quite devoid of jealousy. There would 
have been no prudential restraint from marriage, and the 
sexes would have freely united at an early age. Hence the 
progenitors of man would have tended to increase rapidly; 

* "Primitive Marriage," 1865. 

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


but checks of some kind, either periodical or constant, must 
have kept down their numbers, even more severely than 
with existing savages. What the precise nature of these 
checks were we cannot say, any more than with most other 
animals. We know that horses and cattle, which are not 
extremely prolific animals, when first turned loose in South 
America, increased at an enormous rate. The elephant, 
the slowest breeder of all known animals, would in a few 
thousand years stock the whole world. The increase of 
every species of monkey must be checked by some means; 
but not, as Brehm remarks, by the attacks of beasts of 
prey. No one will assume that the actual power of repro- 
duction in the wild horses and cattle of America, was at 
first in any sensible degree increased; or that, as each dis- 
trict became fully stocked, this same power was diminished. 
No doubt in this case, and in all others, many checks con- 
cur, and different checks under different circumstances; 
periodical dearths, depending on unfavorable 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 vari- 
able in body 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,* to the 
most diversified conditions. 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, f 
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 

*See some good remarks to this effect by W. Stanley Jevons, "A 
Peduction from Darwin's Theory," " Nature," 1869, p. 231, 
. f Lathftm, "Man and his Migrations," 1851, p. 135. 


at long intervals of time, but to mere individual differences. 
We know, for instance, that the muscles of our hands and 
feet, which determine our powers of movement, are liable, 
like those of the lower animals,* to incessant variability. 
If then the progenitors of man inhabiting any district, es- 
pecially one undergoing some change in its conditions, were 
divided into two equal bodies, the one-half which included 
all the individuals best adapted by their powers of move- 
ment for gaining subsistence, or for defending themselves, 
would on an average survive in greater numbers, and pro- 
create more offspring than the other and less well endowed 

Man in the rudest state in which he now exists is the 
most dominant animal that has ever appeared on this earth. 
He has spread more widely than any other highly organized 
form: and all others have yielded before him. He mani- 
festly owes this immense superiority to his intellectual fac- 
ulties, to his social habits, which lead him to aid and defend 
his fellows, and to his corporeal structure. The supreme 
importance of these characters has been proved by the final 
arbitrament of the battle for life. Through his powers of 
intellect, articulate language has been evolved; and on this 
his wonderful advancement has mainly depended. As Mr. 
Ohauncey Wright remarks:f '^a psychological analysis of 
the faculty of language shows, that even the smallest pro- 
ficiency in it might require more brain power than the 
greatest proficiency in any other direction.^'' He has in- 
vented and is able to use various weapons, tools, traps, etc., 
with which he defends himself, kills or catches prey, and 
otherwise obtains food. He has made rafts or canoes for 
fishing or crossing over to neighboring fertile islands. He 
has discovered the art of making fire, by which hard and 
stringy roots can be rendered digestible, and poisonous roots 
or herbs innocuous. This discovery of fire, probably the 
greatest ever made by man, excepting language, dates from 
before the dawn of history. These several inventions, by 

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

f Limits of Natural Selection, "North American Beview/' Oct- 
1870, p. 295. 


which man in the rudest state has become so pre-eminent, 
are the direct results of the development of his powers of 
observation, memory, curiosity, imagination, and reason. I 
cannot, therefore, understand how it is that Mr. Wallace* 
maintains, that '^ natural selection could only have endowed 
the savage with a brain a little superior to that of an ape."*' 

Although the intellectual powers and social habits of 
man are of paramount importance to him, we must not un- 
derrate 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 facul- 
ties being discussed in a later 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 a Fuegian in defend- 
ing himself, or in killing birds, requires the most consum- 
mate perfection in the correlated action of the muscles of 
the hand, arm, and shoulder, and, further, a fine sense of 
touch. In throwing a stone or spear, and in many other 
actions, a man must stand firmly on his feet; and this again 
demands the perfect co-adaptation of numerous muscles. 
To chip a fiint 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, f re- 
marks, the shaping fragments of stone into knives, lances, 
or arrow-heads, shows '^'extraordinary ability and long 

* "Quarterly Review," April, 1869, p. 392. This subject is more 
fully discussed in Mr. Wallace's " Contributions to the Theory of 
Natural Selection," 1870, in which all the essays referred to in this 
work are republished. The "Essay on Man," has been ably criti- 
cized by Prof. Claparede, one of the most distinguished zoologists in 
Europe, in an article published in the " Bibliotheque Universelle," 
June, 1870. The remark quoted in my text will surprise every one 
who has read Mr. Wallace's celebrated paper on " The Origin of 
Human Races deduced from the Theory of Natural Selection," orig- 
inally published in the " Anthropological Review," May, 1864, p. 
clviii. I cannot here resist quoting a most just remarli by Sir J. 
Lubbock ("Prehistoric Times," 1865, p. 479) in reference to this 
paper, namely, .that Mr. Wallace, "with characteristic unselfishness, 
ascribes it (i. e. the idea of natural selection) unreservedly to Mr. 
Darwin, although, as is well known, he struck out the idea inde- 
pendently, and published it, though not with the same elaboration, 
at the same time." 

f 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. 


practice/' This is to a great extent proved by the fact that 
primeval men practiced a division of labor ; each man did 
not manufacture his own flint tools or rude pottery, but 
certain individuals appear to have devoted themselves to 
such work, no doubt receiving in exchange the produce of 
the chase. Archaeologists are convinced that an enormous 
interval of time elapsed before our ancestors thought of 
grinding chipped flints into smooth tools. One can hardly 
doubt, that a man-like animal who possessed a hand and 
arm sufliciently perfect to throw a stone with precision, or 
to form a flint into a rude tool, could, with sufficient prac- 
tice, as far as mechanical skill alone is concerned, make 
almost any thing which a civilized man can make. The 
structure of the hand in this respect may be compared with 
that of the vocal organs, which in the apes are used for 
uttering various signal-cries, or, as in one genus, musical 
cadences; but in man the closely similar vocal organs 
have become adapted through the inherited effects of 
use for the utterance of articulate language. 

Turning now to the nearest allies of men, and therefore 
to the best representatives of our early progenitors, we find 
that the hands of the Quadrumana are constructed on the 
same general pattern as our own, but are far less perfectly 
adapted for diversified uses. Their hands do not serve for 
locomotion so well as the feet of a dog; as may be seen in 
such monkeys as the chimpanzee and orang, which walk on 
the outer margins of the palms, or on the knuckles.* 
Their hands, however, are admirably adapted for climbing 
trees. Monkeys seize thin branches or ropes, with the 
thumb on one side and the fingers and palm on the other, 
in the same manner as we do. They can thus also lift 
rather large objects, such as the neck of a bottle, to their 
mouths. Baboons turn over stones, and scratch up roots 
with their hands. They seize nuts, insects, or other small 
objects with the thumb in 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 
branches until the rind is cracked, and then tear it off with 
the fingers of the two hands. In a wild state they break 
open hard fruits with stones. Other monkeys open mussel- 
ehells with the two thumbs. With their fingers they pull 

*Owen, *' Anatomy of Vertebrates," vol. iii, p. 71. 


out thorns and burrs, and hunt for each other's parasites. 
They roll down stones, or throw them at their enemies: 
nevertheless, they are clumsy in these various actions, and, 
as I have myself seen, are quite unable to throw a stone 
with precision. 

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

As soon as some ancient member in the great series of the 
Primates came to be less arboreal, owing to a change in its 
manner of procuring subsistence, or fo some change in the 
surrounding conditions, its habitual manner of progression 
would have been modified; and thus it would have been 
rendered more strictly quadrupedal or bipedal. Baboons 
frequent hilly and rocky districts, and only from necessity 
climb high trees ; | and they have acquired almost the gait 
of a dog. Man alone has become a biped; and we can, I 
think, partly see how he has come to assume his erect atti- 
tude, which forms one of his most conspicuous characters. 
Man could not have attained his present dominant position 
in the world without the use of his hands, which are so 
admirably adapted to act in obedience to his will. Sir 0. 
Bell§ insists that ^Hhe hand supplies all instruments, and 

*" Quarterly Review," April, 1869, p. 892. 

f In Hylobates syndactylus, as tlie name expresses, two of the toes 
regularly cohere ; and this, as Mr. Blyth informs me, is occasionally 
the case with the toes of H. agilis, lar, and leuciscus. Colobus is 
strictly arboreal and extraordinarily active (Brehm, " Thierleben," 
B. i, s. 50), but whether a better climber than the species of the 
allied ijenera, I do not know. It deserves notice that the feet of the 
sloths, the most arboreal animals in the world, are wonderfully 

t Brehm, " Thierleben," B. i, s. 80. 

§ " The Hand," etc. *' Bridgewater Treatise," 1833, p. 38. 


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 before remarked, so 
long as they were especially fitted for climbing trees. Such 
rough treatment would also have blunted the sense of 
touch, on which their delicate use largely depends. From 
these causes alone it would have been an advantage to man 
to become a biped,; but for many actions it is indispensable 
that the arms and whole upper part of the body should be 
free; and 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 has been peculiarly modified, though this 
has entailed the almost complete loss of its power of pre- 
hension. It accords with the principle of the division of 
physiological labor, prevailing throughout the animal 
kingdom, that as the hands became perfected for prehen- 
sion, the feet should have became perfected for support 
and locomotion. AVith some savages, however, the foot 
has not altogether lost its prehensile power, as shown by 
their manner of climbing trees and of using them in other 
ways. * 

If it be an advantage to man to stand firmly on his feet 
and to have his hands and arms free, of which, from his 
pre-eminent success in the battle of life, there can be no 
doubt, then I can see no reason why it should not have been 
advantageous to the progenitors of man to have become more 
and more erect or bipedal. They would thus have been 
better able to defend themselves with stones or clubs, to 
attack their prey, or otherwise to obtain food. The best 
built individuals would in the long run have succeeded 
best and have 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 

* Hackel has an excellent discussion on tlie steps by whicli man 
became a biped: "Natiirliclie Scliopfungsgeschiclite," 1868, s. 507. 
Dr. Bilchner (" Conferences sur la Tbeorie Darwinienne," 1869, p. 
135) has given good cases of the use of the foot as a prehensile organ 
by man ; and has also written 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 


animal could not have been gradually converted from a 
quadruped into a biped, as all the individuals in an inter- 
mediate condition would have been miserably ill-fitted for 
progression. But we know (and this is well worthy of re- 
flection) that the anthropomorphous apes are now actually 
in an intermediate condition ; and no one doubts that they 
are on the whole well adapted for their conditions of life. 
Thus the gorilla runs with a sidelong shambling gait, but 
more 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 
piove awkwardly and much less securely than man. We 
$ee, in short, in existing monkeys a manner of progression 
intermediate between that of a quadruped and a biped; 
but, as an unprejudiced judge* insists, the anthropo- 
morphous apes approach in structure more nearly to the 
Mpedal than to the quadrupedal type. 

As the progenitors of man became more and more erect, 
with their hands and arms more and more modified for 
prehension and other purposes, with their feet and legs at 
trie same time transformed for firm support and progres- 
6'ion, endless other changes of structure would have be- 
come necessary. The pelvis would have to be broadened, 
tJhe spine peculiarly curved, and the head fixed m an 
a/tered position, all of which changes have been attained 
by man. Prof. Schaafihausenf maintains that ^' the pow- 
erful mastoia processes of the human skull are the result 
of his erect position;" and these processes are absent in 
the orang, chimpanzee, etc., and are smaller in the go- 
rilla than in man. Various other structures, which appear 
connected with man's erect position, might here have been 
added. It is very difficult to decide how far these corre- 
lated modifications are the result of natural selection, and 
how far of the inherited effects of the increased use of cer- 
tain parts or of the action of one part on another. 

* Prof. Broca, La Constitution des Vertebres caudales ; ** La Revue 
d' f^nthropologie," 1872, p. 36 (separate copy). 

f " On the Primitive Form of the Skull," translated in "Anthrop- 
ological Review," Oct 1868, p. 428. Owen ("Anatomy of Verte- 
brates," vol. ii, 1866, p. 551) on the mastoid processes ia the higher 


No doubt these means of change often co-operate; thiv» 
when certain muscles, and the crests of bone to which 
they are attached, become enlarged by habitual use, this 
shows that certain actions are habitually performed and 
must be serviceable. Hence the individuals which per- 
formed 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 forefathers of man were, as 
previously stated, probably furnished with great canine 
teeth; but as they gradually acquired the habit of using 
stones, clubs, or other weapons for fighting with their 
enemies or rivals they would use their jaws and teeth less 
and less. In this case the jaws, together with the teeth, 
•would become reduced in size, as we may feel almost 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 to their habits of 
fighting with their incisor teeth and hoofs. 

In the adult male anthropomorphous apes, as Rliti- 
meyer* and others have insisted, it is the effect on the 
skull of the great development of the jaw-muscles that causes 
it to differ so greatly in many respects from that of man, 
and has given to these animals ''a truly frightful physi- 
ognomy.^^ Therefore, as the jaws and teeth in man^s pro- 
genitors gradually become reduced in size, the adult skull 
would have come to resemble more and more that of exist- 
ing man. As we shall hereafter see, a great reduction of 
the canine teeth in the males would almost certainly affect 
the teeth of the females through inheritance. 

As the various mental faculties gradually developed 
themselves the brain would almost certainly become larger. 
No one, I presume, doubts that the large proportion which 
the size of man's brain bears to his body, compared to the 
same proportion in the gorilla or orang, is closely connected 
with his higher mental powers. We meet with closely 
analogous facts with insects, for in ants the cerebral gan- 
glia are of extraordinary dimensions, and in all the Hyme- 

*"Die Grenzen der Thierwelt, eijie Betrachtung zu Darwin's 
I^elire," 1868, s. 6J. 


noptera these ganglia are many times larger than in the 
less intelligent orders, such as beetles.* On the other 
hand, no one supposes that the intellect of any two ani- 
mals or of any two men can be accurately gauged by the 
cubic contents of their skulls. It is certain that there 
may be extraordinary mental activity with an extremely 
small absolute mass of nervous matter: thus the wonder- 
fully diversified instincts, mental powers and affections of 
ants are notorious, yet their cerebral ganglia are not so 
large as the quarter of a small pin's head. Under this 
point of view the brain of an ant is one of the most mar- 
velous atoms of matter in the world, perhaps more so than 
the brain of a man. 

The belief that there exists in man some close relation 
between the size of the brain and the development of the 
intellectual faculties is supported by the comparison of the 
skulls of savage and civilized races, of ancient and modern 
people, and by the analogy of the whole vertebrate series. 
Dr. J. Barnard Davis has proved,! ^J niany careful meas- 
urements, 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 cubic inches. 
Professor Broca J found that the nineteenth century 
skulls from graves in Paris were larger than those from 
vaults of the tAvelfth century, in the proportion of 1484 to 
1426; and that the increased size, as ascertained by meas- 
urements, was exclusively in the frontal part of the skull — 
the seat of the intellectual faculties. Prichard is per- 
suaded that the present inhabitants of Britain have 
*' much more capacious brain-cases '^ than the ancient in- 
habitants. 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 

*Dujardin, ** Annales des Sc. Nat.," 3d 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 tlie Formica rufa. 

t " PMlosopliical Transactions," 1869, p. 513. 

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

§ In the interesting article just referred to. Prof. Broca has well 
remarked, that in civilized nations, the average capacity of the skull 


respect to the lower animals, M. E. Lartet,* by comparing 
the crania of tertiary and recent mammals belonging to 
the same groups, has come to the remarkable conclusion 
that the brain is generally larger and the convolutions are 
more complex in the more recent forms. On the other 
hand, I have shown f 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 confined during many genera- 
tions, so that they have exerted their intellect, instincts, 
senses and voluntary movements but little. 

The gradually increasing weight of the brain and skull 
in man must have influenced the development of the sup- 
porting spinal column, more especially while he was becom- 
ing erect. As this change of position was being brought 
about, the internal pressure of the brain will also have in- 
fluenced the form of the skull; for many facts show 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 se- 
vere burn, have permanently modified the facial bones. In 
young persons whose heads have become fixed either side- 
ways or backward, owing to disease, one of the two eyes 
has changed its position, and the shape of the skull has 
been altered apparently by the pressure of the brain in a 
new direction. J I have shown that with long-eared rabbits 

must be lowered by the preservation of a considerable nnmber of in- 
dividuals, weak in mind and body, wlio would have been promptly 
eliminated in the savage state. On the other hand, with savages, the 
average includes only the more capable individuals, who have been 
able to survive under extremely hard conditions of life. Broca thus 
explains the otherwise inexplicable fact, that the mean capacity of 
the skull of the ancient Troglodytes of Lozere is greater than that of 
modern Frenchmen. 

* " Comptes-rendus des Sciences," etc., June 1, 1868. 

The Variation of Animals and Plants under Domestication," 
pp. 124-129. 

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

A. 1, 


even so trifling a cause as the lopping forward of one ear 
drags forward almost every bone of the skull on that side; 
so that the bones on the opposite side no longer strictly 
correspond. Lastly, if any animal were to increase or 
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 cer- 
tainly be altered. I infer this from my observations on 
domestic rabbits, some kinds of which have become very 
much larger than the wild animal, while others have re- 
tained nearly the same size, but in both cases the brain has 
been much reduced relatively to the size of the body. Now 
I was at first much surprised on finding that .in all these 
rabbits the skull had become elongated or dolichocephalic; 
for instance, of two skulls of nearly equal breadth, the one 
from a wild rabbit and the other from a large domestic 
kind, the former was 3.15 and the latter 4.3 inches in 
length.* One of the most marked distinctions in different 
races of men is that the skull in some is elongated and in 
others .rounded; and here the explanation suggested by the 
case of the rabbits may hold good; for Welcker finds that 
short " men incline more to brachycephaly, and tall men 
to dolichocephaly;^''f and tall men may be compared with 
the larger and longer-bodied rabbits, all of which have 
elongated skulls, or are dolichocephalic. 

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

Another most conspicuous difference between man and 
the lower animals is the nakedness of his skin. Whales 
and porpoises (Cetacea), dugongs (Sirenia) and the hippo- 
potamus 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 in- 
habit the colder regions are protected by a thick layer of 
blubber, serving the same purpose as the fur of seals and 

*" Variation of Animals," etc., vol. i, p. 117, on tlie elongation of 
the skull ; p. 119, on the effect of the lopping of one ear. 

f Quoted by SchaafEhausen, in **Anthropolog. Review," Oct., 1868, 
p. 419. 


otters. Elephants and rhinoceroses are almost hairless; 
and as certain extinct species, which formerly lived under 
an Arctic climate, were covered with long wool or hair, it 
would almost appear as if the existing species of both 
genera had lost their hairy covering from exposure to heat. 
This appears the more probable, as the elephants in India 
which live on elevated and cool districts are more hairy * 
than those on the lowlands. May we then infer that man 
became divested of hair from having aboriginally inhabited 
some tropical land? That the hair is chiefly retained in 
the male sex on the chest and face, and in both sexes at 
the junction of all four limbs with the trunk, favors this 
inference — on the assumption that the hair was lost before 
man became erect; for the parts which now retain most 
hair would then have been most protected from the heat of 
the sun. The crown of the head, however, offers a curious 
exception, for at all times it must have been one of the 
most exposed parts, yet is thickly clothed with hair. The 
fact, however, that the other members of the order of 
Primates, to which man belongs, although inhabiting 
various hot regions, are well clothed with hair, generally 
thickest on the upper surface, f is opposed to the supposi- 
tion that man became naked through the action of the sun. 
Mr. Belt believes X that within the tropics it is an advant- 
age to man to be destitute of hair, as he is thus enabled to 
free himself of the multitude of ticks (acari) and other 
parasites, with which he is often infested, and which some- 
times cause ulceration. But whether this evil is of suffi- 
cient magnitude -to have led to the denudation of his body 
through natural selection, may be doubted, since none of 
the many quadrupeds inhabiting the tropics have, as far as 

*Owen, "Anatomy of Vertebrates," vol. iii, p. 619. 

f Isidore Geoffroj St.-Hilaire remarks ("Hist. Nat, Generale," tom. 
ii, 1859, pp. 215-2i7) on tke head of man being covered witb long 
hair ; also on the upper surfaces of monkeys and of other mammals 
being more thickly clothed than the lower surfaces. This has like- 
wise been observed by various authors. Prof. P. Gervais (" Hist. 
Nat. des Mammiferes," tom. 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. 

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


I know, acquired any specialized means of relief. The 
view which seems to me the most probable is that man, or 
rather primarily woman, became divested of hair for orna- 
mental purposes, as we shall see under Sexual Selection; 
and, according to this belief, it is not surprising that man 
should differ so greatly in hairiness from all other Primates, 
for characters, gained through sexual selection, often differ 
to an extraordinary degree in closely related forms. 

According to a popular impression, the absence of a tail 
is eminently distinctive of man ; but as those apes which 
come nearest to him are destitute of this organ its disap- 
pearance does not relate exclusively to man. The tail 
often differs remarkably in length within the same genus : 
thus in some species of Macacus it is longer than the whole 
body, and is formed 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, while in the mandrill there are ten very small 
stunted caudal vertebrae, or, according to Cuvier,* some- 
times only five. The tail, whether it be long or short, 
almost always tapers toward the end ; and this, I presume, 
results from the atrophy of the terminal muscles, together 
with their arteries and nerves, through disuse, leading to 
the atrophy of the terminal bones. But no explanation 
can at present be given of the great diversity which often 
occurs in its length. Here, however, we are more specially 
concerned with the complete external disappearance of the 
tail. Prof. Broca has recently shownf that the tail in all 
quadrupeds consists of tAVO portions, generally separated 
abruptly from each other ; the basal portion consists of 
vertebrae, more or less perfectly channeled and furnished 
with apophyses like ordinary vertebrae; whereas those of 
the terminal portion are not channeled, are almost smooth, 
and scarcely resemble true vertebrae. A tail, though not 
externally visible, is really present in man and the anthro- 
pomorphous apes, and is constructed on exactly the same 
pattern in both. In the terminal portion of the vertebrae, 

*Mr. St. George Mivart, " Proc. Zoolog. Soc," 1865, pp. 563, 583. 
Dr. J. E. Gray, "Cat. Brit. Mus.: Skeletons." Owen, "Anatomy 
of Vertebrates," vol. ii, p. 517. Isidore Geoffroy "Hist. Nat. Gen." 
toiu. ii, p. 244. 

f " Revue d'Anthropologie," 1872 ; " La Constitution des Vertebres 
cau dales,** 


constituting the os coccyx, are quite rudimentary, being 
much reduced in size and number. In the basal portion, 
the vertebras are likewise few, are united firmly together, 
and are arrested in development ; but they have been ren- 
dered much broader and flatter than the corresponding 
vertebrae in the tails of other animals ; they constitute 
what Broca calls the accessory sacral vertebrae. These are 
of functional importance by supporting certain internal 
parts and in other ways ; and their modification is directly 
connected with the erect or semi-erect attitude of man and 
the anthropomorphous apes. This conclusion is the more 
trustworthy, as Broca formerly held a different view, which 
he has now abandoned. The modification, therefore, of 
the basal caudal vertebrae in man and the higher apes. may 
have been affected, directly or indirectly, through natural 

But what are we to say about the rudimentary and 
variable vertebrae of the terminal portion of the tail, form^ 
ing the os coccyx 9 A notion which has often been, and will 
no doubt again be, ridiculed, namely, that friction has had 
something to do with the disappearance of the external 
portion of the tail, is not so ridiculous as it at first appears. 
Dr. Anderson* states that the extremely short tail of Maca- 
cus brunneus is formed of eleven vertebrae, including the 
imbedded basal ones. The extremity is tendinous and 
contains no vertebrae; this is succeeded by five rudimentary 
ones, so minute that together they are only one line and a 
half in length, and these are permanently bent to one side 
in the shape of a 'hook. The free part of the tail, only a 
little above an inch in length, includes only four more 
small vertebrae. This short tail is carried erect; but about 
a quarter of its total length is doubled on to itself to the 
left; and this terminal part, which includes the hook-like 
portion, serves '^ to fill up the interspace between the upper 
divergent portion of the calosities;^^ so that the animal sits 
on it and thus renders it rough and callous. Dr. Anderson 
thus sums up his observations : " These facts seem to me 
to have only one explanation; this tail, from its short size, 
is in the monkey^s way when it sits down, and frequently 
becomes placed under the animal while it is in this atti- 
tude; and from the circumstance that it does not extend 

*"Proc. Zoolog.^Soc." 1873, p. 210. 


beyond the extremity of the ischial tuberosities, it seems as 
if the tail originally had been bent round by the will of the 
animal, into the interspace between the callosities, to es- 
cape being pressed between them and the ground, and that 
in time the curvature became permanent, fitting in of itself 
when the organ happens to be sat upon/^ Under these 
circumstances it is not surprising that the surface of the 
tail should have been roughened and rendered callous, and 
J)r. Murie,* who carefully observed this species in the 
Zoological Gardens, as well as three other closely allied 
forms with slightly longer tails, says that when the animal 
Bits down the tail ^^ is necessarily thrust to one side of the 
buttocks; and whether long or short its root is consequently 
liable to be rubbed or chafed." As we now have evidence 
that mutilations occasionally produce an inherited effect, f 
it is not very improbable that in short-tailed monkeys the 
projecting part of the tail, being functionally useless, 
should after many generations have become rudimentary 
and distorted, from being continually rubbed and chafed. 
We see the projecting part in this condition in the Maca- 
cus brunneus, and absolutely aborted in the M. ecaudatus 
and in several of the higher apes. Finally, then, as far as 
we can judge, the tail has disappeared in man and the 
anthropomorphous apes, owing to the terminal portion 
having been injured by friction during a long lapse of time; 
the basal and embedded portion having been reduced and 
modified so as to become suitable to the erect or semi-erect 

I have now endeavored to show that some of the most 
ftistinctive characters of man have in all probability been 
acquired, either directly, or more commonly indirectly, 
through natural selection. We should bear in mind that 
modifications in structure or constitution which do not 
serve to adapt an organism to its habits of life, to the food 

**'Proc. Zoolog. Soc.," 1872, p. 786. 

f I allude to Dr. Brown-Sequard's observations on the transmitted 
effect of an operation causing epilepsy in guinea-pigs, and likewise 
more recently on tlie analogous effects of cutting the sympathetic 
nerve in the neck. I ghall hereafter have occasion to refer to Mr. 
Salvin's interesting case of the apparently inherited effects of mot- 
mots biting off the barbs of their own tail-feathers. See also on the 
general subject ** Variation of Animals and Plants under Pomesti- 
cation/' vol. ii, pp. ^%-^ 


which it consumes, or passively to the surrounding con- 
ditions, cannot 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 fit an organism for a new 
climate or new kinds of food. Nor must we forget the 
principle of correlation, by which, as Isidore Geoffrey has 
shown in the case of man, many strange deviations o± 
structure are tied together. Independently of correlation, 
a change in one part often leads, 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 
color in the plumage of parrots when fed on certain fishes, 
or inoculated with the poison of toads; * for we can thus 
see that the fluids of the system, if altered for some 
special purpose, might induce other changes. We should 
especially bear in mind that modifications acquired and 
continually used during past ages for- some useful purpose, 
would probably become firmly fixed, and might be long 

Thus a large yet undefined extension may safely be given 
to the direct and indirect results of natural selection; but 
I now admit, after reading the essay by Nageli on plants, 
and the remarks by various authors with respect to ani- 
mals, more especially those recently made by Prof. Broca, 
that in the earlier editions of my ^'^ Origin of Species'' I 
perhaps attributed too much to the action of natural selec- 
tion or the survival of the fittest. I have altered the fifth 
edition of the ^'Origin'' so as to confine my remarks to 
adaptive changes of structure; but I am convinced, from 
the light gained during even the last few, years, that very 
many structures which now appear to us useless, will here- 
after be proved to be useful, and will therefore come within 
the range of natural selection. Nevertheless, I did not 
formerly consider sufficiently the existence of structures, 
which, as far as we can at present judge, are neither bene- 
ficial nor injurious; and this I beliere to be one of the 
greatest oversights as yet detected in my work. I may be 

*"The Variation of Animals and Plants under Domestication," 
vol. ii, pp. 380, 283. 


permitted to say, as some excuse, that I had two distinct 
objects in view; firstly, to show that species had not been 
separately created, and secondly, that natural selection had 
been the chief agent of change, though largely aided by 
the inlierited effects of habit, and slightly by the direct 
action of the surrounding conditions. I was not, however, 
able to annul the influence of my former belief, then 
almost universal, that each species had been purposely 
created; and this led to my tacit assumption that every de- 
tail of structure, excepting rudiments, was of some special, 
though unrecognized, service. Any one with this assump- 
tion in his mind would naturally extend too far the action 
of natural selection, either during past or present times. 
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 very far from admitting, or in having exagger- 
ated its power, which is in itself probable, I have at least, 
as I hope, done good service in aiding to overthrow the 
dogma of separate creations. 

It is, as I can now see, probable that all organic 
beings, including man, possess peculiarities of structure, 
which neither are now, nor were formerly of any service to 
them, and which, therefore, are of no physiological im- 
portance. We know not what produces the numberless 
slight differences between the individuals of each species, 
for reversion only carries the problem a few steps back- 
ward, but each peculiarity must have had its efficient 
cause. If these causes, whatever they may be, were to act 
more uniformly and energetically during a lengthened 
period (and against this no reason can be assigned), the re- 
sult would probably be not a mere slight individual differ- 
ence, but a well-marked and constant modification, though 
one of no physiological importance. Changed structures, 
which are in no way beneficial, cannot be kept uniform 
through natural selection, though the injurious will be 
thus eliminated. Uniformity of character would, however, 
naturally follow from the assumed uniformity of the excit- 
ing causes, and likewise from the free intercrossing of 
many individuals. During successive periods, the same 
organism might in this manner acquire successive modifi- 
cations, which 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 spon- 
taneous 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, liiie every other animal, to mul- 
tiform individual differences or slight variations, so no 
doubt were the early progenitors of man; the variations 
being formerly induced by the same general causes, and 
governed by the same general and complex laws as at 
present. As all animals tend to multiply beyond their 
means of subsistence, so it must have been with the pro- 
genitors of man; and this would inevitably lead to a strug- 
gle for existence and to natural selection. The latter pro- 
cess would be greatly aided by the inherited effects of the 
increased use of parts, and these two processes would in- 
cessantly react on each other. It appears, also, as we shall 
hereafter see, that various unimportant characters have 
been acquired by man through sexual selection. An unex- 
plained residuum of change must be left to the assumed 
uniform action of those unknown agencies, which occasion- 
ally induce strongly marked and abrupt deviations of struc- 
ture in our domestic productions. 

Judging from the habits of savages and of the greater 
number of the Quadrumana, primeval men, and even 
their ape-like progenitors, probably lived in society. 
With strictly social animals, natural selection sometimes 
acts on the individual, through the preservation of vari- 
ations which are beneficial to the community. A com- 
munity which includes a large number of well-endowed 
individuals increases in number, and is victorious over 
other less favored ones ; even although each separate 
member gains no advantage over the others of the same 
community. Associated insects have thus acquired many 
remarkable structures, which are of little or no service 
to the individual, such as the pollen-collecting appa- 
ratus, or the sting of the worker-bee, or the great jaws of 
soldier-ants. With the higher social animals, I am not 
aware that any structure has been modified solely for the 
good of the 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 ac- 
quired by the males as weapons for sexual strife, but they 
are used in defense of the herd or troop. In regard to cer- 
tain mental powers the case, as we shall see in the fifth 
chapter, is wholly different; for these faculties have been 
chiefly, or even exclusively, gained for the benefit of the 
'ommunity, and the individuals thereof have at the same 
time gained an advantage indirectly. 

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

In regard to bodily size or strength, we do not know 
whether man is descended from some small species, like 
the chimpanzee, or from one as powerful as the gorilla; 
and, therefore, we cannot say whether man has become 
larger and stronger, or smaller and weaker than his ances- 
tors, We should, however, bear in mind that an animal 

' » "Primeval Man/' 1869, p. 66. 


possessing great size, strength, and ferocity, and which, 
like the gorilla, could defend itself from all enemies, would 
not perhaps have become social: and this would most effect- 
ually have checked the acquirement of the higher mental 
qualities, such as sympathy and the love of his fellows. 
Hence it might have been an immense advantage to man to 
have sprung from some comparatively weak creature. 

The small strength and speed of man, his want of nat- 
ural weapons, etc., are more than counterbalanced, firstly, 
by his intellectual powers, through which he has formed 
for himself weapons, tools, etc., though still remaining in 
a barbarous state, and secondly, by his social qualities which 
lead him to give and receive aid from his fellow-men. No 
country in the world abounds in a greater degree with dan- 
gerous beasts than Southern Africa; no country presents 
more fearful physical hardships than the Arctic regions; 
yet one of the puniest of races, that of the Bushmen, main- 
tains itself in Southern Africa, as do the dwarfed Esqui- 
maux in the Arctic regions. The ancestors of man were, 
no doubt, inferior in intellect, and probably in social dis- 
position to the lowest existing savages; but it is quite con- 
ceivable that they might have existed, or even flourished, 
if they had advanced in intellect, while gradually losing 
their brute-like powers, such as that of climbing trees, etc. 
But these ancestors would not have been exposed to any 
special danger, even if far more helpless and defenseless 
than any existing savages, had they inhabited some warm 
continent or large island, such as Australia, New Guinea, 
or Borneo, which is now the home of the orang. And 
natural selection arising from the competition of tribe with 
tribe in some such large area as one of these, together with 
the inherited effects of habit, would, under favorable con- 
ditions, have sufficed to raise man to his present high 
position in the organic scale. 




The diffeience in paental power between the highest ape and the 
lowest savage, immense — Certain instincts in common — The 
emotions — Curiosity — Imitation — Attention — Memory — Imagi- 
nation — Reason — Progressive improvement — Tools and weapons 
used by animals— Abstraction, self-consciousness— Language — 
Sense of beauty — Belief in God, spiritual agencies, superstitions. 

We have seen in the last two chapters that man bears 
in his bodily structure clear traces of his descent from 
some lower form; but it maybe urged that, as man differs 
so greatly in his mental power from all other animals, 
there must be some error in this* conclusion. No doubt the 
difference in this respect is enormous, even if we compare 
the mind of one of the lowest savages, who has no words 
to express any number higher than four, and who uses 
hardly any abstract terms for common objects or for the 
affections,* with that of the most highly organized ape. 
The difference would, no doubt, still remain immense, even 
if one of the higher apes had been improved or civilized as 
much as a dog has been in comparison with its parent-form, 
the wolf or jackal. The Fuegians rank among, 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 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 

* See the evidence on those points, as given by Lubbock, " Prehis- 
toric Times," p. 354, etc. 


it cau be shown that there is no fundamental difference of 
this kind. We must also admit that there is a much wider 
interval in mental power between one of the lowest fishes, 
as a lamprey or lancelet, and one of the higher apes, than 
between an ape and man; yet this interval is filled up by 
numberless gradations. 

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

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

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

As man possesses the same senses as the lower animals, 
his fundamental intuitions must be the same. Man has 
jUso some few instincts in common, as that of self-preserva' 


tiou, sexual love, the love of the mother for her new-born 
offspring, the desire possessed by the latter to suck, and so 
forth. But man, perhaps, has somewhat fewer instincts 
than those possessed by the 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 afterward avoid, we cannot feel sure that the 
apes do not learn from their own experience or from that of 
their parents what fruits to select. It is, however, certain, 
as we shall presently see, that apes have an instinctive dread 
of serpents, and probably of other dangerous animals. 

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

Although the first dawnings of intelligence, according to 
Mr. Herbert Spencer, J have been developed through the 
multiplication and co-ordination of reflex actions, and 
although many of the simpler instincts graduate into reflex 

* " L'Instinct chez les Insectes," "Revue des Deux Mondes." Feb. 
1870, p. 690. 

f '* The American Beaver and His Works," 1868. 

% " The Principles of Psychology," 2d edit., 1870, pp. 418-443. 


actions, and can hardly be distinguished from them, as in 
the case of young animals sucking, yet the more complex 
instincts seem to have originated independently of intelli- 
gence. I am, however, very far from wishing to deny that 
instinctive actions may lose their fixed and untaught char- 
acter and be replaced by others performed by the aid of the 
free will. On the other hand, some intelligent actions, 
after being performed during several generations, become 
converted into instincts and are inherited, as when birds 
on oceanic islands learn to avoid man. These actions may 
then be said to be degraded in character, for they are no 
longer performed through reason or from experience. But 
the greater number of the more complex instincts appear 
to have been gained in a wholly different manner, through 
the natural selection of variations of simpler instinctive 
actions. Such variations appear to arise from the same 
unknown causes acting on the cerebral organization, which 
induce slight variations or individul differences in other 
parts of the body ; and these variations, owing to our 
ignorance, are often said to arise spontaneously. We can, 
I think, come to no other conclusion with respect to the 
origin of the more complex instincts, when we reflect on 
the marvelous instincts of sterile worker-ants and bees, 
which leave no offspring to inherit the effects of experience 
and of modified habits. 

Although, as we learn from the above-mentioned insects 
and the beaver, a high degree of intelligence is certainly 
compatible with complex instincts, and although actions, 
at first learned voluntarily, can soon through habit be 
performed with the quickness and certainty of a reflex 
action, yet it is not improbable that there is a certain 
amount of interference between the development of free 
intelligence and of instinct, which latter implies some in- 
herited modification of the brain. 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 very intricate 
channels of the freest intercommunication; and as a conse- 
quence each separate part would perhaps tend to be less 
well fitted to answer to particular sensations or associations 
in a definite and inherited — that is instinctive — manner. 
There seems even to exist some relation between a low de- 
gree of intelligence and a strong tendency to the formation 


of fixed, though not inherited habits; for as a sagacious 
physician remarked to me, persons who are slightly imbecile 
tend to act in everything by routine or habit; and they are 
rendered much happier if this is encouraged. 

I have thought this digression worth giving, because we 
may easily underrate the mental powers of the higher ani- 
mals, and especially of man, when we compare their actions 
founded on the memory of past events, on foresight, reason 
and imagination, with exactly similar actions instinctively 
performed by the lower animals; in this latter case the 
capacity of performing such actions has been gained, step 
by step, through the variability of the mental organs and 
natural selection, without any conscious intelligence on the 
part of the animal during each successive generation. No 
doubt, as Mr. Wallace has argued,* much of the intelligent 
work done by man is due to imitation and not to reason; 
but there is this great difference between his actions and 
many of those performed by the lower animals, namely, 
that man cannot, on his first trial, 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, and a spider its wonderful web, 
quite as well,t the first time it tries as when old and 

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

The fact that the lower animals are excited by the same 
emotions as ourselves is so well established that it will 
not be necessary to weary the reader by many details. 
Terror acts in the same manner on them as on us, causing 
the muscles to tremble, the heart to palpitate, the 

* "Contributions to tlie Theory of Natural Selection," 1870, p 212. 

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

X " Recherches sur les Moeurs des Fourmis," 1810, p. 173. 


sphincters to be relaxed, and the hair to stand on end. 
Suspicion, the offspring of fear, is eminently characteristic 
of most wild animals. It is, I think, impossible to read the 
account given by Sir E. Tennent, of the behavior of the 
female elephants, used as decoys, without admitting that 
they intentionally practice deceit, and well know what they 
are about. Courage and timidity are extremely variable 
qualities in the individuals of the same species, as is plainly 
seen in our dogs. Some dogs and horses are ill-tempered 
and easily turn sulky; others are good-tempered; and these 
qualities are certainly inherited. Every one knows how 
liable animals are to furious rage and how plainly they 
show it. Many, and probably true, anecdotes have been 
published on the long-delayed and artful revenge of various 
animals. The accurate Rengger and Brehm* state that 
the American and African monkeys which they kept tame 
certainly revenged themselves. Sir Andrew Smith, a zoolo- 
gist whose scrupulous accuracy was known to many persons, 
told me the following story of which he was himself an eye- 
witness: At the Cape of Good Hope an officer had often 
plagued a certain baboon, and the animal, seeing him ap- 
proaching one Sunday for parade, poured water into a hole 
and hastily made some thick mud, which he skillfully 
dashed over the officer as he passed by, to the amusement 
of many bystanders. For long afterward the baboon re- 
joiced and triumphed whenever he saw his victim. 

The love of a dog for his master is notorious ; as an old 
writer quaintly says: f '^A dog is the only thing on this 
earth that luvs you -more than he luvs himself.''^ 

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

As Whewell X has well asked : '* Who that reads the 

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

•f- Quoted by Dr. Lauder Lindsay, in his "Physiology of Mind in 
the Lower Animals;" "Journal of Mental Science," April, 1871, p. 

'\ " Bridgewater Treatise," p. 363. 


touching instances of maternal affection, related so often 
of the women of all nations and of the females of all ani- 
mals, 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, Eengger observed an Ameri- 
can 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 in- 
tense is the grief of female monkeys for the loss of their 
young that it invariably caused the death of cert§,in kinds 
kept under confinement by Brehm in N. Africa. Orphan 
monkeys were always adopted and carefully 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 this affec- 
tionate baboon, who certainly had a fine intellect, for she was 
much astonished at being scratched, and immediately exam- 
ined the kit ten^s feet, and without more ado bit off the claws.* 
In the Zoological Gardens I heard from the keeper that an 
old baboon ( G. cliacma) had adopted a Ehesus monkey; but 
when a young drill and mandrill were placed in the cage 
she seemed to perceive that these monkeys, though distinct 
species, were her nearer relatives, for she at once rejected 
the Rhesus and adopted both of them. The young Ehesus, 
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 they are attached, from the attacks of other dogs. 
But we here trench on the subjects of sympathy and fidel- 
ity, to which I shall recur. Some of Brehm^s monkeys 

*A critic, witliout any grounds (" Quarterly Review," July, 1871, 
p. 73), disputes the possibility of this act as described by Brehm, for 
the sake of discrediting my work. Therefore I tried, and found that 
I could readily seize with my own teeth the sharp little claws of a 
kitten nearly five weeks old. 


took muoh delight in teasing a certain old dog whom they 
disliked, as well as other animals, in various ingenious ways. 

Most of the more complex emotions are common to the 
higher animals and ourselves. Every one has seen how 
jealous a dog is of his master's affection if lavished on any 
other creature; and I have observed the same fact with 
monkeys. This shows that animals not only love, but have 
a desire to be loved. Animals manifestly feel emulation. 
They love approbation or praise; and a dog carrying a bas- 
ket for his master exhibits in a high degree self-complac- 
ency 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 th-ey sometimes in- 
vent imaginary offenses. In the Zoological Gardens I saw 
a baboon who always got into a furious rage when his keeper 
took out a letter or book and read it aloud to him; and his 
rage was so violent that, as I witnessed on one occasion, he 
bit his own leg till the blood flowed. Dogs show what may 
be fairly called a sense of humor as distinct from mere play; 
if a bit of stick or other such object be thrown to one, he 
will often carry it away for a short distance ; and then 
squatting down with it on the ground close before him, will 
wait until his master comes quite close to take it away. 
The dog will then seize it and rush away in triumph, re- 
peating the same maneuver, aiid evidently enjoying the 
practical joke. 

We will now turn to the more intellectual emotions and 
faculties, which aire very important, as forming the basis 
for the developfiient of the higher mental powers. Animals 
manifestly enjoy excitement, and suff'er from ennui, as may 
be seen with dogs, and, according to Rengger, with mon- 
keys. All animals feel Wondei- and many exhibit Curiosity, 
They sometimes suffer from this latter quality, as when 
the hunter plays antics and thus attracts them; I have wit- 
nessed this with deer, and so it is with the wary chamois, 
and with some kinds of wild-ducks. Brelim gives a curious 
account of the instinctive dread, which his monkeys exhib- 
ited, for snakes; but their curiosity was so great that they 
could not desist from occasionally satiating their horror 
m a most human fashion by lifting up the lid of the box 


in which the snakes were kept. I was so much surprised 
at his account that I took a stuffed and coiled-up snake 
into the monkey-house at the Zoological Gardens, and the 
excitement thus caused was one of the most curious spec- 
tacles 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 ohl 
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 col- 
lected round it in a large circle, and, staring intently, pre- 
sented a most kidicrous appearance. They became ex- 
tremely nervous; so that when a wooden ball, with which 
they were familiar as a plaything, was accidentally moved 
in the straw, under which it was partly hidden, they all in- 
stantly started away. These monke3^s behaved very dif- 
ferently when a dead fish, a mouse,* a living turtle, and 
other new objects were placed in their cages; for though at 
first frightened, they soon approached, handled and ex- 
amined them. I then placed a live snake in a paper bag, 
with the mouth loosely closed, in one of the larger com- 
partments. 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 a momentary peep into 
the upright bag, at the dreadful object lying quietly at the 
bottom. It would almost appear as if monkeys had some 
notion of zoological affinities, for those kept by Brehm ex- 
hibited a strange, though mistaken, instinctive dread of 
innocent lizards and frogs. An orang, also, has been 
known to be much alarmed at the first sight of a turtle, f 
The principle of Imitation is strong in man, and espe- 
cially, as I have myself observed, with savages. In certain 
morbid states of the brain this tendency is exaggerated to an 
extraordinary degree; some hemiplegic patients and others, 
at the commencement of inflammatory softening of the brain, 
unconsciously imitate every word which is uttered, whether 

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

f W. C. L. Martin, " Nat. HLst. of Mammalia," 1841, p, 405. 


in their own or in a foreign language, and every gesture oi 
action which is performed near them.* Desorf has re- 
marked that no animal voluntarily imitates an action per- 
formed by man, until in the ascending scale we come to 
monkeys, which are well known to be ridiculous mockers. 
Animals, however, sometimes imitate each other's actions ; 
thus two species of wolves, which had been reared by dogs,' 
learned to bark, as does sometimes the jackal, J; but whethex 
this can be called voluntary imitation is another question. 
Birds imitate the songs of their parents, and sometimes of 
other birds; and parrots are notorious imitators of any sound 
which they often hear. Dureau de la Malle gives an account§ 
of a dog reared by a cat, who learned to imitate the well- 
known action of a cat licking her paws, and thus washing 
her ears and face; this was also witnessed by the celebrated 
naturalist Audouin. I have received several confirmatory 
accounts; in one of these, a dog had not been suckled by a 
cat, but had been brought up with one, together with 
kittens, and had thus acquired the above habit, which ha 
ever afterward practiced during his life of thirteen years. 
Dureau de la Malleus dog likewise learned from the kittens 
to play with a ball by rolling it about with his fore paws 
and springing on it. A correspondent assures me that a 
cat in his house used to put her paws into jugs of milk 
having too narrow a mouth for her head. A kitten of this 
cat soon learned the same trick, and practiced it ever 
afterward whenever there was aix opportunity. 

The parents of many animals, trusting to the principle 
of imitation in their young, and more especially to their 
instinctive or inherited tendencies, may be said to educate 
them. We see this when a cat brings a live mouse to her 
kittens; and Dureau de la Malle has given a curious ac- 
count (in the paper above quoted) of his observations on 
hawks which taught their young dexterity, as well as judg- 
ment of distances, by first dropping through the air dead 
mice and - sparrows, which the young generally failed to 

*Drc Bateman "On Aphasia," 1870, p. 110. 

f Quoted hj Vogt, " Memoire sur les Microcephales," 1867, p. 168. 

* " The Variation of Animals and Plants under Domestication," vol. 
1, p. 27. 

§ •' Annales des Sc. Nat.",Clst series), tom. xxii, p. 397. 


catch, and then bringing them live birds and letting them 

Hardly any faculty is more important for the intellectual 
progress of man ihMi Attentio7i. 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 ap- 
proached. Mr. Bartlett has given me a curious proof how 
variable this faculty is in monkeys. A man who trains 
monkeys to act in plays used to purchase common kinds 
from the Zoological Society at the price of five pounds for 
each; but he oftered to give double the price if he might 
keep three or four of them for a few days in order to select 
one. When asked how he could possibly learn so soon 
whether a particular monkey would turn out a good actor, 
he answered that it all depended on their power of 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 inattentive 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 excel- 
lent me?nories for persons and places. A baboon at the 
Cape of Good Hope, as I have been informed by Sir An- 
drew Smith, recognized him with joy after an absence of 
nine months. I had a dog who was savage and averse to 
all strangers, and I purposely tried his memory after an 
absense of five years and two days. I went near the stable 
where he lived and shouted to him in my old manner; he 
showed no joy, but instantly followed me out 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* has clearly shown, recog- 
nized their fellow-ants belonging to the same community 
after a separation of four months. Animals can certainly 
by some means judge of the intervals of time between 
recurrent events. 

The Imagination is one of the highest prerogatives of 
man. By this faculty he unites former images and ideas, 

* "Les Moeurs des Fourmis/' 1810, p. 150. 


independently of the will, and thus creates brilliant and 
novel results. A poet, as Jean Paul Richter remarks,* 
" who must reflect whether he shall make a character say 
yes or no — to the devil with him ; he is only a stupid 
corpse." Dreaming gives us the best notion of this power; 
as Jean Paul again says, *' The dream is an 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 \ have vivid dreams, and this is shown by their 
movements and the sounds uttered, we must admit that 
they possess some power of imagination. There must be 
something special which causes dogs to howl in the night, 
and especially during moonlight, in that remarkable and 
melancholy manner called baying. All dogs do not do so; 
and, according to Houzeau,^: they do not then look at the 
moon, but at some fixed point near the horizon. Houzeau 
thinks that their imaginations are disturbed by the vague 
outlines of the surrounding objects, and conjure up before 
them fantastic images ; if this be so, their feelings may 
almost be called superstitious. 

Of all the faculties of the human mind, it will, I pre- 
sume, be admitted that Reason stands at the summit. Only 
a few persons now dispute that animals possess some power 
of reasoning. Animals may constantly be seen to pause, 
deliberate, and resolve.. It is a significant fact, that the 
more the habits of any particular animal are studied by a 
naturalist, the more he attributes to reason and the less"^ to 
unlearned instincts. § In future chapters we shall see that 
some animals extremely low in the scale apparently display 

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

•f-Dr. Jerdon, "Birds of India," vol, i, 1862, p. 21. Houzeau says 
that his paroquets and canary birds dreamed; " Facultis Mentales," 
torn, ii, p. 136. 

X "Facultes Mentales des Animaux," 1872, torn, ii, p. 181. 

§Mr. L. U. Morgan's work on "The American Beaver," 1866, 
offers a good illustration of this remark. I cannot help thinking, 
however, that he goes too far in underrating the power of instinct. 


a certain amount of reason. No doubt it is often difficult 
to distinguish between the power of reason and that of in- 
stinct. For instance. Dr. Hayes, in his work on "The 
Open Polar Sea/' repeatedly remarks 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 warning which the travelers received that the 
ice was becoming thin and dangerous. Now, did the dogs 
act thus from the experience of each individual, or from 
the example of the older and wiser dogs, or from an inher- 
ited habit, that is, from instinct? This instinct may pos- 
sibly have arisen since the time, long ago, when dogs were 
first employed by the natives in drawing their sledges; or 
the Arctic wolves, the parent-stock of the Esquimau dog, 
may have acquired an instinct impelling them not to attack 
their prey in a close pack, when on thin ice. 

We can only judge by the circumstances under which 
actions are performed, whether they are due to instinct, or 
to reason, or to the mere association of ideas; this latter 
principle, however, is intimately connected with reason. A 
curious case has been given by Prof. Mobius,* of a pike, 
separated by a plate of glass from an adjoining aquarium 
stocked with fish, and who often dashed himself with such 
violence against the glass in trying to catch the other fishes, 
that he was sometimes completely stunned. The pike went 
on thus for three months, but at last learned caution, and 
ceased to do so. The plate of glass was then removed, but 
the pike would not attack these particular fishes, though he 
would devour others which were afterward introduced ; so 
strongly was the idea of a violent shock associated in his 
feeble mind with the attempt on his former neighbors. If 
a savage, who had never seen a large plate-glass window, 
were to dash himself even once against it, he would for a 
long time afterward associate a shock wdtli a window-frame; 
but, very differently from the pike, he would probably 
reflect on the nature of the impediment, and be cautious 
under analogous circumstances. Now with monkeys, as we 
shall presently see, a painful or merely a disagreeable 
impression, from an action once performed, is sometimes 
sufficient to prevent the animal from repeating it. If we 

* "Pie Bewegungen der Tliiere," etc., 1873, p. U. 


attribute this difference between the monkey and the pike 
solely to the association of ideas being so much stronger 
and more persistent in the one than the other, though the 
pike often received much the more severe injury, can we 
maintain in the case of man that a similar diiference 
implies the possession of a fundamentally different mind? 

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

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

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

* Facult^s Mentales des Animaux," 167^, torn. ii. p. 265k 


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

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

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

f Mr. Belt, in his most interesting work, "The Naturalist in Nic- 
aragua," 1874 (p. 119), likewise describes various actions of a tamed 
Cebus, which, I think, clearly show that this animal possessed somv 
i'easouing power. 


The following cases relate to dogs. Mr. Colquhonn* 
winged two wild-ducks, which fell on the farther 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 otlier, and returned for the dead bird. Col. 
Hutchinson relates that two partridges were shot at once, 
one being killed, the other w^ounded; the latter ran away 
and was caught by the retriever, who on her return came 
across the dead bird; ^^she stopped, evidently greatly puz- 
zled, 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 giv- 
ing it a severe crunch, and afterward brought away both 
together. This was the only known instance of her ever 
having wilfully injured any game."*^ Here we have reason, 
though not quite peWect, for the retriever might have 
brought the wounded bird first and then returned for the 
dead one, as in the case of the two wild-ducks. I give the 
above cases as resting on the evidence of two independent 
witnesses, and because in both instances the retrievers, after 
deliberation, broke through a habit which is inherited by 
them (that of not killing the game retrieved), and because 
they show how strong their reasoning faculty must have 
been to overcome a fixed habit. 

I will conclude by quoting a remark by the illustrious 
Humboldt, t ^^ The muleteers in South America say, *I 
will not give you the mule whose step is easiest, but la mas 
racional — the one that reasons best ;' " and, as he adds, 
^' this popular expression, dictated by long experience, com- 
bats the system of animated machines better perhaps than 
all the arguments of speculative philosophy." Neverthe- 
less some writers even yet deny that the higher animals pos- 
sess a trace of reason; and they endeavor to explain away, 
by what appears to be mere verbiage, J all such facts as those 
above given. 

* " Tlie Moor and the Locli," p. 45. Col. Hutchinson on "Dog 
Breaking," 1850, p. 46. 

f '• Personal Narrative," Eng. translat., vol. iii, p. 106. 

X I am glad to find that so acute a reasoner as Mr. Leslie Stephen 
("Darwinism and Divinity, Essays on Free-thinking," 1873, p. 80), 
in speaking of the supposed impassable barrier between the minds of 
man and the lower animals, says- " The distinctions, indeed, whiclj 


It has, I think, now been shown that man and the higher 
animals, especially the Primates, have some few instincts in 
common. All have the same senses, intuitions and sensa- 
tions — similar passions, affections and emotions, even the 
more complex ones, such as jealousy, suspicion, emulation, 
gratitude and magnanimity; they practice deceit and are 
revengeful; they are sometimes susceptible to ridicule, and 
even have a sense of humor; they feel wonder and curiosity; 
they possess the same faculties of imitation, attention, de- 
liberation, choice, memory, imagination, the association of 
ideas and reason, though in very different degrees. The 
individuals of the same species graduate in intellect from 
absolute imbecility to high excellence. They are also liable 
to insanity, though far less often than in the case of man.* 
Nevertheless, many authors have insisted that man is 
divided by an insuperable barrier from all the lower animals 
in his mental faculties. I formerly made a collection of 
above a score of such aphorisms, but they are almost worth- 
less, as their wide difference and number prove the diffi- 
culty, if not the impossibility, of the attempt. It has been 
asserted that man alone is capable of progressive improve- 
ment; that he alone makes use of tools or fire, domesticates 
other animals, or possesses property; that no has the 
power of abstraction or of forming general concepts, is self- 
conscious and comprehends itself; that no animal employs 
language; that man alone has a sense of beauty, is liable to 
caprice, has the feeling of gratitude, mystery, etc. ; believes 
in God, or is endowed with a conscience. I will hazard a 
f CAV remarks on the more important and interesting of these 

Archbishop Sumner formerly maintainedf that man 
alone is capable of progressive improvement. That he is 
capable of incomparably greater and more rapid improve- 

have been drawn, seem to us to rest upon no better foundation than 
a great many other metaphysical distinctions ; that is, the assumption 
that because you can give two things different names, they must 
therefore have different natures. It is ditficult to understand how 
anybody who has ever kept a dog, or seen an elephant, can have any 
doubts as to an animal's power of performing the essential processes 
of reasoning." 

*See "Madness in Animals," by Dr. W. Lauder Lindsay, iu 
"Journal of Mental Science," July, 1871. 

fQuoted by Sir a Lyell, " Antiquity of Man," p. 497. 


ment than is any other animal, admits of no dispute; and 
this is mainly due to his power of speaking and handing 
down his acquired knowledge. With animals, looking first 
to the individual, every one who has had any experience in 
setting traps, knows that young animals can be caught 
much more easily than old ones; and they can be much 
more easily approached by an enemy. Even with respect 
to old animals, it is impossible to catch many in the same 
place and in the same kind of trap, or to destroy them by 
the same kind of poison ; yet it is improbable that all 
should have partaken of the poison, and impossible that all 
should have been caught in a trap. They must learn cau- 
tion by seeing their brethren caught or poisoned. In North 
America, where the fur-bearing animals have long been pur- 
sued, they exhibit, according to the unanimous testimony of 
all observers, an almost incredible amount of sagacity, caution 
and cunning; but trapping has been there so long carried 
on that inheritance may possibly have come into play. I 
have received several accounts that when telegraphs are first 
set up in any district many birds kill themselves by flying 
against the wires, but that in the course of a few years they 
learn to avoid this danger by seeing, as it would appear, 
their comiades killed.* 

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

Our domestic dogs are descended from wolves and jackals, § 
and though they may not have gained in cunning, and may 

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

fSee, with respect to birds on oceanic islands, my. ''Journal of 
Researches during the voyage of the ' Beagle,' " 1845, p. 398. " Ori- 
gin of Species," 5th edition, p. 260. 

:}:*'Lettres Phil, sur I'lntelligence des Animaux,*' nouvelle edit,, 
1892, p. 86. 

§See the evidence on this head in chap, i, vol. i, '* On the Vatia- 
tion of Animals and Plants under Domestication." 


have lost in wariness and suspicion, yet they have pro- 
gressed in certain moral qualities, such as in affection, trust- 
worthiness, temper and probably in general intelligence. 
The common rat has conquered and beaten several other 
species throughout Europe, in parts of North America, 
New Zealand, and recently in Formosa, as well as on the 
mainland of China. Mr. Swinhoe,* who describes these 
two latter cases, attributes the victory of the common rat 
over the large Mus cotmiga to its superior cunning; and 
this latter quality may probably be attributed to the habit- 
ual exercise of all its faculties in avoiding extirpation by 
man, as well as to nearly all the less cunning or weak- 
minded rats having been continuously destroyed by him. 
It is, however, possible that the success of the common rat 
may be due to its having possessed greater cunning than its 
fellow-species before it became associated with man. To 
maintain, independently of any direct evidence, that no 
animal during the course of ages has progressed in intellect 
or other mental faculties is to beg the question of the evo- 
lution of species. We have seen that, according to Lartet, 
existing mammals belonging to several orders have larger 
brains than their ancient tertiary prototypes. 

It has often been said that no animal uses any tool; but 
the chimpanzee in a state of nature cracks a native fruit, 
somewhat like a walnut, with a stone, f Eengger J easily 
taught an American monkey thus to break open hard palm- 
nuts; and afterward of its own accord it used stones to 
open other kinds of nuts, as well as boxes. It thus also 
removed the soft rind of fruit that had a disagreeable 
flavor. Another monkey was taught to open the lid of a 
large box with a stick, and afterward it used the stick as a 
lever to move heavy bodies; and I have myself seen a young 
orang put a stick into a crevice, slip his hand to the other 
end, and use it in the proper manner as a lever. The 
tamed elephants in India are well known to break off 
branches of trees and use them to drive away the flies; and 
this same act has been observed in an elephant in a state of 

* ''Proc. Zoolog. Soc," 1864, p. 186. 

f Savage and Wyman in ** Boston Journal of Nat. Hist.,** vol. iv, 
1843-44, p. 383. 

X ■" Saugetliiere von Paraguay," 1830, 8. 51-56. 


nature.* I have seen a young orang, when she thought 
she was going to be whipped, cover and protect herself 
Avith a blanket or straw. In these several cases stones and 
sticks were employed as implements; but they are likewise 
used as weapons. . Brehmf states^ on the authority of the 
well-known traveler Schimper, that in Abyssinia when the 
baboons belonging to one species ( G. gelada) descend in troops 
from the mountains to plunder the fields they sometimes 
encounter troops of another species (C. liamadryas), and 
then a fight ensues. The Geladas roll down great stones, 
which the Hamadryas try to avoid, and then both species, 
making a great uproar, rush furiously against each other. 
Brehm, when accompanying the Duke of Coburg-Gotha, 
aided in an attack with firearms on a troop of baboons in 
the pass of Mensa in Abyssinia. The baboons in return 
rolled so many stones down the mountain, some as large as 
a man^s head, that the attackers had to beat a hasty retreat; 
and the pass was actually closed for a time against the 
caravan. It deserves notice that these baboons thus acted 
in concert. Mr. Wallace J; on three occasions saw female 
orangs, accompanied by their young, *^ breaking off 
branches and the great spiny fruit of the Durian tree, with 
every appearance of rage; causing such a shower of missiles 
as effectually kept us from approaching too near the tree." 
As I have repeatedly seen, a chimpanzee will throw any 
object at hand at a person who offends him; and the before- 
mentioned baboon at the Cape of Good Hope prepared mud 
for the purpose. 

In the Zoological Gardens a monkey, which had weak 
teeth used to break open nuts with a stone; and I was 
assured by the keepers that after using the stone he hid it 
in the straw, and would not let any other monkey touch it. 
Here, then, we have the idea of property; but this idea is 
common to every dog with a bone, and to most or all birds 
with their nests. 

The Duke of Argyll§ remarks that the fashioning of an 
implement for a special purpose is absolutely peculiar to 
man; and he considers that this forms an immeasurable 
gulf between him and the brutes. This is no doubt a very 

* The " Indian Field," March 4, 1871. 

t " Thierleben," B. i, s. 79, 82. 

X "The Malay Archipelago," vol. i, 1869, p. 87. 

§ " Primeyai Mau," 1869. pp. 145. 147. 


important distinction; but there appears to me much truth 
in Sir J. Lubbock's suggestion^* that when primeval man 
first used flint-stones for any purpose, he would have acci- 
dentally splintered them, and would then have used the 
sharp fragments. From this step it would be a small one 
to break the flints on purpose, and not a very wide step to 
fashion them rudely. This latter advance, hov/ever, may 
have taken long ages, if we may judge by the immense in- 
terval 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 anthropomor- 
phous apes, guided probably by instinct, build for them- 
selves temporary platforms; but as many instincts are largely 
controlled by reason, the simpler ones, such as this of build- 
ing 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 sev- 
eral habits, we probably see the fi^st steps toward some of 
the simpler arts, such as rude architecture and dress, as 
they arose among the early progenitors of man. 

Abstraction, General Conceptions, Self -consciousness, 
Mental Individuality. — It would be very difficult for any 
one with even much more knowledge than I possess to de- 
termine how far animals exhibit any traces of these high 
mental powers. This difficulty arises from the impossibility 
of judging what passes through the mind of an animal; 
and again, the fact that writers difl;er to a great extent in 
the meaning which they attribute to the above terms, 
causes a further " difficulty. If one may judge from 
various articles which have been published lately, the great- 
est stress seems to be laid on the supposed entire absence 
in animals of the power of abstraction, or of forming general 
concepts. But when a dog sees another dog at a distance, 

* " Prehistoric Times/' 1865, p. 473, etc. 


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

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

*Mr. Hookham, in a letter to Prof. Max Miiller, in the "Birm- 
ingham News," May 1873. 

f " Conferences sur la Theorie Darwinienne," French translat., 
1869, p. 132. 


We see at least that such powers are developed in children 
by imperceptible degrees. 

That animals retain their mental individuality is unques- 
tionable. When my voice awakened a train of old associa- 
tions in the mind of the before-mentioned dog, he must 
have retained his mental individuality, although every atom 
of his brain had probably undergone 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." * 

Language. — This faculty has justly been considered as 
one of the chief distinctions between man and the lower 
animals. But man, as a highly competent judge. 
Archbishop AVhately 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 ex- 
pressed by another, "f In Paraguay the Cehu^ azarce when 
excited utters at least six distinct sounds, which excite in 
other monkeys similar emotions. X The movements of the 
features and gestures of monkeys are understood by us, and 
they partly understand ours, as Rengger and others declare. 
It is a more remarkable fact that the dog, since being 
domesticated, has learned to bark§ in at least four or five 
distinct tones. Although barking is a new art, no doubt 
the wild parent-species of the dog expressed their feelings 
by cries of various kinds. With the domesticated dog we 
have the bark of eagerness, as in the chase; that of anger, 
as well as growling; the yelp or howl of despair, as when 
shut up; the baying at night; the bark of joy, as when 
starting on a walk with his master; and the very distinct 

* The Rev. Dr. J. M'Cann, "Anti-Darwinism," 1869, p. 13. 
f Quoted in " Anthropological Review," 1864, p. 158. 
X Rengger, ibid, s. 45. 

§ See my " Variation of Animals and Plants under Domestication," 
vol. i, p. 27. 


one of demand or supplication, as when wishing for a door 
or window to be opened. According to Houzeau, who paid 
particular attention to the subject, the domestic fowl utters 
at least a dozen significant sounds.* 

The habitual use of articulate language is, however, 
peculiar to man; but he uses, in common with the lower 
animals, inarticulate cries to express his meaning, aided by 
gestures and the movements of the muscles of the face. \ 
This specially 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. That which distinguishes man from the lower ani- 
mals is not the understanding of articulate sounds, for, as 
every one knows, dogs understand many words and sen- 
tences. In this respect they are at the same stage of devel- 
opment as infants, between the ages of ten and twelve 
months, who understand many words and short sentences, 
but cannot yet utter a single word. It is not the mere ar- 
ticulation which is our distinguishing character, for parrots 
and other birds possess this power. Nor is it the mere 
capacity of connecting definite sounds with definite ideas; 
for it is certain that some parrots, which have been taught 
to speak, connect unerringly words with things and per- 
sons with events. J; The lower animals differ from man 

* "Facultes Mentales des Animaux," torn, ii, 1872, pp. 346-349, 
f See a discussion on this subject in Mr. E. B. Tylor's very inter- 
esting work, " Researches into the Early History of Mankind/' 1865, 
chaps, ii to iv. 

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


solely in his almost infinitely larger power of associating 
together the most diversified sounds and ideas, and this 
obviously depends on the high development of his mental 

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 better simile. It 
certainly is not a true instinct, for every language has to be 
learned. It diifers, however, widely from all ordinary arts, 
for man has an instinctive tendency to speak, as we see in 
the babble of our young children; while no child has an 
instinctive tendency to brew, bake, or write. Moreover, no 
philologist now supposes that any language has been delib- 
erately invented; it has been slowly and unconsciously de- 
veloped 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 in- 
stinctive cries expressive of their emotions; and all the 
kinds which sing exert their power instinctively; but the 
actual song, and even the call-notes, are learned from their 
parents or foster-parents. These sounds, as Daines Bar- 
ringtonf has proved, '^ are no more innate than language 
is in man.^^ The first attempts to sing ^'^may be compared 
to the imperfect endeavor in a child to babble.^' The 
young males continue practicing, or as the bird-catchers 
say, '^recording," "for ten or eleven months. Their first 
essays show hardly a rudiment of the future song; but as 
they grow older we can perceive what they are aiming at; 
and at last they are said *^^ to sing their song round.^^ 
Nestlings which have learned the song of a distinct species, 
as with the canary birds educated in the Tyrol, teach and 
transmit their new song to their offspring. The slight 
natural differences of song in the same species inhabiting 
dift'erent districts may be appositely compared, as Barring- 

* See some good remarks on this head \>j Prof. Whitney, in his 
'' Oriental and Linguistic Studies," 1873, p. 354. He observes that 
the desire of communication between man is the living force, which, 
in the development of language, "works both consciously and un- 
consciously; consciously as regards the immediate end to be attained; 
unconsciously as regards the further consequences of the act." 

fllon. Daines Barrington in "Philosoph. Transactions," 1773, p. 
263. See also Dureau de la Malle, in ''Ann. des. Sc. Nat.," 3d 
series, Zoolog. torn, x, p. 119. 


ton remarks, ''to provincial dialects;^* and the songs of 
allied though distinct species may be compared with the 
languages of distinct races of man. I have given the fore- 
going details to show that an instinctive tendency to 
acquire an art is not peculiar to man. 

With respect to the origin of articulate language, after 
having read on the one side the highly interesting works of 
Mr. Hensleigh Wedgwood, the Rev. F. Farrar, and Prof. 
Schleicher,* and the celebrated lectures of Prof. Max Miil- 
ler on the other side, I cannot doubt that language owes its 
origin to the imitation and modification of various natural 
sounds, the voices of other animals and man's own instinctive 
cries, aided by signs and gestures. When we treat of sexual 
selection we shall see that primeval man, or rather some 
early progenitor of man, probably first used his voice in 
producing true musical cadences, that is in singing, as do 
some of the gibbon-apes at the present day; and we may 
conclude from a widely-spread analogy, that this power 
would have been especially exerted during the courtship of 
the sexes — would have expressed various emotions, such as 
love, jealousy, triumph — and would have served as a chal- 
lenge to rivals. It is, therefore, probable that the imita- 
tion of musical cries by articulate sounds may have given 
rise to words expressive of various complex emotions. The 
strong tendency in our nearest allies, the monkeys, in 
microcephalous idiots, f and in the barbarous races of man- 
kind, to imitate whatever they hear deserves notice, as 
bearing on the subject of imitation. Since monkeys cer- 
tainly understand much that is said to them by man, and 
when wild utter signal-cries of danger to their fellows; \ 
and since fowls give distinct warnings for danger ou the 
ground, or in the sky from hawks (both, as well as a third 

* " On the Origin of Language," by H. Wedgwood, 1866. " Chap- 
ters on Language," bj- the Rev. 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. Schleicher has been translated by Dr. Bikkers into En- 
glish, under the title of "Darwinism tested by the Science of Lan- 
guage," 1869. 

fVogt, "Memoire sur les Microcephales," 1867, p. 169. With 
respect to savages, I have given some facts in my "Journal of Re- 
searches," etc., 1845, p. 206. 

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


cry, intelligible to dogs*), may not some unusually wise 
ape-like animal have imitated the growl of a beast of prey, 
and thus told his fellow-monkeys the nature of the expected 
danger? This would have been a first step in the forma- 
tion 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 wouldf 
have reacted on the power of speech. But the relation be- 
tween the continued use of language and the development 
of the brain, has no doubt been far more important. The 
mental powers in some early progenitor of man must have 
been more highly developed than in any existing ape, 
before even the most imperfect form of speech could have 
come into use; but we may confidently believe that the 
continued use and advancement of this power would have 
reacted on the mind itself, by enabling and encouraging it 
to carry on long trains of thought. A complex train of 
thought can no more be carried on without the aid of 
words, whether spoken or silent, than a long calculation 
without the use of figures or algebra. It appears, also, 
that even an ordinary train of thought almost requires, or 
is greatly facilitated by some form of language, for the 
dumb, deaf, and blind girl, Laura Bridgman, was observed 
to use her fingers while dreaming, f Nevertheless, a long 
succession of vivid and connected ideas may pass through 
the mind without the aid of any form of language, as we 
may infer from the movements of dogs during their 
dreams. We have, also, seen that animals are able to 
reason to a certain extent, manifestly without the aid of 
language. The intimate connection between the brain, as 
it is now developed in us, and the faculty of speech, is 
well shown by those curious cases of brain-disease in which 
speech is specially affected, as when the power to remem- 
ber substantives is lost, while other words can be correctly 
used, or where substantives of a certain class, or all 
except the initial letters of substantives and proper 

* Houzeau ^ives a very curious account of his observations on this 
subject in bis " Facultes Mentales des Animaux," torn, ii, p. 348. 

f See remarks on this bead by Dr. Maudsley, **Tlie Physiology 
and Pathology of Mind,'-' 2d edit.. 186^1 d. 199. 


names are forgotten. * There is no more improbability m 
continued use of the mental and vocal organs leading to 
inherited changes in their structure and functions, than in 
the case of handwriting, which depends partly on the form 
of the hand and partly on the disposition of the mind; and 
handwriting is certainly inherited, f 

Several writers, more especially Prof. Max Miiller,]; havo 
lately insisted that the use of language implies the power of 
forming general concepts; and that as no animals are sup- 
posed to possess this power, an impassable barrier is formed 
between them and man.§ With respect 'to animals, I have 
already endeavored to show that they have this power, at 
least in a rude and incipient degree. As far as concerns 
infants of from ten to eleven months old, and deaf-mutes, 
it seems to me incredible that they should be able to con- 
nect certain sounds with certain general ideas as quickly as 
they do, unless such ideas were already formed in their 
minds. The same remark may be extended to the more 
intelligent animals; as Mr. Leslie Stephen observes,] '^A 

* Many curious cases have been recorded. See, for instance, Dr. 
Bateman, "On Aphasia," 1870, pp. 27, 31, 53, 100, etc. Also, "In- 
quiries Concerning the Intellectual Powers," by Dr. Abercrombie, 
1838, p. 150. 

f '• The Variation of Animals and Plants under Domestication," 
vol. ii, p. 6. 

X Lectures on "Mr. Darwin's Philosophy of Language,*' 1873. 

§The judgment of a distinguished philologist, such as Prof. Whit- 
ney, will have far more weight on this point than anything that I 
can say. He remarks (" Oriental and Linguistic Studies," 1873, p. 
297), in speaking of Bleek's views: "Because on the grand scale 
language is the necessary auxiliary of thought, indispensable to the 
development of the power of thinking, to the distinctness and variety 
and complexity of cognitions to the full mastery of consciousness; 
therefore he would fain make thought absolutely impossible without 
speech, identifying the faculty with its instrument. He might just 
as reasonably assert that the human hand cannot act without a tool. 
With such a doctrine to start from, he cannot stop short of Miiller's 
worst paradoxes, that an infant {in fans, not speaking) is not a 
human being, and that deaf-mutes do not become possessed of reason 
until they learn to twist their fingers into imitation of spoken 
words." Max Miiller gives in italics (" Lectures on Mr. Darwin's 
Philosophy of Language," 1873, third lecture) the following aphor- 
ism: " There is no thought without words, as little as there are 
words without thought." What a strange definition must here be 
given to the word thought. 
, \ " Essays on Free-thinking," etc., 1873, p. 83. 


dog frames a general concept of cats or sheep, and knows 
the corresponding words as well as a philosopher. And the 
capacity to understand is as good a proof of vocal intelli- 
gence, though in an inferior degree, as the capacity to 

Why the organs now used for speech should have been 
originally perfected for i\n.z purpose, rather than any other 
organs, it is not difficult to see. Ants have considerable 
powers of intercommunication, by means of their antennae, 
as shown by Huber, who devotes a whole chapter to their 
language. AVe might have used our fingers as efficient in- 
struments, for a person with practice can report to a deaf man 
every word of a speech rapidly delivered at a public meeting; 
but the loss of our hands while thus employed would have 
been a serious inconvenience. As all the higher mammals 
possess vocal organs, constructed on the same general plan as 
ours, and used as a means of communication, it was ob- 
viously probable that these same organs would be still further 
developed if the power of communication hadto be improved; 
and this has been effected by the aid of adjoining and well 
adapted parts, namely, the tongue and lips.* The fact of 
the higher apes not using their vocal organs for speech, no 
doubt depends on their intelligence not having been suffi- 
ciently 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 only for croak- 
ing, t If it be asked why apes have not had their intellects 
developed to the same degree as that of man, general causes 
only can be assigned in answer, and it is unreasonable to 
expect anything more definite, considering our ignorance 

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

f Macgillivray, "Hist, of British Birds," vol. ii, 1839, p. 29. An 
excellent observer, Mr. Black wall, remarks that the magpie learns to 
pronounce single words, and even short sentences, more readily than 
almost any other British bird: yet, as he adds, after long and closely 
investigating its habits, he has never known it, in a state of nature, 
display any unusual capacity for imitation. ** Researches in Zool» 
ogy," 1834, p. 158. 

102 THE DESGEm Ot" MAN, 

with respect to the successive stages of development through 
which each creature has passed. 

The formation- of different languages and of distinct 
species, and the proofs that both have been developed 
through a gradual process, are curiously parallel. * But we 
can trace the formation of many words further back than 
that of species, for we can perceive how they actually arose 
from the imitation of various sounds. We find in distinct 
languages striking homologies due to community of de- 
scent, and analogies due to a similar process of formation. 
The manner in which certain letters or sounds change 
when others change is very like correlated growth. We 
have in both cases the reduplication of parts, the eUects of 
long-continued use, and so forth. The frequent preeence 
of rudiments, both in languages and in species, is still more 
remarkable. The letter m in the word am, means /; so 
that in the expression / am, a superfluous and useless rudi- 
ment has been retained. In the spelling also of words, let- 
ters often remain as the rudiments of ancient forms of pro- 
nunciation. Languages, like organic beings, can be classed 
in groups under groups; and they can be classed either nat- 
urally according to descent, or artificially by other charac- 
ters. 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 0. Lyell 
remarks, reappears. The same language never has two 
birth-places. Distinct languages may be crossed or blended 
together.! 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 lan- 
guages, gradually become extinct. As Max MiillerJ has 
well remarked: '^ A struggle for life is constantly going on 
among the words and grammatical 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 

* See the very interesting parallelism between the development of 
species and languages, given by Sir C. Lyell in " The Geolog. Evi- 
dences of the Antiquity of Man," 1863, chap, xxiii. 

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

X " Nature," Jan. 6, 1870, p. 257. 


the survival of certain words mere novelty and fashion may 
be added; for there is in the mind of man a strong love for 
slight changes in all things. The survival or preservation 
of certain favored words in the struggle for existence is 
natural selection. 

The perfectly regular and wonderfully complex 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 civiliza- 
tion of their founders. Thus F. von Schlegel writes: *^In 
those languages which appear to be at the lowest grade of 
intellectual culture, we frequently observe a very high and 
elaborate degree of art in their grammatical structure. This 
is especially the case with the Basque and the Lapponian, 
and many of the American languages.^^* 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. Philol- 
ogists now admit that conjugations, declensions, etc., 
originally existed as distinct words, since joined together ; 
p,nd as such words express the most obvious relations be- 
t>veen objects and persons, it is not surprising that they 
should have been used by the men of most races during the 
earliest ages. With respect to perfection, the following 
illustration will best show hoAV easily we may err; a Crinoid 
sometimes consists of no less than 150,000 pieces of shell, f 
all arranged with perfect symmetry in radiating lines; but 
a naturalist does not consider an animal of this kind as 
more perfect than a bilateral one with comparatively few 
parts, and with none of these parts alike, excepting on the 
opposite sides of the body. He justly considers the differ- 
entiation and specialization of organs as the test of perfec- 
tion. So with languages; the most symmetrical and com- 
plex ought not to be ranked above irregular, abbreviated, 
and bastardized languages, which have borrowed expressive 
words and useful forms of construction from various con- 
quering, 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 

* Quoted by C. S Wake, *• Chapters on Man," 1868, p, 101 
f Buckland; ** Bridgewater Treatise/' p. 411. 


to a special act of creation.* Nor, as we have seen, does 
the faculty of articulate speech in itself offer any insuper- 
able objection to the belief that man has been developed 
from some lower form. 

8e7ise of Beauty. — This sense has been declared to be 
peculiar to man. I refer here only to the pleasure given by 
certain colors, forms and sounds, and which may fairly be 
called a sense of the beautiful; with cultivated men such 
sensations are, however, intimately associated with complex 
ideas and trains of thought. When we behold a male bird 
elaborately displaying his graceful plumes or splendid colors 
before the female, while other birds, not thus decorated, 
make no such display, it is impossible to doubt that she 
admires the beauty of her male partner. As women every- 
wher-e deck themselves with these plumes, the beauty of 
such ornaments cannot be disputed. As we shall see later, 
the nests of humming-birds, and the playing passages of 
bower-birds are tastefully ornamented with gayly-colored ob- 
jects; and this shows that they must receive some kind of pleas- 
ure from the sight of such things. With the great majority 
of animals, however, the taste for the beautiful is confined, 
as far as we can judge, to the attractions of the opposite 
sex. The sweet strains poured forth by many male birds 
during the season of love are certainly admired by the 
females, of which fact evidence will hereafter be given. If 
female birds had been incapable of appreciating the beauti- 
ful colors, the ornaments and voices of their male partners, 
all the labor and anxiety exhibited by the latter in display- 
ing their charms before the females would have been thrown 
away; and this it is impossible to admit. Why certain 
bright colors should excite pleasure cannot, I presume, be 
explained any more than why certain flavors and scents are 
agreeable; but habit has something to do with the result, 
for that which is at first unpleasant to our senses ultimately 
becomes pleasant, and habits are inherited. With respect 
to sounds, Helmholtz has explained to a certain extent on 
physiological principles why harmonies and certain cadences 
are agreeable. But besides this, sounds frequently recur- 
ring at irregular intervals are highly disagreeable, as every 

* See some good remarks on tlie simplification of languages, by 
Sir J. Lubbock, " Origin of Civilization," 1870, p. 278. 


one will admit who has listened at night to the irregular 
flapping of a rope on board ship. The same principle seems 
to come into play with vision, as the eye prefers symmetry 
or figures with some regular recurrence. Patterns of this 
kind are employed by even the lowest savages as ornaments; 
and they have been developed through sexual selection for 
the adornment of some male animals. Whether we can or 
not give any reason for the pleasure thus derived from vision 
and hearing, yet man and many of the lower animals are 
alike pleased by the same colors, graceful shading and 
forms, and the same sounds. 

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

Many of the faculties which have been of inestimable 
service to man for his progressive advancement, such as the 
powers of the imagination, wonder, .curiosity, an undefined 
sense of beauty, a tendency to imitation, and the love of 
excitement or novelty, could hardly fail to lead to capricious 
changes of customs and fashions. I have alluded to this 
point because a recent writer* has oddly fixed on Caprice 
'' as one of the most remarkable and typical differences be- 
tween savages and brutes." But not only can we partially 
understand how it is that man is from various conflicting 
influences rendered capricious, but that the lower animals 
are, as we shall hereafter see, likewise capricious in their 
affections, aversions, and sense of beauty. There is also 
reason to suspect that they love novelty for its own sake. 

Belief in God — Religion. — There is no evidence that 
man was aboriginally endowed with the ennobling belief in 

* " The Spectator," Dec. 4, 1869, p. 1430. 


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

If, however, we include under the term *' religion " the 
belief in unseen or spiritual agencies, the case is wholly 
different; for this belief seems to be universal with the less 
civilized races. Nor is it difficult to comprehend how it 
arose. As soon as the important faculties of the imagina- 
tion, wonder, and curiosity, together with some power of 
reasoning, had become partially developed, man would 
naturally crave to understand what was passing around him, 
and would have vaguely speculated on his own existence. 
As Mr. McLennan \ 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 hypothe- 
sis, and the first to occur to men, seems to have been that 
natural phenomena are ascribable to the presence in 
animals, plants, and things, and in the forces of nature, of 
such spirits prompting to action as men are conscious they 
themselves possess." It is also probable, as Mr. Tylor has 
shown, that dreams may have first given rise to the notion 
of spirits; for savages do not readily distinguish between 
subjective and objective impressions. When a savage 
dreams, the figures which appear Before him are 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." J But 

* See an excellent article on tliis subject by tlie Rev. F. W. Farrar, 
in the "Anthropological Review," Aug., 1864, p. 217. For fur- 
ther facts see Sir J. Lubbock, "Prehistoric Times," 2d edit., 1869, p. 
564; and especially the chapters on Religion in his " Origin of Civil- . 
ization," 1870. 

f " The Worship of Animals and Plants," in the " Fortnightly Re- 
view," Oct. 1, 1869, p. 422. 

J Tylor, "Early History of Mankind," 1865, p. 6. See also the 
three striking chapters on the Development of Religion, in Lub- 
]t?0Ck'8 " Origin of Civilization," 1870. In a like manner Mr. Herbert 


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

The tendency in savages to imagine that natural objects 
and agencies are animated by spiritual or living essences, is 
perhaps illustrated by a little fact which I once noticed: 
my dog, a full-grown and very sensible animal, was lying 
on the lawn during a hot and still day; but at a little dis- 
tance 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 par- 
asol 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 that no stranger had a right to be on his territory. 

The belief in spiritual agencies would easily pass into the 
belief in the existence of one or more gods. For savages 
would naturally attribute to spirits the same passions, the 
tsame love of vengeance or simplest form of justice, and the 
same affections which they themselves feel. The Fuegians 
appear to be in this respect in an intermediate condition, 
for when the surgeon on board the ^^ Beagle ^^ shot some 
young ducklings as specimens York Minster declared in 
the most solemn manner: ^^ Oh, Mr. Bynoe, much rain, 
much snow, blow much;" and this was evidently a retribu- 
tive punishment for wasting human food. So again he 
related how, when his brother killed a "wild man," storms 
long raged, much rain and snow fell. Yet we could never 

Spencer, in liis ingenious essay in the " Fortnightly Review " (May 
t, 1870, p. 535), accounts for tlie earliest forms of religious belief 
tlirougliout 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 propitiated by various gifts and ceremonies, 
and its aid invoked. He then further shows that names or nick- 
nan\es given from some animal or other object, to the early progeni- 
tors or founders of a tribe, are supposed after a long interval to rep- 
resent the real progenitor of the tribe; and such animal or object is 
then naturally believed still to exist as a spirit, is held sacred, and 
worshiped 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 gf 
life, and with mental faculties analogous to our own. 


discover that the Fuegians believed in what we should call a 
God or practiced 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 remark- 
able, as with savages the belief in bad spirits is far more 
common than that in good ones. 

The feeling of religious devotion is a highly complex 
one, consisting of love, complete submission to an exalted 
and mysterious superior, a strong sense of dependence,* 
fear, reverence, gratitude, hope for the future, and per- 
haps other elements. No being could experience so com- 
plex an emotion until advanced in his intellectual and 
moral faculties to at least a moderately high level. K"ever- 
theless, 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 behavior of a dog when returning to his master after 
an absence, and, as I may add, of a monkey to his beloved 
keeper, is widely different from that toward their fellows. 
In the latter case the transports of joy appear to be some- 
what less, and the sense of equality is shown in every 
action. Prof. Braubach goes so far as to maintain that a 
dog looks on his master as on a god.f 

The same high mental faculties which first led man to 
believe in unseen spiritual agencies, then in fetichism, 
polytheism, and ultimately in monotheism, would infallibly 
lead him, as long as his reasoning powers remained poorly 
developed, to various strange superstitions and customs. 
Many of these are terrible to think of — such as the sacrifice 
of human beings to a blood-loving god; the trial of inno- 
cent persons by the ordeal of poison or fire, witchcraft, 
etc. — ^yet it is well occasionally to reflect on these supersti- 
tions, for they show us what an infinite debt of gratitude 
we owe to the improvement of our reason, to science, and 
to our accumulated knowledge. As Sir J. LubbockJ has 

* See an able article on the "Physical Elements of Religion," by 
Mr. L. Owen Pike, in " Anthropolog. Review," April, 1870, p. 63. 

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

:}:" Prehistoric Times," 2d edit., p. 571. In this work (p. 571) 
there will be found an excellent account of the many strange an4 
capricious customs of savages. 


well observed, " it is not too much to say that the horrible 
dread of unknown evil hangs like a thick cloud over savage 
life and embitters every pleasure." These miserable and 
indirect consequences of our highest faculties may be com- 
pared with the incidental and occasional mistakes of the 
instincts of the lower animals. 




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 alona re- 
garded by savages — The self- regarding virtues acquired at a 
later stage of development — The importance of the judgment of 
the members of the same community on conduct — Transmission 
of moral tendencies — Summary. . 

I FULLY subscribe to tlie judgment of those writers* 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 Mackintosh f remarks, 
" has a rightful supremacy oyer every other principle of 
human action;"' it is summed up in that short but imperi- 
ous 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 1 Wondrous 
thought, that workest neither by fond insinuation, flattery, 
nor by any threat, but merely by holding up thy naked law 
in the soul, and so extorting for thyself always reverence, if 
not always obedience; before whom all appetites are dumb, 
however secretly they rebel; whence thy original?" J 

* See, for instance, on this subject, Quatrefages, ** Unit6 de TEs- 
p^ce Humaine," 1861, p. 21, etc. 

f ''Dissertation on Ethical Philosophy," 1837, p. 231, etc. 

X •' Metaphysics of Ethics," translated by J. W. Semple, Edin- 
burgh, 1836, p. 136. 


This great question has been discussed by many writers * 
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 approached it exclusively from 
the side of natural iiistory. The investigation possesses, 
also, some independent interest, as an attempt to see how 
far the study of the lower animals throws light on one of 
the highest psychical facuicies of man. 

The following proposition seems to me in a high degree 
probable — namely, that any animal whatever, endowed with 
well-marked social instincts,! the parental and filial affec- 
tions being here included, would inevitably acquire a 
moral sense or conscience, as soon as its intellectual powers 
had become as well, or nearly as well developed, as in man. 
For, firstly f the social instincts lead an animal to take 
pleasure in the society of its fellows, to feel a certain 
amount of sympathy with them, and to perform various 
services for them. The services may be of a definite and 
evidently instinctive nature , or there may be only a wish 

*Mr, Bain gives a list('' Mental and Moral Science," 1868, pp. 543- 
725) of twenty-six British autliors 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, Sir J. 
Lubbock and others, might be added. 

f Sir B. Brodie, after observing that man is a social animal (•' Psy- 
chological Enquiries," 1854, p. 192), asks the pregnant question, 
'* ought dot this to settle the disputed questioja as to the existence of 
a moral sense?" Similar ideas have probably occurred to many per- 
sons, as they did long ago to Marcus Aurelius. Mr. J. S. Mill 
speaks, in his celebrated work, ** Utilitarianism," (1864, pp. 45, 46), 
of the social feelings as a '* powerful natural sentiment," and as *' the 
natural basis of sentiment for utilitarian morality." Again he says, 
*' Like the other acquired capacities above referred to, the moral 
faculty, if not a part of our nature, is a natural outgrowth from it, 
capable, like them, in a certain small degree of springing up sponta- 
neously." But in opposition to all this, he also remarks, " if, as is 
my own belief, the moral feelings are not innate, but acquired, they 
are not for that reason less natural." It is with hesitation that I 
venture to differ at all from so profound a thinker, but it can hardly 
be disputed that the social 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. The ignoring of all transmitted mental 
qualities will, as it seems to me, be hereafter judged as a irost serious 
blemish i» th« wmr^- of Mr. M U- 


and readiness, as with most of the higher social animals, to 
aid their fellows in certain general ways. But these feel- 
ings and services are by no means extended to all the indi- 
viduals of the same species, only to those of the same asso- 
ciation. Secondly, as soon as the mental faculties had 
become highly developed, images of all past actions and 
motives would be incessantly passing through the brain of 
each individual; and that feeling of dissatisfaction, or even 
misery, which invariably results, as we 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 impression. 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 recalled. Thirdly ^ after the power of 
language had been acquired, and the wishes of the commu- 
nity could be expressed, the common opinion how each 
member ought to act for the public good, would naturally 
become in a paramount degree the guide to action. But it 
should be borne in mind that however great weight we may 
attribute to public opinion, our regard for the approbation 
and disapprobation of our fellows depends on sympathy, 
which, as we shall see, forms an essential part of the social 
instinct, and is indeed its foundation-stone. Lastly, habit 
in the individual would ultimately play a very important 
part in guiding tlie*conduct of each member; for the social 
instinct, together with sympathy, is, like any other instinct, 
greatly strengthened by habit, and so consequently would 
be obedience to the wishes and judgment of the community. 
These several subordinate propositions must now be discussed, 
and some of them at considerable length. 

It may be well first to premise that I do not wish to 
maintain that any strictly social animal, if its intellectual 
faculties were to become as active and as highly developed 
as in man, 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 different lines of conduct. 
If, for instance, to take an extreme case, men were reared 
under precisely the same conditions as hive-bees, there can 


hardly be a doubt that our unmarried females would, like 
the worker-bees, think it a sacred duty to kill their 
brothers, and mothers would strive to kill their fertile 
daughters; and no one would thinK: of interfering. * Niver- 
theless, the bee, or any other social animal, would gain in 
our supposed case, as it appears to me, some feeling of 
right or wrong, or a conscience. For each individual 
would have an inward sense of possessing certain strouger 
or more enduring instincts, and others less strong or 
enduring; so that there would often be a struggle as to 
which impulse should be followed; and satisfaction, dissat- 
isfaction, or even misery would be felt, as past impressions 
were compared during their incessant passage through the 
mind. In this case an inward monitor would tell the 
animal that it would have been better to have followed the 
one impulse rather than the other. The one course ought 
to have been followed, and the other ought not; bhe one 
would have been right and the other wrong; but to these 
terms I shall recur. 

Sociability. — Animals of many kinds are social; we find 
even distinct species living together; for example, somo 
American monkeys; and united flocks of rooks, jackdaws 
and starlings. Man shows the same feeling in his strong 
love for the dog, which the dog returns with interest. Every 
one must have noticed how miserable horses, dogs, sheep, 
etc., are when separated horn, their companion:;, and what 

* Mr. H. Sidgwick remarks, in an able discussion on this subject 
(tlie "Academy," June 15, 1872, p, 231), * a superior bee, we may 
feel sure, would aspire to a milder solution of the population ques- 
tion." Judging, however, from the habits of many or most savages, 
man solves the problem by female infanticide, polyandry and pro- 
miscuous intercourse, therefore it may well be doubted whether it 
w»uld be by a milder method. Miss Cobbe, in commenting (" Darwin- 
ism in Morals," ''Theological Review," April, 1872, pp. 188-191) on 
the same illustration, says, the principles of social duty would be 
thus reversed; and by this, I presume, she means that the fulfill- 
ment of a social duty would tend to the injury of ndivlduals; but 
she overlooks the fact, which she would doubtless idmii, tha^ tho 
instincts of the bee have been acquired for fcho good 3f tho commu- 
nity. She goes so far as to say that if the theory 3f ethics -lidvocated 
in this chapter were ever generally accepted, ' '■ I cannot but believe 
that in the hour of iheir triumph would be sounded tho knell of ths 
virtue of mankind." It is to be hoped that the belief m xhe perma- 
nence of virtue on this earth is not held by many persons on so weak 
a tenure. 


strong mutual affection the two former kinds, at least, 
show on their reunion. It is curious to speculate on the 
feelings of a dog, who will rest peacefully for hours in a 
room with his master or any of the family, without the least 
notice being taken of him; but if left for a short time by 
himself, barks or howls dismally. We will confine our at- 
tention to the higher social animals, and pass over insects, 
although some of these are social, and aid one another in 
many important ways. The most common mutual service 
in the higher animals is to warn one another of danger by 
means of the united senses of all. Every sportsman knows, 
as Dr. Jaeger remarks,* 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 of them who first discovers an enemy, warns the others. 
Eabbits stamp loudly on the ground with their hind feet as 
a signal ; sheep and chamois do the same with their fore 
feet, uttering likewise a whistle. Many birds and some 
mammals, post sentinels, which in the case of seals are saidf 
generally to be the females. The leader of a troop of mon- 
keys acts as the sentinel, and utters cries expressive both of 
danger and of safety. | Social animals perform many little 
services for each other; horses nibble, and cows lick each 
other, on any spot which itches; monkeys search each other 
for external parasites; and Brehm states that after a troop 
of the CercopWiecus griseo-viridis has rushed through a 
thorny brake, each monkey stretches itself on a branch, 
and another monkey sitting by, *' conscientiously " examines 
its fur> and extracts every thorn or burr. 

Animals also render more important services to one 
another; thus wolves and some other beasts of prey hunt in 
packs, and aid one another in attacking their victims. Peli- 
cans fish in concert. The Hamadryas baboons turn over 
stones to find insects, etc. ; and when they come to a large 
one, as many as can stand round, turn it over together and 

* " Die Darwin'sche Theorie/' s. 101. 

•(•Mr. R. Brown in ^'Proc. Zoolog. Soc," 1868, p. 409. 

^ Brehm, '■' Thierleben," B. i, 1864, s. 52, 79. For tlie case of the 
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 eaglOi 6. 56. 


share the booty. Social animals mutually defend each other. 
Bull bisons in North America, when there is danger, drive 
the cows and calves into the middle of the herd, while they 
defend the outside. I shall also in a future chapter give an 
account of two young wild bulls at Ohillingham attacking 
an old one in concert, and of two stallions together trying 
to drive away a third stallion from a troop of mares. In 
Abyssinia, Brehm encountered a great troop of baboons 
who were crossing a valley ; some had already ascended 
che opposite mountain, and some were still in the valley; 
the latter were attacked by the dogs, but the old males im- 
mediately hurried down from the rocks, and with mouths 
widely opened, roared so fearfully that the dogs quickly 
drew back. They were again encouraged to the attack; but 
by this time all the baboons had reascended the heights, 
excepting a young one about six months old, who, loudly 
calling f or -jid, climbed on a block of rock and was sur- 
rounded. jS'ow 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 Oercopithecus, 
which, by clinging to a branch, was not at once carried off; 
it cried loudly for assistance, upon which the other mem- 
bers 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 n6ver again 
attack a single monkey of a troop. * 

It is certain that associated animals have a feeling of love 
for each other which is not felt by non-social adult animals. 
How far in most cases they actually sympathize in the pains 
and pleasures of others is more doubtful, especially with 
respect to pleasures. Mr, Buxton, however, who had excel- 
lent means of observation, f states that his macaws, which 

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

f" Annals of Mag. of Nat. Hist.," Nov., 1868, p. 383, 


lived free in Norfolk, took '' an extravagant interest" in a 
pair with a nest; and whenever the female left it she was 
Burrounded by a troop '^ screaming horrible acclamations in 
her honor/' It is often difficult to judge whether animals 
have any feeling for the sufferings of others of their kind. 
Who can say what cows feel when they surround and stare 
intently on a dying or dead companion; apparently, how- 
ever, as Houzeau remarks, they feel no pity. That animals 
sometimes are far from feeling any sympathy is too certain; 
for they will expel a wounded animal from the herd, or. 
gore or worry it to death. This \«, almost the blackest fact 
in natural history, unless, indeed, the explanation which 
has been suggested is true, that their instinct or reason 
leads them to expel an injured companion, lest beasts of 
prey, including man, should bo 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 com- 
rades to perish on the plains; or the Fijiarv*?^ who, when 
their parents get old, or fall ill, bury them alive.* 

Many animals, however, certainly sympathize with each 
other's distress or danger. This is the case even with birds. 
Capt. Stansburyf found on a salt lake in Utah an old 
and completely blind pelican, which was very fat, and 
must have been well fed for a long time by his companions. 
Mr. Blyth, as he informs me, saw Indian crows feeding two 
or three of their companions which were blind; and I have 
heard of an analogous case with the domestic cock. We 
may, if we choose, call these actions instinctive; but such 
cases are much too rare for the development of any special 
instinct.]; I have myself seen a dog, who never passed 
a cat who lay sick in a basket, and was a great friend of his, 
without giving her a few licks with his tongue, the surest 
sign of kind feeling in a dog. 

It must be called sympathy that leads a courageous dog 
to fly at any one who strikes his master, as he certainly will. 

»Sir .J. Lubbock, ^'Prehistoric Times," 2d edit., p. 446. 

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

X As Mr. Bain states, " effective aid to a sufferer springs from 
sympathy proper." "Mental and Moral Science," 1868, p 245. 


I saw a person pretending to beat a lady, who had a very 
timid little dog on her lap, and the trial had never been 
made before; the little creature instantly jumped away, but 
after the pretended beating was over, it was really pathetic 
to see how perseveringly he tried to lick his mistress^ face, 
and comfort her. Brehm * states that when a baboon in 
confinement was pursued to be punished, the others tried 
to protect him. It must have been sympathy in the cases 
above given which led the baboons and Cercopitheci to 
defend their young comrades from the dogs and the eagle. 
I will give only one other instance of sympathetic and 
heroic conduct, in the case of a little American monkey. 
Several years ago a keeper at the Zoological Gardens showed 
me some deep and scarcely healed wounds on the nape 
of his own neck, inflicted on him, while 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 in 
peril, he rushed to the rescue, and by screams and bites so 
distracted the baboon that the man was able to escape, 
after, as the surgeon thought, running great risk of his 

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

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

* " Thierleben," B. i, s. 85. 

t " De I'Espece et de la Classe," 1869, p. 97. 

^ " Die Dwrwiu'scbe An-Lehre," 1809, s, 54, 


prevent their sinking deeper in the mud; and the driver 
was dreadfully afraid lest the animal should have seized 
Dr. Hooker and crushed him to death. But the driver 
himself, as Dr. Hooker was assured, ran no risk. This for- 
bearance, under an emergency so dreadful for a heavy 
animal, is a wonderful proof of noble fidelity. * 

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

With respect to the impulse which leads certain animals 
to associate together, and to aid one another in many ways, 
we may infer that in most cases they are impelled by the 
same sense of satisfaction or pleasure which they experi- 
ence in performing other instinctive actions ; or by the 
same sense of dissatisfaction as when other instinctive 
actions are checked. We see this in innumerable instances 
and it is illustrated in a striking manner by the acquired 
instincts of our domesticated animals; thus a young shep- 
herd-dog delights in driving and running round a flock of 
sheep, but not in worrying them ; a young fox-hound 
delights in hunting a fox, while some other kinds of dogs, 

*See also Hooker's "Himalayan Journals," vol. ii, 1854, p. 333. 
fBrehm, * * Thierleben, " B. i, s. 76. 

XSee his extremely interesting paper on " Gregariousness in Cat- 
tle and in Man," * ' Macmillan's Mag.," Feb., 1871; p. 353. 


as I have witnessed, utterly disregard foxes. What a 
strong feeling of inward satisfaction must impel a bird so 
full of activity, to brood day after day over her eggs. 
Migratory birds are quite miserable if stopped from migra- 
ting; perhaps they enjoy starting on their long flight; but 
it is hard to believe that the poor pinioned goose, described 
by Audubon, which started on foot at the proper time for 
its Journey of probably more than a thousand miles, could 
have felt any joy in doing so. Some instints are determined 
solely by painful feelings, as by fear, which leads to self- 
preservation, and is in some cases directed toward special 
enemies. No one, I presume, can analyze the sensations 
of pleasure or pain. In many instances, however, 
it is probable that instincts are persistently followed 
from the mere force of inheritance, without the stimulus 
of either pleasure or pain. A young pointer, when it first 
scents game, apparently cannot help pointing. A squirrel 
in a cage who pats the nuts which it cannot eat, as if to 
bury them in the ground, can hardly be thought to act 
thus, either from pleasure or pain. Hence the common 
assumption that men must be impelled to every action by 
experiencing some pleasure or pain may be erroneous. 
Although a habit may be blindly and 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 experienced. 

It has often been assumed that animals were in the first 
place rendered social, and that they feel as a consequence 
uncomfortable when separated from each other, and com- 
fortable while together; but it is a more probable 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 tlie 
parental or filial affections, since the social instinct seems 
to be developed by the young remaining for a long time 
with their parents; and this extension may be attributed in 
part to habit, but chiefly to natural selection. With those 
animals which were benefited by living in close association, 
the individuals which took the greatest pleasure in society 
would best escape various dangers, while those that cared 


least for their comrades, and lived solitary, would perish in 
greater numbers. With respect to the origin of the parental 
and filial aifections, which apparently lie at the base of the 
social instincts, we know not the steps by which they have 
been gained; but we may infer that it has been to a large 
extent through natural selection. So it has almost cer- 
tainly been with the unusual and opposite feeling of hatred 
between the nearest relations, as with the worker-bees 
which kill their brother drones, and with the queen bees 
which kill their daughter queens; the desire to destroy 
their nearest relations having been in this case of service to 
the community. Parental affection, or some feeling which 
rejilaces it, has been developed in certain animals extremely 
low in the scale, for example, in star-fishes and spiders. 
It is also occasionally present in a few members alone in a 
whole group of animals, as in the genus Eorficula, or 

The all-important emotion of sympathy is distinct from 
that of love. A mother may passionately love her sleep- 
ing and passive infant, but she can hardly at such times 
be said to feel sympathy for it. The love of a man for 
his dog is distinct from sympathy, and so is that of a dog 
for his master. Adam Smith formerly argued, as has 
Mr. Bain recently, that the basis of sympathy lies in our 
strong retentiveness of former states of pain or pleasure. 
Hence, ^^tlie sight of another person enduring hunger, 
cold, fatigue, revives in us some recollection of the 
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.* 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. 

* See the first and striking chapter in Adam Smitli's " Theory of 
Moral Sentiments." Also Mr. Bain's "Mental and Moral Science," 
1868, pp. 244 and 275-282. Mr. Bain states, that '* sympathy is, in- 
directly, a source of pleasure to the sympathizer;" and he accounts 
for this through reciprocity. He remarks that "the person bene- 
fited, 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 
ftlmost every other instinct. 


The mere si^lit of suffering, independently of love, would 
STiffice to call up in us vivid recollections iind associations. 
The explanation may lie in the fact that, with all animals, 
Bympathy is directed solely toward the members of the same 
community, and therefore toward known and more or less 
beloved members, but not to all the individuals of the same 
species This fact is not more surprising than that the 
fears of many animals should be directed against special 
enemies. Species which are not social, such as lions and 
tigers, no doubt feel sympathy for the suffering of their own 
young, but not for that of any other aniinal. AVith man- 
kind selfishness, experience, and imitation, probably add, 
as ^Ir. Bain has shown, to the power of sympathy; for we 
are led by the hope of receiving good in return to perform 
acts of sympathetic kindness to others; and sympathy is 
much strengthened by habit. In however complex a 
manner this feeling may have originated, as it is one of high 
importance to all those animals which aid and defend one 
another, it will have been increased through natural selec- 
tion; for those communities, which included the greatest 
number of the most sympathetic members, would llcurish 
best and rear the greatest number of oifspring. 

It is, however, impossible to decide in many cases v\rhethcr 
certain social instincts have been acquired through natural 
selection, or are the indirect result of other instincts and 
faculties, such as sympathy, reason, experience, and a ten- 
dency to imitation; or again, whether they arc simply the 
result of long-continued habit. So remarkable an instinct 
as the placing sentinels to warn the community of danger 
can hardly have been the indirect result of any of these 
faculties; it must, therefore, have been directly acquired. 
On the o.ther hand, the habit followed by the males of some 
social animals of defending the community, and of attack- 
ing 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 pleas- 
ure in their performance, and more distress in their pre- 
vention, than others; or, which is probably quite as impor- 
tant, they are, through inheritance, more persistently 
followed, without exciting aay special feeling of pleasuio 


or pain. We are ourselves conscious that somo habits are 
much more dilticult to cure or change than others, llenco 
a struggle may often be observed in animals between dif- 
ferent 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 
young puppies and for her master — for she may be seen to 
slink away to them as if half-ashamed of not accompanying 
her master. But the most curious instance known to me of 
one instinct getting the better of another, is the migratory 
instinct conquering the maternal instinct. The former is 
wonderfully strong ; a confined bird will at the proper 
season beat her breast against the wires of her cage until 
it is bare and bloody. It causes young salmon to leap out 
of the fresh water, in which they could continue to exist, 
and thus unintentionally to commit suicide. Every one 
knows how strong the maternal instinct is, leading even 
timid birds to face great danger, though with hesitation, 
and in opposition to the instinct of self-preservation. 
Nevertheless, th? migratory instinct is so powerful that 
late in the autumn swallows, house-martins, and swifts fre- 
quently desert their tender young, leaving them to perish 
miserably in their nests.* 

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 num- 
bers. Whether this is the case with the migratory in com- 
parison with the maternal instinct, may be doubted. The 

* This fact, the Rev. L. Jenyns states (see his edition of " White's 
Nat. liist. of Selborne,'" 1853, p. 204) was first recorded by the illus- 
trious Jenner, in " Phil. Transact.," 1834, and has since been confirmed 
by several observers, especially by Mr. Blackwall. This latter care- 
ful observer examined, late in the autumn, during two years, thirty- 
six nests; he found that twelve contained young dead birds, five con- 
tained eggs on the pf)int of being hatclied, and three, eggs not nearly 
hatched. Many birds, not yet old enough for a prolonged flight, are 
likewise deserted anrl left beliind. See Blackwall, ** Researches in 
Z ;o!ogy." 1831, pp. 108, 118. For some additional evidence, although 
this is not wanted, see Leroy, " Lettres Phil.," 1802, p. 217. For 
swifts, Gould's "Introduction to the Birds of Great Britain," 1823, 
p. 5. Similar have been observed in Canada by Mr. Adamsj 
**Pop. Science Keview," July, 1873, p. 283. 


great persistence or steady action of the former at certain 
seasons of the year during the whole day, may give it for a 
time paramount force. 

Matt a Social Animal. — Every one will admit that man is 
a social being. We see this in his dislike of solitude, and 
in his wish for society beyond that of his own family. 
Solitary confinement is one of the severest punishments 
which can be inflicted. Some authors suppose that man 
primevally lived in single families; but at the present day, 
though single families,, or ojnly two or three together, roam 
the solitudes of some savage lands, they always, as far as I 
can discover, hold friendly relations with other families 
inhabiting the same district. Such families occasionally 
meet in council, and unite for their common defense. It 
is no argument against savage man being a social animal, 
that the tribes inhabiting 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 majority of the Quadrumana, it is 
probable that the early ape-like progenitors 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 extremely 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;* but 
our consciousness does not tell us whether they are instinct- 
ive, 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 almost certain that he would inherit a 
tendency to be faithful to his comrades and obedient to 
the leader of his tribe; for these qualities are common to 
most social animals. He would consequently possess some 
capacity for self-command. He Avould from an inherited 

*^ Hume remarks (' An Enquiry Concerning the Principles of 
Morals." eait. of 1751, p, 132), "Tbere seems a necessity for con- 
fessing that the bappinesii and misery of others are not' spectacles 
altogether indifferent to us, but thai the view of the former . , . 
communicates a secret joy; the appearance of the latter . , . 
tiiiows a melajjciioiy damp over the imagination." 


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

The More Endtiring Social Ins finds Conquer the Less Per- 
sistent Instincts. — We have not, however, as yet considered 
the main point, on which, from our present point of view. 

* '• Meutal and Moral Science," 1868, p. 254. 


the whole question of the moral sense turns. "Why should 
a man feel that he ought to obey one instinctive desire 
rather than another? Why is he bitterly regretful, if he 
has yielded to a strong sense of self-preservation, and has 
not risked his life to save that of a fellow -creature? or why 
does he regret having stolen food from hunger? 

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

I am aware that some persons maintain that actions per- 
formed 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 when 
prompted by some exalted motive. But it appears scarcely 
possible to draw any clear line of distinction of this kind.* 

* I refer here to the distinction between wliat has been called 
mate.rialaLr\f\ formal mnvi\\\ty. I am glacl to find that Prof. Huxley 
("Critiques and Addresses'" 1878, p. 287) takes the same view on 
this subject as I do. Mr. Leslie Stephen remarks ('* Essays on Free- 
thinking and Plain Speaking," 1873, p. 83), "the metaphysical dis- 
tinction, between material and formal morality is as irrevelant a« 
Other such distinctioiis." 


As far as exalted motives are concerned, many instances 
have been recorded of savages, destitute of any feeling of 
general benevolence toward mankind, and not guided by 
any religious motive, who have deliberately sacriticed their 
lives as prisoners,* 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, animals may be seen doubting between 
opposed instincts, in rescuing their offspring or comrades 
from danger; yet their actions, though aone for the good 
of others, are not called moral. Moreover, anything per- 
formed very often by us, will at last be done without 
deliberation or hesitation, and can then hardly be distin- 
guished from an instinct; yet surely no one will pretend 
that such an action ceases to be moral. On the contrary, 
we all feel that an act cannot be considered as perfect, or 
as performed in the most noble manner, unless it be done 
impulsively, without deliberation or effort, in the same 
manner as by a man in whom the requisite qualities are 
innate. He who is forced to overcome his fear or want of 
sympathy before he acts, deserves, however, in one way 
higher credit than the m.iin 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 aa 
moral, if 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 this capacity; therefore, when a Newfoundland dog 
drags a child out of the water, or a monkey faces danger to 
rescue its comrade, or takes charge of an orphan monkey, 
we do not call its conduct moral. But in the case of man, 
who alone can with certainty be ranked as a moral being, 
actions of a certain class are called moral, whether per- 
formed deliberately, after a struggle with opposing motives, 
or impulsively through instinct, or from the effects of 
slowly gained habit. 

But to return to our more immediate subject. Although 
some instincts are more powerful than others, and thus lead 
to corresponding actions, yet it is untenable, that in man 

*I have given one such case, namely, of three Patagonian Indians 
who preferred being shot, one after the other, to betraying the plans 
of tlieix compamons in war (" Journal of Kesearches," 1845, p. 103>. 


tho social instincts (including the love of praise and fear of 
blame) possess greater strength, or have, througn ".ong 
habit, acquired greater strength than the instincts ot self- 
preservation, hunger, lust, vengeance, etc. Why then does 
man regret, even though trying to banish such regret, that 
he has followed the one natural impulse rather than the 
other; and why does he further feel that he ought to regret 
his conduct? Man in this respect differs profoundly from 
the lower animals. Nevertheless we can, I think, Eee with 
some degree of clearness the reason of this difference. 

Man, from the activity of his mental faculties, cannot 
avoid reflection; past impressions and images are incessantly 
and clearly passing through his mind. Now with those 
animals which live permanently in a body, the social 
instincts are ever present and persistent. Such animals are 
always ready to utter the danger-signal, to defend the com- 
munity, and to give aid to their fellows in accordance with 
their habits; they feel at all times, Avithout the stimulus of 
any special passion or desire, some degree of love and sym- 
pathy for them; they are unhappy if long separated from 
them, and always happy to be again in their company. So 
it is with ourselves. Even when we are quite alone, how 
often do we think with pleasure or pain of what others 
think of us — of their imagined approbation or disapproba- 
tion; and this all follows from sympathy, a fundamental 
element of the social instincts, A man who possessed no 
trace of such instincts would be an unnatural monster. On 
the other hand, the desire to satisfy hunger, or any passion 
such as vengeance, is in its nature temporary, and can for a 
time be fully satisiied. Nor is it easy, perhaps hardly pos- 
sible, to call up with complete vividness the feeling, for 
instance, of hunger; nor indeed, as has often been remarked, 
of any suffering. The instinct of self preservation is not 
felt except in the presence of danger, and many a coward 
has thought himself brave until he has met his enemy face 
to face. The wish for another man's property is perhaps 
as persistent a desire as any that can be named- but even 
in this case the satisfaction of actual possession is generally 
a weaker feeling than the desire, many a thief, if not an 
habitual one. after success has wondered why he stole some 
article. * 

* Enmity or hatred seems also to be a Liglily persistent feeling-, 
perliaps more so than an> ctker that cau be uaaied Envy ie defined 


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

The above case of the swallow aft'ords an illustration, 
though of a reversed nature, of a temporary though for the 
time strongly persistent instinct conquering another in- 
stinct, which is usually dominant over all others. At the 
proper season these birds seem all day long to be impressed 
with the desire to migrate ; their habits change ; they 
become restless, are noisy and congregate in flocks. AVhile 
the mother-bird is feeding, or brooding over her nestlings, 
the maternal instinct is probably stronger than the migra- 
tory; but the instinct which is the 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 migratory 
instinct has ceased to act, what an agony of remorse the 
bird would feel if, from being endowed with great mental 

as hatred of anctlier for some excellence or success; and Bacon in- 
sists (Essay ix), *' Of all other affections envy is the most importune 
and continual." Dogs are very apt to hate both strange men and 
strange dogs, especially if they live near at hand, but do not belong 
to the same family, tribe, or clan; this feeling would thus seem to be 
innate, and is certainly a most persistent one. It seems to be the 
complement and converse of the true social instinct. From what we 
hear of savages, it would appear that something of the same kind 
holds good with them. If this be so. it would be a small step m any 
one to transfer such feelings to any member of the same tribe if he 
ba 1 done him an injury and had become his enemy. Kor is it 
probable that the primitive conscience would reproach a man for in- 
juring his enemy; rather it would reproach him, if he had not 
rev'enged himself. To do good in return for evil, to love your 
enemy, is a height of morality to which it may be doubted whether 
the social instincts would, by themselves, have ever led us. It is 
necessary that these instincts, togethei" with sympathy, should have 
been highly cultivated and extended by the aid ot reason, instruc- 
tion, and tlie love or Ukxv of God, before any suck golden rule would 
ever be thought of and obeved. 


activity, she could not prevent the image constantly passing 
through her mind of her young ones perishing in the bleak 
north from cold and hunger. 

At the moment of action man will no doubt be apt to 
follow ihe stronger impulse; and though tliis may occa- 
sionally prompt him to the noblest deeds, it will more com- 
monly lead him to gratify his own desires at the expense of 
ether men. But after their gratification, when past and 
weaker impressions are judged by the ever-enduring social 
instinct, and by his deep regard for the good opinion of 
his fellows, retribution will surely come. He vvill then 
feel remorse, repentance, regret or shame; this latter feel- 
ing, nowever, relates almost exclusively to the judgment of 
others. He will consequently resolve more or less lirmly 
to act differently for the future; and this is conscience; for 
conscience looks backward and serves as a guide for the 

The nature and strength of the feelings which we call 
regret, shame, repentance or remorse, depend apparently 
not only on the strength of the violated instinct, but partly 
on the strength of the temptation, and often still more on 
the Judgment of our fellows. How far each values 
the appreciation of others depends on the strength of his 
innate or acquired feeling of sympathy; and on his own 
capacity for reasoning out the remote consequences of his 
acts. Another element is most important, although not 
necessary, the reverence or fear of the gods, or spirits 
believed in by each man; and this applies especially in 
cases of remorse. Several critics have objected that 
tliough some slight res^ret or repentance may be explained 
by the view advocated in this chapter, it is impossible thus 
to account for the soul-shaking feeling of remorse. But I 
can see little force in this objection. My critics do not 
define what they mean by remorse, and 1 can find no defi- 
nition implying more than an overwhelming sense of 
repentance. Remorse seems to bear the same relation to 
rep3ntance as rage does to anger, or agony to pain. It is 
far from strange that an instinct so strong and so gener- 
ally admired, as maternal love, should, if disobeyed: lead to 
the deepest misery, as soon as the impression of the past 
cause of disobedience is weakened. Even when an action 
is opposed to no special instinct, merely to know that our 
friends and equals despise us for it, is enough to cause great 


misery. Who can doubt that the refusal to fight a duel 
through fear has caused many men an agony of shame? 
Many a Hindoo, it is said, has been stirred to the bottom 
of his soul by having partaken of unclean food. Here is 
another case of what must, I think, be called remorse. 
Dr. Landor acted as a magistrate in West Australia, and 
relates,* that a native on his farm, after losing one of his 
wives from disease^ came and said that ^'' he was going to 
a distant tribe to spear a woman, to satisfy his sense of 
duty to his wife. I told him that if he did so I would 
send him to prison for life. He remained about the farm 
for some months, but got exceedingly thin, and complained 
that he could not rest or eat, that his wife's spirit was 
haunting him, because he had not taken a life for hers. I 
was inexorable, and assured him that nothing should save 
him if he did.'' Nevertheless the man disappeared for 
more than a year, and then returned in high condition ; 
and his other wife told Dr. Landor that her husband had 
taken the life of a woman belonging to a distant tribe, but 
it was impossible to obtain legal evidence of the act. The 
breach of a rule held sacred by the tribe will thus, as it 
seems, gi\k> rise to the deepest feelings — and this quite 
apart from the social instincts, excepting in so far as the 
rule is grounded on the judgment of the community. 
How so many strange superstitions have arisen throughout 
the world we know not; nor can we tell how some real and 
great crimes, such as incest, have come to be held in an 
abhorrence (which is not however quite universal) by the 
lowest savages. It is even doubtful whether in some tribes 
incest would be looked on with greater horror than would 
the marriage of a man with a woman bearing the same 
name, though not a relation. *"' To violate this law is a 
crime which the Australians hold in the greatest abhor- 
rence, in this agreeing exactly with certain tribes of North 
America. When the question is put in either district, is 
it worse to kill a girl of a foreign tribe, or to marry a girl 
of one's ow.i, an answer just opposite to ours would be given 
without i.'3ioi;ation."f We may, therefore, reject the 
belief, la!:e_y insisted on by some writers, that the abhor- 

* " insani«7 ;p. J.lelation to Law," Ontario, United States, 1871, 
f E. B. Tylor in *• Contemporary Keview," April, 1873, p. 707. 

MORAL SEjySE, 131 

reiicG of incest is due to our possessing a special God- 
implanted conscience. On the whole it is intelligible, that 
a man urged by so powerful a sentiment as remorse though 
arising as above explained, should be led to act in a manner, 
which he has been taught to believe serves as an expiation, 
such as delivering himself up to justice. 

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

If any desire or instinct leading to an action opposed to 
the good of others still appears, when recalled to mind, as 
strong as, or stronger than, the social instinct, a man will 
feel no keen regret at having followed it; but he will be 
conscious that if his conduct were know^n to his fellows, it 
would meet with their disapprobation; and few are so desti- 
tute of sympathy as not to feel discomfort when this is 
realized. If he has no such sympathy, and if his desires 
leading to bad actions are at the time strong, and when 
recalled are not overmastered by the persistent social 
instincts, and the judgment of others, then he is essen- 
tially. p bad man;* and the sole restraining motive left; 
is t'l^'j 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. / 

*Dr. Prosper Despine in bis " Psycbologie Naturelle," 1868 (tora. 
}, p. 243; torn, ii, p. 169), gives many curious cases of the worst 
Cfimiuals, vvko apparently have been entirely destitute of conscience. 


It is obvious that every one may with an easy conscience 
ratify his own desires, if they do not interfere with his 
Dcial 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 disap- 
probation, whether reasonable or not, of his fellow-men. 
Kor must he break through the fixed habits of his life, 
especially if these are supported by reason; for if he does, 
he will assuredly feel dissatisfaction. He must likewise 
avoid the reprobation of the one God or gods in whom, 
according to his knowledge or superstition, he may believe; 
but in this case the additional fear of divine punishment 
often supervenes. 

The Strictly Social Virtues at First Alone Regarded. — 
The above view of the origin and nature of the moral sense, 
wnich tells us what we ought to do, and of the conscience 
which reproves us if we disobey it, accords well with what 
we see of the early and undeveloped condition of this faculty 
in mankind. The virtues which must be practiced, at least 
generally, by rude men, so that they may associate in a body, 
are those which aie still recognized as the most important. 
But they are practiced almost exclusively in relation to the 
men of the same tribe; and their opposites are not regarded 
as crimes in relation to the men of other tribes. No tribe 
could hold together if murder, robbery, treachery, etc., 
were common, consequently such crimes within the limits 
of the same tribe " are branded with everlasting infamy;"* 
but excite no such sentiment beyond these limits. K North 
American Indian is well pleased with himself, and is hon- 
ored by others, when he scalps a man of another tribe; and 
a Dyak 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, f 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 gt -leraliy 

*See an able article in the *' North Britisli Review," 1867, p. «.95. 
See also Mr. W, Bagehot's articles on the *' Importance of Obediencw" 
and " Coherence to Primitive Man," in the " Fortnightly Keview,'* 
1867, p. 529, and 1868, p. 457, etc. 

f Tlie fullest account which I have met with is by Dr. Gerland, in 
his •' Ueber dan Anssterben der Natnr^olker " 1868; but I shall have 
to recur to the subject of iufantioidtf 4M>4uture chapter. 

ifOrUL SENSB, 133 

consklercd as a crime,* out rather, from the courage dis- 
playetl, as an honorable act, and it is still practiced by some 
Bemi-civilized and savage nations without reproach, for it 
does not obviously concern others of the tribe. It has 
been recorded that an Indian Thug conscientiously lugret- 
ted that he had not robbed and strangled as many trav- 
elers as did his father before him. In a rude state of 
civilization the robbery of strangers is, indeed, generally 
considered as honorable. 

Slavery, although in some ways beneficial during ancient 
times, t is a great crime; yet it was not so regarded until 
quite recently, even by the most civilized nations. And 
this was especially the case, because the slaves belonged in 
general to a race different from that of their masters. As 
barbarians do not regard the opinions 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 well known that the women 
and children of the North American Indians aided in tor- 
taring their enemies. Some savages take a horrid pleas- 
ure in cruelty to animals, J and humanity is an unknown 
virtue. Kevertheless, besides the family affections, kind- 
ness is common, especially during sickness, between the 
members of the same tribe, and is sometimes extended 
beyond these limits. Mungo Park's touching account of 
the kindness of the negro women of the interior to him 
is well known. Many instances could be given of the noble 
fidelily of savages toward each other, but not to strangers; 
common experience justifies the maxim of the Spainard. 
" 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 

*See tlie very interesting discussion on Suicide in Lecky's " Hist- 
ory of European Morals," vol. i, 1869, p. 223. With respect to sav- 
ages, Mr. Winwood Reade informs nie that the negroes of West 
Africa often commit suicide. It is well known how common it was 
among the miserable Aborigines of South America after the Spanish 
conquest. For New Zealand, see the voyage of the " Novara," and 
for the Aleutian Islands, Miiller, as quoted by Ilouzeau, " Les 
Facultes Memales," etc., tom. ii, p. 136. 

t See Mr. Bagehot, "Physics and Politics," 1872, p. 72. 

:}:See, for Instance, Mr. Hamilton's account of the Kaflfirs, **An> 
tliropological Kevievv," 1870, p. 15. 


heard the negro women teaching their young children to 
love the truth. This, again, is one of the virtues which 
becomes so deeply rooted in the mind that it is sometimes 
practiced by savages, even at a high cost, toward strangers; 
but to lie to your enemy has rarely been thought a sin, as 
the history of modern diplomacy too plainly shows. As 
soon as a tribe has a recogidzed leader disobedience becomes 
a crime, and even abject submission is looked at as a sacred 

As during rude times no man can be useful or faithful to 
his tribe without courage, this quality has universally been 
placed in the highest rank; and although in civilized coun- 
tries a good yet timid man may be far more useful to the 
community than a brave one, we cannot help instinctively 
honoring the latter above 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 mati can practice the virtues 
necessary for the welfare of his tribe without self-sacrifice, 
self -command, and the power of endurance, these qualities 
have been at all times highly and most justly valued. The 
American savage voluntarily su omits to the most horrid 
tortures without a groan, to prove and strengthen his forti- 
tude and courage; and we cannot 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 so-called self-regarding virtues, which do not 
obviously, though they may really, affect the welfare of the 
tribe, nave never been esteemed by savages, though now 
highly appreciated by civilized nations. The greatest 
intemperance is no reproach with savages. Utter licen- 
tiousness and unnatural crimes prevail to an astounding 
extent.* As soon, however, as marriage, whether polyga- 
mous or monogamous, becomes common, jealousy will lead 
to the inculcation of female virtue; and this being honored, 
m\\ 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 honored, from a very early period in the moral history 
of civilized mar?. As a consequence of this, the senseless 
practice of celibacy has been ranked from a remote penod 

*Mr M'Lennan has given ( • Primitive Marriage," 1865, p. 176) a 
Kood collection of facts ou this head 


as a virtue.* The hatred of indecency, which appears to 
lie 60 natural as to be thought innate, and which is so val- 
uabie an aid to chastity, is a modern virtue, appertaining 
exclusively, as Sir G. Staunton remarks,! to civilized life. 
This is shown by the ancient religious rites of various 
nations, by the drawings on the 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 obviously affect the welfare *of the tribe 
— not that of the species, nor that of an individual member 
of the tribe. This conclusion agrees well with the belief 
that the so-called moral sense is aboriginally derived from 
the social instincts, for both relate at first exclusively to 
the community. 

The chief causes of the low morality of savages, as 
judged by our standard, are, firstly, the confinement of 
sympathy to the same tribe. Secondly, powers of reason- 
ing insufficient to recognize the bearing of many virtues, 
especially of the self-regarding virtues, on the general w^el- 
fare of the tribe. Savages, for instance, fail to trace the 
multiplied evils consequent on a want of temperance, 
chastity, etc. 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 immorality 
of savages, J; because some authors have recently taken a 
high view of their moral nature, or have attributed most of 
their crimes to mistaken benevolence. § These authors 
appear to rest their conclusion on savages possessing those 
virtues which are serviceable, or even necessary, for the 
existence of the family and of the tribe — qualities which 
they undoubtedly do possess, and often in a high degree. 

Concluding Remarks. — It was assumed formerly by phi- 
losophers of the derivative || school of morals that the 

*Lecky, ''History of European Morals," vol. i, 1869, p. 109. 

f '* Embassy to Cbina." vol. ii, p. 348. 

J See on this subject co])ious evidence in chap, vii, of Sir J, Lub- 
bock, "Origin of Civilization," 1870 

§For instance, Lecky " Hist. European Morals," vol. 1. p. 124. 

J Tins term is used in an able article in the " Westminster Re- 
view, " Oct., 18G9, p. 498. For the "greatest happiness principle," 
see J. S. Mil], ** Utilitarianism." u 17. 


foundation of morality lay in a form of Selfishness; but 
more recently the '* .iiieatest happiness principle" has been 
brought prominently forward. It is, however, more cor- 
rect to speak of the latter principle as the standard, and 
not as the motive of conduct. Nevertheless, all the authors 
whose works I have consulted, with a few exceptions,* 
write as if there must be a distinct motive for every action, 
and that this must be associated with some pleasure or dis- 
pleasure. But man seems often to act impulsively, that is 
from instinct or long habit, without any consciousness of 
pleasure, in the same manner as does probably a bee or ant, 
when it blindly follows its instincts. Under circumstances 
of extreme peril, as during afire, when a man endeavors to 
save a fellow-creature without a moment's hesitation, he 
can hardly feel pleasure; and still less has he time to reflect 
on the dissatisfaction which he might subsequently cxperi-. 
ence if he did not make the attempt. Should he afterward 
reflect over his own conduct, he would feel that there lies 
within him an impulsive power widely difl'erent from a 
search after pleasure or happiness; and this seems to be tho 
deeply })lanted social instinct. 

In the case of the lower animals it seems much more 
appropriate to speak of their social instincts as having 
been developed for the general good rather than for tho 
general h?>.ppiiiess of the species. The term, general good, 
may be defined as the rearing of the greatest number of 
individuals in full vigor and health, with all their faculties 
perfect, under the conditions to which they are subjected. 

*Mill recognizes (*' System of Logic,'' vol. ii, p 422) in the clear- 
est manner, tliat actions may be performed tliroug-b habit \vitliout 
the anticipation of pleasure. Mr. H. Sidgwick also, in bis essay on 
Pleasure and Desire (" The Contemporary Keview." April 1872, p. 
671), remarks: "To sum up, in contravention of the doctrine that 
our conscious active iujpulses are always directed toward the pro- 
duction of agreeable sensations in ourselves, I would maintain that 
we find everywhere in consciousness extra-regarding impulse, di- 
rected toward something that is not pleasure; that in many cases tho 
imi)uKse is so far incom^tatible with the self regarding that the two 
do not easily ci^exist in the same moment of consciousness." A dim 
feeling that our impulses do not by any mean-s always arise from any 
contemporaneous or anticii)ated j)leasure, has, I cannot but think, 
been one chief cause of the acceptance of the intuitive theory of 
morality, and of the rejection of the utilitarian or 'greatest happi- 
Qpsh '* theo.-y With respect to the latter ilieory the standard and 
the n^ofive M ".onduct have no doubl often beea cuufusedj but they 
are realiy jn 6Qia^ 4e^rtH) blended. 


As the social iiistiDcts both of man and the lower animals 
have no doubt been developed by nearly the same steps, it 
would be advisable, if found practicable, to use the same I 
Jefiintion in both cases, and to take as the standard of ' 
morality the general good or welfare of the community, 
rather than the general happiness ; but this definition 
would perhaps require some limitation on account of 
political ethics. 

When a man risks his life to save that of a fellow-creat- 
ure it seems also more correct to say that he acts for the 
general good rather than for the general happiness of man- 
kind. No doubt the welfare and the happiness of the 
individual usually coincide; and a contented, happy tribo 
will flourish better than one that is discontented and 
unhappy. We have seen that even at an early period in 
the history of man the expressed wishes of the community 
will have naturally influenced to a large extent the conduct j 
of each member; and as all wish for happiness, the *^ great- i 
est happiness principle '^ will have become a most impor- ■ 
tant secondary guide and object; the social instinct, how- i 
ever, together with sympathy (which leads to our regarding 
the approbation and disapprobation of others), having ■ 
served as the primary impulse and guide. Thus the re- ] 
proach is removed of laying the foundation of the noblest j 
part of our nature in the base principle of selfishness; j 
unless, indeed, the satisfaction which every animal feels, j 
when it follows Us proper instincts, and the dissatisfaction 1 
felt when prevented be called selfish. j 

The wishes and opinions of the memxbers of the same ^ 
community, expressed at first orally but later by writing 
also, either form the sole guides of our conduct or greatly 
re-enforce the social instincts; such opinions, however, have 
sometimes a tendency directly opposed to these instincts. 
This latter fact is well exemplified by the Jmw of Honor, 
that is, the law of the opinion of our equals and not of all 
our countrymen. The breach of this law, even when thei 
breach is known to be strictly accordant with true moral- 
ity, has caused many a man more agony than a real crime. 
We recognize the same influence in the burning sense of 
diame which most of us have felt, even after the interval 
of years, when calling to mind some accidental breach of a 
trifling, though fixed rule of etiquette. The judgment of 
the communitj will generally be guided by some rude 


experience of what is best in the long run for all the mem- 
bers; but tills judgment will not rarely eir from ignorance 
and weak powers of reasoning. Hence the strangest cus- 
toms and superstitions, in complete opposition to the true 
welfare and happiness of mankind, have become all-power- 
ful throughout the world. AVe see this in the horror felt 
by a Hindoo who breaks his caste, and in many other such 
cases. It would be difficult to distinguish between the 
remorse felt by a Hindoo who has yieldei to the tempta- 
tion of eating 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 quarters 
of the world, so deeply impressed on the minds of men; 
but it is worthy of remark that a belief constantly incul- 
cated during the early years of life, while the brain is im-. 
pressible, appears to acquire almost the nature of ap 
instinct; and the very essence of an instinct is that it is 
followed independently of reason. Neither can we say wny 
certain admirable virtues, such as the love of truth, art 
much more highly appreciated by some savage tribes than 
by others;* nor, again, why similar differences prevail even 
among higi:ly civilized nations. Knowing iiow firmly 
fixed many strange customs and superstitions have become, 
we need feel no surprise that the self-regarding virtues, 
supported as they are by reason, should now appear to us 
so natural as to be thought innate, although they were not 
valued by man in his early condition. 

Notwithstanding many sources of doubt, man can gener- 
ally 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 im- 
plying self-sacrifice hardly deserve to be called lower, relate 
chiefly to self, and arise from public opinion, matured by 
experience and cultivation; for they are not practiced by 
rude tribes. 

As man advances in civilization, and small tribes are 

*Good instances are given by Mr. Wallace in " Scientific OpiHion," 
Sept. 15, 1869, and more fully in liis " Contribationsto the Theory 
of Natural Selection/' 1870, p. 353. 


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 artificial barrier to pre- 
vent his sympathies extending to the men of all nations 
and races. If, indeed, such men are separated from him 
by great differences m appearance or habits, experience 
unfortunately shows us how long it is, before we look at 
them as our fellow-creatures. Sympathy beyond the con- 
fines 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 toward their pets. IIow little 
the old Romans knew of it is showm by their abhorrent 
gladiatorial exhibitions. The very idea of humanity, as 
far as I could observe, was new to most of the Gauchos of 
the Pampas. This virtue, one of the noblest with which 
man is endowed, seems to arise incidentally from our sym- 
pathies becoming more tender and more widely diffused, 
until they are extended to all sentient beings. As soon as 
this virtue is honored and practiced by some few men, it 
spreads through instruction and example to the young, and 
eventually becomes incorporated in public opinion. 

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

thoughts, "t 

Our great philosopher, Herbert Spencer, has recently 
explained his views on the moral sense. He says 4 *'I 
believe that the experiences of utility organized and con- 
solidated through all past generations of the human race, 
have been producing corresponding modifications, which, 

* Tennyson's " Idylls of tbe King," p. 244. 

f *' The Tbougbls of tbe Emperor M. Aurelins Antoninus," Eng. 
translat., 2d edit., 1869, p. 112. Marcus Aurelius was born A. D. 

J Letter to Mr. Mill iu Bain s " Mental and Moral Science," 18G8. 
p. 722. 


by continued transmission and accumulation, have become 
in us certain faculties of moral intuition — certain rit.otione 
responding to right and wrong conduct, which have no 
apparent Xasis in the individual experiences of utility." 
There is not the least inherent improbability, as it Eeems tO 
me, in virtuous tendencies being more or less strongly 
inherited; for. not to mention the various dispositions and 
habits transmitted by many of our domestic animals to 
their offspring, I have heard of authentic cases in which a 
desire to steal and a tendency to lie appeared to run in 
families of the upper ranks; and as stealing is a rare crime 
in the wealthy classes, we can hardly account by accidental 
coincidence for tlie tendency occurring in two or tliree 
members of the same family. If bad tendencies are trans- 
mittf^d, it is probable that good ones are likewise trans- 
mitted. That the state of the bodv by affecting the brain 
has great influence on the moral tendencies is known 
to most of those who have suffered from chronic derange- 
ments of the digestion or liver. The same fact is likewise 
shown by the ''perversion or destruction of the moral 
sense being often one of the earliest symptoms of mental 
derangement;"' * and insanity is notoriously often inherited. 
Except through the principle of the transmission of moral 
tendencies, we cannot understand the differences believed 
to exist in this respect between the various races of 

Even the partial transmission of virtuous tendencies 
would be an immense assistance to the primary impulse 
derived directly and indirectly from the social instincts. 
Admitting for a moment that virtuous tendencies are 
inherited, it appears probable, at least in such cases as 
chastity, temperance, humanity to animals, etc., that they 
become first impressed on the mental organization through 
habit, instruction and example, continued during seveial 
generations in the same family, and in a quite subordinate 
degree, or not at all, by the individuals possessing such 
virtues having succeeded best in the struggle for life. My 
chief source of doubt with respect to any such inheritance, 
is that senseless customs, superstitions and tastes, such ap 
the horror of a Hindoo for unclean food, ought on the same 
principle to be transmitted. I have not met with any 

♦Maudsley, "Body and Mind," 18T0, p. 60. 


evidence in support of tho transmission of superstitious 
customs or senseless habits, although in itself it is per- 
hii])s not less probable than that animals should acquire 
inherited tastes for certain kinds of food or fear of certain 

Finally the social instincts, which no doubt were acquired 
by man as by the lower animals for the good of the com- 
munity, will from the first have given to him some wish to 
aid his fellows, some feeling of sympathy, and have com- 
pelled him to regard their approbation and disapprobation, 
hsuch impulses will have served/iiim 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 
sufticieiit knowledge to reject baneful customs and su])er- 
stitions; as he regarded more and more not only the wel- 
fare, but the happiness of his fellow-men; as from habit, 
following on beneficial experience, instruction and example, 
his sympathies became more tender and widely ditfused, 
extending to men of ail races, to the imbecile, maimed, and 
other useless members of society, and finally to the lower 
animals — so would the standard of his morality rise higher 
and higher. And it is admitted by moralists of the deriva- 
tive school and by some intuitionists, that the standard of 
morality has risen since an early period in the history of 

As a struggle may sometimes be seen going on between 
the various instincts of the lowei animals, it is not surpris- 
ing that there should be a struggle in man between his 
social instincts, vvith their derived virtues, and his lower, 
though momentarily stronger impulses or desires. This, as 
Mr. Galtonf has remarked, is all the less surprising, as man 
has emerged from a state of barbarism within a compara- 
tively recent period. After having yielded to some temp- 
tation we feel a sense of dissatisfaction, shame, repentance, 

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

f See his remarkable work on "Hereditary Genius," 1869, p. 349. 
The Duke of Argyll (" Primeval Man." 1869, p. 188) has some good 
remarks on the contest iu man's uatvu'e between right and wrong. 


or remorse, analogous to the feelings caused by other power* 
fal instincts or desires, when left unsatisfied or balked. 
We compare the weakened impression of a past temptation 
witli the ever present social instincts, or with habits, gained 
in early youth and strengthened during our whole lives 
until they have become almost as strong as instincts. If 
with the temptation still before us we do not yield, it is 
becaus3 either the social instinct or some custom is at the 
moment predominant, or because we have learned that it 
will appear to us hereafter the stronger, when compared 
with the weakened impression of the temptation, and we 
realize that its violatioii would cause us suffering. 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 c^'se the struggle between our 
higher and lower impulses will be less severe, and virtue 
will be triumphant. 

Summary of the Last Two Cliapfers. — 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 
Btones for fighting or for breaking open nuts, yet that the 
thought of fashioning a stone into a tool was quite beyond 
his scope. Still less, as he would admit, could he follow 
out a train of metaphysical reasoning, or solve a mathemat- 
ical problem, or reflect on God, or admire a grand natural 
scene. Some apes, however, would probably declare that 
they could and did admire the beauty of the colored skin 
and fur of their partners in marriage. They would admit, 
that though they could make other apes understand by 
cries some of their perceptions and simpler wants, the notion 
of ei^pressing definite ideas by delinite sounds had never 
crossed llieir minds. They might insist that tliey 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; bnt they would be forced to acknowledge 
that disinterested love for all living creatures, the most 
noble attribute of man, was quite beyond their compre- 


Nevertheless the difference in mind between man and 
the higher animals, groat as it is, certainly is one of degree 
and not of kind. We have seen that the senses and intui- 
tions, the various emotions and faculties, such as love, 
memory, attention, curiosity, imitation, reason, etc., of 
■which man boasts, may be found in an incipient, or even 
Bometimes in a well-developed condition, in the lower 
animals. They are also capable of some inherited improve- 
ment, as we see in the domestic dog coro.pared with the 
wolf or jackal. If it could be proved that certain high 
mental powers, such as the formation of general con- 
cepts, self-consciousness, etc., were absolutely peculiar to 
man, which seems extremely doubtful, it is not improbable 
that these qualities are merely the incidental results of 
other highly-advanced intellectual faculties ; and these 
again mainly the result of the continued use of a perfect 
language. At what age does the new-born infant possess 
the power of abstraction, or become self-conscious and 
reflect on its own existence ? We cannot answer; nor can 
we answer in regard to the ascending organic scale. The 
half-art, half-instinct of language still bears the stamp 
of its gradual evolution. The ennobling belief in God 13 
not universal with man; and the belief in spiritual agencies 
naturally follows from other mental powers. The moral 
sense perhaps affords the best and highest distinction 
between man and the lower animals; but I need say noth- 
ing on this head, as I have so lately endeavored to show 
that the social instincts — the prime principle of man's 
moral constitution* — with the aid of active intellectual 
powers and the effects of habit, naturally lead to the golden 
rule, " As ye would that m3n should do to you, do ye to 
them likewise;" and this lies at the foundation of morality. 

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

Tan ITioughts of Marcus Aurelius," etc., p. 139. 






Advancement of the intellectual powers through natural selection — 
liuj-.oriauce of imitaiiou — Social ami moral faculties — 'I'heir 
development within the limits of the same tribe — Natural 
selection as affecting civilized nations — Evidence that civilized 
nations were once barbarous. 

The subjects to be discussed in this chapter are of the 
highest interest, but are treated by me in an imperfect and 
fragmentary manner. Mr. Wallace, in an admirable paper 
before referred to,* argues that man, after he had partially 
acquired those intellectual and moral faculties which dis- 
tinguish him from the lower animals, would have been but 
little liable to bodily modilications through natural selec- 
tion or any other means. For man is enabled through his 
mental faculties " to keep with an unchanged body in har- 
mony with the changing universe." lie has great power 
of adapting his habits to new conditions of life. He 
invents weapons, tools, and various stratagems to procure 
food and to defend himself. When he migrates into a 
colder climate he uses clothes, builds sheds, and makes 
fires; and by the aid of fire cooks food otherwise indigesti- 
ble. H3 aids his fellow-men in many ways, and anticipates 
future events. Even at a remote period he practiced some 
division of labor. 

The lower animals, on the other hand, must have their 
bodily structure modified in order to survive under greatly 
changed conditions. They must be rendered stronger, or 
ac(piire more eifective teeth or claws, for defense against 
ucw enemies; or they must be reduced in size, so as to 

* "Ajithropological Review," May, 1S64, p. 153- 


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. "Ucdiace 
has with justice insisted, in relation to the intellectual and 
moral faculties of man. These faculties are variable; and 
we have every reason to believe that the vaviations tend to 
be inherited. Therefore, if they were formerly of high 
importance to primeval man and to his ape-like progenitors, 
they would have been perfected or r^dvanced through 
natural selection. Of the high importance of the intel- 
lectual faculties there can be no doubt, for man mainly 
owes to them his predominant position in the world. We 
can see, that in the rudest state of society, the individuals 
who were the most sagacious, who invented and used the 
best weapons or traps, and who were best able to defend 
themselves, would rear the greatest number of offspring. 
The tribes, which included the largest number of men thus 
endowed, would increase in number and supplant other 
tribes. Numbers depend primarily on the means of sub- 
sistence, and this depends partly on the physical nature of 
the country, but in a much higher degree on the arts 
which are there practiced. As a tribe increases and is vic- 
torious, it is often still further increased by the absorption 
of other tribes.* The stature and strength of the men of a 
tribe are likewise of some importance for its suci^ess, 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 race more powerful, 
and, judging from their sword -handles, with laj-ger hands;} 
but their success was probably still more due to their 
superiority in the arts. 

All that we know about savages, or may infer from theii 
tiaditions and from old monuments, the liistory of which 
is quite forgotten by the present inhabitants,"show that 
from the remotest times successful tribes liave supplanted 
other tribes. Relics of extinct or forgotten tribes have been 
discovered throughout the civilized regions of the earth, on 

* After a time the nieniLers or tribes wliich are absorbed into 
another tribe assume, as Sir Henry Maine remarks ("Ancient Law," 
1861, p. 131), that tbey are tbe co-descendants of the same aucebtors, 

iMorlot, "Soc Vaud. Sc. ^'at." laeo. d. 29^ 


the wild plains of America, and on the isolated islands in 
the Facitic Ocean. At the present day civilized nations 
are everywhere supplanting barbarous nations, excepting 
where the climate opposes a deadly barrier; and they suc- 
ceed mainly, though not exclusively, through their arts, 
which are the ])roducts of the intellect. It is, therefore, 
highly probable that with mankind the intellectual facul- 
ties have been mainly and gradually perfected through 
natural selection; and this conclusion is sufficieut for our 
purpose. Undoubtedly it would be interesting to trace the 
development of each separate faculty from the state in 
which it exists in the lower animals to that in which it 
exists in man; but neither my ability nor knowledge per- 
mits 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 principle of imitation and reason and experi- 
ence would have increased and much modified the intel- 
lectual powers in a way, of which we see only traces in the 
lower animals. Apes are much given to imitation, as are 
the lowest savages: and the simple fact previously referred 
to, that after a time no animal can be caught in the same 
place by the same sort of trap, shows that animals learn by 
experience and imitate the caution of others. Now, if some 
one man in a tribe, more sagacious than the others, invented 
a new snare or weapon, or other means of attack or defense, 
the plainest self-interest, without the assistance of much 
reasoning power, would prompt the other members to imi- 
tate him; and all would thus profit. The habitual practice 
of each new art must likewise in some slight degree 
^rengthen the intellect. If the new invention were an 
Miportant one, the tribe would increase in number, spread, 
and supplant other tribes. In a tribe thus rendered more 
numerous there would always be a rather greater chance of 
the birth of other superior and 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 decid- 
edly better. Even if they left no children, the tribe would 
still include their blood-relations; and it has been a.-"cer- 
tained by agriculturists* that by preserving and breeding 

* I Lave given instances in my " Variation of Animals under Do- 
mestication," vol. ii, p. 190. 


from the family of an animal which when slaughtered was 
found to be valuable, the desired character has been 

Turning now to the social and moral faculties. In order 
that primeval men, or the ape-like progenitors of man, 
should become social, they must have acquired the same 
instinctive feelings, which impel other animals to live in a 
body; and they no doubt exhibited the same general dispo- 
sition. 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 defense. All this im- 
plies some degree of sympathy, fidelity and courage. Such 
social qualities, the paramount importance of which to the 
lower animals is disputed by no one, were no doubt acquired 
by the progenitors of man in a similar manner, namely, 
through natural selection, aided by inherited habit. When 
two tribes of primeval man, living in the same country, 
came into competition, if (other circumstances being equal) 
the one tribe included a great number of courageous, sym- 
pathetic and faithful members, who were always ready to 
warn each other of danger, to aid and defend each other, 
this tribe would succeed better and conquer the other. Let 
it be borne in mind how all-important in the never-ceasing 
wars of savages, fidelity and courage must be. The advan- 
tage 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 
shown,* is of the highest value, for anv form of government 
is better than none. Selfish and contentious people will 
not cohere, and without coherence nothing cs.n be effected. 
A tribe rich in the above qualities would npread and be 
victorious over other tribes; but in the course of time it 
would judging from all past history, be in its turn over- 
come by some other tribe still more highly endowed. Thus 
the social and moral qualities would tend slowly to advance 
and be diffused throughout the wovld. 

But it may be asked, how within the limits of the same 
tribe did a large number of members first become endowed 

*See a remarkable series of articles on " Plivsics and Politics," in 
the "Fortnightly Keview,' ^^ov., 18G7; April' 1, 1668; July 1, 1869. 
since s^-parately publislied. 


with these social and moral qualities, and how was the 
standard of excellence raised? It is extremely doubtful 
whether the off s^, ring of the more sympathetic and benevo- 
lent parents, or of those who were tlie most faithful to 
their comrades, would be reared in greater numbers than 
the children of selfish and treacherous parents belonging to 
the same tribe. He who was ready to sacrifice his life., as 
many a savage has been, rather than betray his comrades, 
would often leave no olfspring to inherit his noble nature. 
The bravest men, who were always willing to come to the 
front in war, and who freely risked their lives for others, 
would on an average perish in larger numbers than other 
mt-n. Therefore it hardly seems probable, that the number 
of men gifted with such virtues, or that the standard of 
thi'ir excellence could be increased through natural selec- 
ticQ. that is. by the survival of the fittest : for we are not 
here speaking of one tribe being victorious over another. 

Although the circumstances, leading to an increase in 
the number of those thus endowed within the same tribe 
are too complex to be clearly followed out we can trace 
some of the probable steps. In the first place, as the rea- 
soning powers and foresight of the members became im- 
proved, each man would soon learn that if he aided his 
fellow-men he would commonly receive aid in return. 
From this low motive he might acquire the habit of aiding 
his fellows; and the habit of performing benevolent actions 
certainly strengthens the feeling of sympathv which gives 
the first impulse to benevolent actions. Habits, more- 
over, followed during many generations probably tend to 
be inherited. 

But another and much more powerful stimulus to the 
development of the social virtues is afforded by the praise 
and the blame of our fellow-men. To the instinct of 
sympathy, as we have already seen, it is primarily due that 
we habitually bestow both praise and blame on others, 
while we love the former and dread the latter when applied 
to ourselves; and this instinct no doubt was originally 
acquired, like all the other social instincts, through nat- 
ural selection. At how early a period the progenitors of 
man in the course of their development became capable of 
feeling and being impelled by the praise or blam^e of their 
fellow-creatures we cannot of course say. But it appears 
that even dogs appreciate encouragement, praise, and 

mohal faculties. UO 

blame. The rudest savages feel the sentiment of glory, as 
they clearly show by preserving the trophies of their 
prowess, by their habit of excessiv-e boasting, and even by 
the extreme care which they take of their personal appear- 
ance and decorations; for unless they regarded the opinion 
of their comrades such habits would be senseless. 

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

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

With increased experience and reason, man perceives the 
more remote consequences cf his actions, and the self -regard- 
ing virtues, such as temperance, chastity, etc., which during 
early times are, as we have before seen, utterly disregarded, 
come to be highly esteemed or even held sacred. I need 
not, however, repeat what I have said on this head in the 
fourth chapter. Ultimately our moral sense or conscience 
becomes a highly complex sentiment — originating in the 

*Mr. Wallace gives cases in his "Contributions to the Theory of 
Natural Selection," 1870, p. 354. 


social instincts, largely guided by the approbation of our 
fellow-men, ruled by reason, self-interest, and in later 
times by deep religious feelings, and confirmed by instruc- 
tion and habit. 

It must not be forgotten that although a high standard 
of morality gives but a slight or no advantage to each 
individual man and his children over the other men of the 
same tribe, yet that an increase in the number of well- 
endowed men and an advancement in the standard of 
morality will certainly give an immense advantage to one 
tribe over another. A tribe including many members who, 
from possessing in a high degree the spirit of patriotism, fidel- 
ity, obedience, courage and sympathy, were always ready to 
aid one another, and to sacrifice themselves for the common 
good, would be victorious over most other tribes; and this 
would be natural selection. At all times throughout the 
world tribes have supplanted other tribes; and as morality 
is one important element in their success, the standard of 
morality and the number of well-endowed men will thus 
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 civilization. Many savages 
are in the same condition as when first discovered several 
centuries ago. As Mr. Bagehot has remarked, we are apt 
to look at progress as normal in human society; but history 
refutes this. The ancients did not even entertain the idea, 
nor do the Oriental nations at the present day. According 
to another hi^h authority. Sir Henry Maine,* *'the greatest 
part of mankind has never shown a particle of desire that its 
civil institutions should be improved." Progress seems to 
depend on many concurrent favorable conditions, far too 
complex to be followed out. But it has often been remarked, 
that a cool climate, from leading to industry and to the 
various arts, has been highly favorable thereto. The Esqui- 
maux, 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 detri- 
mental. While observing the barbarous inhabitants of 

* •' Ancient Law," 1861, p. 23. For Mr. Bageliot's remarks, 
*' FortttigUtly Review," April 1, 1868, p. 453. 


T'crra del Fiiego, 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 civilization. 
Such habits almost necessitate the cultivation of the ground; 
and the first steps in cultivation would probably result, as 
I have elsewhere shown,* from some such accident as the 
^eeds of a fruit-tree falling on a heap of refuse, and pro- 
lucing an unusually fine variety. The problem, however, 
of the first advance of savages toward civilization is at pres- 
ent much too difficult to be solved. 

Natural Selection as Affecting Civilized Nations. — T have 
hitherto only considered* the advancement of man from a 
semi-human condition to that of the modern savage. But 
some remarks on the action of natural selection on civilized 
nations may be worth adding. This subject has been ably 
discussed by Mr. W. R. Greg,t and previously by Mr. AVal- 
lace and Mr. Gal ton. | Most of my remarks are taken from 
these three authors. With savages, the "sveak in body or 
mind are soon eliminated; and those that survive commonly 
exhibit a vigorous state of health. We civilized men, on 
ihe other hand, do our utmost to check the process of elim- 
ination; we build asylums for the imbecile, the maimed, 
and the sick; we inetitute 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 civilized societies propagate their kind. 
No one who has attended to the breeding of domestic ani- 

*"Tlie Variation of Animals and Plants under Domestication," 
^ol. i, \). 309. 

f " Fraser's Magazine," Sept., 1868, p. 353. Tliis article seems to 
have struck many persons, and lias given rise to two remarkable 
essays and a rejoinder in the "Spectator," Oct. 3 and 17, 18G8. It 
Las 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. Ray Lankester in his "Com- 
parative Longevity," 1870. p. 128. Similar views a])peared pre- 
viously in the " Australasian," July 13, 1867. I have borrowed ideas 
from several of these writers. 

t For Mr. Wallace, see " Anthropolog. Review," as before cited. 
Mr. Gallon in "Macmillan's Magazine." Aug., 1865, p. 318; also lii3 
great work, "Hereditary Genius," 1870. 


mals will doubt that this must be highly injurious to the 
race of man. It is orprising hoAv soon a want of care, or 
care wrongly directed, leads to the degeneration of a domes- 
tic race; but excepting in the case of man himself, hardly 
any one is so ignorant as to allow his worst animals to 

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

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

Man accumulates property and bequeaths it to his chil- 
dren, so that the children of the rich have an advantage 
over the poor in the race for success, independently of 
bodily or mental superiority. On the other hand, the 
children of parents who are short-lived, and are therefore 
on an average deficient in health and vigor, come into their 
property sooner than other children, and will be likely 

*Prof. H. Pick ('* Einfluss der Natarwissenschaft auf das Reclit," 
June, 1872) has some good remarks on this head, and on other such 


to marry earlier, and leave a larger number of offspring to 
inherit their inferior constitutions. But the inheritance of 
property by itself is very far from an evil; for without the 
accumulation of capital the arts could not progress; and it 
is chiefly through their power that the civilized races have 
extended, and are now everywhere extending their range, 
so as to take the place of the lower races. Nor does the 
moderate accumulation of wealth interfere with the process 
of selection. When a poor man becomes moderately rich, 
his children enter trades or professions in which there is 
struggle enough, so that the able in body and mind succeed 
best. The presence of a body of well-instructed men, who 
liave not to labor for their daily bread, is important to a 
degree which cannot be overestimated; as all high intel- 
lectual work is carried on by them, and on such work, 
material progress of all kinds mainly depends, not to men- 
tion other and higher advantages. No doubt wealth when 
very great tends to convert men into useless drones, but 
their number is never large; and some degree of elimina- 
tion here occurs, for we daily see rich men, who happen to 
be fools or profligates, squandering away their wealth. 

Primogeniture with entailed estates is a more direct evil, 
though it may formerly have been a great advantage by the 
creation of a dominant class, and any government is better 
than none. Most eldest sons, though they may be weak in 
body or mind, marry, while 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 
civilized life are so complex that some compensatory checks 
intervene. The men who are rich through primogeniture 
are able to select generation after generation the more 
beautiful and charming women; and these must generally 
be healthy in body and active in mind. The evil conse- 
quences, such as they may be, of the continued preserva- 
tion 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. Gal ton * has shown, 
apt to be sterile; and thus noble families are continually 

* " Ilei-editar^ Uenius/' 1870, pp. 13S-U0. 


cut off in the direct line, and their wealth flows into soms 
side channel ; but unfortunately this channel is not 
determined by superiority of any kind. 

Although civilization thus checks in many ways the action 
of natural selection, it apparently favors the better develop- 
mejit of the body, by means of good food and the freedom 
from occasional hardships. This may be inferred from 
civilized men having been found, wherever compared, to he 
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 cf our aristocracy, at all ages and of both sexes, is vepy 
little iaferior to that of healthy English lives in the lower 
classes. \ 

We will now look to the intellectual faculties. If in 
each grade of society the members were divided into two 
equal bodies, the one including the intellectually superioi- 
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 labor, 
a very small one. Hence in civilized nations there will bo 
some tendency to an increase both in the number and in 
the standard of the intellectually able. But I do not wisli 
to assert that this tendency may not be more than counter- 
balanced in othei' ways, as by the multiplication of the reck- 
less and improvident; but even to such as these, ability 
mnet be some advantage. 

It has often been objected to views like the foregoing, 
that the most eminent men who have ever lived have left 
no offspring to inherit their great intellect. Mr. Gal ton 
says:I *' I regret I am unable to solve the simple question 
whether, and how far. m.en and women who are prodigie? 
of genius are infertile. I have, however, shown that meu 
of eminence are by no means so.'' Great lawgivers, tht 

* Qiiat.-efnges, '* Revue des Cours Scieutifiques," lbC7-68, p. 659. 

•(■See the fifth and sixth columns, compiled from good authorities, 
in the table given in Mr. E. K. Laukester's "Comparative Longev 
it;," 1870. p. 115. 

X " Hereditary aenius," 1870, p. 330. 


founders of beneficent religions, great philosophers and dis- 
coverers in science, aid the progress of raantind in a far 
higher degree by their works than by leaving a numerous 
progeny. In the case of corporeal structures, it is the 
selection of the slightly better-endowed and the elimination 
of the slightly less well-endowed individuals, and not 
the preservation of strongly-marked and rare anomalies, 
that leads to the advancement of a species.* So it will bo 
with the intellectual faculties, since the somewhat abler 
men in each grade of society succeed rather better than the 
less able, and consequently increase in number, if not other- 
wise prevented. When in any nation the standard of intel- 
lect and the number of intellectual men have increased, we 
may expect from the law of the deviation from an average, 
that prodigies of genius will, as shown by Mr. Galton, 
appear somewhat more frequently than before. 

In regard to the moral qualities, some elimination of the 
worst dispositions is always in progress even in the most 
civilized 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. The restless who will not follow 
any steady occupation — and this relic of barbarism is a 
great check to civilizationf — emigrate to newly-settled 
countries, where they prove useful pioneers. Intemperance 
is so highly destructive that the expectation of life of the 
intemperate at the age of thirty for instance, is only 13.8 
years; while for the rural laborers of England at the same 
age it is 40.59 years. J Profligate women bear few children, 
and profligate men rarely marry; both suffer from disease. 
In the breeding of domestic animals, the elimination of 
those individuals, though few in number, which are in any 
marked manner inferior, is by no means an unimportant 
element toward success. This especially holds good with 
injurious characters which tend to reappear through rever- 
sion, such as blackness in sheep; and with mankind some 

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

I '' Hereditary Genius," 1870, p. 347. 

X E. Ray Lankester, " Comparative Longevity," 1870, p. 115. The 
table of the intemperate is from Neison's " Vital Statistics." In 
regard to protiigacy, see Dr. Farr, " Influence of Marriage on Mor- 
tality," "Nat. Assoc, for the Promotion of Social Science," 1858. 


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 recognized in the common expression that such men 
are the black sheep of the family. 

With civilized nations, as far as an advanced standard of 
morality, and an increased number of fairly good men are 
concerned, natural selection apparently effects but little; 
though the fundamental social instincts were originally 
thus gained. But I have already said enough, while treat- 
ing 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 — exam- 
ple and imitation — reason — experience, and even self-inter- 
est — instruction during youth, and religious feelings. 

A most important obstacle in civilized countries to an 
increase in the number of men of a superior class has been 
strongly insisted on by Mr. Greg and Mr. Gal ton,* namely, 
the fact that the very poor and reckless, who are often 
degraded by vice, almost invariably marry early, while the 
careful and frugal, who are generally otherwise virtuous, 
marry late in life, so that they may be able to support 
themselves and their children in comfort. Those who 
marry early produce within a given period not only a 
greater number of generations, but, as shown by Dr. Dun- 
can,! ^^^y 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 so- 
ciety, tend to increase at a quicker rate than 
the provident and generally virtuous members. Or, as Mr. 
Greg puts the case: "^^ The careless, squalid, unaspiring 
Irishman multiplies like rabbits; the frugal, foreseeing, 

*" Eraser's Magazine," Sept., 1868, p. 353. " Macmillan's Maga- 
zine/* Aug., 1865, p. 318. The Rev. F. W. Farrar (" Fraser's Mag.," 
Aug., 1870, p. 264) takes a different view. 

f " On the Laws of the Fertility of Women," in " Transact. Royal 
Soc," Edinburgh, vol. xxiv. p. 287; now published separately under 
the title of " Fecundity, Fertility and Sterility," 1871. See, also, 
Mr. Qalton, "Hereditary Geuius," pp. 353-357, for observations to 
the above effect. 


self-respecting, ambitious Scot, stern in his morality, 
spiritual in his faith, sagacious and disciplined in his intel- 
ligence, 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 popu- 
lation 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 ex- 
istence ' it would be the inferior and less favored race that 
had prevailed — and prevailed by virtue not of its good 
qualities but of its faults." 

There are, however, some checks to this downward ten- 
dency. We have seen that the intemperate suffer from a 
high rate of mortality, and the extremely profligate leave 
few offspring. The poorest classes crowd into towns, and 
it has been proved by Dr. Stark from the statistics of ten 
years in Scotland* that at all ages the death rate is higher 
m towns than in rural disticts, '^ and during the first five 
years of life the town death rate is almost exactly double 
that of the rural districts." As these returns include both 
the rich and the poor, no doubt more than twice the 
number of births would be requisite to keep up the number 
of the very poor inhabitants in the towns relatively to those 
in the country. With women, marriage at too early an 
age is highly injurious; for it has been found in France 
that " twice as many wives under twenty die in the year 
as died out of the same number of the unmarried." The 
mortality, also, of husbands under twenty is " excessively 
high,"t 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 

* " Tenth Annual Report of Birtlis, Deaths," etc., in Scotland, 
1867, jk. 29. 

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


much larger proportion than the married ; for instance, out 
of every 1,000 unmarried men, between the ages of twenty 
and thirty, 11.3 annually died, while of the married only 
6.5 died.* A similar law was proved to hold good, during 
the years 1863 and 1864, with the entire population 
above the age of twenty in Scotland; for instance, out 
of every 1,000 unmarried men between the ages of 
'twenty and thirty, 14.97 annually died, while of the mar- 
ried only 7.24 died, that is less than half.f Dr. Stark 
remarks on this: "Bachelorhood is more destructive 
to life than the most unwholesom^e trades, or than 
residence in an unwholesome house or district where there 
has never been the most distant attempt at sanitary improve- 
ment.'' 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 likewise be admitted that men with a weak constitu- 
tion, ill-health, or any great infirmity in body or mind, will 
often not wish to marry, or will be rejected. Dr. Stark 
seems to have come to the conclusion that marriage in 
itself is a main cause of prolonged life, from finding that 
aged married men still have a considerable advantage in 
this respect over the unmarried of the same advanced age; 
but every one must have known instances of men, who with 
weak health during youth did not marry, and yet have sur- 
vived to old age, though remaining weak, and therefore 
always with a lessened chance of life or of marrying. There 
is another remarkable circumstance which seems to sup- 
port Dr. Stark's conclusion, namely, that widows and 
widowers in France suffer in comparison with the married 
a very heavy rate of mortality; but Dr. Farr attributes this 
to the poverty and evil habits consequent on the disruption 
of the family and to grief. On the whole we may conclude 
with Dr. Farr that the lesser mortality of married than of 

*Dr. Farr, ibid. Tlie quotations given below are extracted from 
tlie same striking paper. 

f I have taken the mean of the quinquennial means, given in " The 
Tenth Annual Report of Births, Deaths, etc.. in Scotland, " 1867- 
The quotation from Dr. Stark is copied from an article in the " Daily 
News," Oct. 17, 1868, which Dr. Farr cjnsiders very carefully 


tinmanied men, which seems to be a general law, *'ia 
mainly due to the constant elimination of imperfect types, 
and to the skillful selection of the finest individuals out of 
each successive generation;" the selection relating only to 
the marriage state, and acting on all corporeal, intellectual, 
and moral qualities.* We may, therefore, infer that sound 
and good men who out of prudence remain for a time 
unmarried do not suffer a high rate of mortality. 

If the various checks speciried in the two last paragraphs, 
and perhaps others as yet unknown, do not prevent the 
reckless, the vicious and otherwise inferior members of 
society from increasing at a quicker rate than the bettei 
class of men> the nation will retrograde, as has too often 
occurred in the history of the world. We must remember 
that progress is no invariable rule. It is very difficult to 
say why one civilized nation rises, becomes more powerful, 
and spreads more widely, than another; or why the same 
nation progresses more quickly at one time than at another. 
We can only say that it depends on an increase in the actual 
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 
appears to have little influence, except so far as vigor of 
body loads to vigor of mind. 

It has been urged by several writers that as high intellec- 
tual powers are advantageous to a nation, the old Greeks, 
who stood some grades higher in intellect than any race that 
has ever existed, + ought, if the power of natural feelection 
were real, to have risen still higher in the scale, increased 
in number, and stocked the whole of Europe. Here we 
have the tacit assumption, so often made with respect to 
corporeal structures, that there is some innate tendency 
toward continued development in mind and body. But 
development of all kinds depends on many concurrent 
favorable circumstances. Natural selection acts only tenta- 
tively. Individuals and races may have acquired certain 
indisputable advantages, and yet have perished from failing 

*Dr. Duncan remarks ("Fecundity, Fertility," etc., 1871, p. 334) 
on this subject: "At every age the healthy and beautiful go over 
from the unmarried side to the married, leaving the unmarried 
columns crowded with the sickly and aufoi-tunate." 

f See the ingenious and original argument on this subject by Mr. 
Gallon, " Hereditary Genius," pp. 340-343. 


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 frorti extreme sensuality; for they did 
not succumb until '^ they were enervated and corrupt to 
the very core/' * The western nations of Europe, who now 
so immeasurably surpass their former savage progenitors 
and stand at the summit of civilization, owe little or none 
of their superiority to direct inheritance from the old 
Greeks, though they owe much to the written works of that 
wonderful people. 

Who can positively say why the Spanish nation, so domi- 
nant at one time, has been distanced in the race. The 
awakening of the nations of Europe from the dark ages is 
a still more perplexing problem. At that early period, as 
Mr. Galton has remarked, almost all the men of a gentle 
nature, those given to meditation or culture of the mind, 
had no refuge except in the bosom of a Church which 
demanded celibacy; f 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 is incalculable, 
though- no doubt counterbalanced to a certain, perhaps to 
a large, extent in other ways; nevertheless, Europe has 
progressed at an unparalleled rate. 

The remarkable success of the English as colonists, com- 
pared to other European nations, has been ascribed to 
their ^''daring and persistent energy;^' a result which is 
well illustrated by comparing the progress of the Canadians 
of English and French extraction; but who can say how 
the English gained their energy ? There is apparently 

*Mr. Greg, "Eraser's Magazine," Sept., 1868, p. 357. 

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


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; for the more 
energetic, restless, and courageous men from all parts of 
Europe have emigrated during the last ten or twelve 
generations to that great country, and have there succeeded 
best.* Looking to the distant future, I do not think that 
the Rev. Mr. Zincke takes an exaggerated view when he 
says : t "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 pur- 
pose and value when viewed in connection with, or rather 
as subsidiary to . , , the great stream of Anglo-Saxon 
emigration to the west." Obscure as is the problem of the 
advance of civilization, we can at least see that a nation 
which produced during a lengthened period the greatest 
number of highly intellectual^ energetic, brave, patriotic 
and benevolent men, would generally prevail over less 
favored nations. 

Natural selection follows from the struggle for existence; 
and this from a rapid rate of increase. It is impossible not 
to regret bitterly, but whether wisely is another question, 
the rate at which man tends to increase; for this leads in 
barbarous tribes to infanticide and many other evils, and in 
civilized nations to abject poverty, celibacy, and to the late 
marriages of the prudent. But as man suffers from the 
same physical evils as the lower animals, he has no right to 
expect an immunity from the evils consequent on the strug- 
gle for existence. Had he not been subjected during 
primeval times to natural selection, assuredly he would 
never have attained to his present rank. Since we see in 
many parts of the world enormous areas of the most fertile 
land capable of supporting numerous happy homes, but 
peopled only by a few wandering savages, it might be 
argued that the struggle for existence had not been suf- 
ficiently severe to force man upward to his highest standard. 
Judging from all that we know of man and the lower ani- 
mals, there has always been sufficient variability in their 
intellectual and moral faculties, for a steady advance 

*Mr. Galton, '♦ Macmillan's Magazine," Aug., 1865, p. 325. See 
also "Nature," "On Darwinism and National Life," Dec, 1869, p. 

f "Last Winter in the United States," 1868, p, 89, 


through natural selection. Ko doubt such advance 
demands many favorable concurrent circumstances; but it 
may well be doubted whether the most favorable v/ould have 
sufficed, had not the rate of increase been rapid, and the 
consequent struggle for existence extremely severe. It even 
appears from what we see, for instance, in parts of South 
America, that a people which may be called civilized, such 
as the Spanish settlers, is liable to become indolent and to 
retrograde, when the conditions of life are very easy. AVith 
highly civilized nations continued progress depends in a 
subordinate degree on natural selection; for such nations 
do not supplant and exterminate one another as do savage 
tribes. Nevertheless the more intelligent members within 
the same community will succeed better in the long run 
than the inferior, and leave a more numerous progeny, and 
this is a form of natural selection. The more efficient 
causes of progress seem to consist of a good education 
during youth while the brain is impressible, and of a high 
standard of excellence, inculcated by the ablest and best 
men, embodied in the laws, customs and traditions of the 
nation, and enforced by public opinion. It should, however, 
bo borne in mind that the enforcement of public opinion de- 
pends on our appreciation of the approbation and disapproba- 
tion of others; and this appreciation is founded on our sympa- 
thy, which it can hardly be doubted was originally developed 
through natural selection as one of the most important 
elements of the social instincts.* 

On the Evidence That All Civilized Nations Were Once 
Barbarous. — The present subject has been treated in so full 
and admirable a manner by Sir J. Lubbock, f Mr. Tylor, 
Mr. M'Lennan and others, that I need here give only the 
briefest summary of their results. The arguments recently 
advanced by the Duke of Argyll J and formerly by Arch- 
bishop Whately, in favor of the belief that man came into 
the woi'ld as a civilized being, and that all savages have 
since undergone degradation, seem to me weak in compari- 

^ I am much indebted to Mr Jobn Morley for some good criticisms 
on this subject see, also, Broca, "Les Selections," ''Revue d'Au- 
thropf)h)gie," 1872. 

f -On the Origin of Civilization," "Proc. Ethnological Soc," 
Nov 2G. 18G7 

% '• Primeval Man," 


son with those advanced on the other side. Many nations, 
no doubt, liave fallen av/ay in civilization, and some may 
have lapsed into utter barbarism, though on this latter head 
1 have met with no evidence. The ]?uegians were probably 
compelled by other conquering hordes to settle in their 
inhospitable country, and they may have become in conse- 
quence somewhat more degraded; but it would be difficult.^ 
to prove that they have fallen much below the Botocudos, ' 
who inhabit the finest parts of Brazil. 

The evidence that all civilized nations are the descend 
ants of barbarians, consists, on the one side, of clear traces 
of their former low condition in still-existing customs, 
beliefs, language, etc.; and on the other side, of proofs 
that savages are independently able to raise themselves a 
few steps in the scale of civilization^ and have actually thus 
risen. The evidence on the first head is extremely curious, 
but cannot be here given, I refer to such cases as that of 
the art of enumeration, which, as Mr, Tylor clearly shows 
by reference to the words still used in some places, origi- 
nated in counting the fingers, first of one hand and then of 
the other, and lastly of the toes. We have traces of this 
in our own decimal system, and in the Roman numerals, 
where, after the V, which is supposed to be an abbreviated 
picture of a human hand, we pass on to VI, etc., when 
the other hand no doubt was used. So again, '* when we 
speak of three-score and ten, we are counting by the vigesi- 
riial system, each score thus ideally made standing for 20 — 
for 'one man 'as a Mexican or Carib would put it."* 
According to a large and increasing school of philologists, 
every language bears the marks of its slow and gradual evo- 
lution. So it is with the art of writing, for letters are 
rudiments of pictorial representations. It is hardly possi- 
ble to read Mr. M'Lennan's work \ and not admit that 
almost all civilized nations still retain traces of such rude 
habits as the forcible capture of wives. What ancient 

*" Royal Institution of Great Britain." March 15, 1867, Also 
'' llesearclies Into the Early History of Mankind," 1865. 

f " Primitive Marriage," 1885. See, likewise, an excellent article, 
evidently by the same author, in the " North British Review," July, 
1869. Also, Mr. L. H. Morgan, 'A Conjectural Solution of the 
Origin of the Class System of Relationship," in '' Proc. American 
Acad, of Sciences," vol vii, I-eb., 1868. Prof. Schaafthausen 
(" Anthropolog. Review," Oct.. 1869, ]>. 373)remarkson "the vestiges 
of liuman gacri^ces t'ouad botk iu Homer and the Old Testameat" 


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

Turning to the other kind of evidence: Sir J. Lubbock 
has shown that some savages have recently improved a little 
in some of their simpler arts. From the extremely curious 
account which he gives of the weapons, tools and arts in 
use among savages in various parts of the world it cannot 
be doubted that these have nearly all been independent dis- 
coveries, excepting perhaps the art of making fire.* The 
Australian boomerang is a good instance of one such inde- 
pendent discovery. The Tahitians when first visited had 
advanced in many respects beyond the inhabitants of most 
of the other Polynesian islands. There are no just grounds 
for the belief that the high culture of the native Peruvians 
and Mexicans was derived from abroad ;t many native 
plants were there cultivated and a few native animals 
domesticated. We should bear in mind that, judging from 
the small influence of most missionaries, a wandering crew 
from some semi-civilized land, if washed to the shores of 
America, would not have produced any marked effect on 
the natives unless they had already become somewhat ad- 
vanced. 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 tnat 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 

*Sir J. Lubbock, " Prebistoric Times," 2d edit., 1869, chap, xv 
and xvi, et passim. See also tbe excellent nintb chapter in Tylor's 
"Early History of Mankind," 2d edit., 1870. 

f Dr. F. Miiller has made some good remarks to this effect in tb<> 
" Reise der Novara: Antbropolog. Tbeil," Abtheil. iii, 1868, s 137. 


countries, which include nearly the whole civilized world, 
were once in a barbarous condition. To believe that man 
was aboriginally civilized and then suffered utter de^ada- 
tion in so many regions is to take a pitiably low view of 
human nature. It is apparently a truer and more cheerful 
view that progress has been much more general than retro- 
gression; that man has risen, though by slow and inter- 
rupted steps, from a lowly condition to the highest standard 
as yet attained by him in knowledge, morals and religion. 




Position of man in ilie anima! series— Tlie 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 CDunecting links— Lower stages in the geneal- 
ogy of man. as inferred, firstly from his affinities and secondly 
from his structure — Early audrogyuou.'s condition of liie verte- 
brata — ( onclusiou. 

Even" if it be ffranteJ that the difference between man 
and his nearest allies is as great iu 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 earlier chapters appear to declare, 
m the plainest manner, that man is descended from some 
lower form, notwithstanding that connecting-links have not 
hitherto been discovered. 

Man is liable to numerous, slight and diversified varia- 
tions, which are induced by the same general causes, are 
governed and transmitted in accordance with the same gen- 
eral laws as in the lower animals. Man has multiplied so 
rapidly that he has necessarily been exposed to struggle for 
existence, and consequently to natural selection. He has 
given rise to many races, some of which differ so much from 
each other, that they have often been ranked by naturalists 
as distinct species. His body is constructed on the same 
homological plan as that of other mammals. He passes 
through the same phases of embryological development. 
He retains many rudimentary and useless structures, which 
no doubt were once serviceable. Characters occasionally 
make their reappearance in him, which we have 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 fi large extent, if man is the co-descendant with 
other mammals of son\e unknown and lower form. 

8ome naturalists, from being deeply impressed with the 
mental and spiritual ])owers of man. have divided the whole 
organic world into three kingdoms, the Human, the Animal, 
and the Vegetable, thus giving to man a separate kingdom.* 
Spiritual powers cannot be compared or classed by the nat- 
uralist; but he may endeavor to show, as I have done, that 
the mental faculties of man and the lower animals do not 
ditfer in kind, although immensely in degree. A difference 
in degree, however great, does n.ot justify us in placing man 
in a distinct kingdom, as will perhaps be best illustrated 
by comparing the mental powers of two insects, namely, 
a coccus or scale-insect and an ant, which undoubtedly be- 
long to the same class. The difference is here greater than, 
though of a somewhat different kind from, that between 
man and the highest mammal. The female coccus, while 
young, attaches itself by its proboscis to a plant; sucks the 
sap, but never moves again; is fertilized and lays eggs; and 
this is its whole history. On the other hand, to describe 
the habits and mental powers of worker -ants, would 
require, as Pierre Euber has shown, a large volume; I may, 
however, briefly specify a few points. Ants certainly com- 
municate information to each other, and several unite for 
the same work, or for games of play. They recognize their 
fellow-ants after months of absence, and feel sympathy for 
each other. They build great edifices, keep them clean, 
close the doors in the evening, and post sentries. They 
make roads as well as tunnels under rivers, and temporary 
bridges over them, by clinging together. They collect food 
for the community, and when an object, too large for 
entrance, is brought to the nest, they enlarge the door, and 
afterward build it up again. They store up seeds, of which 
they prevent the germination, and which, if damp, are 
brought up to the surface to dry. They keep aphides and 
other insects as milch-cows. They go out to tattle in regu- 
lar bands, and freely sacrifice their lives for the common 
weal. They emigrate according to a preconcerted plan. 
They capture slaves. They move the eggs of their aphides, 
as well as their own eggs and cocoons, into warm parts of 

* Isidore GeofTroy Si. Hilaire gives a detailed account of the posi- 
tion asFigned to man by vanons naturalists in their classifications; 
••aist. :sal. Gen.," torn, ii, 1859, pu. 170-189. 


the nest, in order that they may be quickly hatched; and 
endless similar facts could be given.* On the whole, the 
difference in mental power between an ant and a coccus is 
immense; yet no one has ever dreamed of placing these 
insects in distinct classes, much less in distinct kingdoms. 
No doubt the difference is bridged over by other insects; 
and this is not the case with man and the higher apes. But 
we have every reason to believe that the breaks in the series 
are simply the results of many forms having become 

Prof. Owen, relying chiefly on the structure of the braiuj 
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 mammals as are these two 
latter groups conjoined. This view has not been accepted, 
as far as I am aware, by any naturalist capable of forming 
an independent judgment, and therefore need not here be 
further considered. 

We can understand why a classification founded on any 
single character or organ — even an organ so wonderfully 
complex and important as the brain — or on the high devel- 
opment 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 arti- 
ficial, f Classifications ma}'', of course, be based on any 
character whatever, as on size, color, or the element inhab- 
ited; but naturalists have long felt a profound conviction 
that there is a natural system. This system, it is now generally 
admitted, must be, as far as possible, genealogical in arrange- 
ment — that is, the co-descendants of the same form must be 
kept together in one group, apart from the co-descendants 
of any other form; but if the parent-forms are related, so 
will be their descendants, and the two groups together will 
form a larger group. The amount of difference between 
the several groups — that is, the amount of modification 

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

f WestwQod, ** Modern Class of Insects," vol. ii. 1840, p. 87, 


wliicli each has undergone — is expressed by such terms as 
genera, families, orders and classes. As we have no record 
of the lines of descent, the pedigree can be discovered only 
by observing the degrees of resemblance between the beings 
which are to be classed. For this object numerous points 
of 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 multi- 
tude of words and points of construction, they would be 
universally recognized as having sprung from a common 
source, notwithstanding that they differed greatly in some 
few words or points of construction. But with organic 
beings the points of resemblance must not consist of adapta- 
tions 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 several unimportant structures, in use- 
less and rudimentary organs, or not now functionally active, 
or in an embryological condition, are by far the most serv- 
iceable 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 modification 
in some one character ought not to lead us to separate 
widely any two organisms. A part which already differs 
much from the sanie part in other allied forms has 'already, 
according to the theory of evolution, varied much; conse- 
quently it would (as long as the organism remained exposed 
to the same exciting conditions) be liable to further varia- 
tions of the same kind; and these, if beneficial, would be 
preserved, and thus be continually augmented. In many 
cases the continued development of a part, for instance, of 
the beak of a bird, or of the teeth of a mammal, would not 
aid the species in gaining its food, or for any other object; 
but with man we can see no definite limit to the continued 
development of the brain and mental faculties, as far as 
advantage is concerned. Therefore in determining the 
position of man in the natural or genealogical system the 
extreme development of his brain ought not to out- 
weigh a multitude of resemblances in other less important 
or quite unimportant points. 

The gre?.ter number of naturalists who have taken into 


consideration the whole structure of man, incliKlins- his 
mental faculties, have followed Blumenbach and i'avier, 
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, etc. Recently many of our 
best naturalists have recurred to the view tirst 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: for in the first i)lace, we must bear in mind 
the comparative insignificance for classification of the great 
development of the brain in man, and that the strongly- 
marked differences between the skulls of man and the 
Quadrumana (lately insisted upon by Bischolf, 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 sti'Licture of their limbs, far more than does man from 
the higher apes; yet in most systems, from that of Cuvier 
to the most recent one by Mr. Flower,* seals are ranked 
as a mere family in the order of the Carnivora. If man 
had not been his own classifier he would never have thought 
of founding a separate order for his own reception. 

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

In an early part of this work I brought forward various 
facts, sho wing how closely man agr ees in constitution with 

* " Proc. Zoolog. Soc." 1863, p. 4. 

f •* Evidence as to Man's Place in Nature," 1S63, p. 70, et passim. 


tlie higher mammals: and this agreement must depend on 
our close similarity in minute structure and chemical com- 
position. I gave, as instances, our liability to the same dis- 
eases and to the attacks of allied parasites; our tastes in 
common for the same stimulants, and the similar effects 
produced by them, as well as by various drugs, and other 
6uch facts. 

As small, unimportant points of resemblance between 
man and the Qaadrumana are not •commonly noticed in 
systematic works, and as, when numerous, they clearly 
reveal our relationship, I will specify a few such points. 
The relative position of our features is manifestly t.he same; 
and the various emotions are displayed by nearly similar 
movements of the muscles and skin, chiefly above the 03-0- 
brows and round the mouth. Some few expressions are, 
indeed, almost the same, as in the weeping of certain kinds 
of monkeys and in the laughing noise made by others, 
during which the corners of the mouth are drawn back- 
ward and the lower eye-lids wrinkled. The external ears 
are curiously alike. In man the nose is much more prom- 
inent than in most monkeys; but we may trace the com- 
mencement of an aquiline curvature in the nose of the 
Hoolock Gibbon; and this in the Senincqjitlieciis lutsica is 
carried to a ridiculous extreme. 

The faces of many monkeys are ornamented with beards, 
whiskers, or mustaches. The hair on the head grows to 
a great length in some species of Semnopithecus ; * and 
in the Bonnet monkey (Macaciis radiahis) it radiates from 
a point on the crown, with a parting down the middle. It 
is commonly said that the forehead gives to man his noble 
and intellectual appearance; but the thick hair on the head 
of the Bonnet monkey terminates downward abruptly, and 
is succeeded by hair so short and fine that at a little dis- 
tance 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 Eschrichtf states that in our chil- 
dren the limit between the hairy scalp and the naked fore- 
head is sometimes not well defined; so that here we seem 

*Jsid. GeofTroy, " Hist. Nat. Gen.,*' toin. ii. 1859. p. 217. 
f*'Uel)er die Hiclitimg der Haaie/' etc, Mailer's *'Arcliiv. fClr 
Auat. und Pbys.," 1827. s. 51. 


to lijive 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 con- 
verge 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 gorrilla, chimpanzee, orang, 
some species of Hylobates, and even to some few American 
monkeys. But in Hylolates agilis the hair on the forearm 
is directed downwardT or toward the wrist in the ordinary 
manner; and in H. lar it is nearly erect, with only a very 
slight forward inclination; so that in this latter species it 
is in a transitional state. It can hardly be doubted that 
with most mammals the thickness of the hair on the back 
and its direction is adapted to throw off the rain; even the 
transverse hairs on the fore legs of a dog may serve for this 
end when he is coiled up asleep. Mr. Wallace, who has 
carefully studed the habits of the orang, remarks that the 
convergence of the hair toward the elbow on the arm,s of 
the orang may be explained as serving to throw off the 
rain, for this animal during rainy weather sits with its 
arms bent and with the hands clasped round a branch or 
over its head. According to Livingstone, the gorilla also 
"sits in pelting rain with his hands over his head. ■*'* If 
the above explanation is correct, as seems probable, the 
direction of the hair on our own arms offers a curious 
record of our former state; for no one supposes that it is 
now of any use in throwing off the rain; nor in our present 
erect condition is it properly directed for this purpose. 

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

* Quoted by Reade, " The African Sketch Book," vol. i, 1873, p. 
I On the hair in Hylobates, see " Nat. Hist, of Mammals," by C. Ia 


It must not be supposed that the resemblances between 
man and certain apes in the above and in many other 
points — such as in having a naked forehead, long tresses on 
the head, etc. — ^are all necessarily the result oi unbroken 
inheritance from a common progenitor, or of subsequent 
reversion. Many of these resemblances are more probably 
due to analogous variation, which follows, as I have else- 
where attempted to show,* from co-descended organisms 
having a similar constitution, and having been acted on by 
like causes inducing similar modifications. With respect 
to the similar direction of the hair on the forearms of man 
and certain monkeys, as this character is common to almost 
all the anthropomorphous apes, it may probably be attribu- 
ted to inheritance; but this is not certain, as some very 
distinct American monkeys are thus characterized. 

Although, as we have now seen, man has no just right to 
form a separate Order for his own reception, he may per- 
haps claim a distinct sub-order or family. Prof. Huxley, 
in his last work,t divides the Primates into three sub- 
orders; namely, the Anthropidse with man alone, the Simi- 
adas, including monkeys of all kinds, and the Lemuridas 
with the diversified genera of lemurs. As far as differ- 
ences 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, from a genealogical point of view 
it appears that this rank is too high, and that man ought 
to form merely a family, or possibly even only a sub- 
family. If we imagine three lines of descent proceeding 
from a common stock, it is quite conceivable that two of 
them might after the lapse of ages be so slightly changed 
as still to remain a species of the same genus, while the 
third line might become so greatly modified as to deserve 
to rank as a distinct sub-family, family, or even order. 
But in this case it is almost certain that the third line 

Martin, 1841, p. 415. Also, Isid. GeofEroy on tlie American monkeys 
and other kinds, "Hist. Nat. Gen.," vol. ii, 1859, pp. 216, 243, 
Bscliriclit, ibid, ss. 46, 55, 61. Owen, **Anat. of Vertebrates." vol. 
iii, p. 619. Wallace, ** Contributions to the Theory of Natural Selec- 
tion," 1870, p. 344. 

*" Origin of Species," 5th edit., 1869, p. 194. "The Variation of 
Animals and Plants under Domestication," vol. ii, 1868, p. 348 
f " An Introduction to the Classification of Animals," 1869, p. 99. 


would still retain through inheritance numerous small 
points of resemblence with the other two. Here, then, 
would occur the difficulty, at present insoluble, how much 
weight we ought to assign in our classifications to strongly- 
marked differences in some few points — that is, to the 
amount of modification undergone, and how much to close 
!esemblance in numerous unimportant points, as indicating 
the lines of descent or genealogy. To attach much weight 
to the few but strong differences is the most obvious and 
pel haps the safest course, though it appears more correct 
to pay great attention to the many small resemblances, as 
giving a truly natural classification. 

In forming a judgment on this head with reference to 
man, we must glance at the classification of the vSimiadse. 
This family is divided by almost all naturalists into the 
Catarrhine group, or Old World monkeys, all of which are 
characterized (as their name expresses) by the peculiar 
structure of their nostrils, and by having four premolars in 
each jaw; and into the Platyrrhine group or Xcw World 
monkeys (including two very distinct sub-groups), all of 
which are characterized by differently constructed nostrils 
and by having six premolars in each jaw. vSome other 
small differences might be mentioned. Now man un- 
questionably belongs in his dentition, in the structure 
of his nostrils, and some other resi)ects, to the Catarrhine or 
Old World division; nor does he resemble the Platyrrhines 
more closely than the Catarrhinesin any characters, except- 
ing in a few of not much importance and apparently of an 
adaptive nature. It is therefore against all probability that 
some New World species should have formerly varied and 
produced a man-like creature, with all the distinctive char- 
acters proper to the Old World division; losing at the same 
time all its own distinctive characters. There can, conse- 
quently, hardly be a doubt that man is an off-shoot from 
the Old World .Simian stem; and that under a genealogical 
point of view he must be classed with the Catarrhine 

*TIii.s is nearly the same classification as that provisionally 
adopted by Mr St. <ieorge Mivart ("'J'ransacl. Plulosopli Soc," 
1867. p. ;300). who. alter sei)arating ibe Lemnridae, divides the 
remainder of tlie Primates into the Hotninidae. the Siiniadae which 
answer to the <.'atarrhines. the Cebidae, and the Hapaiid*e — these two 
latter <;roiips answering to the Platyrrhines. Mr. Mivart still abides 
by the same view; see ••^Jature," 1871, p. 481. 


The anthropomorphous apea. namely, the gorilla, chim- 
panzeo, oraiig, ami iiylobates, aiv by modt naturalists sepa- 
rated from the other Old Wurul monkeys, as a distinct 
sub-gronp. I am aware thai (iratiolet, relying on the 
etrnetnre of the brain, does not admit tlie existence of this 
snb-grou}), and no doubt it is a broken one. Thus the 
orang, as Mr. St. (r. Mivart remarks,* •* is one of the most 
peculiar and aberrant forms to be found in the order." The 
remaining non-anthropomorphous Old \yorld monkej's are 
again divided by some naturalists into two or three smaller 
sub-groups; the genus Semnopitheous, 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 8emnopithecus 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 vvhich he possesses in common with 
the whole Catarrhine group, but in other peculiar characters, 
such as the absence of a tail and of callosities, and in gen- 
eral appearance, we may infer that some ancient member of 
the anthropomorphous sub-group gave birth to man. It is 
not probable that, through the law of analogous variation, 
a member of one of the other lower sub-groups should have 
given rise to a man-like creature 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 -conse- 
quence of the great development of his brain and his erect 
position; nevertheless, we should bear in mind that he "is 
but one of several exceptional forms of Primates." \ 

Every naturalist who believes in the principle of evolu- 
tion will grant that the two main divisions of the Simiada?, 
namely, the Catarrhine and Platyrrhine monkeys, with their 
sub-groups, have all proceeded from some one extremely 
ancient progenitor. The early descendants of this progen- 
itor, before they had diverged to any considerable extent 
from each other, would still have formed a single natural 

**• Transact. Zoolog. Soc," vol. vi. 1867. p. 214. 

f Mr. St. U. Mivart, "Transact. Pliil. Soc," 1867, p. 410. 


froup; but Bome of the species or incipient genera would 
ave already be^un to indicate by their diverging characters 
the future distinctive marks of the Catarrhine and 
Platyrrhine divisions. 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 Catarrhine monkeys in one way and the Platyrrhines 
in another way, but would have resembled in this respect 
the allied Lemuridse, which differ greatly from each other 
in the form of their muzzles,* and to an extraordinary 
degree in their dentition. 

The Catarrhine and Platprhine monkeys agree in a. multi- 
tude of characters, as is shown by their unquestionably 
belonging to one and the same order. The many charac- 
ters which they possess in common can hardly have been 
independently acquired by so many distinct species; so that 
these characters must have been inherited. But a naturalist 
would undoubtedly have ranked as an ape or a monkey, an 
ancient form which possessed many characters common to 
the Catarrhine and Platyrrhine monkeys, other characters in 
an intermediate condition, and some few, perhaps, distinct 
from those now found in either gToup. And as man from 
a genealogical point of view belongs to the Catarrhine or Old 
World stock, we must conclude, however much the conclu- 
sion may revolt our pride, that our early progenitors would 
have been properly thus designated, f 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 inquire, where was the birthplace of man 
at that stage of descent when our progenitors diverged from 
the Catarrhine stock? The fact that they belonged to this 
stock clearly shows that they inhabitated the Old World ; 
but not Australia nor any oceanic island, as we may infer 

* Messrs. Murie and Mivart on the Lemuroidea, ** Transact, Zoolog. 
Soc," vol. vii. 1869, p. 5. 

fHSckel has come to this same conclusion. See '*tJeber die 
Entstehung des Menschengeschlechts," in Virchow's "Sammlung. 
gemein. wissen. Vortrage, " 1868, s. 61. Also his "NatQ.rliche Schop- 
fiingsgeschichte." 1868, in which he gives in detail his views on th^ 
genealogy of man. 


from the laws of geographical 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 th^ Africa was formerly inhabited by extinct apes 
closely allied to the gorilla and chimpanzee; and as these 
two species are now man^s nearest allies, it is somewhat 
more probable that our early progenitors lived on the 
African continent than elsewhere. But it is useless to 
speculate on this subject; for two or three anthropomor- 
phous apes, one the Dryopithecus * of Lartet, nearly as 
large as a man, and closely allied to Hylobates, existed in 
Europe during the Miocene age; and since so remote a 
period the earth has certainly undergone many great revo- 
lutions, and there has been ample time for migration on the 
largest scale. 

At the period and place, whenever and wherever it was, 
when man first lost his hairy covering, he probably 
inhabited a hot country; a circumstance favorable for 
the frugiferous diet on which, judging from analogy, 
he subsisted. We are far from knowing how long ago 
it was when man first diverged from the Catarrhine stock; 
but it may have occurred at an epoch as remote as the 
Eocene period; for that the higher apes had diverged from 
the lower apes as early as the Upper Miocene period is 
shown by the existence of the Dryopithecus. We are also 
quite ignorant at how rapid a rate organisms, whether high 
or low in the scale, may be modified under favorable cir- 
cumstances; 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 
some of the co-descendants of the same species may be not 
at all, some a little, and some greatly changed, all within 
the same period. Thus it may have been with man, who 
has undergone a great amount of modification in certain 
characters in comparison with the higher apes. 

The great break in the organic chain between man and 
his nearest allies, which cannot be bridged over by any ex- 
tinct or living species, has often been advanced as a grave 
objection to the belief that man is descended from some 
lower form; but this objection will not appear of much 

*Dr. C. Forsytli Major, "Sur les Singes Fossiles trouves en 
Italie: " Soc. Ital. des Sc. Nat.," torn, xv, 1873. 


weight to those who, from general reasons, believe m the 
general principle of evolution. Breaks often occur in all 
parts of the series, some being wide, sharp and defined, 
others less so in various degrees; as between tlfe orang and. 
its nearest allies — between the Tarsius and the other 
Lenmridae — between the elephant, and in a more striking 
manner between the Ornithorhynchus or PJchidna, and all 
other mammals. But these breaks depend merely on the 
number of related forms which have become extinct. At 
some future period, not very distant as measured by cent- 
uries, the civilized races of man will almost certainly ex- 
terminate and replace the savage races throughout the 
world. At the same time the anthropomorphous apes, as 
Prof. Schaaffhausen has remarked,* will no doubt be ex- 
terminated. The break between man and his nearest allies 
will then be wider, for it will intervene between man in a 
more civilized state, as we may hope, even than the Cauca- 
sian, and some ape as low as a baboon, instead of as now 
between the negro or Australian and the gorilla. 

AVith 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 reads Sir C Lyell's discus- 
eion.f where he shows that in all the vertebrate classes the 
d:?/.*overy of fossil remains has been a very slow and fortuit- 
ous process. Nor should it be forgotten that those regions 
which are the most likely toafTorrl remains connecting man 
with -some extinct aj)e-like creature have not as yet been 
searched by geologists. 

Lower Stages in the nei^enlocjij nf Man. — W"e have seen 
tliat jnan appears to have diverged from the Catarrhine or 
Old World division of theSimiadae after these had diverged 
from the New World division. We will now endeavor to 
follow the remote traces of his genealogy, trusting princi- 
pally to the mutual affinities between the various classes 
ami orders, with some slight reference to the periods, as 
far as ascertained, of their successive appearance on the 
earth. 'I'he I-.emuiidi¥ stand below and near to theSimiadae, 

id con.sti'ute a eery distinct family of the Primates, or, 
cor l!ng to HacKel and others, a «Hstinct onler. This 

*" Anthropoltjgica! l{Hvi**\v." April. 18G7. p. v;H(j. 
•f " Klemt-nts of ii<?o]ojy," 1S65, pp. 583-565. "Anliquiiy of 
Man," 1863, p. 145. 


gror.p is rlivcrsificd and broken to an extraordinary degree, 
and includes many aberrant forms. It has, therefore, proba- 
bly suffered much extinction. Most of the remnants sur- 
vive on ishinds, such as Madagascar and the Malayan Archi- 
pelago, where they have not been exposed to so severe a 
competition as they would have been on well-stocked con- 
tinents. This group likewise presents many gradations, 
leading, as Huxley remarks,* *' insensibly from the crown 
and summit of the animal creation down to creatures 
from which there is but a step, as it seems, to the lowest, 
smallest and the least intelligent of the placental mam- 
malia.'"' From these various considerations it is probable 
that the Simiadae were originally developed from the pro- 
genitors of the existing Lemurida^; 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 
mucli more extensive than at present. Hence the Placen- 
tata are generally supposed to have been derived from the 
Implacentata or Marsupials ; not, however, from forms 
closely resembling the existing Marsupials, but from their 
early progenitors. The Monotremata are plainly allied to 
the Mf^rsupials, forming a third and still lower division in 
the great mammalian series. They are represented at the 
present day solely by the Ornithorhynchus and Echidna; 
and these two forms may be safely considered as relics of a 
much larger group, representatives of which have been pre- 
served in Australia, through some favorable concurrence of 
circumstances. The Monotremata are eminently interesting, 
as leading in several important points of structure toward 
the class of reptiles. 

In attempting to trace the genealogy of the mammalia, 
and therefore of man, lower down in the series, we become 
involved in greater and greater obscurity; but as a most 
capable Judge, Mr. Parker, has remarked, we have good 
reason to believe, that no true bird or reptile interienes in 
the direct line of descent. He who wishes to see what 
ingenuity and knowledge can effect, may consult Prof* 
Hiickers works. f I vvill content myself with a few general 

*" Man's Place in Nature,'* p. 105. 

f Elaborate tables are ^\\e\\ in bis Genere'.le Morpliologie " (B, 
ii, s. 153 and s. 425;; and with mure especial re.ereuce to man in Lis 


remarks. Every eYolntionist will adi;nit that the five grea^ 
vertebrate classes, namely, mammals, birds, reptiles, amphib- 
ians and fishes, are descended from some one prototype; for 
they have much in common, especially during their embry- 
onic state. As the class of fishes is the most lowly organ- 
ized, and appeared before the others, we may conclude that 
all the members of the vertebrate kingdom are derived 
from some fish-like animal. The belief that animals so 
distinct as a monkey, an elephant, a humming-bird, a 
snake, a frog, and a fish, etc., could all have sprung from 
the same parents, will appear monstrous to those who have 
not attended to the recent progress of natural history. For 
this belief implies the former existence of links binding 
closely together all these forms, now so utterly unlike. 

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

** Naturliche SchSpfungsgeschi elite," 1868. Prof. Huxley, in review- 
ing this latter work (" The Academy," 1869, p. 42) says, that he con- 
siders the phylum or lines of descent of the vertebrata to be admir- 
ably discussed by Hackel, although he differs on some points. He 
expresses, also, his high estimate of the general tenor and spirit of 
the whole work. 
* " Palaeontology," 1860, p. 199. 


been preserved from utter extinction by inhabiting rivers, 
which are harbors of refuge, and are related to the great 
waters of the ocean in the same way that islands are to 

Lastly, one single member of the immense and diversi- 
fied class of fishes, namely, the lancelet or amphioxus, is so 
different from all other fishes, that Hackel maintains that 
it ought to form a distinct class in the vertebrate kingdom. 
This fish is remarkable for its negative characters; it can 
hardly be said to possess a brain, vertebral column, or heart, 
etc. ; so that it was classed by the older naturalists among 
the worms. Many years ago Prof. Groodsir perceived that 
the lancelet presented some affinities with the Ascidians, 
which are invertebrate, hermaphrodite, marine creatures 
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 
Mulluscoida of Huxley — a lower division of the great king- 
dom of the Mollusca; but . they have recently been placed 
by some naturalists among the Vermes or worms. Their 
larvae somewhat resemble tadpoles in shape,* and have the 
power of swimming freely about. M. Kovalevsky f has 
lately observed that the larvae of Ascidians are related to 
the vertebrata, in their manner of development, in the 
relative position of the nervous system, and in possessing a 
structure closely like the chorda dorsalis of vertebrate ani- 
mals ; and in this he has been since confirmed by 
Prof. Kupffer. M. Kovalevsky writes to me from 
jSTaples, that he has now carried these observations yet fur- 
ther, and should his results be well established, the whole 
will form a discovery of the very greatest value. Thus, if 
we may rely on embryology, ever the safest guide in classi- 

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

f '• Memoires de I'Acad. des Sciences de St. Petersbourg," toin. :k, 
No. 15, 186a. 


lication, it seems that we have at last gained a clew to the 
Eouice whence the vertebrata were derived.* AVe should 
the!i be justified in believing that at an extremely remote 
peiioil 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 develop- 
ment and producing the present class of Ascidians, tho 
other rising to the crown and summit of the animal king- 
dom by giving birth to the vertebrata. 

We have thus far endeavored rudely to trace the geneal- 
007 of the vertebrata by the aid 01 their mutual affinities. 
We will now look to man as he exists; and we shall, I think;, 
be able partially to restore the structure of our early pro- 
genitors, during successive periods, but not in due order of 
time. This can be effected by means of the rudiments 
which man still retains, by the characters which occasion- 
ally make their appearance in him through reversion, and 
by the aid of the principles of morphology and embryology. 
The various facts, to which I shall here allude, have been 
given in the previous chapters. 

The early progenitors of man must have been once cov- 
ered with hair, both sexes having beards; their ears were 
probably pointed and capable of movement ; and their 
bodies were provided with a tail, having the proper muscles. 
Their limbs and bodies v/ere also acted on by many mus- 
cles which now only occasionally reappear, butare normally 
present i:i the Quadrnmana. At this or some earlier period 
the great artery an:l nerve of tho humerus ran through a 
supracondyloid foramen. The intestine gavo forth a much 
larger diverticulum or ca3cum than that now existing. Tho 
foot was then prehensile, judging from the condition of fbo 
great toe ii^. the foevus; and our progenitors, no doubt, wore 
arboreal in their habits, and frequented some warm, forest- 
clad land. The males had great canine teeth, which served 

* But I am bound to add chat ^ome competent judges dispute this 
conclusion; for instance, M. Giard, jn a series of papers In the 
*• Archives de Zooiogie tCxpenmentale.'* ^oy 1872. Nevertheless, this 
naturalist remarks, p 281. ' L organ izatirjn de la larve ascidieune en 
dehors de toate bypotiiese et de toute theorie, nous montre coii.ment 
la nature pent pro.iuue la disposition fondamentale du tvpe veltebre 
(rexistence d'une C(»r<le dor>ale) die/ un invertebre ])ar la seule con- 
diiion vitale de I'adnptation, c't cette simple ])ossibilite <iu passage 
supprime I'abfme eiitre les deux sous-reguus, encore bien gu'en iguora 
far ou ie passage s'est fait ea realite.'* 


them as formidable weapons. At a much earlier period the 
uterus was double ; the excreta were voided through a 
cloana; and tlie eye was protected by a third eye-lid or nic- 
titating membrane. At a still earlier perioil the progenitors 
of man must have been aquatic in their habits; for morphology 
plainly tells us that our lungs consist of a modified swim- 
bladder, which once served as a float. The clefts on the 
neck in the embryo of man show where the branchiae once 
existed. In the lunar or weekly recurrent periods of some 
of our functions we apparently still retain traces of our 
primordial birth-place, a shore washed by the tides. At 
about this same early period the true kidneys Avere replaced 
by the corpora wolffiana. The heart existed as a simple 
pulsating vessel; and the chorda dorsalis took the place of 
a vertebral column. These early ancestors of man, thus 
seen in the dim recesses of time, must have been as simply, 
or even still more simply, organized than the lancelet or 

There is one other point deserving a fuller notice. It 
has long been known that in the vertebrate kingdom one 
sex bears rudiments of various accessory parts, appertain- 
ing 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 possessed true male 
and female glands. Hence some remote progenitor of the 
whole vertebrate kingdom appears to have been hermaph- 
rodite or androgynous.* But here we encounter a singu- 
lar difficulty. In the mammalian class the males possess 
rudiments of a uterus with the adjacent passage, in their 
vesiculas prostaticae; they bear also rudiments of mammae, 
and some male Marsupials htive traces of a marsupial sack.f 
Other analogous facts could be added. Are we, then, to 
suppose that some extremely ancient mammal continued 

*This is tlie conclusion of Prof. Gegenbaur, one of tlie lng.liest 
authorities in comparative anatomy; see '" Grundziige der verp:leich. 
Anat.," 1870 s. 876. Tlie result Las been arrived at chiefly from the 
study of the Am])hibia; but it appears from the researches of Wald- 
eyer (as quoted in *' Journal of Anat. and Phys.." 1869. p. 161), that 
the sexual organs of even " the liigher vertebrata are in their early 
condition hermaphrodite." Similar views have long been held by 
some authors, though until recently without a firm basis. 

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


androgynous, after it had acquired the chief distinctions of 
its class, and, therefore, after it had diverged from the 
lower classes of the vertebrate kingdom? This seems very 
improbable, for we have to look to fishes, the lowest of all 
the classes, to find any still existent androgynous forms.* 
That various accessory parts, proper to each sex, are found 
in a rudimentary condition in the opposite sex, may be 
explained by such organs having been gradually acquired 
by the one sex, and then transmitted in a more or less 
imperfect state to the other. When we treat of sexual 
selection we shall meet with innumerable instances of this 
form of transmission — as in the case of the spurs, plumes, 
and brilliant colors, acquired for battle or ornament by 
male birds and inherited by the females in an imperfect or 
rudimentary condition. 

The possession by male mammals of functionally imper- 
fect mammary organs is, in some respects, especially 
curious. The Monotremata have the proper milk-secreting 
glands with orifices, but no nipples; and as these animals 
stand at the very base of the mammalian series, it is proba- 
ble that the progenitors of the class also had milk-secreting 
glands, but no nipples. This conclusion is supported by 
what is known of their manner of development; for Prof. 
Turner informs me, on the authority of Kolliker and 
Langer, that in the embryo the mammary glands can be 
distinctly traced before the nipples are in the least visible; 
and the development of successive parts in the individual 
generally represents and accords with the development of 
successive beings in the same line of descent. The Mar- 
supials -differ from the Monotremata by possessing nipples; 
so that probably these organs were first acquired by the 
Marsupials, after they had diverged from, and risen above, 
the Monotremata, and were then transmitted to the 

* Hermapliroditism has been observed in several species of Ser- 
ranus, as well as in some other fishes, where it is either normal and 
symmetrical, or abnormal and unilateral. Dr. Zouteveen has given 
me references on this subject, more especially to a paper by Prof. 
Halbertsma, in the "Transact, of the Dutch Acad, of Sciences," vol. 
xvi. Dr. Giinther doubts the fact, but it has now been recorded by 
too many good observers to be any longer disputed. Dr. M. Lessona 
writes to me that he has verified the observations made by Cavolini 
on Serranus. Prof. Ercolani has recently shown (" Accad. delle 
Scieus5e," Bologna, Dec. 28, 1871) that eels are androgynous. 


placental mammals.* 'Eo one will suppose that the Mar- 
supials still remained androgynous after they had approx- 
imately acquired their present structure. How then are 
we to account for male mammals possessing mammae? It 
is possible that they were first developed in the females and 
then transferred to the males, but from what follows this is 
hardly probable. 

It may be suggested, as another view, that long after the 
progenitors of the whole mammalian class had ceased to be 
androgynous, both sexes yielded milk, and thus nourished 
their young; and in the case of the Marsupials, that both 
sexes carried their young marsupial sacks. This will not 
appear altogether improbable, if we reflect that the males 
of existing syngnathous fishes receive the eggs of the 
females in their abdominal pouches, hatch them, and after- 
ward, as some believe, nourish the young; f 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 Avind them round their own 
thighs, keeping them there until the tadpoles are born; 
that certain male birds undertake the whole duty of incuba- 
tion, and that male pigeons, as well as the females, feed 
their nestlings with a secretion from their crops. But the 
above suggestion first occurred to me from the mammary 
glands of male mammals being so much more perfectly 
developed than the rudiments of the other accessory repro- 
ductive 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 rudiment- 
ary; they are merely not fully developed and not functionally 

*Prof. Gegenbaur has sliovvn (" Jenaische Zeitsclirift," Bd. vii, p. 
212)tliat two distinct types of nipples prevail throughout the several 
mammalian orders, but that it is quite intelligible how both could 
have been derived from the nipples of the Marsupials, and the latter 
from those of the Monotremata. See, also, a memoir by Dr. Max 
Huss, on the mammary glands, ibid., B. viii, p. 176. 

f 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. 


active. They are sympathetically affected under the influ- 
ence of certain diseases, like the same organs in the female. 
They often secrete a few drops of milk at birth and at 
puberty; this latter fact occurred in the curious case, before 
referred to, where a young man possessed two pairs of 
mammae. In man and some other male mammals these 
organs have been known occasionally to become so well 
developed during maturity as to yield a fair supply of milk. 
Now if we suppose that during a former prolonged period 
male mammals aided the females in nursing their offspring,* 
and that afterward from some cause (as from the production 
of a smaller number of young) the males ceased to give this 
aid, disuse of the organs during maturity would lead to their 
becoming inactive; and from two well-known principles of 
inheritance, this state of inactivity would probably be trans- 
mitted to the males at the corresponding age of maturity. 
But at an earlier age these organs would be left unaffected, 
so that they would be almost equally well developed in 
the young of both sexes. 

Conclusion. — Von Baer has defined advancement or prog- 
ress in the organic scale better than any one else as resting 
on the amount of differentiation and specialization of the 
several parts of a being — when arrived at maturity, as I 
should be inclined to add. Now, as organisms have become 
slowly adapted to diversified lines of life by means of nat- 
ural selection, their parts will have become more and more 
differentiated and specialized for various functions from 
the advantage gained by the division of physiological labor. 
The same part appears often to have been modified first for 
one purpose, and then long afterward for some other and 
quite distinct purpose; and thus all the parts are rendered 
more and more complex. But each organism still retains 
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 organiza- 
tion on the whole has advanced throughout the world by 
slow and interrupted steps. In the great kingdom of the 
vertebrata it has culminated in man. It must not, how- 
ever, be supposed that groups of organic beings are always 

* Maddle. C. Royer has suggested a similar view iu her " Origine 
de rHomme," etc., 1870. 


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 look- 
ing at the existing members of any lowly organized group 
as perfect 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* resem- 
bling the larvae of existing Ascidians. These animals 
probably gave rise to a group of fishes, as lowly organized 
as the lancelet ; and from these the Ganoids, and other 
fishes like the Lepidosiren, must have been developed. 
From such fish a very small advance would carry us on to 
the Amphibians. We have seen that birds and reptiles 

* The inliabitants of the seashore must be greatly affected by the 
tides; animals living either about the mean bigh- water mark, or about 
tbe mean low-water mark, pass tbrougb a complete cycle of tidal 
changes in a fortnight. Consequently their food supply will undergo 
marked changes week by week. The vital functions of such ani- 
mals, living under these conditions for many generations, can hardly 
fail to run their course in regular weekly periods. Now it is a mys- 
terious fact that in the higher and now terrestrial vertebrata, as well 
as in other classes, many normal and abnormal processes have one or 
more whole weeks as their periods; this would be rendered intelligi- 
ble if the vertebrata are descended from an animal allied to the 
existing tidal Ascidians. Many instances of such periodic processes 
might be given, as the gestation of mammals, the duration of fevers, 
etc. The hatching of eggs affords also a good example, for, accord- 
ing to Mr. Bartlett ("Land and Water," Jan. 7, 1871), the eggs of 
the pigeon are hatched in two weeks; those of the fowl in three; 
those of the duck in four; those of the goose in five; and those of the 
ostrich in seven weeks. As far as we can judge, a recurrent period, 
if approximately of the right duration for any process of function, 
would not, when once gained, be liable to change; consequently it 
might be thus transmitted through almost any number of genera- 
tions. But if the function changed, the period would have to 
change, and would be apt to change almost abruptly by a whole 
week. This conclusion, if sound, is highly remarkable; for the 
period of gestation in each mammal, and the hatching of each bird's 
eggs, and many other vital processes, thus betray to us the primor- 
dial Inrthplace of these aniuTals. 


were once intimately connected together; and the Monotre- 
mata now connect mammals with reptiles in a slight degree. 
But no one can at present say by what line of descent the 
three higher and related classes, namely, mammals, birds, 
and reptiles, were derived from the two lower vertebrate 
classes, namely, amphibians and fishes. In the class of 
mammals the steps are not difficult to conceive which led 
from the ancient Monotremata to the ancient Marsupials ; 
and from these to the early progenitors of the placental 
mammals. We may thus ascend to the Lemuridae; and the 
interval is not very wide from these to the Simiadae. 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, 

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 pres- 
ent knowledge, approximately recognize our parentage; nor 
need we feel ash*amed of it. The most humble organism is 
something much higher than the inorganic dust under our 
feet ; and no one with an unbiased mind can study any 
living creature, however humble, without being struck with 
enthusiasm at its marvelous structure and properties. 




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

It is not my intention here to describe the several so- 
called races of men; but I am about to inquire what is the 
value of the differences between them under a classificatory 
point of view and how they have originated. In determin- 
ing whether two or more allied forms ought to be ranked 
as species or varieties, naturalists are practically guided by 
the following considerations, namely, the amount of differ- 
ence 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 
shown, or rendered probable, that the forms in question 
have remained distinct for a long period, this becomes an 
argument of much weight in favor of treating them as 
species. Even a slight degree of sterility between any two 
forms when first crossed, or in their offspring, is generally 
considered as a decisive test of their specific distinctness; 
and their continued persistence without blending within 
the same area, is usually accepted as sufficient evidence, 
either of some degi*ee of mutual sterility, or in the case of 
animals of some mutual repugnance to pairing. 

Independently of fusion 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 vari- 
able and yet not yield intermediate varieties. Geographical 
distribution is often brought into play unconsciously and 
sometimes consciously; so that forms living in two widely 
separated areas, in which most of tlie other inhabitants are 
specifically 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 nat- 
uralist would any other animal. In regard to the amount 
of difference between the races, we must make some allow- 
ance for our nice powers of discrimination gained by the 
long habit of observing ourselves. In India, as Elphinstone 
remarks, 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 are much 
more like each other in form than would at first be sup- 
posed; certain negro tribes must be excepted, while others, 
as Dr. Rohlf s writes to me, and as I have myself seen, have 
Caucasian features. This general similarity is well shown 
by the French photographs in the Collection Anthropolo- 
gique du Museum de Paris of the men belonging to various 
races, the greater number of which njight pass for Euro- 
peans, as many persons to whom I have shown them have 
remarked. Nevertheless, these men, if seen alive, would 
undoubtedly appear very distinct, so that we are clearly 
much influenced in our judgment by the mere color of the 
skin and hair, by slight differences in the features, and by 

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 propor- 
tions of all parts of the body,t the capacity of the 

*" History of India," 1841, vol. i, p. 323. Father Ripa makes 
exactly the same remark with respect to the Chinese. 

f A vast number of measurements of Whites, Blacks and Indians 
are given in the " Investigations in the Military and Anthropolog. 


lungs, the form and capacity of the skull, and even 
in the convolutions of the brain.* But it would be 
an endless task to specify the numerous points of dif- 
ference. The races differ also in constitution, in acclima- 
tization 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 com- 
parison must have been struck with the contrast between 
the taciturn, even morose, aborigines of South America and 
the light-hearted, talkative negroes. There is a nearly sim- 
ilar contrast between the Malays and the Papuans,! who 
live under the same physical conditions and are separated 
from each other only by a narrow space of sea. 

We will first consider the arguments which may be 
advanced in favor of classing the races of man as distinct 
species, and then the arguments on the other side. If a 
naturalist, who had never before seen a Negro, Hottentot, 
Australian or Mongolian, were to compare them, he would 
at once perceive that they differed in a multitude of char- 
acters, some of slight and some of considerable importance. 
On inquiry he would find that they were adapted to live under 
widely different climates, and that they differed somewhat in 
bodily constitution and mental 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 con- 
clusion 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 4,000 
years ago.]; He would also hear, on the authority of an 

Statistics of American Soldiers," by B. A. Gould, 1869, pp. 298-358; 
"On the capacity of the lungs," p. 471. See also the numerous and 
valuable tables, by Dr. Weisbach, from the observations of Dr. 
Scherzerand Dr. Schwarz, in the " Reise der No vara; Anthropolog. 
Theil," 1867. 

* See, for instance, Mr. Marshall's account of the brain of a Bush- 
woman, in "Phil. Transact.," 1864, p. 519. 

fWallace, " The Malay Archipelago," vol. ii. 1869, p. 178. 

X With respect to the figures in the famous Egyptian caves of 
Abou-Simbel, M. Pouchet says ("The Plurality of the Human 


excellent observer. Dr. Lund,* that tlie human skulls 
found in the caves of Brazil, entombed with many extinct 
mammals, belonged to the same type as that now prevail- 
ing throughout the American Continent. 

Our naturalist would then perhaps turn to geographical 
distribution, and he would probably declare that those 
forms must be distinct species, which differ not only in 
appearance, but are fitted for hot, as well as damp or dry 
countries, and for the Arctic regions. He might appeal to 
the fact that no species in the group next to man — namely, 
the Quadrumana, can resist a low temperature, or any con- 
siderable change of climate; and that the species which 
come nearest to man have never been reared to maturity, 
even under the temperate climate of Europe. He would 
be deeply impressed with the fact, first noticed by Agassiz, f 
that the different races of man are distributed over the 
world in the same zoological provinces as those inhabited 
by undoubtedly distinct species and genera of mammals. 
This is manifestly the case with the Australian, Mongolian, 
and Negro races of man; in a less well-marked manner 
with the Hottentots; but plainly with the Papuans and 
Malays, who are separated, as Mr. Wallace has shown, by 
nearly the same line which divides the great Malayan and 
Australian zoological provinces. The Aborigines of America 

Races," Eng. translat., 1864, p. 50), that lie was far from finding 
recognizable representations of the dozen or more nations wliicli 
some authors believe that they can recognize. Even some of the 
most strongly-marked races cannot be identified with that degree of 
unanimity which might have been expected from what has been 
written on the subject. Thus Messrs. Nott and Gliddon (" Types of 
Mankind," p. 148), state that Eameses II, or the Great, has features 
superbly European; whereas Knox, another firm believer in the 
specific distinctness of the races of man (" Races of Man," 1850, p. 
201), speaking of young Memnon (the same as Rameses II, as I am 
informed by Mr. Birch), insists in the strongest manner that he is 
identical in character with the Jews of Antwerp. Again, when I 
looked at the statue of Amunoph III, I agreed with two oflScers of 
the establishment, both competent judges, that he had a strongly- 
marked negro type of features; but Messrs. Nott and Gliddon (ibid, 
p. 146, fig. 53), describe him as a hybrid, but not of "negro inter- 

* 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. 

f "Diversity of Origin of the Human Races," in the " Christcai 
Examiner," July, 1850. 


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 opossum, range from the one into 
the other, as did formerly some of the gigantic Edentata. 
The Esquimaux, like other Arctic animals, extend round the 
whole polar regions. It should be observed that the 
amount of difference between the mammals of the several 
zoological provinces does not correspond with the degree of 
separation between the latter; so that it can hardly be con- 
sidered as an anomaly that the Negro differs more, and the 
American much less from the other races of man, than do 
the mammals of the African and American Continents 
from the mammals of the other provinces. Man, it may be 
added, does not appear to have aboriginally inhabited any 
oceanic island; and in this respect he resembles the other 
members of his class. 

In determining whether the supposed varieties of the 
same kind of domestic animal sliould be ranked as such, or 
as specifically distinct, that is, whether any of them are 
descended from distinct wild species, every naturalist would 
lay much stress on the fact of their external parasites being 
specifically distinct. All the more stress would be laid on 
this fact, as it would be an exceptional one; for I am in- 
formed 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 coun- 
tries from the different races of man;* and he finds that 
they differ, not only in color, but in the structure of their 
claws and limbs. In every case in which many specimens 
were obtained the differences were constant. The surgeon 
of a whaling ship in the Pacific assured me that 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 days. These Pedi- 
culi were darker colored and appeared different from those 
proper to the natives of Chili, 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 

* "Transact. R. Soc. of Edinburgh," vol. xxii, 1861, p. 567. 


Eastern and Western coasts, from the Hottentots and 
Kaffirs; 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 diiferent districts. With insects slight struct- 
ural differences, if constant, are generally esteemed of 
specific value; and the fact of the races of man being in- 
fested by parasites which appear to be specifically distinct 
might fairly be urged as an argument that the races them- 
selves 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 con- 
sult the work* of Prof. Broca, a cautious and philosophical 
observer, and in this he would find good evidence that 
some races were quite fertile together, but evidence of an 
opposite nature in regard to other races. Thus it has been 
asserted that the native women of Australia and Tasmania 
rarely produce children to European men; the evidence, 
however, on this head has now been shown to be almost 
valueless. The half-castes are killed by the pure blacks; 
and an account has lately been published of eleven half- 
caste youths murdered and burned at the same time whose 
remains were found by the police, f Again, it has often 
been said that when mulattoes intermarry they produce 
few children; on the other hand, Dr. Bachman, of Charles- 
ton,]; 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 con- 

*"0n the Phenomena of Hybridity in the Genus Homo," Eng. 
translat., 1864. 

f See the interesting letter by Mr. T. A. Murray, in the " Anthro- 
polog. Review," April, 1868, p. 53. In this letter Count Strzelecki's 
statement that Australian women who have borne children to a white 
man are afterward sterile with their own race is disproved. M. A. 
de Quatrefages has also collected (" Revue des Cours Scientifiques," 
March, 1869, p. 239) much evidence that Australians and Europeans 
are not sterile when crossed. 

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


elusion.* In the United States the census for the year 
1854 inckided, according to Dr. Bachman, 405,751 mulat- 
toes; and this number, considering all the circumstances 
of the case, seems small; but it may partly be accounted for 
by the degraded and anomalous position of the class and 
by the profligacy of the women. A certain amount of 
absorption of mulattoes into negroes must always be in 
progress; and this would lead to an apparent diminution of 
the former. The inferior vitality of mulattoes is spoken of 
in a trustworthy workf as a well-known phenomenon; and 
this, although a different consideration from their lessened 
fertility, may perhaps be advanced as a proof of the specific 
distinctness of the parent races. No doubt both animal 
and vegetable hybrids, when produced from extremely dis- 
tinct 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 vigor, and yet so sterile, shows how little necessary 
connection there is in hybrids between lessened fertility 
and vitality; other analogous cases could be cited. 

Even if it should hereafter be proved that all the races 
of men were perfectly fertile together, he who was inclined 
from other reasons to rank them as distinct species, might 
with justice argue that fertility and sterility are not safe 
criterions of specific 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 fer- 
tility of converse crosses between the same two species. 
With forms which must be ranked as undoubted species, a 
perfect series exists from those which are absolutely sterile 
when crossed, to those which are almost or completely fer- 
tile. The degrees of sterility do not coincide strictly with 

* Dr. Rohlfs writes to me that lie found the mixed races in the 
Great Sahara, derived from Arabs, Berbers, and Negroes of three 
tribes, extraordinarily fertile. On the other hand, Mr. Winwood 
Reade informs me that the Negroes on the Gold Coast, though admir- 
ing white men and mulattoes, have a maxim that mulattoes should 
not intermarry, as the children are few and sickly. This belief, as 
Mr. Reade remarks, deserves attention, as white men have visited 
and resided on the Gold Coast for four hundred years, so that the 
natives have had ample time to gain knowledge through experience. 

f " Military and Anthropolog. Statistics of American Soldiers," by 
B. A. Gould, 1869, p. 319. 


the degrees of difference between the parents in external 
structure or habits of life. Man in many respects may be 
compared with those animals which have long been domes- 
ticated, and a large body of evidence can be advanced in 
favor of the Pallasian doctrine,* that domestication tends 
to eliminate the sterility which is so general a result of the 
crossing of species in a state of nature. From these sev- 
eral considerations, it may be justly urged that the perfect 
fertility of the intercrossed races of man, if established, 
would not absolutely preclude us from ranking them as 
distinct species. 

Independently of fertility, the characters presented by 
the offspring from a cross have been thought to indicate 
whether or not the parent-forms ought to be ranked as 

* " 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 so to external structure or to ordinary differences in constitution. 
One important element in the sterility of crossed species apparently 
lies in one or both having been long habituated to fixed conditions; 
for we know that changed conditions have a special influence on the 
reproductive system, and we have good reason to believe (as before 
remarked) that the fluctuating conditions of domestication tend to 
eliminate that sterility which is so general with species, in a natural 
state, when crossed. It has elsewhere been shown by me (ibid., vol. 
ii, p. 185, and " Origin of Species," 5th edit., p. 317), that the steril- 
ity of crossed species has not been acquired through natural selection; 
we can see that when two forms have already been rendered very 
sterile, it is scarcely possible that their sterility should be aug- 
mented by the preservation or survival of the more and more sterile 
individuals; for, as the sterility increases, fewer and fewer offspring 
will be produced from which to breed, and at last only single indi- 
viduals will be produced at the rarest intervals. But there is even a 
higher grade of sterility than this. Both Gartner and Kcilreuter 
have proved that in genera of plants, including many 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, as shown by the 
swelling of the germen. It is here manifestly impossible to select 
the more sterile individuals, which have already ceased to yield 
seeds; so that the acme of sterility, when the germen alone is 
affected, cannot have been gained through selection. This acme, 
and no doubt the other grades of sterility, are the incidental results 
of certain unknown differences in the constitution of the reproductive 
system of the species which are crossed, 


species or varieties; but after carefully studying the evi- 
dence, I have come to the conclusion that no general rules 
of this kind can be trusted. The ordinary result of a cross 
is the production of a blended or intermediate form; but in 
certain cases some of the offspring take closely after one 
parent-form and some after the other. This is especially 
apt to occur when the parents differ in characters which 
first appeared as sudden variations or monstrosities.* 1 
refer to this point because Dr. Rohlfs informs me that he 
has frequently seen in Africa the offspring of negroes crossed 
with members of other races, either completely black or 
completely white, or rarely piebald. On the other hand, it 
is notorious that in America mulattoes commonly present 
an intermediate appearance. 

We have now seen that a naturalist might feel himself 
fully justified in ranking the races of man as distinct spe- 
cies; for he has found that they are distinguished by many 
differences in structure and constitution, some being of 
importance. These differences have also remained nearly 
constant for very long periods of time. Our naturalist will 
have been in some degree influenced by the enormous range 
of man, which is a great anomaly in the class of mammals, 
if mankind be viewed as a single species. He will have 
been struck with the distribution of the several so-called 
races, which accords with that of other undoubtedly dis- 
tinct 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 nat- 
uralist were to inquire whether the forms of man keep dis- 
tinct like ordinary species when mingled together in large 
numbers in the same country, he would immediately dis- 
cover that this was by no means the case. In Brazil he 
would behold an immense mongrel population of Negroes 
and Portuguese; in Chili and other parts of South Amer- 
ica he would behold the whole population consisting of In- 
dians and Spaniards blended in various degrees, f In many 

* " The Variation of Animals," etc., vol. ii, p. 92. 

I'M. de Quatrefages Las given (" Anthropolog. Review," Jan., 
1869. p. 22) an interesting account of the success and energy of the 
Paulistas in Brazil, who are a much crossed race of Portuguese and 
Indians, with a mixture of the blood of other race^ 


parts of the same continent he would meet with the most 
complex crosses between Negroes, Indians, and Europeans; 
and judging from the vegetable kingdom such triple 
crosses afford the severest test of the mutual fertility of the 
parent forms. In one island of the Pacific he would find a 
small population of mingled Polynesian and English blood; 
and in the Fiji Archipelago a population of Polynesian and 
Negritos crossed in all degrees. Many analogous cases 
could be added; for instance, in Africa. Hence the races 
of man are not sufficiently distinct to inhabit the same 
country without fusion; and the absence of fusion affords 
the usual and best test of specific distinctness. 

Our naturalist would likewise be much disturbed as soon 
as he perceived that the distinctive characters of all thp 
races were highly variable. This fact strikes every one on 
first beholding the negro slaves in Brazil, who have been 
imported from all parts of Africa. The same remark holds 
good with the 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 been often asserted. Hotten- 
tot women offer certain peculiarities, more strongly marked 
than those occurring in any other race, but these are 
known not to be of constant occurrence. In the several 
American tribes, color and hairiness differ considerably; as 
does color to a certain degree, and the shape of the 
features greatly, in the negroes of Africa. The shape of 
the skull varies much in some races;* and so it is with 
every other character. Now all naturalists have learned 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 treat- 
ing the races of man as distinct species, is that they gradu- 
ate into each other, independently in many cases, as far as 
we can judge, of their having intercrossed. Man has been 
studied more carefully than any other animal, and yet there 
is the greatest possible diversity among capable judges 
whether he should be classed as a single species or race, or 

* 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 
gUort and as broad as those of the Tartars," etc. 


as two (Virey), as three (Jacqiiinot), as four (Kant), five 
(Blumenbach), six (Buffon), seven (Hunter), eight (Agas- 
siz), eleven (Pickering), fifteen (Bory St. Vincent), sixteen 
(Desmoulins), twenty-two (Morton), sixty (Crawfurd), or 
as sixty-three, according to Burke.* This diversity of 
judgment does not prove that the races, ought not to be 
ranked as species, but it shows that they graduate into each 
other, and that it is hardly possible to discover clear 
distinctive characters between them. 

Every naturalist who has had the misfortune to under- 
take tlie description of a group of highly varying organ- 
isms has encountered cases (I speak after experience) 
precisely like that of man; and if of a cautious disposition, 
he will end by uniting all the forms which graduate into 
each other under a single species; for he will say to him- 
self 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; while 
in other genera, as in Cercopithecus, most of the species 
can be determined with certainty. In the American genus 
Cebus, the various forms are ranked by some naturalists as 
species, by others as mere geographical races. Now if 
numerous specimens of Cebus were collected from all parts 
of South America, and those forms which at present appear 
to be specifically distinct were found to graduate into each 
other by close steps, they would usually be ranked as mere 
varieties or races; and this course has been followed by 
most naturalists with respect to the races of man. Never- 
theless, it must be confessed that there are forms, at least 
in the vegetable kingdom, f which we cannot avoid naming 
as species, but which are connected together by numberless 
gradations, independently of intercrossing. 

Some naturalists have lately employed the term *■*" sub- 
species " to designate forms which possess many of the char- 
acteristics of true species, but which hardly deserve so high 

*See a good discussion on this subject in Waitz, **Introduct. to 
Anthropology," Eng. translat., 1863, pp. 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. 

f Prof. Nageli has carefully described several striking cases in his 
"Botanische Mittheilungen, " B. ii, 1866, ss. 294-369. Prof. Asa 
Gray has made analogous remarks on some intermediate forms in the 
Compositse of North Americt^* 


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

The question whether mankind consists of one or sev- 
eral species has of late years been much discussed by anthro- 
pologists, who are divided into the two schools of monogen- 
ists and polygenists. Those who do not admit the prin- 
ciple of evolution must look at species as separate creations, 
or as in some manner as distinct entities; and they must 
decide what forms of man they will consider as species by the 
analogy of the method commonly pursued in ranking other 
organic beings as species. But it is a hopeless endeavor to 
decide this point, until some definition of the term 
" species " is generally accepted; and the definition must 
not include an indeterminate element such as an act of 
creation. We might as well attempt without any definition 
to decide whether a certain number of houses should be 
called a village, town or city. We have a practical illus- 
tration of the difficulty in the never-ending doubts whether 
many closely-allied mammals, birds, insects and plants, which 
represent each other respectively in North America and 
Europe, should be ranked as species or geographical races; 
and the like holds true of the 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 

**• Origin of Species," 5tli edit. p. 68. 


majority of rising men, will feel no doubt that all the races 
of man are descended from a single primitive stock ; 
whether or not they may think fit to designate the races as 
distinct species, for the sake of expressing their amount of 
difference.* With our domestic animals the question 
whether the various races have arisen" from one or more 
species is somewhat different. Although it may be admit- 
ted that all the races, as well as all the natural species 
within the same genus, have sprung from the same primi- 
tive stock, yet it is a fit subject for discussion, whether all 
the domestic races of the dog, for instance, have acquired 
their present amount of difference since some one species 
was first domesticated by man; or whether they owe some 
of their characters to inheritance from distinct species, 
which had already been differentiated in a state of nature. 
With man no such question can arise, for he cannot be said 
to have been domesticated at any particular period. 

During an early stage in the divergence of the races of 
man from a common stock, the differences between the 
races and their number must have been small; consequently 
as far as their distinguishing characters are concerned, they 
then had less claim to rank as distinct species than the 
existing so-called races. Nevertheless, so arbitrary is the 
term of species, that such early races would perhaps have 
been ranked by some naturalists as distinct species, if their 
differences, although extremely slight, had been more con- 
stant than they are at present, and had not graduated into 
each other. 

It is, however, possible, though far from probable, that 
the early progenitors of man might formerly have diverged 
much in character, until they became more unlike each 
other than any now existing races; but that subsequently, 
as suggested by Yogt, f they converged in character. When 
man selects the offspring of two distinct species for the 
same object, he sometimes induces a considerable amount 
of convergence, as far as general appearance is concerned. 
This is the case, as shown by Von Kathus ius,]; with the 

*See Prof. Huxley to tliis effect in the " Fortnightly Review," 
1865, p. 275. 

f " Lectures on" Man," Eng. translat., 1864, p. 468. 

j"Die Racen des Schweines," 1860, s. 46. " Vorstudien fiir 
Geschichte, etc., Schweineschadel," 1864, s, 104. With respect to 
cattle, see M. de Quatrefages, "Unite de I'Espece Humaine," 1861, 
J). 119. 


improved breeds of the pig, which are descended from two 
distinct species; and in a less marked manner with the 
improved breeds of cattle. A great anatomist, Gratiolet, 
maintains that the anthropomorphous apes do not form a 
natural sub-group ; but that the orang is a highly devel- 
oped gibbon or semnopithecus, the chimpanzee a highly 
developed macacus, and the gorilla a highly developed man- 
drill. If this conclusion, which rests almost exclusively on 
brain-characters, be admitted, we should have a case of con- 
vergence at least in external characters, for the anthropomor- 
phous 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 con- 
vergence; but this term has never been applied to super- 
ficial and adaptive resemblances. It would, however, be 
extremely rash to attribute to convergence close similarity 
of character in many points of structure among the modi- 
fied descendants of widely distinct beings. The form of a 
crystal is deterniined solely by the molecular forces, and it 
is not surprising that dissimilar substances should some- 
times assume the same form; but with organic beings we 
should bear in mind that the form of each depends on an 
infinity of complex relations, namely, on variations due to 
causes" far too intricate to be followed — on the nature of 
the variations preserved, these depending on the physical 
conditions, and still more on the surrounding organisms 
which compete with each — and lastly, on inheritance (in 
itself a fluctuating element) from innumerable progenitors, 
all of which have have had their forms determined through 
equally complex relations. It appears incredible that the 
modified descendants of two organisms, if these differed 
from each other in a marked manner, should ever after- 
ward converge so closely as to lead to a near approach to 
identity throughout their whole organization. In the case 
of the convergent races of pigs above referred to, evidence 
of their descent from two primitive stocks is, according to 
Von Nathusius, still plainly retained in certain bones of 
their skulls. If the races of man had descended, as is sup- 
posed by some naturalists, from two or more species which 
differed from each other as much, or nearly as much, as 
does the orang from the gorilla it can hardly be doubted 
that marked differences in the structure of certain bones 
would still be discoverable in man as he now exists, 


Although the existing races of man differ in many re- 
spects as in color, hair, shape of skull, proportions of the 
body, etc., yet if their whole structure be taken into con- 
sideration they are found to resemble each other closely in 
a multitude of points. Many of these are of so unimpor- 
tant or of so singular a nature that it is extremely improb- 
able 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 are as different from each other in mind as 
any three races that can be named; yet I was incessantly 
struck while living with the Fuegians on board the 
'^ Beagle^' with the many little traits of character showing 
how similar their minds were to ours; and so it was with 
a full-blooded negro with whom I happened once to be 

He who will read Mr. Tylor's and Sir J. Lubbock^s in- 
teresting works* can hardly fail to be deeply impressed 
with the close similarity between the men of all races in 
tastes, dispositions and habits. This is shown by the pleas- 
ure which they all take in dancing, rude music, painting, 
tattooing and otherwise decorating themselves ; in their 
mutual comprehension of gesture-language, by the same 
expression in their features, and by the same inarticulate 
cries, when excited by the same emotions. This similarity, 
or rather identity, is striking, when contrasted with the 
different expressions and cries made by distinct species of 
monkeys. There is good evidence that the art of shooting 
with bows and arrows has not been handed down from any 
common progenitor of mankind, yet as Westropp and 
Nilsson have remarked,! the stone arrow-heads, brought 
from the most distant parts of the world, and manufactured 
at the most remote periods, are almost identical; and this 
fact can only be accounted for by the various races having 
similar inventive or mental powers. The same observation 

* Tylor's " Early History of Mankind," 1865; with respect to ges- 
ture-language, see p. 54. Lubbock's •* Prehistoric Times/' 2d edit., 

f " On Analogous Forms of Implements," in "Memoirs of Anthro- 
polog. Soc," by H. M. Westropp. "The Primitive Inhabitants of 
Scandinavia," Eng. translat., eHjted by Sir J. Lubbock, 1868, p, 104. 


has been made by archaeologists * with respect to certain 
widely-prevalent ornaments^ such as zig-zags, etc.; 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 \ that there, as in 
80 many other parts of the world, men have generally 
chosen the summits of lofty hills to throw up piles of 
stones, either as a record of some remarkable event, or for 
burying their dead. 

Now when naturalists observe a close agreement in 
numerous small details of habits, tastes, and dispositions 
between two or more domestic races, or between nearly 
allied natural forms, they use this fact as an argument that 
they are descended from a common progenitor who was 
thus endowed; and consequently that all should be classed 
under the same species. The same argument may be 
applied with much force to the races of man. 

As it is improbable that the numerous and unimportant 
points of resemblance between the several races of man in 
bodily 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 had these same characters. We thus gain some insight 
into the early state of man, before he had spread step by 
step over the face of the earth. The spreading of man to 
regions widely separated by the sea, no doubt, preceded any 
great amount of divergence of character in the several 
races; for otherwise we should sometimes meet with the 
same race in distinct continents; and this is never the case. 
Sir J. Lubbock, after comparing the arts now practiced by 
savages in all parts of the world, specifies those which man 
could not have known, when he first wandered from his 
original birthplace; for if once learned they would never 
have been forgotten. | He thus shows that ^*^ the spear, 
which is but a development of the knife-point, and the 
club, which is but a long hammer, are the only things left.^' 
He admits, however, that the art of making fire probably 
had been already discovered, for it is common to all the 

* Westropp, " On Cromleclis," etc., " Journal of Ethnological Soc," 
as given in " Scientific Opinion," June 2, 1869, p. 3. 

f "Journal of Researclies; Voyage of the ' Beagle,* " p. 46. 
I " Prehistoric Times," 1869, p. 574. 


races now existing, and was known to the ancient cave- 
inhabitants of Europe. Perhaps the art of making rude 
canoes or rafts was likewise known; but as man existed at a 
remote epoch, when the land in many places stood at a very 
different level to what it does now, he would have been able, 
without the aid of canoes, to have spread widely. Sir J. 
Lubbock further remarks how improbable it is that our 
earliest ancestors could have ^* counted as high as ten, con- 
sidering that so many races now in existence cannot get 
beyond four." Nevertheless, at this early period, the intel- 
lectual and social faculties of man could hardly have been 
inferior in any extreme degree to those possessed at present 
by the lowest savages; otherwise primeval man could not 
have been so eminently successful in the struggle for life, 
as proved by his early and wide diffusion. 

From the fundamental differences between certain lan- 
guages, 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 intel- 
lect could have risen to the standard implied, by his domi- 
nant position at an early period. 

Whether primeval man, when he possessed but few arts, 
and those of the rudest kind, and when his power of lan- 
guage was extremely imperfect, would have deserved to be 
called man, must depend on the definition which we 
employ. In a series of forms graduating insensibly from 
some ape-like creature to man as he now exists, it would be 
impossible to fix on any definite point when the term 
'^ man " ought to be used. But this is a matter of very 
little importance. So again, it is almost a matter of indif- 
ference whether the so-called races of man are thus desig- 
nated, or are ranked as species or sub-species; but the latter 
term appears the more appropriate. Finally, we may con- 
clude that when the principle of evolution is generally 
accepted, as it surely will be before long, the dispute 
between the monogenists and the polygenists will die a silent 
and unobserved death. 

One other question ought not to be passed over without 


notice, namely, whether, as is sometimes assumed, each 
sub-species or race of man has sprung from a single pair of 
progenitors. With our domestic animals a new race can 
readily he formed by carefully matching the varying off- 
spring from a single pair, or even from a single individual 
possessing some new character; but most of our races have 
been formed, not intentionally from a selected pair, but 
unconsciously by the preservation of many individuals 
which have varied, however slightly, in some useful or 
desired manner. If in one country stronger and heavier 
horses, and in another country lighter and fleeter ones, were 
habitually preferred, we may feel sure that two distinct 
sub-breeds would be produced in the course of time, with- 
out any one pair having been separated and bred from, in 
either country. Many races have been thus formed, and 
their manner of formation is closely analogous to that of 
natural species. We know, also, that the horses taken to the 
Falkland Islands have, during successive generations, 
become smaller and weaker, while 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 rever- 
sion. The new sub-breeds in such cases are not descended 
from any single pair, but from many individuals which 
have varied in different degrees, but in the same general 
manner; and we may conclude that the races of man have 
been similarly produced, the modifications being either the 
direct result of exposure to different conditions, or the 
indirect result of some form of selection. But to this 
latter subject we shall presently return. 

On the Extinction of the Races of Man. — The partial or 
complete extinction of many races and sub-races of man is 
historically known. Humboldt saw in South America a 
parrot which was the sole living creature that could speak 
a word of the language of a lost tribe. Ancient monuments 
and stone implements found in all parts of the world, about 
which no tradition has been preserved by the present 
inhabitants, indicate much extinction. Some small and 
broken tribes, remnants of former races, still survive in 
isolated and generally mountainous districts. In Europe 


the ancient races were all, according to Schaaffhausen,* 
^* lower in the scale than the rudest living savages •" they 
must therefore have differed, to a certain extent^ from any- 
existing race. The remains described by Prof. Broca from 
Les Eyzies, though they unfortunately appear to have 
belonged to a single family, indicate a race with a most 
singular combination of low or simious, and of high char- 
acteristics. This race is " entirely different from any 
other, ancient or modern, that we have heard of."f It 
differed, therefore, from the quaternary race of the caverns 
of Belgium. 

Man can long resist conditions which appear extremely 
unfavorable for his existence. J; He has long lived in the 
extreme regions of the north, with no wood for his canoes 
or implements, and with only blubber as fuel and melted 
snow as drink. 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 arid plains, where dangerous 
beasts abound. Man can withstand the deadly influence 
of the Terai at the foot of the Himalaya and the pestilen- 
tial shores of tropical Africa. 

Extinction follows chiefly from the competition of tribe 
with tribe and race with race. Various checks are always 
in action, serving to keep down the numbers of each 
savage tribe — such as periodical famines, nomadic habits 
and the consequent deaths of infants, prolonged suckling, 
wars, accidents, sickess, licentiousness, the stealing of 
women, infanticide, and especially lessened fertility. If 
any one of these checks increases in power, even slightly, 
the tribe thus affected tends to decrease ; and when of two 
adjoining tribes one becomes less numerous and less power- 
ful than the other, the contest is soon settled by war, 
slaughter, cannibalism, slavery, and absorption. Even 
when a weaker tribe is not thus abruptly swept away, if it 
once begins to decrease, it generally goes on decreasing 
until it becomes extinct. § 

* Translation in "Anthropological Review," Oct., 1868, p. 431. 

f ** Transact. Internat. Congress of Prehistoric Arch.," 1868, pp. 
172-175. See also Broca (translation) in "Anthropological Review," 
Oct., 1868, p. 410. 

± Dr. Gerland, " Ueber das Aussterben der Naturvolker," 1868, s, 82. 

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


When civilized nations come into contact with barba- 
rians the struggle is short, except where a deadly climate 
gives its aid to the native race. Of the causes which lead 
to the victory of civilized nations some are plain and sim- 
ple, others complex and obscure. We can see that the 
cultivation of the land will be fatal in many ways to sav- 
ages, for they cannot, or will not, change their habits. 
New diseases and vices have in some cases proved highly 
destructive; and it appears that a new disease often causes 
much death until those who are most susceptible to its 
destructive influence are gradually weeded out;* and so it 
may be with the evil effects from spirituous liquors, as well 
as with the unconquerably strong taste for them shown by 
so many savages. It further appears, mysterious as is the 
fact, that the first meeting of distinct and separated people 
generates disease. \ Mr. Sproat, who in Vancouver Island 
closely attended to the subject of extinction, believed that 
changed habits of life, consequent on the advent of Euro- 
peans, induces much ill-health. He lays, also, great stress 
on the apparently trifling cause that the natives become 
" bewildered and dull by the new life around them; they 
lose the motives for exertion and get no new ones in their 
place. ^'I 

The grade of their civilization seems to be a most impor- 
tant element in the success of competing nations. A few 
centuries ago Europe feared the inroads of Eastern barba- 
rians; now any such fear would be ridiculous. It is a more 
curious fact, as Mr. Bagehot has remarked, that savages 
did not formerly waste away before the classical nations as 
they now do before modern civilized nations; had they 
done so the old moralists would have mused over the event; 
but there is no lament in any writer of that period over the 
perishing barbarians. § The most potent of all the causes 
of extinction appears in many cases to be lessened fertility 

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

fl have collected ("Journal of Researches, Voyage of the 
'Beagle,' "p. 435) a good many cases bearing on this subject; see 
also Gerland, ibid, s. 8. Poeppig speaks of the " breath of civiliza- 
tion as poisonous to savages." 

ij: Sproat, " Scenes and Studies of Savage Life," 1868, p. 284 

§ Bagehot, "Physics and Politics," "Fortnightly Review," Aprl' 
I, 1868, p. 405. 


and ill-health, especiiilly among the children, arising from 
clianged conditions of life, notwithstanding that the new 
conditions may not be injurious in themselves. I am much 
indebted to Mr. H. H. Howorth for having called my 
attention to this subject and for having given me informa- 
tion respecting it. I have collected the following cases: 

When Tasmania was first colonized the natives were 
roughly estimated by some at 7,000, and by others at 20,000. 
Their number was soon greatly reduced, chiefly by fighting 
with the English and with each other. After the famous 
hunt by all the colonists, when the remaining natives deliv- 
ered themselves up to the government, they consisted only of 
120 individuals,* who were in 1832 transported to Flinders 
Island. This island, situated between Tasmania and Aus- 
tralia, is forty miles long, and from twelve to eighteen miles 
broad; it seems healthy, and the natives were well treated. 
Nevertheless, they suffered greatly in health. In 1834 they 
consisted (Bonwick, p. 250) of forty-seven adult males, 
forty-eight adult females, and sixteen children, or in all of 
one hundred and eleven souls. In 1835 only one hundred 
were left. As they continued rapidly to decrease, and as 
they themselves thought that they should not perish so 
quickly elsewhere, they were removed in 1847 to Oyster 
Cove in the southern part of Tasmania. They then con- 
sisted (Dec. 20, 1847) of fourteen men, twenty-two women 
and ten children. \ But the change of site did no good. 
Disease and death still pursued them, and in 1864 one man 
(who died in 18G9) and three elderly women alone survived. 
The infertility of the women is even a more remarkable 
fact than the liability of all to ill-health and death. At 
the time when only nine women were left at Oyster Cove 
they told Mr. Bonwick (p. 386) that only two had ever 
borne children; and these two had together produced only 
three children! 

With respect to the cause of this extraordinary state of 
things Dr. Story remarks that death followed the attempts 
to civilize the natives. '' If left to themselves to roam as 
they were wont and undisturbed they would have reared 
more children and there would have been less mortality." 

* All tlie statements liere given are taken from "The Last of the 
Tasmanians," by J. Bonwick, 1870. 

f This is the statement of the Governor of Tasmania, Sir W. Deni 
Bon, " Varieties of Vice-Regal Life," 1870, vol. i, p. 67, 


Another careful observer of the natives, Mr. Davis, remarks, 
' ' The births have been few and the deaths numerous. 
This may have been in a great measure owing to their 
change of living and food; but more so to their banishment 
from the mainland of Van Diemen's Land and consequent 
depression of spirits " (Bonwick, pp. 388, 390). 

Similar facts have been observed in two widely different 
parts of Australia. The celebrated explorer, Mr. Gregory, 
told Mr. Bonwick, that in Queensland ^' the want of repro- 
duction was being already felt with the blacks, even in the 
most recently settled parts, and that decay would set 
in." Of thirteen aborigines from Shark^s Bay who visited 
Murchison River, twelve died of consumption within three 

The decrease of the Maories of New Zealand has been 
carefully investigated by Mr. Fenton, in an admirable 
report, from which all the following statements, with one 
exception, are taken, f The decrease in number since 1830 
is admitted by every one, including the natives themselves, 
and is still steadily progressing. Although it has hitherto 
been found impossible to take an actual census of the 
natives, their numbers were carefully estimated by resi- 
dents in many districts. The result seems trustworthy, 
and shows that during the fourteen years, previous to 1858, 
the decrease was 19.42 per cent. Some of the tribes, thus 
carefully examined, lived above a hundred miles apart, 
some on the coast, some inland; and their means of sub- 
sistence and habits differed to a certain extent (p. 28). 
The total number in 1858 was believed to be 53,700, and 
in 1872, after a second interval of fourteen years, another 
census was taken, and the number is given as only 
36,359, showing a decrease of 32.29 per cent. ! | 
Mr. Fenton, after showing in detail the insufficiency of 
the various causes usually assigned in explanation of this 
extraordinary decrease, such as new diseases, the profligacy 
of the women, drunkenness, wars, etc., concludes on 
weighty grounds that it depends chiefly on the unproduc- 

* For these cases see Bonwick's " Daily Life of tlie Tasmanians,'* 
1870, p. 90; and the " Last of the Tasmanians," 1870, p. 386. 

f ' ' Observations on the Aboriginal Inhabitants of New Zealand, *' 
published by the Government, 1859. 

% " New Zealand," by Alex. Kennedy, 1873, p. 47. 


ti veil ess of the women and on the extraordinary mortality 
of the young children (pp. 31, 34). In proof of this he 
shows (p. 33) that in 1844 there was one non-adult for 
every 2.57 adults; whereas in 1858 there was only one non- 
adult for every 3.27 adults. The mortality of the adults is 
also great. He adduces as a further cause of the decrease 
the inequality of the sexes; for fewer females are born than 
males. To this latter point, depending perhaps on a widely 
distinct cause, I shall return in a future chapter. Mr. 
Fenton contrasts with astonishment the decrease in New 
Zealand with the increase in Ireland; countries not very 
dissimilar in climate, and where the inhabitants now follow 
nearly similar habits. The Maories themselves (p. 35) 
*^ attribute their decadence, in some measure, to the intro- 
duction of new food and clothing, and the attendant 
change of habits ;^^ and it will be seen, when we consider 
the influence of changed conditions on fertility, that they 
are probably right. The diminution began between the 
years 1830 and 1840; and Mr. Fenton shows (p. 40) that 
about 1830, the art of manufacturing putrid corn (maize), 
by long steeping in water, was discovered and largely prac- 
ticed; and this proves that a change of habits was begin- 
ning among the natives, even when New Zealand was only 
thinly inhabited by Europeans. When I visited the Bay 
of Islands in 1835, the dress and food of the inhabitants 
had already been much modified ; they raised potatoes, 
maize and other agricultural produce, and exchanged them 
for English manufactured goods and tobacco. 

It is evident from many statements in the life of Bishop 
Patteson,* that the Melanesians of the New Hebrides and 
neighboring archipelagoes, suffered to an extraordinary 
degree in health, and perished in large numbers, when they 
were removed to New Zealand, Norfolk Island and other 
salubrious places, in order to be educated as missionaries. 

The decrease of the native population of the Sandwich 
Islands is as notorious as that of New Zealand. It has 
been roughly estimated by those best capable of judging, 
that when Cook discovered the Islands in 1779, the popula- 
tion amounted to about 300,000. According to a loose 
census in 1823, the numbers then were 142,050. In 1832, 

* " Life of J. C. Patteson," by C. M. Younge, 1874; see more 
especially vol. 1, p. 530. 



and at several subsequent periods, an accurate census was 
officially taken, but I have been able to obtain only the fol- 
lowing returns: 

Annual rate of decrease per 

Native Population. 

cent., assuming it to have 
been uniform between the 


(Except during 1832 and 1836, 

successive censuses; these 

when the few foreigrners in 

censuses being taken at ir- 

the islands were included.) 

regular intervals. 




















1872 . 

51,531 ^ 

We here see that in the interval of forty years, between 
1832 and 1872, the population has decreased no less than 
sixty-eight per cent. ! This has been attributed by most 
writers to the profligacy of the women, to former bloody 
wars, and to the severe labor imposed on conquered tribes 
and to newly introduced diseases, which have been on sev- 
eral occasions extremely destructive. 'No doubt these and 
other such causes have been highly efficient, and may 
account for the extraordinary rate of decrease between the 
years 1832 and 1836; but the most potent of all the causes 
seems to be lessened fertility. According to Dr. Ruschen- 
berger of the United States Navy, who visited tliese islands 
between 1835 and 1837, in one district of Hawaii, only 
twenty-five men out of 1,134, and in another district only 
ten out of 637, had a family with as many as three 
children. Of eighty married women, only thirty-nine had 
ever borne children ; and ^' the official report gives an 
average of half a child to each married couple in the 
whole island." This is almost exactly the same average as 
with the Tasmanians at Oyster Cove. Jarves, who pub- 
lished his history in 1843, says that ^^ families who have 
three children are freed from all taxes; those having more,, 


are rewarded by gifts of land and other encouragements/* 
This unparalleled enactment by the government well shows 
how infertile the race had become. The Eev. A. Bishop 
stated in the Hawaiian "" Spectator " in 1839, that a large 
proportion of the children die at early ages, and Bishop 
Staley informs me that this is still the case, just as in New 
Zealand. This has been attributed to the neglect of the 
children by the women, but it is probably in large part due 
to innate weakness of constitution in the children, in rela- 
tion to the lessened fertility of their parents. There is, 
moreover, a further resemblance to the case of New Zeal- 
and, in the fact that there is a large excess of male over 
female births; the census of 1872 gives 31,650 males to 
25,247 females of all ages, that is 125.36 males for every 
100 females; whereas in all civilized countries the females 
exceed the males. No doubt the profligacy of the women 
may in part account for their small fertility; but their 
changed habits of life is a much more probable cause, and 
which will at the same time account for the increased mor- 
tality, especially of the children. The islands were visited 
by Cook in 1779, by Vancouver in 1794, and often subse- 
quently by whalers. In 1819 missionaries arrived, and 
found that idolatry had been already abolished, and other 
changes effected by the king. After this period there was 
a rapid change in almost all the habits of life of the natives, 
and they soon became *^ the most civilized of the Pacific 
Islanders." One of my informants, Mr. Coan, who was 
born on the islands, remarks that the natives have under- 
gone a greater change in their habits of life in the course 
of fifty years than Englishmen during a thousand years. 
From information received from Bishop Staley, it does 
not appear that the poorer classes have ever much changed 
their diet, although many new kinds of fruit have been 
introduced, and the sugar-cane is in universal use. Owing 
however, to their passion for imitating Europeans, they 
altered their manner of dressing at an early period, and 
the use of alcoholic drinks became very general. Although 
these changes appear inconsiderable, I can well believe, 
from what is known with respect to animals, that they 
might suffice to lessen the fertility of the natives.* 

* The foregoing statements are taken chiefly from the following 
works: " Jarves' History of the Hawaiian Islands," 1843, pp. 400- 
407. Cheever, "Life in the Sandwich Islands," 1851. p. 377. 


Lastly, Mr. Macnamara states * that the low and de- 
graded inhabitants of the Andaman Islands, on the eastern 
side of the Gulf of Bengal, are '' eminently susceptible to 
any change of climate; in fact, take them away from their 
island homes, and they are almost certain to die, and that 
independently of diet or extraneous influences." He further 
states that the inhabitants of the Valley of Nepal, which is 
extremely hot in summer, and also the various hill-tribes 
of India, suifer from dysentery and fever when on the 
plains; and they die if they attempt to pass the whole year 

We thus see that many of the wilder races of man are 
apt to suffer much in health when subjected to changed 
conditions or habits of life and not exclusively from being 
transported to a new climate. Mere alterations in habits, 
which do not appear injurious in themselves, seem to have this 
same effect; and in several cases the children are particularly 
liable to suffer. It has often been said, as Mr. Macnamara 
remarks, that man can resist with impunity the greatest 
diversities of climate and other changes; but this is true 
only of the civilized races. Man in his wild condition 
seems to be in this respect almost as susceptible as his near- 
est allies, the anthropoid apes, which have never yet sur- 
vived long, when removed from their native country. 

Lessened fertility from changed conditions, as in the case 
of the Tasmanians, Maories, Sandwich Islanders, and 
apparently the Australians, is still more interesting than 
their liability to ill-health and death; for even a slight 
degree of infertility, combined with those other causes 
which tend to check the increase of every population, would 
sooner 0/ later lead to extinction. The diminution of fertility 
may be explained in some cases by the profligacy of the 
women (as until lately with the Tahitians), but Mr. Fenton 
has shown that this explanation by no means sufhces with 
the New Zealanders, nor does it with the Tasmanians. 

Rusclienberger is quoted by Bonwick, "Last of the Tasmanians," 
1870, p. 378. Bishop is quoted by Sir E. Belcher, " Voyage Round 
the World," 1848, vol. i, p. 272. I owe the census of the several 
years to the kindness of Mr. Coan, at the request of Dr. Youmans, of 
New York; and in most cases I have compared the Youmans figures 
with those given in several of the above-named works. I have 
omitted the census for 1850, as I have seen two widely different num- 
bers given. 
* '• The Indian Medical Gazette/' Nov. \, 1871, p. 240, 


In the paper above quoted, Mr. Macnamara gives reasons 
for believing that the inhabitants of districts subject to 
malaria are apt to be sterile; but this cannot apply in sev- 
eral of the above cases. Some writers have suggested that 
the aborigines of islands have suffered in fertility and 
health from long continued inter-breeding; but in the above 
cases infertility has coincided too closely with the arrival 
of Europeans for us to admit this explanation. Nor have 
we at present any reason to believe that man is highly sen- 
sitive to the evil effects of inter-breeding, especially in 
areas so large as New Zealand and the Sandwich Archi- 
pelago with its diversified stations. On the contrary, it is 
known that the present inhabitants of Norfolk Island are 
nearly all cousins or near relations, as are the Todas in 
India, and the inhabitants of some of the Western Islands 
of Scotland; and yet they seem not to have suffered in 
fertility. * 

A much more probable view is suggested by the analogy 
of the lower animals. The reproductive system can be 
shown to be susceptible to an extraordinary degree (though 
why we know not) to changed conditions of life; and this 
susceptibility leads both to beneficial and to evil results. 
A large collection of facts on this subject is given in chap- 
ter xviii, of volume ii, of my ^' Variation of Animals and 
Plants under Domestication." I can here give only the 
briefest abstract; and every one interested in the subject 
may consult the above work. Very slight changes increase 
the health, vigor and fertility of most or all organic beings, 
while other changes are known to render a large number of 
animals sterile. One of the most familiar cases is that of 
tamed elephants not breeding in India; though they often 
breed in Ava, where the females are allowed to roam about 
the forests to some extent, and are thus placed under more 
natural conditions. The case of various American mon- 
keys, both sexes of which have been kept for many years 
together in their own countries, and yet have very rarely 
or never bred, is a more apposite instance, because of their 
relationship to man. It is remarkable how slight a change 

* On the close relationship of the Norfolk Islanders, see Sir W. 
Denison, "Varieties of Vice-Regal Life," vol. i, 1870, p. 410. For 
the Todas, see Col. Marshall's work, 1873, p. 110. For the Western 
Islands of Scotland, Dr. Mitchell, "Edinburgh Medical Journal," 
March to June, 1865, 


in the conditions often induces sterility in a wild animal 
when captured; and this is the more strange as all our 
domesticated animals have become more fertile than they 
were in a state of nature; and some of them can resist the 
most unnatural conditions with undiminished fertility.* 
Certain groups of animals are much more liable than others 
to be affected by captivity; and generally all the species of 
the same group are affected in the same manner. But 
sometimes a single species in a group is rendered sterile^ 
while the others are not so; on the other hand, a single 
species may retain its fertility while most of the others fail 
to breed. The males and females of some species when 
confined, or when allowed to live ahnost but not quite free, 
in their native country never unite; others thus circum- 
stanced frequently unite but never produce offspring; 
others again produce some offspring, but fewer than in a 
state of nature; and as bearing on the above cases of man 
it is important to remark that the young are apt to be 
weak and sickly, or malformed, and to perish at an early 

Seeing how general is this law of the susceptibility of the 
reproductive system to changed conditions of life, and that 
it holds good with our nearest allies, the Quadrumana, I 
can hardly doubt that it applies to man in his primeval state. 
Hence, if savages of any race are induced suddenly to change 
their habits of life they become more or less sterile, and 
their young offspring suffer in health in the same manner 
and from the same cause as do the elephant and hunting- 
leopard in India, many monkeys in America, and a host 
of animals of all kinds on removal from their natural 

We can see why it is that aborigines, who have long 
inhabited islands, and who must have been long exposed to 
nearly uniform conditions, should be specially affected by 
any change in their habits, as seems to be the case. Civil- 
ized races can certainly resist changes of all kinds far 
better than savages ; and in this respect they resemble 
domesticated animals, for though the latter sometimes 
suffer in health (for instance European dogs in India), yet 
they are rarely rendered sterile, though a few such 

*For tlie evidence on this head, see " Variation of Animals," etc., . 
vol. ii, p. 111. 


instances have been recorded.* The immunity of civilized 
races and domesticated animals is probably due to their 
having been subjected to a greater extent, and, therefore, 
having grown somewhat more accustomed, to diversified or 
varying conditions, than the majority of wild animals; and 
to their having formerly immigrated or been carried from 
country to country, and to different families or sub-races 
having inter-crossed. It appears that a cross with civilized 
races at once gives to an aboriginal race an immunity from 
the evil consequences of changed conditions. Thus the 
crossed offspring from the Tahitians and English, when 
settled in Pitcairn Island, increased so rapidly that the 
island was soon overstocked; and in June, 1856, they were 
removed to Norfolk Island. They then consisted of 
60 married persons and 134 children, making a total of 
194. Here they likewise increased so rapidly that, 
although 16 of them returned to Pitcairn Island in 1859, 
they numbered in January, 1868, 300 souls; the males and 
females being in exactly equal numbers. What a contrast 
does this case present with that of the Tasmanians; the 
Norfolk Islanders increased in only twelve and a half years 
from 194 to 300; whereas the Tasmanians decreased during 
15 years from 120 to 46, of which latter number only 10 
were children, f 

So again in the interval between the census of 1866 and 
1872 the natives of full blood in the Sandwich Islands 
decreased by 8,081, while the half-castes, who are believed 
to be healthier, increased by 847; but I do not know 
whether the latter number includes the offspring from 
the half-castes, or only the half-castes of the first genera- 

The cases which I have here given all relate to aborigines 
who have been subjected to new conditions as the result of 
the immigration of civilized men. But sterility and ill- 
health would probably follow if savages were compelled by 
any cause, such as the inroad of a conquering tribe, to 
desert their homes and to change their habits. It is an 

*" Variation of Animals," etc., vol. ii, p. 16. 

f These details are taken from " The Mutineers of the ' Bounty,' '* 
by Lady Belcher, 1870; and from "Pitcairn Island," ordered to be 
printed by the House of Commons, May 29, 1863. The following" 
statements about the Sandwich Islanders are from the "Honolulu 
Gazette," and from Mr. Coan. 


interesting circumstance that tlie chief check to wild ani- 
mals becoming domesticated, which implies the power of 
their breeding freely when first captured, and one chief 
check to wild men, when brought into contact with civil- 
ization, surviving to form a civilized race, is the same, 
namely, sterility from changed conditions of life. 

Finally, although the gradual decrease and ultimate 
extinction of the races of man is a highly complex 
problem, depending on many causes which differ in 
different places and at different times ; it is the same 
problem as that presented by the extinction of one of 
the higher animals — of the fossil horse, for instance, which 
disappeared from South America, soon afterward to be 
replaced, within the same districts, by countless troups of 
the Spanish horse. The New Zealander seems conscious of 
this parallelism, for he compares his future fate with that 
of the native rat now almost exterminated by the Euro- 
pean rat. Though the difficulty is great to our imagi- 
nation, and really great, if we wish to ascertain the precise 
causes and their manner of action, it ought not to be so to 
our reason, as long as we keep steadily in mind that the 
increase of each species and each race is constantly checked 
in various ways; so that if any new check, even a slight 
one, be superadded, the race will surely decrease in number; 
and decreasing numbers will sooner or later lead to extinc- 
tion; the end, in most cases, being promptly determined 
by the inroads of conquering tribes. 

Ofi the Formation of the Races of Man. — In some cases 
the crossing of distinct races has led to the formation of a 
new race. The singular fact that the Europeans and Hin- 
doos, who belong to the same Aryan stock and speak 'a 
language fundamentally the same, differ widely in appear- 
ance, while Europeans differ but little from Jews, who 
belong to the Semitic stock and speak quite another lan- 
guage, has been accounted for by Broca,* through certain 
Aryan branches having been largely crossed by indigenous 
tribes during their wide diffusion. AVhen two races in 
close contact cross the first result is a heterogeneous mix- 
ture; thus Mr. Hunter, in describing the Santali or hill- 

*" On Anthropology," translation " Antliropolog. Review," Jan., 
1868, p. 38. 


tribes of India, says that hundreds of imperceptible grada- 
tions may be traced '^ from the black, squat tribes of the 
mountains to the tall olive-colored Brahman, with his intel- 
lectual brow, calm eyes, and high but narrow head;" so 
that it is necessary in courts of justice to ask the wit- 
nesses whether they are Santalis or Hindoos.* 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 homogeneous, is not known from direct evi- 
dence. But as with our domesticated animals, a cross- 
breed can certainly be fixed and made uniform by careful 
selection f in the course of a few generations, we may infer 
that the free intercrossing of a heterogeneous mixture 
during a long descent would supply the place of selection 
and overcome any tendency to reversion ; so that the 
crossed race would ultimately become homogeneous, 
though it might not partake in an equal degree of the 
characters of the two parent-races. 

Of all the differences between the races of man, the color 
of the skin is the most conspicuous and one of the best 
marked. It was formerly thought that differences of this 
kind could be accounted for by long exposure to 
different climates ; but Pallas first showed that this 
is not tenable and he has since been followed 
by almost all anthropologists. I This view has been 
rejected chiefly because the distribution of the variousl}^ 
colored races, most of whom must have long inhabited their 
present homes, does not coincide with corresponding dif- 
ferences of climate. Some little weight may be given to 
such cases as that of the Dutch families, who, as we hear on 
excellent authority, § have not undergone the least change 
of color after residing for three centuries in S. Africa. 
An argument on the same side may likewise be drawn 

* " The Annals of Rural Bengal," 1868, p. 134. 

•f-"Tlie Variation of Animals and Plants under Domestication," 
vol. ii, p. 95. 

X Pallas, " Act. Acad. St. Petersburg," 1780, part ii, p. 69. He 
was followed by Rudolpbi, in bis " Beytrage zur Anthropologie, " 
1812. An excellent summary of the evidence is given by Godron, 
" De I'Espece," 1859, vol. ii, p. 246, etc. 

§ Sir Andrew Smitb, as quoted by Knox, " Races of Man," 1850, 
p. 473. 


from the uniform appearance in various parts of the world 
of gypsies and Jews, though the uniformity of the latter 
has been somewhat exaggerated.* A very damp or a very 
dry atmosphere has been supposed to be more influential in 
modifying the color of the skin than mere heat; but as 
D^Orbigny in South America, and Livingstone in Africa, 
arrived at diametrically opposite conclusions with respect to 
dampness and dryness, any conclusion on this head must 
be considered as very doubtful. \ 

Various facts, which I have given elsewhere, prove that 
the color of the skin and hair is sometimes correlated in a 
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 from the 
deadly influence of the miasma of their native countries, 
during a long series of generations. 

I afterward found that this same idea had long ago 
occurred to Dr. Wells. J It has long been known that 
negroes, and even mulattoes are almost completely exempt 
from the yellow fever, so destructive in tropical America. § 
They likewise escape to a large extent the fatal intermit- 
tent fevers that prevail along at least 2,600 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. || This immunity in the negro seems to be partly 
inherent, depending on some unknown peculiarity of con- 
stitution and partly the result of acclimatization. Pouchet^ 
states that the negro regiments recruited near the Soudan 

* See De Quatref ages on this head, ' ' Revue des Cours Scien- 
tifiques," Oct. 17, 1868, p. 731. 

f Livingstone's "Travels and Researches in S. Africa," 1857, pp. 
338, 339. D'Orbigny, as quoted by Godron, " De I'Espece," vol. ii, 
p. 266. 

X See a paper read before tlie 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. 16) to my " Origin of Species." Various 
cases of color correlated with constitutional peculiarities are given in 
my " Variationof Animals under Domestication," vol. ii, pp. 227, 335. 

§ See, for instance, Nott and Gliddon, " Types of Mankind," p. 68. 

II Maj. Tulloch, in a paper read before the Statistical Society, April 
20, 1840, and given in the " Athenaeum," 1840, p. 353. 

Y' The Plurality of the Human Race " (translate), 1864, p 60. 


and borrowed from the Viceroy of Egypt for the Mexican 
war escaped the yellow fever almost equally with the 
negroes originally brought from various parts of Africa and 
accustomed to the climate of the West Indies. That 
acclimatization plays a part is shown by the many cases in 
which negroes have become somewhat liable to tropical 
fevers, after having resided for some time in a colder 
climate.* The nature of the climate under which the 
white races have long resided, likewise has some influence 
on them; for during the fearful epidemic of yellow fever 
in Demerara during 1837 Dr. Blair found that the death- 
rate of the immigrants was proportional to the latitude of 
the country whence they had come. With the negro the 
immunity, as far as it is the result of acclimatization, 
implies exposure during a prodigious length of time; for 
the aborigines of tropical America who have resided there 
from time immemorial are not exempt from yellow fever; 
and the Kev. H. B. Tristram states that there are districts 
in Northern Africa w^hich the native inhabitants are com- 
pelled annually to leave, though the negroes can remain 
with safety. 

That the immunity of the negro is in any degree corre- 
lated with the color of his skin is a mere conjecture; it 
may be correlated with some difference in his blood, nerv- 
ous system or other tissues. Nevertheless, from the facts 
above alluded to and from some connection apparently ex- 
isting between complexion and a tendency to consumption, 
the conjecture seemed to me not improbable. Conse- 
quently I endeavored, with but little success, f to ascertain 

* Quatrefages, " Unite de I'Espece Humaine," 1881, p. 205. Waitz, 
*' Introduct. to Anthropology," translat., vol. i, 1863, p. 134. Liv- 
ingstone gives analogous cases in his " Travels." 

f 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 color of the dermal 
appendages and the constitution; and it being notorious that there is 
some limited degree of relation between the color of the races of man 
and the climate inhabited by them; the following investigation seems 
worth consideration. Namely, whether there is any relation in Euro- 
peans between the color of their hair and their liability to the diseases 
of tropical countries. If the surgeons of the several regiments, when 
gtatioued in unhealthy tiopical districts, would be so good as first to 


how far it holds good. The late Dr. Daniell, who had 
long lived on the west coast of Africa, told me that he did 
not believe in any such relation. He was himself unusually- 
fair and had withstood the climate in a wonderful manner. 
"When he first arrived as a boy on the coast an old and ex- 
perienced negro chief predicted from his appearance that 
this would prove the case. Dr. Nicholson, of Antigua, 
after having attended to this subject, writes to me that 
dark-colored Europeans escape the yellow fever more than 
those that are light colored. Mr. J. M. Harris altogether 
denies that Europeans with dark hair withstand a hot cli- 
mate better than other men; on the contrary, experience 
has taught him in making a selection of men for service on 
the coast of Africa to choose those with red hair. * As far, 
therefore, as these slight indications go, there seems no 
foundation for the hypothesis that blackness has resulted 
from the darker and darker individuals having survived 
better during long exposure to fever-generating miasma. 
Dr. Sharpe remarks, \ that a tropical sun, which burns 

count, as a standard of comparison, how many men, in the force 
whence the sick are drawn, have dark and light-colored hair and 
hair of intermediate or doubtful tints; and if a similar account were 
kept by the same medical gentlemen of all the men who suffered 
from malarious and yellow fevers, or from dysentery, it would soon 
be apparent, after some thousand cases had been tabulated, whether 
there exists any relation between the color of the hair and constitu- 
tional liability to tropical diseases. Perhaps no such relation would 
be discovered, but the investigation is well worth making. In case 
any positive result were obtained it might be of some practical use 
in selecting men for any particular service. Theoretically the result 
would be of high interest, as indicating one means by which a race 
of men inhabiting from a remote period an unhealthy tropical cli- 
mate, might have become dark-colored by the better preservation of 
dark-haired or dark-complexioned individuals during a long succes- 
sion of generations. " 

*" Anthropological Review," Jan., 1866, p. 21. Dr. Sharpe also 
says, with respect to India (" Man a Special Creation," 1873, p. 118), 
" that it has been noticed by some medical officers that Europeans 
with light hair and florid complexions suffer less from diseases of 
tropical countries than persons with dark hair and sallow complex- 
ions; and, so far as I know, there appear to be good grounds for 
this remark." On the other hand, Mr. Heddle, of Sierra Leone, 
" who has had more clerks killed under him than any other man," 
by the climate of the West African Coast (W. Reade, "African 
Sketch Book," vol. ii, p. 522), holds a directly opposite view, as does 
Capt. Burton. 

f ''Man a Special Creation," 1873, p. 119. 


and blisters a white skin, does not injure a black one at all; 
and, as he adds, this is not due to habit in the individual, 
for children only six or eight months old are often carried 
about naked, and are not affected. I have been assured by 
a medical man that some years ago during each summer, 
but not during the winter, his hands became marKed with 
light brown patches, like, although larger than freckles, 
and that these patches were never affected by sun-burning, 
while the white parts of his skin have on several occasions 
been much inflamed and blistered. With the lower ani- 
mals there is, also, a constitutional difference in liability to 
the action of the sun between those parts of the skin 
clothed with white hair and other parts.* Whether the 
saving of the skin from being thus burned is of sufficient 
importance to account for a dark tint having been gradually 
acquired by man through natural selection I am unable to 
judge. If it be so, we should have to assume that the 
natives of tropical America have lived there for a much 
shoL-ter time than the negroes in Africa, or the Papuans in 
the southern parts of the Malay Archipelago, just as the 
lighter-colored Hindoos have resided in India for a shorter 
time than the darker aborigines of the central and southern 
parts of the peninsula. 

Although with our present knowledge we cannot account 
for the differences of color in the races of man, through 
any advantage thus gained, or from the direct action of 
climate; yet we must not quite ignore the latter agency, 
for there is good reason to believe that some inherited effect 
is thus produced, f 

We have seen in the second chapter that the conditions 
of life affect the development of the bodily frame in a 
direct manner, and that the effects are transmitted. Thus, 
as is generally admitted, the European settlers in the 
United States undergo a slight but extraordinary rapid 

* " Variation of Animals and Plants under Domestication," vol. ii, 
pp. 336, 387. 

f See, for instance, Quatrefages (" Revue des Cours Scientifiques," 
Oct. 10, 1868, p. 724) on tlie effects of residence in Abyssinia and 
Arabia, and other analogous cases. Dr. Rolle (''Der Menscb, seine 
Abstammung," etc., 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 
color, according to the position of the valleys inhabited by tnem. 


change of appearance. Their bodies and limbs become 
elongated; and I hear from Col. Bernys that during the 
late war in the United States, good evidence was afforded 
of this fact by the ridiculous appearance presented by the 
German regiments when dressed in ready-made clothes 
manufactured for the American market, and which were 
much too long for the men in every way. There is, also, a 
considerable body of evidence showing that in the Southern 
States the house slaves of the third generation present a 
markedly different appearance from the field slaves.* 

If, however, we look to the races of man as distributed 
over the world we must infer that their characteristic dif- 
ferences 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 exclu- 
sively 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 inhabit- 
ants of Southern China, who live entirely on vegetable 
food and are exposed almost naked to a hot, glaring cli- 
mate. The unclothed Fuegians live on the marine pro- 
ductions of their inhospitable shores ; the Botocudos of 
Brazil wander about the hot forests of the interior and live 
chiefly on vegetable productions; yet these tribes resemble 
each other so closely that the Tuegians 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 ex- 
posed to a nearly similar climate and follow nearly the 
same habits of life. 

Nor can the differences between the races of man be ac- 
counted for by the inherited effects of the increased or 
decreased use of parts except to a quite insignificant degree. 
Men who habitually live in canoes may have their legs 
somewhat stunted; those who inhabit lofty regions may 
have their chests enlarged; and those who constantly use 
certain sense organs may have the cavities in which they 
are lodged somewhat increased in size, and their features 
consequently a little modified. With civilized nations the 

* Harlan, ** Medical Researches," p. 532. Quatrefages ("Unite de 
I'Espece Humaine," 1861, p. 128) has collected much evidence on this 


reduced size of the jaws from lessened nse — the habitual 
play of different muscles serving to express different emo- 
tions — and the increased size of the brain from greater 
intellectual activity have together produced a considerable 
effect on their general appearance when compared with 
savages. * Increased bodily stature, without any corre- 
sponding increase in the size of the brain, may (judging 
from the previously adduced case of rabbits), have given 
to some races an elongated skull of the dolichocephalic 

Lastly, the little understood principle of correlated de- 
velopment has sometimes come into action, as in the case 
of great muscular development and strongly projecting 
supra-orbital ridges. The color of the skin and hair are 
plainly correlated, as is the texture of the hair with its 
color in the Mandans of North America. \ The color also 
of the skin and the odor emitted by it are likewise in some 
manner connected. With the breeds of sheep the number 
of hairs within a given space and the number of the ex- 
cretory pores are related. J If we may judge from the 
analogy of our domesticated animals, many modifications 
of structure in man probably come under this principle 
of correlated development. 

We have now seen that the external characteristic differ- 
ences between the races of man cannot be accounted for in 
a satisfactory manner by the direct action of the conditions 
of life, nor by the effects of the continued use of parts, 
nor through the principle of correlation. We are there- 
fore led to inquire whether slight individual differences, to 
which man is eminently liable, may not have been pre- 
served and augmented during a long series of generations 
through natural selection. But here we are at once met 

*See Prof. ScTiaaffliausen, translat., in " Antliropological Review," 
Oct., 1868, p. 429. 

fMr, Catlin states (" North American Indians," 3d edit., 1842, vol. 
i, p. 49) tbat in the whole tribe of the Mandans, about one in ten or 
twelve of the members, of all ages and both sexes, have bright sil- 
very gray hair, which is hereditary. Now this hair is as coarse and 
harsh as that of a horse's mane, while the hair of other colors is fine 
and soft. 

XOn the odor of the skin, Godron, " Sur I'Espece," tom ii, p. 217. 
On the pores in the skin, Dr. Wilckens, ** Die Aufgaben der Land- 
wirth. Zootechnik," 1869, s. 7. 


by the objection that beneficial variations alone can be 
thus preserved; and as far as we are enabled to judge, 
although always liable to err on this head, none of the dif- 
ferences between the races of man are of any direct or 
special service to him. The intellectual and moral or 
social faculties must of course be excepted from this 
remark. The great variability of all the external differ- 
ences between the races of man, likewise indicates that 
they cannot be of much importance; for if important, they 
would long ago have been either fixed and preserved or 
eliminated. In this respect man resembles those forms, 
called by naturalists protean or polymorphic, which have 
remained extremely variable, owing, as it seems, to such 
variations being of an indifferent nature, and to their 
having thus 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 Selec- 
tion, which appears to have acted powerfully on man, as 
on many other animals. I do not intend to assert that 
sexual selection will account for all the differences between 
the races. An unexplained residuum is left, about which 
we can only say, in our ignorance, that as individuals are 
continually born with, for instance, heads a little rounder 
or narrower, and with noses a little longer or shorter, such 
slight differences might become fixed and uniform, if the 
unknown agencies which induced them were to act in a 
more constant manner, aided by long-continued inter- 
crossing. Such variations come under the provisional 
class, alluded to in our second chapter, which for the want 
of a better term are often called spontaneous. Nor do I 
pretend that the effects of sexual selection can be indicated 
with scientific precision ; but it can be shown that it 
would be an inexplicable fact if man had not been modi- 
fied by this agency, which appears to have acted power- 
fully on innumerable animals. It can further be shown 
that the differences between the races of man, as in color, 
hairiness, form of features, etc., are of a kind which might 
have been expected to come under the influence of sexual 
selection. But in order to treat this subject properly, I 
have found it necessary to pass the whole animal kingdom 
in review. I have therefore devoted to it Part II of this 
work. At the close I shall return to man, and, after 


attempting to show how far he has been modified through 
sexual selection, will give a brief summary of the chapters 
in Part I. 

Note on the Resemblances and Diffekences in the Structure 
AND the Development op the Brain in Man and Apes. 
By Prof. Huxley, F.R.S. 

The controversy respecting the nature and the extent of the differ- 
ences in the structure of the brain in man and the apes, which arose 
some fifteen years ago, has not yet come to an end, though the sub. 
ject matter of the dispute is, at present, totally different from what 
it was formerly. It jvas originally asserted and reasserted, with sin- 
gular pertinacity, that the brain of all the apes, even the highest, 
differs from that of man, in the absence of such conspicuous struct- 
ures as the posterior lobes of the cerebral hemispheres, with the pos- 
terior cornu of the lateral ventricle and the hippocampus minor, con- 
tained in those lobes, which are so obvious in man. 

But the truth that the three structures in question are as well 
developed in apes as in human brains, or even better; and that it is 
characteristic of all the Primates (if we exclude the Lemurs) to have 
these parts well developed, stands at present on as secure a basis as 
any proposition in comparative anatomy. Moreover, it is admitted 
by every one of the long series of anatomists who, of late years, have 
paid special attention to the arrangement of the complicated sulci 
and gyri which appear upon the surface of the cerebral hemispheres 
in man and the higher apes, that they are disposed after the very 
same pattern in hin; as in them. Every principal gyrus and sulcus 
of a chimpanzee's brain is clearly represented in that of a man, so 
that the terminology which applies to the one answers for the other. 
On this point there is no difference of opinion. Some years since, 
Prof. Bischoff published a memoir* on the cerebral convolutions of 
man and apes; and as the purpose of my learned colleague was cer- 
tainly not to diminish the value of the differences between apes and 
men in this respect, I am glad to make a citation from him. 

** That the apes, and especially the orang, chimpanzee and gorilla, 
come very close to man in their organization, much nearer than to 
any other animal, is a well-known fact, disputed by nobody. Look- 
ing at the matter from the point of view of organization alone, no 
one probably would ever have disputed the view of Linnseus, that 
man should be placed, merely as a peculiar species, at the head of 
the mammalia and of those apes. Both show, in all their organs, so 
close an affinity that the most exact anatomical investigation is needed 
in order to demonstrate those differences which really exist. So it is 
with the brains. The brains of man, the orang, the chimpanzee, the 
gorilla, in spite of all the important differences which they present, 
come very close to one another " (1. c, p. 101). 

There remains, then, no dispute as to the resemblance in funda- 
mental characters, between the ape's brain and man's; nor any as to 

*"Die Grosshirn-Windungen des Menschen;" *' AbUandlungeu der K. 
BayeriscUen Akademie," Bd. x. 1868. 


tlie wonderfully close similarity between tlie chimpanzee, orang and 
man, in even the details of the arrangement of the gyri and sulci of 
the cerebral hemispheres. Nor, turning to the differences between 
the brains of the highest apes and that of man, is there any serious 
question as to the nature and extent of these differences. It is ad- 
mitted that the man's cerebral hemispheres are absolutely and rela- 
tively larger than those of the orang and chimpanzee; that his frontal 
lobes are less excavated by the upward protrusion of the roof of the 
orbits; that his gyri and sulci are, as a rule, less symmetrically dis- 
posed, and present a greater number of secondary plications. And it 
is admitted that, as a rule, in man, the temporo-occipital or '* exter- 
nal perpendicular " fissure, which is usually so strongly marked a 
feature of the ape's brain is but faintly marked. But it is also clear, 
that none of these differences constitutes a sharp demarcation between 
the man's and the ape's brain. In respect to the external perpendic- 
ular fissure of Gratiolet, in the human brain for instance, Prof. Turner 
remarks : * 

" In some brains it appears simply as an indentation of the margin 
of the hemisphere, but in others it extends for some distance more or 
less transversely outward. I saw it in the right hemisphere of a 
female brain pass more than two inches outward; and on another 
specimen, also the right hemisphere, it proceeded for four-tenths of 
an inch outward, and then extended downward as far as the lower 
margin of the outer surface of the hemisphere. The imperfect defi- 
nition of this fissure in the majority of human brains, as compared 
with its remarkable distinctness in the brain of most Quadrumana, is 
owing to the presence in the former of certain superficial, well- 
marked, secondary convolutions which bridge it over and connect the 
parietal with the occipital lobe. The closer the first of these bridg- 
ing gyri lies to the longitudinal fissure the shorter is the external 
parieto-occipital fissure " (1. c, p. 12). 

The obliteration of the external perpendicular fissure of Gratiolet, 
therefore, is not a constant character of the human brain. On the 
other hand, its full development is not a constant character of the 
higher ape's brain. For, in the chimpanzee, the more or less exten- 
sive obliteration of the external perpendicular sulcus by "bridging 
convolutions," on one side or the other, has been noted over and over 
again by Prof, RoUeston, Mr. Marshall, M. Broca and Prof. Turner. 
At the conclusion of a special paper on this subject the latter writes:f 

'* The three specimens of the brain of a chimpanzee just described, 
prove that the generalization which Gratiolet has attempted to draw 
of the complete absence of the first connecting convolution and the 
concealment of the second, as essentially characteristic features in the 
brain of this animal, is by no means universally applicable. In only 
one specimen did the brain, in these particulars, follow the law 
which Gratiolet has expressed. As regards the presence of the 
superior bridging convolution, I am inclined to think that it has 
existed in one hemisphere, at least, in a majority of the brains of this 

* " Convolutions of the Human Cerebrum Topographically Considered," 
1866, p. 12. 

t Notes more especially on the bridging convohitions in the brain of the 
chimpanzee, " Proceedings of the Royal Society of Edinburgh," 1865-66, 


animal wliicli liave, up to this time, been figured or described. Tlie 
superficial position of the second bridging convolution is evidently 
less frequent, and has as yet, I believe, only been seen in the brain 
(A) recorded in this communication. The asymmetrical arrangement 
in the convolutions of the two hemispheres, which previous observ- 
ers have referred to in their descriptions, is also well illustrated in 
these specimens " (pp. 8, 9). 

Even were the presence of the temporo-occipital, or external per- 
pendicular, sulcus, a mark of distinction between the higher apes 
and man, the value of such a distinctive character would be ren- 
dered very doubtful by the structure of the brain in the Platyrrhine 
apes. In fact, while the temporo-occipital is one of the most con- 
stant of sulci in the Catarrhine, or Old World, apes, it is never very 
strongly developed in the New World apes; it is absent in the smaller 
Platyrrhini; rudimentary in Pithecia ;* and more or less obliterated 
by bridging convolutions in Ateles. 

A character which is thus variable within the limits of a single 
group can have no great taxonomic value. 

It is further established that the degree of asymmetry of the con- 
volution of the two sides in the human brain is subject to much indi- 
vidual variation; and that, in those individuals of the Bushman 
race who have been examined, the gyri and sulci of the two hemis- 
pheres are considerably less complicated and more symmetrical than 
in the European brain, while, in some individuals of the chimpanzee, 
their complexity and asymmetry become notable. This is particu- 
larly the case in the brain of a young male chimpanzee figured by M. 
Broca ("L'ordre des Primates," p. 165, fig. 11). 

Again, as respects the question of absolute size, it is established 
that the difference between the largest and the smallest healthy 
human brain is greater than the difference between the smallest 
healthy human brain and the largest chimpanzee's or orang's brain. 

Moreover, there is one circumstance in which the orang's and the 
chimpanzee's brains resemble man's, but in which they differ from the 
lower apes, and that is the presence of two corpora candicantia — the 
Gynomorpha having but one. 

In view of these facts 1 do not hesitate in this year, 1874, to 
repeat and insist upon the proposition which I enunciated in 1863 :f 

" So far as cerebral structure goes, therefore, it is clear that man 
differs less from the chimpanzee or the orang than these do even 
from the monkeys, and that the difference between the brain of the 
chimpanzee and of man is almost insignificant when compared with 
that between the chimpanzee brain and that of a Lemur." 

In the paper to which I have referred. Prof, Bischoff does not 
deny the second part of this statement, but he first makes the irrele- 
vant remark that it is not wonderful if the brains of an orang and a 
Lemur are very different; and secondly, goes on to assert that, "If 
we successively compare the brain of a man with that of an orang; 
the brain of this with that of a chimpanzee; of this with that of a 
gorilla, and so on of a Hylobates, Semriopithecus, Cynocephalus, Ger- 

* Flower "On the Anatomy of Pithecia JfowocAw," " Proceedings of the 
. Zoological Society," 1862. 

t " Man's Place m Nature," p. 103, 


copithecuH, Macacus, Cebus, GalUthrix, Lemur, Stenops, Ilapate, we 
shall not meet with a greater, or even as great, a break in the degree 
of development of the convolutions as we find between the brain of 
a man and that of an orang or chimpanzee." 

To which I reply, firstly, that whether this assertion be true or 
false, it has nothing whatever to do with the proposition enunciated 
in "Man's Place in Nature," which refers not to the development of 
the convolutions alone, but to the structure of the whole brain. If 
Prof. Bischoff had taken the trouble to refer to p. 96 of the work he 
criticises, in fact, he would have found the following passage; " And 
it is a remarkable circumstance that though, so far as our present 
knowledge extends, there is one true structural break in the series of 
forms of Simian brains, this hiatus does not lie between man and the 
manlike apes, but between the lower and the lowest Simians, or in 
other words, between the Old and New World apes and monkeys and 
the Lemurs. Every Lemur which has yet been examined, in fact, 
has its cerebellum partially visible from above; and its posterior lobe, 
with the contained posterior cornu and hippocampus minor, more or 
less rudimentary. Every marmoset, American monkey. Old World 
monkey, baboon, or manlike ape, on the contrary, has its cerebellum 
entirely hidden, posteriorly, by the cerebral lobes, and possesses a 
large posterior cornu with a well-developed hippocampus minor." 

This statement was a strictly accurate account of what was known 
when it was made; and it does not appear to me to be more than 
apparently weakened by the subsequent discovery of the relatively 
small development of the posterior lobes in the Siamang and in the 
Howling monkey. Notwithstanding the exceptional brevity of the 
posterior lobes in these two species, no one will pretend that their 
brains in the slightest degree approach those of the Lemurs. And 
if, instead of putting Hapale out of its natural place, as Prof, Bischoff 
most unaccountably does, we write the series of animals he has 
chosen to mention as follows : Homo, Pithecus, Troglodytes, Hylo- 
hates, Semnopithecus, Cynocephalus, Cercopithecus, Macacus, Cebus, 
Callithrix, Hapale, Lemur, Stenops. I venture to reaffirm that the 
great break in this series lies between Hapale and Lemur, and that 
this break is considerably greater than that between any other two 
terms of that series. Prof. Bischoff ignores the fact that long before 
he wrote Gratiolet had suggested the separation of the Lemurs from 
the other Primates on the very ground of the difference in their cere- 
bral characters ; and that Prof. Flower had made the following 
observations in the course of his description of the brain of the Javan 
Loris : * 

"And it is especially remarkable that, in the development of the 
posterior lobes, there is no approximation to the Lemurine, short- 
hemisphered brain, in those monkeys which are commonly supposed 
to approach this family in other respects, viz. , the lower members of 
the Platyrrhine group." 

So far as the structure of the adult brain is concerned, then, the 
very considerable additions to our knowledge, which have been made 
by the researches of so many investigators during the past ten years 
fully justify the statement which I made in 1863. But it has been 

♦ *' Transaotioiw pf tbe Zoological Sooioty,"'yol. t, 1868. 

ms RAGES OF MAN, ^31 

said that, admitting tlie similarity between the adult brains of man 
and apes, tbey are, nevertheless, in reality, widely different, because 
they exhibit fundamental differences in the mode of their develop- 
ment. No one would be more ready than I to admit the force of this 
argument, if such fundamental differences of development really 
exist. But I deny that they do exist. On the contrary, there is a 
fundamental agreement in the development of the brain in men and 

Gratiolet originated the statement that there is a fundamental dif- 
ference in the development of the brains of apes and that of man — 
•consisting in this; that in the apes the sulci which first make their 
appearance are situated on the posterior region of the cerebral hem- 
ispheres, while in the human foetus the sulci firpt become visible on 
the frontal lobes.* 

This general statement is based upon two observations, the one of 
a Gibbon almost ready to be born, in which the posterior gyri were 
"well developed," while those of the frontal lobes were *' hardly 
indicated"! (1. c, p. 39), and the other of a human foetus at the 
22d or 23d week of uterogestation, in which Gratiolet notes that the 
insula was uncovered, but that nevertheless "des incisures sement 
de lobe anterieur, une scissure peu profonde indique la separation du 
lobe occipital, tres-reduit, d'ailleurs des cette epoque. Le reste de la 
surface cerebrale est encore absolument lisse." 

Three views of this brain are given in plate 2, figs. 1, 2, 3, of the 
work cited, showing the upper, lateral and inferior views of the 
hemispheres, but not the inner view. It is worthy of note that the 
figure by no means bears out Gratiolet's description, inasmuch as the 
fissure (antero -temporal) on the posterior half of the face of the hem- 
isphere is more marked than any of those vaguely indicated in the 
anterior half. If the figure is correct, it in no way justifies Gratio- 
let's conclusion: "II y a done entre ces cerveaux [those of a Calli- 
thrix and of a Gibbon] et celui du foetus humain une difference fonda- 
mental. Chez celui-ci, longtemps avant que les plis temporaux 
apparaissent, les plis frontaux essayent ^'e-si^Xer" 

Since Gratiolet's time, however, the development of the gyri and 

* " Chez tous les singes, les plis posterieurs se developpent les premiers ; 
les plis anterieurs se developpent plus tard, aussi la vertebre occipitale et la 
parietale sont-elles relativement tresgrandes chez le fcEtus. L'Homme pres- 
ente une exception remarquable quant a I'epoque de I'apparition des plis 
frontaux, qui sont les premiers indiques ; mais le developpement general du 
lobe frontal, envisage seulement par rapport a son volume, suit les memes lois 
que dans les singes ;" Gratiolet, " Memoire sur les plis cerebraux de I'Homme 
et des Primates," p. 39, Tab. Iv, fig. 3. 

t Gratiolet's words are (1. c., p. 39): "Dans le foetus dont il a'agit les plis 
cerebraux posterieurs sont bien developpes, tandis que les plis du lobe frontal 
sont a peine indiques." The figure, however (PI. iv, fig. 3), shows the fissure 
of Rolando, and one of the frontal sulei, plainly enough, l^evertheless, M. 
Alix, in his " Notice sur les travaux anthropologiques de Gratiolet " (Mem. de 
la Societe d'Anthropologie de Paris," 18()8, p. 3-4), writes thus: " Gratiolet a 
eu entre les mains le cerveau d'un foetus de Gibbon, singe eminemment supe- 
rieur, et tellement rapproche de Porang, que des naturalistes tres-competents 
I'ont range parmi les anthropoides. M. Huxley, par exemple, n'hesite pas sur 
ce point. Eh bien, c'est sur le cerveau d'un foetus de Gibbon que Gratiolet a 
vu " les circonvolutions du lobe temporo-sphenoidal d^a derelojrpees lorsguHl n'^eocist- 
ent pas encor^; de plis mr le lobe ^frontal. II etait done bien autorise a dire que, 
chez I'Homme les circonvolutions apparaissent d'a en w^ tandis que chez les 
8iiiges elles se developnent ^'w «{i 0.^'^ 


sulci of the brain has been made tlie subject of renewed investigation 
by Schmidt, Bischoff, Pansch,* and more particularly by Ecker,f 
whose work is not only the latest, but by far the most complete 
memoir on the subject. 

The final results of their inquiries may be summed up as follows: 

1. In the human foetus, the sylvian fissure is formed in the course 
of the third month of uterogestation. In this, and in the fourth 
month, the cerebral hemispheres are smooth and rounded (with the 
exception of the sylvian depression), and they project backward far 
beyond the cerebellum. 

2. The sulci, properly so called, begin to appear in the interval 
between the end of the fourth and the beginning of the sixth month 
of foetal life, but Ecker is careful to point out that, not only the 
time, but the order, of their appearance is subject to considerable 
individual variation. In no case, however, are either the frontal or 
the temporal sulci the earliest. 

The first which appears, in fact, lies on the inner face of the hem- 
isphere (whence doubtless Gratiolet, who does not seem to have 
examined that face in his foetus, overlooked it), and is either the 
internal perpendicular (occipito- parietal), or the calcarine sulcus, 
these two being close together and eventually running into one 
another. As a rule the occipito-parietal is the earlier of the two. 

3. At the latter part of this period, another sulcus, the " posterio- 
parietal," or " Fissure of Rolando," is developed, and it is followed, 
in the course of the sixth month by the other principal sulci of the 
frontal, parietal, temporal and occipital lobes. There is, however, 
no clear evidence that one of these constantly appears before the 
other; and it is remarkable that, in the brain at the period described 
and figured by Ecker (1. c, p. 212-213, Taf. II, figs. 1, 2, 3, 4), the 
antero-temporal sulcus {scissure parallele) so characteristic of the ape's 
brain, is as well if not better developed than the fissure of Rolando, 
and is much more marked than the proper frontal sulci. 

Taking the facts as they now stand, it appears to me that the 
order of the appearance of the sulci and gyri in the foetal human 
brain is in perfect harmony with the general doctrine of evolution, 
and with the view that man has been evolved from some ape-like 
form; though there can be no doubt that that form was, in many 
respects, different from any member of the Primates now living. 

Von Baer taught us, half a century ago, that, in the course of 
their development, allied animals put on at first, the characters of 
the greater groups to which they belong, and, by degrees, assume 
those which restrict them within the limits of their family, genus, 
and species; and he proved, at the same time, that no developmental 
stage of a higher animal is precisely similar to the adult condition of 
any lower animal. It is quite correct to say that a frog passes through 
the condition of a fish, inasmuch as at one period of its life the tad- 
pole has all the characters of a fish, and if it went no further would 

♦"Ueber die typische Anordnung derFurchen und Windungen auf den 
Grosshirn-Hemispbaren des Menschen und der Affen." " Archiv. f ur Anthro- 
pologie," iii, 1868. 

t " Zur Entwickelungs Geschichte der Furehen und Windunge i der Gross- 
hirn-Hemispharen im Foetus des Menschen." " Archiv. fur Anthropologies* ' 

fHl£ MACB8 OP MAN. 233 

have to be grouped among fishes. But it is equally true that a tad- 
pole is very different from any known fish. 

In like manner, the brain of a human foetus, at the fifth month, 
may correctly be said to be, not only the brain of an ape, but that of 
an Arctopithecine or marmoset-like ape; for its hemispheres, with 
their great posterior lobster, and with no sulci but the sylvian and 
the calcarine, present the characteristics found only in the group of 
the Arctopithecine Primates. But it is equally true, as Gratiolot 
remarks, that in its widely open sylvian fissure it differs from the 
brain of any actual marmoset. No doubt it would be much more 
similar to the brain of an advanced foetus of a marmoset. But we 
know nothing whatever of the development of the brain in the mar- 
mosets. In the Platyrrhini proper, the only observation with which 
I am acquainted is due to Pansch, who found in the brain of a foetal 
Cebus Apella, in addition to the sylvian fissure and the deep calcarine 
fissure, only a very shallow antero-temporal fissure {scissure paralUle 
of Gratiolet). 

Now this fact, taken together with the circumstance that the 
antero-temporal sulcus is present in such Platyrrhini as the Saimiri, 
which present mere traces of sulci on the anterior half of the exterior 
of the cerebral hemispheres, or none at all, undoubtedly, so far as it 
goes, affords fair evidence in favor of Gratiolet's hypothesis, that the 
posterior sulci appear before the anterior, in the brains of the 
Platyrrhini. But it by no means follows that the rule which may 
hold good for the Platyrrhini extends to the Gatarrhini. We have 
no information whatever respecting the development of the brain in 
the Gynomorpha; and as regards the Anthropomorpha, nothing but 
the account of the brain of the Gibbon, near birth, already referred 
to. At the present moment there is not a shadow of evidence to show 
that the sulci of a chimpanzee's or orang's brain do not appear in the 
same order as a man's. 

Gratiolet opens his preface with the aphorism : "II est dangereux 
dans les sciences de conclure trop vite." I fear he must have for- 
gotten this sound maxim by the time he had reached the discussion 
of the differences between men and apes in the body of his work. No 
doubt the excellent author of one of the most remarkable contribu- 
tions to the just understanding of the mammalian brain which has 
ever been made, would have been the first to admit the insufficiency 
of his data had he lived to profit by the advance of inquiry. The 
misfortune is that his conclusions have been employed by persons 
incompetent to appreciate their foundation as arguments in favor of 

But it is important to remark that, whether Gratiolet was right or 
wrong in his hypothesis respecting the relative order of appearance 
of the temporal and frontal sulci, the fact remains, that before either 
temporal or frontal sulci appear, the foetal brain of man presents 
characters which are found only in the lowest group of the Primates 
(leaving out the Lemurs); and that this is exactly what we should 
expect to be the case if man has resulted from the gradual modifica- 
tion of the same form as that from which the other Primates have 

* For example, M. I'Abbe Leconite in his terrible pamphlet* " Le Darwia- 
poa^ et rorigiue de rEomme," I87<i. 






Secondary sexual cliaracters — Sexual selection — Manner of action-— 
Excess of males — Polygamy — The male aione generally modified 
tlirough 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 — The proportion of the sexes in 
relation to natural selection. 

"With animals which have their sexes separated, the 
males necessarily differ from the females in their organs of 
reproduction; and these are the primary sexual characters. 
But the sexes often differ in what Hunter has called secondary 
sexual characters, which are not directly connected with 
the act of reproduction; for instance, the male possesses 
certain organs of sense or locomotion, of which the female 
is quite destitute, or has them more highly developed, in 
order that he may readily find or reach her; or again the 
male has special organs of prehension for holding her 
securely. These latter organs, of infinitely diversified 
kinds^ graduate into those which are commonly ranked as 
primary, and in some cases can hardly be distinguished 
from them; we see instances of* this in the complex append- 
ages at the apex of the abdomen in male insects. Unless 
indeed we confine the term '^ primary " to the reproductive 


glands, it is scarcely possible to decide 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, such as the 
mammary glands of mammals and the abdominal sacks of 
the marsupials. In some few cases also the male possesses 
similar organs, which are wanting in the female, such as 
.receptacles for the ova in certain male fishes, and those 
^ temporarily developed in certain male frogs. The females 
of most bees are provided with a special apparatus for col- 
lecting and carrying pollen, and their ovipositor is modified 
into a sting for the defense of the larvae and the community. 
Many similar cases could be given, but they do not here 
concern us. There are, however, other sexual differences 
quite unconnected with the primary reproductive organs, 
and it is with these that we are more especially concerned, 
such as the greater size, strength and pugnacity of the male, 
his weapons of offense or means of defense against rivals, 
his gaudy coloring and various ornaments, his power of song 
and other such characters. 

Besides the primary and secondary sexual differences, 
such as the foregoing, the males and females of some 
animals differ in structures related to different habits 
of life, and not at all, or only indirectly, to the repro- 
ductive functions. Thus the females of certain flies 
(Culicidae and Tabanida?) are blood-suckers, while the 
males, living on flowers, have mouths destitute of mandi- 
bles. * The males of certain moths and of some crustaceans 
(e. g. Tanais) have imperfect, closed mouths, and cannot 
feed. The complemental males of certain Cirripedes live 
like epiphytic plants either on the female or the hermaph- 
rodite form, and are destitute of a mouth and of prehensile 
limbs. In these cases it is the male which has been modi- 
fied and has lost certain important organs which the 
females possess. In other cases it is the female which has 
lost such parts; for instance, the female glow-worm is des- 
titute" of wings, as also are many female moths, some of 
which never leave their cocoons. Many female parasitic 
crustaceans have lost their natatory legs. In some weevil- 

*Westwood, "Modern Class of Insects," vol. ii, 1840, p. 541. 
For the statement about Tanais, mentioned below, I am indebted to 
Fritz Miiller. 


beetles (Curculionidae) there is a great difference between 
the male and the female in the length of the rostrum or 
snout; * but the meaning of this and of many analogous 
differences is not at all understood. Differences of structure 
between the two sexes in relation 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. In the Huia of New Zealand the difference is 
wonderfully great, and we hear from Dr. Buller f that the 
male uses his strong beak in chiseling the larvae of insects 
out of decayed wood, while the female probes the softer 
parts with her far longer, much curved and pliant beak; 
and thus they mutually aid each other. In most cases 
differences of structure between the sexes are more or less 
directly connected with the propagation of the species; thus 
a female, which has to nourish a multitude of ova, requires 
more food than the male, and consequently requires special 
means for procuring it. A male animal, which lives for a 
very short time, might lose its organs for procuring food 
through disuse, without detriment; but he would retain his 
locomotive organs in a perfect state, so that he might reach 
the female. The female, on the other hand, might safely 
lose her organs for flying, swimming, or walking, if she 
gradually acquired habits which rendered such powers 

We are, however, here concerned only with sexual selec- 
tion. This depends on the advantage which certain indi- 
viduals have over others of the same sex and species solely 
in respect of reproduction. When, as in the cases above 
mentioned, the two sexes differ in structure in relation to 
different habits of life, they have no doubt been modified 
through natural selection, and by inheritance limited to 
one and the same sex. So again the primary sexual 
organs, and those for nourishing or protecting the young, 
come under the same influence; for those individuals which 
generated or nourished their offspring best, would leave, 
cceteris paribus, the greatest number to inherit their 
superiority; while those which generated or nourished their 
offspring badly would leave but few to inherit their weaker 
powers. As the male has to find the female he requires 

*Kirby and Spence, ''Introduction to Entomology," vol. iii, 1826, 
p. 309. 
} " Birds of New Zealand," 1872, p. 66. 


organs of sense and locomotion, but if tliese organs are 
necessary for the other purposes of life, as is generally the 
case, they will have been developed through natural selec- 
tion. When the male has found the female he sometimes 
absolutely requires prehensile organs to hold her; thus Dr. 
Wallace informs me that the males of certain moths cannot 
unite with the females if their tarsi or feet are broken. 
The males of many oceanic crustaceans, when adult, have 
their legs and antennae modified in an extraordinary 
manner for the prehension of the female; hence we may 
suspect that it is because these animals are washed about 
by the waves of the open sea that they require these organs 
in order to propagate their kind, and, if so, their develop- 
ment has been the result of ordinary or natural selection. 
Some animals extremely low in the scale have been modified 
for this same purpose; thus the males of certain parasitic 
worms, when fully grown, have the lower surface of the 
terminal part of their bodies roughened like a rasp, and 
with this they coil round and permanently hold the 

When the two sexes follow exactly the same habits of 
life, and the male has the censory or locomotive organs 
more highly developed than those of the female, it may be 
that the perfection of these is indispensable to the male for 
finding the female; but in the vast majority of cases, they 
serve only to give one male an advantage over another, for 
with sufficient time the less well-endowed males w^ould suc- 
ceed in pairing with the females; and judging from the 
structure of the female, they would be in all other respects 
equally well adapted for their ordinary habits of life. Since 
in such cases the males have acquired their present struct- 
ure not from being better fitted to survive in the struggle 

*M. Perrier advances this case ("Revue Scientifique," Feb. 1, 
1873, p. 865) as one fatal to the belief in sexual selection, inasmuch 
as he supposes that I attribute all the differences between the sexes 
to sexual selection. This distinguished naturalist, therefore, like so 
many other E'renchmen, has not taken the trouble to understand even 
the first principles of sexual selection. An English naturalist insists 
that the claspers of certain male animals could not have been devel- 
oped through the choice of the female ! Had I not met with this 
remark I should not have thought it possible for any one to have 
read this chapter and to have imagined that I ijiaintain that the 
choice of the female had anything to do with th^ development of th^ 
prehensile organs in the male. 


for existence, but from having gained an advantage ovei 
other males, and from having transmitted this advantage to 
their male offspring alone, sexual selection must here have 
come into action. It was the importance of this distinction 
which led me to designate this form of selection as sexual 
selection. So again, if the chief service rendered to the 
male by his prehensile organs is to prevent the escape of the 
female before the arrival of other males, or when assaulted 
by them these organs will have been perfected through 
sexual selection, that is, by the advantage acquired by certain 
individuals over their rivals. But in most cases of this 
kind it is impossible to distinguish between the effects of 
natural and sexual selection. Whole chapters could be 
filled with details on the differences between the sexes 
in their sensory, locomotive and prehensile organs. As, 
however, these structures are not more interesting than 
others adapted for the ordinary purposes of life I shall pass 
them over almost entirely, giving only a few instances under 
each class. 

There are many other structures and instincts which 
must have been developed through sexual selection, such 
as the weapons of offense and the means of defense of the 
males for fighting with and driving away their rivals — their 
courage and pugnacity — their various ornaments — their 
contrivances for producing vocal or instrumental music — 
and their glands for emitting odors, most of these latter 
structures serving only to allure or excite the female. It 
is clear that these characters are the result of sexual and 
not of ordinary selection, since unarmed, unornamented, or 
unattractive males would succeed equally well in the battle 
for life and in leaving a numerous progeny, but for the 
presence of better endowed males. We may infer that this 
would be the case, because the females, which are unarmed 
and unornamented, are able to survive and procreate their 
kind. Secondary sexual characters of the kind Just 
referred to, will be fully discussed in the following chap- 
ters, as being in many respects interesting, but especially 
as depending on the will, choice, and rivalry of the indi- 
viduals of either sex. When we behold two males fighting 
for the possession of the female, or several male birds dis- 
playing their, gorgeous plumage and performing strange 
antics before an assembled body of females, we cannot doubt 
that; though led by instinct, they know what they are 


about, and consciously exert tlieir mental and bodily 

Just as man can improve the breed of his game-cocks by 
the selection of those birds which are victorious in the 
cock-pit, so it appears that the strongest and most vigorous 
males, or those provided with the best weapons, have pre- 
vailed under nature, and have led to the improvement of 
the natural breed or species. A slight degree of variability 
leading to some advantage, however slight, in reiterated 
deadly contests would suffice for the work of sexual selec- 
tion; and it is certain that secondary sexual characters are 
eminently variable. Just as man can give beauty, accord- 
ing to his standard of tase, to his male poultry, or more 
strictly can modify the beauty originally acquired by the 
parent species, can give to the Sebright bantam a new and 
elegant plumage, an erect and peculiar carriage — so it 
appears that female birds in a state of nature have by a 
long selection of the more attractive males added to 
their beauty or other attractive qualities. Ko doubt 
this implies powers of discrimination and taste on the part 
of the female, which will at first appear extremely improb- 
able; but by the facts to be adduced hereafter, I hope to 
be able to show that the females actually have these 
powers. When, however, it is said that the lower animals 
have a sense of beauty, it must not be supposed that such 
sense is comparable with that of a cultivated man, with his 
multiform and complex associated ideas. A more just 
comparison would be between the taste for the beautiful in 
animals, and that in the lowest savages, who admire and 
deck themselves with any brilliant, glittering, or curious 

From our ignorance on several points, the precise manner 
in which sexual selection acts is somewhat 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 sectual selection has 
played an important part in the history of the organic 
world. It is certain that among 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 super- 
fluous to give instances. Hence the females have the oppor- 
tunity of selecting one out of several males, on the suppo- 
sition that their mental capacity suffices for the exertion of 


a choice. In many cases special circumstances tend to 
make the struggle between the males particularly severe. 
Thus the males of our migratory birds generally arrive at 
their places of breeding before the females, so that many 
males are ready to contend for each female. I am informed 
by Mr. Jenner Weir, that the bird-catchers assert that this 
is invariably the case with the nightingale and blackcap, 
and with respect to the latter he can himself confirm the 

Mr. Swaysland, of Brighton, has been in the habit during 
the last forty years of catching our migratory birds on 
their first arrival, and lie has never known the females of 
any species to arrive before their males. During one 
spring he shot thirty-nine males of Eay^s wagtail {Budytes 
Bail) before he saw a single female. Mr. Gould has ascer- 
tained by the dissection of those snipes which arrive the 
first in this country that the males come before the females. 
And the like holds good with most of the migratory birds 
of the United States.* The majority of the male salmon 
in our rivers on coming up from the sea are ready to breed 
before the females. So it appears to be with frogs and 
toads. Throughout the great class of insects the males 
almost always are the first to emerge from the pupal state, 
so that they generally abound for a time before any females 
can be seen, f 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 the most eager, would leave the 
largest number of offspring; and these would tend to in- 
herit similar instincts and constitutions. It must be borne 
in mind that it would have been impossible to change very 
materially the time of sexual maturity in the females with- 
out at the same time interfering with the period of the 

*J. A. Allen on the "Mammals and Winter Birds of Florida," 
Bull. Comp. Zoology, Harvard College, p. 268. 

f Even witli those plants in which the sexes are separate, the male 
flowers are generally mature before the female. As first shown by 
C. K. Sprengel, many hermaphrodite plants are dichogamous; that 
is, their male and female organs are not ready at the same time, so 
that they cannot be self-fertilized. Now in such flowers the pollen 
is in general matured before the stigma, though there are exceptional 
cases in which the female organs are beforehand. 


production of the young — a period which must be deter- 
mined by the seasons of the year. On the whole, there 
can be no doubt that with almost all animals in which the 
sexes are separate there is a constantly recurrent struggle 
between the males for the possession of the females. 

Our difficulty in regard to sexual selection lies in under- 
standing how it is that the males which conquer other 
males, or those which prove the most attrative to the 
females, leave a greater number of oif spring to inherit their 
superiority than their beaten and less attractive rivals. 
Unless this result does follow the characters which give to 
certain males an advantage over others could not be per- 
fected and augmented through sexual selection. When 
the sexes exist in exactly equal numbers the worst endowed 
males will (except where polygamy prevails) ultimately 
find females and leave as many offspring as well fitted for 
their general habits of life as the best-endowed males. 
From various facts and considerations I formerly inferred 
that with most animals, in which secondary sexual charac- 
ters are well developed, the males considerably exceeded 
the females in number; but this is not by any means 
always true. If the males were to the females as two to 
one, or 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 
proportion of the sexes I do not believe that any great in- 
equality in number commonly exists. In most cases sexual 
selection appears to have been effective in the following 

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 carefully attended to 
the habits of birds during many years. There can also be 
no doubt that the most vigorous, best-nourished and earliest 
breeders would on an average succeed in rearing the 
largest number of fine offspring.* The males, as we have 

* Here is excellent evidence on tlie cliaracter of the offspring from 
an experienced ornithologist. Mr. J. A. Allen, in speaking (" Mam- 


seen, are generally ready to breed before the females; the 
strongest, and with some species the best armed of the 
males, drive away the weaker; and the former would then 
unite with the more vigorous and better-nourished females, 
because they are the first to breed.* Such vigorous pairs 
would surely rear a larger number of offspring than the 
retarded females, which would be compelled to unite with 
the conquered and less powerful males, supposing the sexes 
to be numerically equal; and this 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 

But in very many cases the males which conquer their 
rivals do not obtain possession of the females, independently 
of the choice of the latter. The courtship of animals is 
by no means so simple and short an affair as might be 
thought. The females are most excited by, or prefer pair- 
ing with, the more ornamented males, or those which are 
the best songsters, or play the best antics; but it is obviously 
probable that they would at the same time prefer the more 
vigorous and lively males, and this has in some cases been 
confirmed by the actual observation, f 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. Both sexes, therefore, of such early 
pairs would, as above explained, have an advantage over 
others in rearing offspring ; and this apparently has 
sufficed during a long course of generations to add not 

mals and Winter Birds of E. Florida," p. 229) of the later broods 
after the accidental destruction of the first, says that these " are found 
to be smaller and paler-colored than those hatched earlier in the sea- 
son. In cases where several broods arc reared each year, as a general 
rule the birds of the earlier broods seem in all respects the most per- 
fect and vigorous." 

* Hermann Mtiller has come to this same conclusion with respect 
to those female bees which are the first to emerge from the pupa each 
year. See his remarkable essay, "Anwendung den Darwin'schen 
Lehre auf Bienen," •* Verb. d. V. Jahrg.," xxix, p. 45. 

f With respect to poultry, I have received information, hereafter to 
be given, to this effect. Even with birds, such as pigeons, which 
pair for life, the female, as I hear from Mr. Jenner Weir, will desert 
her mate if he is injured or grows weak. 


only to the strength and fighting powers of the males, 
but likewise to their various ornaments or other attractions. 
In the converse and much rarer case of the males select- 
ing 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 her in providing for the young. The same principles 
would apply if each sex preferred and selected certain 
individuals of the opposite sex; supposing that they selected 
not only the more attractive, but likewise the more vigor- 
ous individuals. 

Numerical Proportion of the Two Sexes. — I have remarked 
that sexual selection would be a simple aff'air if the males 
were considerably more numerous than the females. Hence 
I was 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 supple- 
mentary discussion so as not to interfere with the course of 
my argument. Domesticated animals alone afford the 
means of ascertaining the proportional numbers at birth; 
but no records have been specially kept for this purpose. 
By indirect means, however, I have collected a considerable 
body of statistics, from which it appears that with most 
of our domestic animals the sexes are nearly equal at birth. 
Thus 25,560 births of race-horses have been recorded during 
twenty-one years, and the male births were to the female 
births as 99.7 to 100. In greyhounds the inequality is 
greater than with any other animal, for out of 6,878 births 
during twelve years, the male births were to the female as 
110.1 to 100. It is, however, in some degree doubtful 
whether it is safe to infer that the proportion would be the 
same under natural conditions as under domestication; for 
slight and unknown differences in the conditions affect the 
proportion of the sexes. Thus with mankind, the male 
births in England are as 104.5, in Kussia as 108.9, and with 
the Jews of Livonia as 120 to 100 female births. But I 
ehall recur to this curious point of the excess of male births 


in the supplement to this chapter. At the Cape of Good 
Hope, however, male children of Eiiropeon extraction have 
been born during several years in the proportion of between 
90 and 99 to 100 female children. 

For our present purpose we are concerned with the pro- 
portion of the sexes, not only at birth, but also at maturity, 
and this adds another element of doubt; for it is a well- 
ascertained fact that with man the number of males dying 
before or during birth and during the first few years of 
infancy is considerably larger than that of females. So it 
almost certainly is with male lambs, and probably with 
some other animals. The males of some species kill one 
another by fighting; or they drive one another about until 
they become greatly emaciated. They must also be often 
exposed to various dangers while wandering about in eager 
search for the females. In many kinds of fish the males 
are much smaller than the females, and they are believed 
often to be devoured by the latter or by other fishes. The 
females of some birds appear to die earlier than the males; 
they are also liable to be destroyed on their nests or while 
in charge of their young. With insects the female larvae 
are often larger than those of the males, and would conse- 
quently be more likely to be devoured. In some cases the 
mature females are less active and less rapid in their move- 
ments than the males and could not escape so well from 
danger. Hence, with animals in a state of nature we must 
rely on mere estimation in order to judge of the propor- 
tions of the sexes at maturity; and this is but little trust- 
worthy except when the inequality is strongly marked. 
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, are considerably more numerous than the 

The proportion between the sexes fluctuates slightly 
during successive years; thus with race-horses, for every 
100 mares born the stallions varied from 107.1 in one year 
to 92.6 in another year, and with greyhounds from 116.3 
to 95.3. But had larger numbers been tabulated through- 
out an area more extensive than England these fluctuations 
would probably have disappeared; and such as they are, 
would hardly suffice to lead to effective sexual selection in 
a, state of nature. Nevertheless, in the cases of some few 


wild animals, as shown in the supplement, the proportions 
seem to fluctuate either during different seasons or in dif- 
ferent localities in a sufficient degree to lead to such selec- 
tion. For it should be observed that any advantage gained 
during certain years or in certain localities by those males 
which were able to conquer their rivals, or were the most 
attractive to the females, would probably be transmitted to 
the offspring and would not subsequently be eliminated. 
During the succeeding seasons, when from the equality of 
the sexes every male was able to 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 weaker or less attractive. 

Polygamy. — The practice of polygamy leads to the same 
results as would follow from an actual inequality in the 
number of the sexes; for if each male secures two or more 
females many males cannot pair; and the latter assuredly 
will be the weaker or less attractive individuals. Many 
mammals and some few birds are polygamous, but with 
animals belonging to the lower classes I have found no evi- 
dence of this habit. The intellectual powers of such ani- 
mals are, perhaps, not sufficient to lead them to collect and 
guard a harem of females. That some relation exists be- 
tween polygamy and the development of secondary sexual 
characters appears nearly certain; and this supports the 
view that a numerical preponderance of males would be 
eminently favorable to the action of sexual selection. 
Nevertheless many animals which are strictly monogamous, 
especially birds, display strongly marked secondary sexual 
characters; while some few animals which are polygamous 
do not have such characters. 

We will first briefly run through the mammals and 
then turn to birds. The gorilla seems to be polygamous, 
and the male 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 color, beard, and vocal organs ; and the male generally 
lives with two or three wives; the male of the Cehus capuci- 
nus differs somewhat from the female, and appears to be 


polygamous.* Little is known on this head with respect to 
most other monkeys, but some species are strictly monoga-, 
mous. The ruminants are eminently polygamous, and they 
present sexual differences more frequently than almost any 
other group of mammals; this holds good, especially in 
their weapons, but also in other characters. Most deer, 
cattle, and sheep are polygamous; as are most antelopes, 
though some are monogamous. Sir Andrew Smith, in 
speaking of the antelopes of S. 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 Pallasf states 
that the male drives away all rivals and collects a herd of 
about a hundred females and kids together; the female is 
hornless and has softer hair, but does not otherwise differ 
much from the male. The wild horse of the Falkland 
Islands and of the Western States of North America is 
polygamous, but, except in his greater size and the propor- 
tions of his body, diff'ers but little from the mare. The 
wild boar presents well-marked sexual characters, in his 
great tusks and some other points. In Europe and in India 
he leads a solitary life, except during the breeding-season ; 
but as is believed by Sir W. Elliot, who has had many 
opportunities in India of observing this animal, he consorts 
at this season with several females. Whether this holds 
good in Europe is doubtful, but it is supported by some 
evidence. The adult male Indian elephant, like the boar, 
passes much of his time in solitude; but as Dr. Campbell 
states, when with others, *^ it is rare to find more than one 
male with a whole herd of females ;" the larger males 
expelling or killing the smaller and weaker ones. The 
male differs from the female in his immense tusks, greater 
size, strength and endurance; so great is the difference in 
these respects, that the males when caught are valued at 

*0n the Gorilla, Savage and Wyman, "Boston Journal of Nat. 
Hist.," vol. v, 1845-47, p. 423. On Cynocephalus, Brebui, " Illust. 
Thierleben," B.i, 1864, s. 77. On Mycetes, Rengger, " Naturgescli.: 
Saugethiere von Paraguay," 1830, ss. 14, 20. Cebus, Brehm, ibid, s. 

f 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, 1868, 
p. 633) gives a table showing incidentally which species of antelopes 
are gregarious. 


one-fifth more than the females.* The sexes of other 
pachydermatous animals differ very little or not at all, and, 
as far as known, they are not polygamists. Nor have I 
heard of any species in the orders of Cheiroptera, Edentata, 
Insectivora and Eodents being polygamous, excepting that 
among the Eodents, the common rat, according to some 
rat-catchers, lives with several females. Nevertheless the 
two sexes of some sloths (Edentata) differ in the character 
and color of certain patches of hair on their shoulders, f 
And many kinds of bats (Cheiroptera) present well- 
marked sexual differences, chiefly in the males possessing 
odoriferous glands and pouches, and by their being of 
a lighter color. X In the great order of Eodents, as far as I 
can learn, the sexes rarely differ, and when they do so it 
is but slightly in the tint of the fur. 

As I hear from Sir Andrew Smith, the lion in S. Africa 
sometimes lives with a single female, but generally with 
more, and, in one case, was found with as many as five 
females; so that he is polygamous. As far as I can dis- 
cover he is the only polygamist among all the terrestrial 
Carnivora, and he alone presents well-marked sexual char- 
acters. If, however, we turn to the marine Carnivora, as 
we shall hereafter see, the case is widely different; for many 
species of seals offer extraordinary sexual differences, 
and they are eminently polygamous. Thus, according to 
Peron, the male sea -elephant of the Southern 'Ocean 
always possesses 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 accompanied 
by even a greater number of females. It is an interesting 
fact, as Dr. Gill remarks, § that in the monogamous species, 
*' or those living in small communities, there is little differ- 
ence in size between the males and females; in the social 
species, or rather those of which the males have harems, 
the males are vastly larger than the females.'^ 

*Dr. Campbell, in " Proc. Zoolog. Soc," 1869, p. 138. See also 
an interesting paper, by Lieut. Johnstone, in ' ' Proc. Asiatic Soc. of 
Bengal," May, 1868. 

f Dr. Gray, in "Annals and Mag. of Nat. Hist.," 1871, p. 302. 

:t:See Dr. Dobson's excellent paper in " Proc. Zoolog. Soc," 187S, 
p. 241. 

§ Tbe Eared Seals, " American Naturalist," vol. iv, Jan., 1871. 


Among birds, many species, the sexes of which differ 
greatly from each other, are certainly monogamous. In 
Great Britain we see well-marked sexual differences, for 
instance, in the wild duck which pairs with a single female, 
the common blackbird, and the bullfinch which is said to 
pair for life. I am informed by Mr. Wallace that the like 
IS true of the Chatterers or Cotingidae of South America, 
and of many other birds. In several groups I have not 
been able to discover whether the species are polygamous or 
monogamous. Lesson says that birds of paradise, so 
remarkable for their sexual differences, are polygamous, but 
Mr. Wallace doubts whether he had sufficient evidence. 
Mr. Salvin tells me he has been led to believe that hum- 
ming - birds are polygamous. The male widow - bird, 
remarkable for his caudal plumes, certainly seems to be a 
polygamist.* I have been assured by Mr. Jenner Weir and 
by others that it is somewhat common for three starlings to 
frequent the same nest; but whether this is a case of 
polygamy or polyandry has not been ascertained. 

The Gallinacese exhibit almost as strongly marked sexual 
differences as birds of paradise or humming-birds, and 
many of the species are, as is well known, polygamous; 
others being strictly monogamous. What a contrast is pre- 
sented between the sexes of the polygamous peacock or 
pheasant, and the monogamous guinea-fowl or partridge! 
Many similar cases could be given, as in the gi'ouse tribe, 
in which the males of the polygamous capercailzie and 
black-cock differ greatly from the females; while the sexes 
of the monagamous red grouse and ptarmigan differ very 
little. In the Cursores, except among the bustards, few 
species offer strongly-marked sexual differences, and the 
great bustard ( Otis tarda) is said to be polygamous. With 
the Grallatores extremely few species differ sexually, but 
the ruff' (Machetes pvgnax) affords a marked exception and 
this species is believed by Montagu to be a polygamist. 
Hence it appears that among birds there often exists a close 
relation between polygamy and the development of strongly- 

* " The Ibis," vol. iii, 1861, p. 133, on the Progne Widow-bird. 
See also on the Vidua axillans, ibid., vol. ii, 1860, p. 211. On the 
polygamy of the Capercailzie and Great Bustard, see L. Llovd, 
"Game Birds of Sweden," 1867, pp. 19, 182. Montagu and Selby 
speak of the Black Grouse as polygamous and of the Red Grouse as 


marked sexual differeoces. 1 asked Mr. Bartlett, of the 
Zoological Gardens, who has had T?ry large oxpeiience 
with birds, whether the male Gragopan (one of the Gailin- 
accEP) was polygamous, and I was struck by his answering, 
*' I do not know, but should think so from his splendid 

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 highly polyga- 
mous. The Rev. W. D. Fox informs me that out of some 
half-tamed wild-ducks, on a large pond in his neighbor- 
hood, so many mallards were shot by the gamekeeper that 
only one was left for every seven or eight females; yet 
unusually large broods were reared. The guinea-fowl is 
strictly monogamous; but Mr. Fox finds that his birds suc- 
ceed best when he keeps one cock to two or three hens. 
Canary-birds pair in a state of nature, but the breeders in 
England successfully put one male to four or five females. 
I have noticed these cases as rendering it probable that 
wild monogamous species might readily become either tem- 
porarily or permanently polygamous. 

Too little is known of the habits of reptiles and fishes 
to enable us to speak of their marriage arrangements. The 
stickle-back (Gasterosteus), however, is said to be a polyg- 
amist;* and the male during the breeding season differs 
conspicuously from the female. 

To sum up on the means through which, as far as we can 
judge, sexual selection has led to the development of second- 
ary sexual characters. It has been shown that the largest 
number of vigorous offspring will be reared from the pair- 
ing of the strongest and best-armed males, victorious in 
contests over other males, with the most vigorous and best- 
nourished females, which are the first to breed in the spring. 
If such females select the more attractive, and at the same 
time vigorous males, they will rear a larger number of off'- 
c«pring than the retarded females, which must pair with the 
less vigorous and less attractive males. So it will be if the 
more vigorous males select the more attractive and at the 
Slime time healthy and vigorous females; and this will espe- 
cially hold good if the male defends the female and aids 
in providing food for the young. The advantage thus 

♦i^oei Humphreys, " River Gardens," 1857. 


gained by the more vio^orous pairs in rearing a larger 
number of offspring lias apparently sufficed to render sex- 
ual selection efficient. But a large numerical preponder- 
ance of males over females will be still more efficient; 
whether the preponderance is only occasional and local, or 
permanent; whether it occurs at birth, or afterward from 
the greater destruction of the females; or whether it in- 
directly follows from the practice of polygamy. 

The Male Generally More Modified than the Female. — 
Throughout the animal kingdom when the sexes differ 
in external appearance, it is, with rare exceptions, the male 
which has been the more modified; for, generally, the 
female retains a closer resemblance to the young of her own 
species and to other adult 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 tight together and sedulously display 
their charms before the females; and the victors transmit 
their superiority to their male offspring. Why both sexes 
do not thus acquire the characters of their fathers will be 
considered hereafter. That the males of all mammals 
eagerly pursue the females is notorious to every one. So it 
is with birds; but many cock birds do not so much pursue 
the hen, as display their plumage, perform strange antics, 
and pour forth their song in her presence. The male in the 
few fish observed seems much more eager than the female: 
and the same is true of alligators, and apparently of 
Batrachians. Throughout the enormous class of insects, 
as Kirby remarks,* ^' the law is that the male shall seek the 
female." Two good authorities, Mr. Blackwall and Mr. C. 
Spence Bate, tell me that the males of spiders and crusta- 
ceans are more active and more erratic in their habits than 
the females. When the organs of sense or locomotion are 
present in the one sex of insects and crustaceans and absent 
in the other, or when, as is frequently the case, they are 
more highly developed in the one than in the other, it is, as 
far as I oan discover, almost invariably the male which 
retains such organs, or has them most developed; and this 

* Kirby and Spence, '* Introduction to Entomology," vol. ili, 1826, 
p. a42. 


bIiows that the male is the more active member in the 
courtship of the sexes.* 

The female, on the other hand, with the rarest excep- 
tions, is less eager than the male. As the illustrious 
Hunter f long ago observed she generally " requires to be 
courted;" she is coy, and may often be seen endeavoring for 
a long time to escape from the male. Every observer of 
the habits of animals will be able to call to mind instances 
of this kind. It is shown by various facts, given hereafter, 
and by the results fairly attributable to sexual selection, 
that the female, though comparatively passive, generally 
exerts some clioice and accepts one male in preference to 
others. Or she may accept, as appearances would some- 
times lead us to believe, not the male which is the most 
attractive to her, but the one which is the least dis- 
tasteful. The exertion of some choice on the part of the 
female seems a law almost as general as the eagerness of the 

We are naturally led to inquire why the male, in so 
many and such distinct classes, has become more eager 
than the female, so that he searches for her and plays 
the more active part in courtship. It would be no 
advantage and some loss of power if each sex searched 
for the other; but why should the male almost always be 
the seeker? The ovules of plants after fertilization have 
to be nourished for a time; hence the pollen is necessarily 
brought to the female organs — being placed on the stigma, 
by means of insects or the wind, or by the spontaneous 
movements of the stamens; and in the Algae, etc., by the 
locomotive power of the antherozooids. With lowly-organ- 
ized aquatic animals, permanently affixed to the same spot 
and having their sexes separate, the male element is invari- 
ably brought to the female; and of this we can see the 

* One parasitic Hymenopterous insect (Westwood, " Modern Class, 
of Insects," vol. ii, p. 160) forms an exception to the rule, as the 
male has rudimentary wings, and never quits the cell in M^hich it is 
born, while the female has well-developed wings. Audouin helieves 
that the females of this species are impregnated by the males which 
are born in the same cells with them; but it is much more probable 
that the females visit other cells, so that close interbreeding is thus 
avoided. We shall hereafter meet in various classes, with a few 
exceptional cases, in which the female, instead of the male, is the 
seeker and wooer. 

f "Essays and Observations," edited by Owen, vol. i, 1861. p. 194. 


reason, for even if the ova were detached before fertiliza- 
tion, and did not require subsequent nourishment or pro- 
tection, there would yet be greater difficulty in transporting 
them than the male element, because, being larger than 
the latter, they are produced in far smaller numbers. So 
that many of the lower animals are, in this respect, analo- 
gous with plants.* The males of affixed and aquatic ani- 
mals having been led to emit their fertilizing elements in 
this way, it is natural that any of their descendants, which 
rose in the scale and became locomotive, should retain the 
same habit; and they would approach the female as closely 
as possible, in order not to risk the loss of the fertilizing 
element in a long passage of it through the water. With 
some few of the lower animals, the females alone are fixed, 
and the males of these must be the seekers. But it is dif- 
ficult to understand why the males of species, of which the 
progenitors were primordially free, should invariably have 
acquired the habit of approaching the females, instead of 
being approached by them. But in all cases, in order that 
the males should seek efficiently, it would be necessary that 
they should be endowed with strong passions; and the 
acquirement of such passions would naturally follow from 
the more eager leaving a larger number of offspring than 
the less eager. 

The great eagerness of the males has thus indirectly led 
to their much more frequently developing secondary sexual 
characters than the females. But the development of such 
characters would be much aided if the males were more 
liable to vary than the females — as I concluded they were — 
after a long study of domesticated animals. Von Nathu- 
eius, who has had very wide experience, is strongly of the 
same opinion. \ Good evidence also in favor of this con- 
clusion can be produced by a comparison of the two sexes 
in mankind. During the Novara Expedition^: a vast 

*Prof. Sachs (" Lelirbucli der Botauik," 1870, s. 633), in speaking 
of the male and female reproductive cells, remarks, '• verhalt sich 
die eine bei der Vereinigung activ, . . . die andere erscheint bei 
der Vereinigung passiv." 

t '' Vortrage iiber Viehzucht," 1872, p. 63. 

X '-Reise der Novara, Anthropolog. Theil," 1867, ss. 216-269. The 
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 Dgmestication/' vol. ii, 1868, p. 75. 


number of measurements was made of various parts of the 
body in different races, 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,* 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 the grejiter 
frequency of deficiency in females before described." Prof. 
Macalister likewise remarksf 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 are said 
to occur. Dr. Burt Wilder J 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 over- 
looked that women would more frequently endeavor to con- 
ceal a deformity of this kind than men. Again, Dr. L. 
Meyer asserts that the ears of man are more variable in 
form than those of a woman. § Lastly, the temperature is 
more varia^)le in man than in woman, n 

The cause of the greater general variability in the male 
sex than in the female is unknown, except in so far as sec- 
ondary sexual characters are extraordinarily variable and 
are usually confined to the males; and, as we shall presently 
see, this fact is, to a certain extent, intelligible. Through 
the action of sexual and natural selection mal6 animals 
have been rendered in very many instances widely different 
from their females ; but independently of selection the 
two sexes, from differing constitutionally, tend to vary in 

* " Proceedings Royal Soc," vol. xvi, July, 1868, pp. 519, 524. 

f " Proc. Royal Irish Academy," vol. x, 1868, p. 123. 

X " Massachusetts Medical Soc," vol. ii, No 3, 1868, p. 9. 

§ " Arcliiv fiir Path. Anat. und Phys,," 1871, p. 488. 

II The conclusions recently arrived at by Dr. J. Stockton Hongh, on 
the temperature of man, are given in the " Pop. Science Review,*' 
Jan. 1, 1874, p. 97, 


a somewhat different manner. The female has to expend 
much organic matter in the formation of her ova, whereas 
the male expends much force in fierce contests with his 
rivals, in wandering about in search of the female, in exert- 
ing his voice, pouring out odoriferous secretions, etc. ; and 
this expenditure is generally concentrated within a short 
period. The great vigor of the male during the season of 
love seems often to intensify his colors independently of 
any marked difference from the female.* In mankind, 
and even as low down in the organic scale as in the Lepi- 
doptera, the temperature of the body is higher in the male 
than in the female, accompanied in the case of man by a 
slower pulse, f On the whole, the expenditure of matter 
and force by the two sexes is probably nearly equal, though 
effected in very different ways and at different rates. 

From the causes just specified the two sexes can hardly 
fail to differ somewhat in constitution, at least during the 
breeding season; and although they may be subjected to 
exactly the same conditions they will tend to vary in a 
different manner. If such variations are of no service to 
either sex they will not be accumulated and increased by 
sexual or natural selection. Nevertheless, they may be- 
come permanent if the exciting cause acts permanently; 
and in accordance with a frequent form of inheritance 
they may be transmitted to that sex alone in which they 
first appeared. In this case the two sexes will come to 
present permanent, yet unimportant, dift'erences of char- 
acter. For instance, Mr. Allen shows that with a large 
number of birds inhabiting the northern and southern 
United States, the specimens from the south are darker- 
colored than those from the north; and this seems to be 
the direct result of the difference in temperature, light, etc., 
between the two regions. Now, in some few cases, the 

*Prof. Mantegazza is inclined to believe (" Lettera a Carlo Dar- 
win," '* Archivio per I'Anthropologia," 1871, p. 306) that tlie bright 
colors, common in so many male animals, are due to the presence and 
retention by them of the spermatic fluid; but this can hardly be the 
case; for many male birds, for instance young pheasants, become 
brightly colored in the autumn of their first year. 

f For mankind, see Dr. J. Stockton Hough, whose conclusions are 
given in the " Pop. Science Review," 1874, p. 97. See Girard's 
observations on the Lepidoptera, as given in the "Zoological Becord," 
1869, p. 847. 

SEX VAL selection: 255 

two sexes of the same species appear to have been differ- 
ently affected; in the Agelceus phoBmceus the males have 
had their colors greatly intensified in the south; whereas 
with Cardinalis virginianus it is the females which have 
been thus affected; with Qniscalus major the females have 
been rendered extremely variable in tint, while the males 
remain nearly uniform.* 

A few exceptional cases occur in various classes of ani- 
mals, in which the females instead of the males have 
acquired well-pronounced secondary sexual characters, such 
as brighter colors, greater size, strength or pugnacity. 
"With birds there has sometimes been a complete transposi- 
tion of the ordinary characters proper to each sex; the 
females having become the more eager in courtship, the 
males remaining comparatively passive, but apparently 
selecting the more attractive females, as we may infer from 
the results. Certain hen birds have thus been rendered 
more highly colored or otherwise ornamented, as well as 
more powerful and pugnacious than the cocks ; these 
characters being transmitted to the female offspring alone. 

It may be suggested that in some cases a double process 
of selection has been carried on; that the males have selected 
the more attractive females and the latter the more attract- 
ive males. This, process, however, though it might lead 
to the modification of both sexes, would not make the one 
sex different from the other, unless indeed their tastes for 
the beautiful differed; but this is a supposition too improba- 
ble to be worth considering in the case of any animal, except- 
ing man. There are, however, many animals in which the 
sexes resemble each other, both being furnished with the 
same ornaments, which analogy would lead us to attribute 
to the agency of sexual selection. In such cases it may be 
suggested with more plausibility that there has been a 
double or mutual process of sexual selection; the more 
vigorous and precocious feaaales selecting the more 
attractive and vigorous males, the latter rejecting all 
except the more attractive females. But from what we 
know of the habits of animals, this view is hardly probable, 
for the male is generally eager to pair with any female. It 
is more probable that the ornaments common to both sexes 
were acquired by one sex, generally the male, and then 

» "Mammals and Birds of E. Florida," pp. 234, 280, 295. 


transmitted to the offspring of both sexes. If, indeed, 
during a lengthened period the males of any species were 
greatly to exceed the females in number, and then during 
another lengthened period, but under different conditions, 
the reverse were to occur, a double, but not simultaneous, 
process of sexual selection might easily be carried on, by 
which the two sexes might be rendered widely different. 

We shall hereafter see that many animals exist, of which 
neither sax is brilliantly colored or provided with special 
ornaments, and yet the members of both sexes ot of one 
alone have probably acquired simple colors, such as white 
or black, 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 having preferred plain black or white. Obscure 
tints have often been developed through natural selection for 
the sake of protection, and the acquirement through sexual 
selection of conspicuous colors appears to have been some- 
times checked from the danger thus incurred. But in 
other cases the males during long ages may have struggled 
together for the possession of the females, and yet no effect 
will have been produced, unless a larger number of 
offspring were left by the more successful males to inherit 
their superiority than by the less successful; and this, as 
previously shown, depends on many 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 indi- 
viduals. Death, indeed, not rarely ensues from the 
conflicts of rival males. But generally the less successful 
male merely fails to obtain a female, or obtains a retarded 
and less vigorous female later in the season, or, if polyga- 
mous, obtains fewer females; so that they leave fewer, less 
vigorous, or no offspring. In regard to structures acquired 
through ordinary or natural selection there is in most cases, 
as long as the conditions of life remain the same, a limit to 
the amount of advantageous modification in relation to 
certain special purposes; but in regard to structures adapted 
to make one male victorious over another, either in fighting 
or in charming the female, there is no definite limit to the 
amount of advantageous modification; so that as long as 
the proper variations arise the work of sexual selection will 
go on. TJiis circumstance may partly account for the 


frequent and extraordinary amount of variability presented 
by secondary sexual characters. Nevertheless, natural 
selection will determine that such characters shall not be 
acquired by the victorious males, if they would be highly 
injurious, either by expending too much of their vital 
powers or by exposing them to any great danger. The 
development, however, of certain structures — of the horns, 
for instance, in certain stags — has been carried to a won- 
derful extreme; and in some cases to an extreme which, as 
far as the general conditions of life are concerned, must be 
slightly injurious to the male. From this fact we learn 
that the advantages which favored males derive from con- 
quering other males in battle or courtship, and thus leaving 
a numerous, progeny, are in the long run greater than those 
derived from rather more perfect adaptation to their condi- 
tions of life. AVe shall further see, and it could never have 
been anticipated, that the power ^ to charm the female has 
sometimes been more important than the power to conquer 
other males in battle. 

Laws of Inheritance. — In order to understand how sexual 
selection has acted on many animyJs of many classes, and 
in the course of ages has produced a conspicuous result, it 
is necessary to bear in mind the laws of inheritance as far 
as they are known. Two distinct elements are included 
under the term ^inheritance'"' — the transmission and the 
development of characters ; but as these generally go 
together the distinction is often overlooked. We see this 
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 its 
own male and female sex to the hybrid oif spring of either 
sex. The same fact is likewise manifest when characters 
proper to the male are occasionally developed in the female 
when she grows old or becomes diseased, as, for instance, 
when the common hen assumes the flowing tail-feathers, 
hackles, comb, spurs, voice, and even pugnacity of the 
cook. Conversely the same thing is evident more or less 


plainly with castrated males. Again, independently of 
old age or disease, characters are occasionally transferred 
from the male to the female, as when in certain breeds of 
the fowl spurs regularly appear in the young and healthy 
females. But in truth they are simply develo]jed in the 
female; for in every breed each detail in the structure of 
the spur is transmitted through the female to her male off- 
spring. Many cases will hereafter be given where the 
female exhibits more or less perfectly characters proper to 
the male, in whom they must have been first developed and 
then transferred to the female. The converse case of the 
first development of characters in the female and of trans- 
ference to the male is less frequent; it will therefore be 
well to give one striking instance. With bees the pollen- 
collecting apparatus is used by the female alone 'for gather- 
ing pollen for the larvae, yet in most of the species it is 
partially developed in the males to whom it is quite useless, 
and it is perfectly developed in the males of Bombus or the 
humble-bee. * As not a single other Hymenopterous insect, 
not even the wasp, which is closely allied to the bee, is 
provided with a pollen-collecting apparatus, we have no 
grounds for supposing that male bees primordially collected 
pollen as well as the females; although we have some reason 
to suspect that male mammals primordially suckled their 
young as well as the females. Lastly, in all cases of rever- 
sion characters are transmitted through two, three or many 
more generations, and are then developed under certain 
unknown favorable conditions. This important distinction 
between transmission and development will be best kept in 
mi?ui by the aid of the hypothesis of pangenesis. Accord- 
ing to this hypothesis every unit or cell of the body throws 
off gemmnles or undeveloped atoms, which are transmitted 
to the offspring of both sexes, and are multiplied by self- 
division. They may remain undeveloped during the early 
years of life or during successive generations; and their 
development into units or cells, like those from which they 
were derived, depends on their affinity for and union with 
other units or cells previously developed in the due order 
of growth. 
Inheritance at Corresponding Periods of Life. — This 

*H. Miiller, " Anwendung der Darwin'schen Lelire," etc. Verli. 
d. n. V . Jakrg. xxix, p. 43. 


tendency is well-established. A new character, appearing 
in a young animal, whether it lasts throughout life^ or is 
only transient, will, in general, reappear in the offspring at 
the same age and last for the same time. If, on the other 
hand, a new character appears at maturity, or even during 
old age, it tends to reappear in the oifspring at the same 
advanced age. When deviations from this rule occur, the 
transmitted characters much oftener appear before than 
after the corresponding age. As I have dwelt on this sub- 
ject sufficiently in another work,* 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 
down-covered chickens, the young birds in their first true 
plumage, and the adults differ greatly from one another, as 
well as from their common parent-form, the Gallus hanhiva; 
and these characters are faithfully transmitted by each 
breed to their offspring at the corresponding periods of 
life. For instance, the chickens of spangled Hamburgs, 
while covered with down, have a few dark spots on me 
head and rump, but are not striped longitudinally, as in 
many other breeds; in their first true plumage, '' they are 
beautifully penciled,'^ that is, each feather is transversely 
marked by numerous dark bars; but in their second plum- 
age the feathers all become spangled or tipped with a dark 
round spot, f Hence in this breed variations have occurred 
at, and been transmitted to, three distinct periods of life. 
The pigeon offers a more remarkable case, because the abo- 
riginal parent-species does not undergo any change of plum- 
age with advancing age, excepting at maturity the breast 
becomes more iridescent ; yet there are breeds which do 
not acquire their characteristic colors until they have 
moulted two, three, or four times; and these modifications 
of plumage are regularly transmitted. 

Inheritance at Corresponding Seasons of the Tear. — With 

*"The Variation of Animals and Plants under Domestication," 
vol. ii, 1868, p. 75. In tlie last chapter but one tlie provisional hypo- 
thesis of pangenesis, above alluded to, is fully explained. 

f These facts are given on the high authority of a great breeder, 
Mr. Teebay; see Tegetmeier's " Poultry Book," 1868, p. 158. On 
the characters of chickens of different breeds, and on the breeds of 
the pigeon, alluded to in the following paragraph, see '* Variation of 
Animals," etc., vol. i, pp. 160, 249; vol. ii, p. 77. 


animals in a state of nature, innumerable instances occur 
of characters appearing periodically at different seasons. 
We see this in tne horns of the stag, and in the fur of the 
Arctic animals, which becomes thick and white during the 
winter. Many birds acquire bright colors and other deco- 
rations during the breeding-season alone. Pallas states,* 
that in Siberia domestic cattle and horses become lighter- 
colored during the winter; and I have myself observed, and 
heard of similar strongly-marked changes of color, that is, 
from brownish-cream color or reddish-brown to a perfect 
white, in several ponies in England. Although I do not know 
that this tendency to change the color of the coat during 
different seasons is transmitted, yet it probably is so, as all 
shades of color are strongly inherited by the horse. Nor is 
this form of inheritance as limited by the seasons, more 
remarkable than its limitation by age or sex. 

Inheritance as Limited ly Sex. — The equal transmission 
of characters to both sexes is the commonest form of inher- 
itance, at least with those animals which do not present 
strongly-marked sexual differences, and indeed with many 
of these. But characters are somewhat commonly trans- 
ferred exclusively to that sex in which they first appear. 
Ample evidence on this head has been advanced in my work 
on ''Variation Under Domestication," but a few instances 
may here be given. There are breeds of the sheep and goat, 
in which the horns of the male differ greatly in shape from 
those of the female; and these differences acquired under 
domestication are regularly transmitted to the same sex. 
As a rule, it is the females alone in cats which are tortoise- 
shell, the corresponding color in the males being rusty-red. 
With most breeds of the fowl the characters proper to each 
sex are transmitted to the same sex alone. So general is 
this form of transmission that it is an anomaly when varia- 
tions in certain breeds are transmitted equally to both 
sexes. There are also certain sub-breeds of the fowl in 
which the males can hardly be distinguished from one 
another, while the females differ considerably in color. 
The sexes of the pigeon in the parent-species do not differ 

* •* N0V8B species Quadrupedum e Glirium ordine," 1778, p. 7. On 
the transmission of color by the Lorse, see " Variation of Animals, 
etc., under Domestication.'' vol. 1, p. 51. Also vol. ii, p. 71, for a 
general discussion on " Inheritauce as Limited by Sex." 


in any external character; nevertheless, in certain domesti- 
cated breeds the male is colored differently from the female.* 
The wattle in the English carrier pigeon and the crop in the 
Pouter are more highly developed in the male than in the 
female; and although these characters have been gained 
through long-continued selection by man, the slight differ- 
ences between the sexes are wholly due to the form of 
inheritance which has prevailed; for they have arisen, not 
from, but rather in opposition to, the wish of the breeder. 

Most of our domestic races have been formed by the 
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 different breeds of the 
same species all gradations between great sexual dissimilar- 
ity and complete similarity. Instances have already been 
given with the breeds of the fowl and pigeon, and under 
nature analogous cases are common. With animals under 
domestication, but whether in nature I will not venture to 
Bay, one sex may lose characters proper to it, and may thus 
come somewhat to resemble the opposite sex; for instance, 
the males of some breeds of the fowl have lost their mascu- 
line tail-plumes and hackles. On the other hand, the dif- 
ferences between the sexes may be increased under domesti- 
cation, as with merino sheep, in which the ewes have lost 
their horns. Again, characters proper to one sex may sud- 
denly appear in the other sex; as in those sub-breeds of the 
fowl in which the hens acquire spurs while young; or, as in 
certain Polish sub-breeds, in which the females, as there is 
reason to believe, originally acquired a crest, and subse- 
quently transferred it to the males. All these cases are 
intelligible on the hypothesis of pangenesis; for they depend 
on the gemmules of certain parts, although present in both 
sexes, becoming, through the influence of domestication, 
either dormant or developed in either sex. 

There is one difficult question which it will be convenient 
to defer to a future chapter ; namely, whether a character 
at first developed in both sexes could through selection be 
limited in its development to one sex alone. If, for 
instance, a breeder observed that some of his pigeons (of 

* Dr. Chapuis, " Le Pigeon Voyageur Beige," 1865, p. 87. Boitard 
et Corbie, " Les Pigeons do Voliere," etc., 1824, p. 173. See, also, 
on similar differences in certain breeds at Modena, " Le variazioiu d€4 
Colombi doiuestici/' del Paolo Bonizzi, 187S, 


which the characters are usually transferred in an equal 
degree to both sexes) varied into pale blue, could he by 
long-continued selection make a breed, in which the malJd 
alone should be of this tint, while the females remained 
unchanged? I will here only say that this, though perhaps 
not impossible, would be extremely difficult; for the natural 
result of breeding from the pale-blue males would be to 
change the whole stock of both sexes to this tint. If, 
however, variations of the 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 with the two sexes of a different color, as indeed 
has been effected with a Belgian breed, in which the males 
alone are streaked with black. In a similar manner, if any 
variation appeared in a female pigeon, which was from the 
first sexually limited in its development to the females, it 
would be easy to make a breed with the females alone thus 
characterized; but if the variation was not thus originally 
limited the process would be extremely difficult, perhaps 

On the Relation Between 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 cer- 
tain sub-breeds of the pigeon black striae, though trans- 
mitted through the female, should be developed in the 
male alone, while every other character is equally trans- 
ferred to both sexes. Why, again, with cats, the tortoise- 
shell color should, with rare exceptions, be developed in 
the female alone. The very same character, such as defi- 
cient or supernumerary digits, color-blindness, etc., may 

* Since the publication of tlie first edition of tliis work, it has been 
highly satisfactory to me to find the following remarks (the " Field," 
Sept., 1872) from so experienced a breeder as Mr. Tegetraeier. 
After describing some curious cases in pigeons, of the transmission ol 
color by one sex alone, and the formation of a sub-breed with this 
character, he says: " It is a singular circumstance that Mr. Darwin 
should have suggested the possibility of modifying the sexual colors 
of birds by a course of artificial selection. When he did so, he was 
in ignorance of these facts that I have related ; but it is remarkable 
bow very closely he suggested the right method of procedure." 


with mankind be inherited by the males alone of one 
family, and in another family by the females alone, though 
in both cases transmitted through the opposite as well as 
through the same sex.* Although we are thus ignorant, 
the two following rules seem often to hold good — that varia- 
tions which first appear in either sex at a late period of life 
tend to be developed in the same sex alone; while varia- 
tions which first appear early in life in either sex tend to 
be developed in both sexes. I am, however, far from sup- 
posing that this is the sole determining cause. As I have 
not elsewhere discussed this subject, and as it has an impor- 
tant bearing on sexual selection, I must here enter into 
lengthy and somewhat intricate details. 

It is in itself probable that any character appearing at an 
early age would tend to be inherited equally by both sexes, 
for the sexes do not differ much in constitution before the 
power of 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 differs 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 
crustaceans, spiders and some few insects, such as certain 
orthoptera and libellulae. In all these cases the variations, 
through the accumulation of which the male acquired his 
proper masculine characters, must have occurred at a some- 
what late period of life; otherwise the young males would 
have been similarly characterized; and conformably with 
our rule, the variations are transmitted to and developed in 
the adult males alone. When, on the other hand, the adult 
male closely resembles the young of both sexes (these, with 
rare exceptions, being alike), he generally resembles the 

* References are given in my " Variation of Animals under Domes' 
tlcation," voL ii, p. 73. 


adult female; and in most of these cases the variations 
through which the young and old acquired their pre&ent 
characters, probably occurred, according to our rule, during 
youth. But there is here room for doubt, for characters 
are sometimes transferred to the offspring at an earlier age 
than that at which they first appeared in the parents, so 
that the parents may have varied when adult and have 
transferred their characters to their offspring while 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. AVe must not, however, overlook the possibility or 
even probability of successive variations of the same nature 
occurring, under exposure to similar conditions, simul- 
taneously in both sexes at a rather late period of life; and 
in this case the variations would be transferred to the off- 
spring of both sexes at a corresponding late age; and there 
would then be no real contradiction to the rule that varia- 
tions occurring late in life are transferred exclusively to the 
sex in which they first appeared. This latter rule seems to 
hold true more generally than the second one, namely, that 
variations which occur in either sex early in life tend to be 
transferred to both sexes. As it was obviously impossible 
even to estimate in how large a number of cases throughout 
the animal kingdom these two propositions held good, it 
occurred to me to investigate some striking or crucial 
instances and to rely on the result. 

An excellent case for investigation is afforded by the 
deer family. In all the species but one the horns are 
developed only in the males, though certainly transmitted 
through the females and capable of abnormal development 
in them. In the reindeer, on the other hand, the female 
is provided with horns; so that in this species the horns 
ought, according to our rule, to appear early in life, long 
before the two sexes are mature and have come to differ 
much in constitution. In all the other species the horns 
ought to appear later in life, which would lead to their 
development in that sex alone in which they first appeared 
in the progenitor of the whole family. Now in seven 
species belonging to distinct sections of the family and 
inhabiting different regions in which the stags alone bear 


horns, I find that the horns first appear at periods varying 
from nine months after birth in the roebuck to ten, twelve 
or even more months in the stags of the six other and 
larger species.* But with the reindeer the case is widely 
different; for, as I hear from Prof. Nilsson, who kindly 
made special inquiries 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 
s}'/ecies of the family and likewise common to both sexes in 
this one species alone. 

In several kinds of antelopes only the males are provided 
with horns, while in the greater number both sexes bear 
horns. With respect to the period of development, Mr. 
Blyth informs me that there was at one time in the Zoo- 
logical Gardens a young koodoo (Ant. strepsiceros) of 
v/hich the males alono are horned, and also the young of a 
closely allied species, the eland {Ant. areas), in which both 
sexos are horned. Now it is in strict conformity with our 
rule that in the young male koodoo, although ten months 
old, the horns were remarkably sm>i]l, considering the size 
ultimately attained by them; whila in the young male 
eland, although only three months old, the horns were 
already very much larger than in the koodoo. It is also a 
noticeable fact that in the prong-horned antelope f only a 
few of the females, about one in five, have horns, and 
these are in a rudimentary state, thongh sometimes above 
four inches long; so that as far as coi'cerns the possession 
of horns by the males alone, this spocies is in an inter- 
mediate condition and the horns do not appear until about 
five or six months after birth. Therefcre in comparison 

* I am much obliged to Mr. Cupples for Laving' mode inquiries for 
me in regard to tbe Roebuck and Red Deer of Scotland from Mr. 
Robertson, tbe experienced bead-forester to tbe Marqui,« of Breadal- 
bane. In regard to Fallow-deer, I bave to tbank Mr, Eyton and 
otbers for information. For tbe Cervus alces of North Auierica. see 
" Land and Water," 1868, pp. 221, 254; and for tbe C, Vv-ginianua 
and strongyloceros of tbe same continent, see J. D. Caton, in '' Ottawa 
Acad, of Nat. Sc," 1868, p. 13. For Cermis Eldi of Pegu, see Lieut. 
Beavan, " Proc. Zoolog. Soc," 1867, p. 762. 

f Antilocapra Americana. I bave to tbank Dr. Canfield for infor- 
mation witb respect to tbe bonis of tbe female; see also bis paper in 
" Proc. Zoolog. Soc." 1868, p. 109. Also Owen, " Anatony of Vertt- 
Vrates," vol. Ui, p. 627. 


with what little we know of the development of the horns 
in other antelopes and from what we do know with respect 
to the horns of deer, cattle, etc., those of the prong-horned 
antelope appear at an intermediate period of life — that is 
not very early, as in cattle and sheep, nor very late, as in 
the larger deer and antelopes. The horns of sheep, goats 
and cattle which are well developed in both sexes, though 
not quite equal in size, can be felt, or even seen, at birth 
or soon afterward.* Our rule, however, seems to fail in 
some breeds of sheep, for instance merinos, in which the 
rams alone are horned; for I cannot find on inquiry f that 
the horns are developed later in life in this breed than in 
ordinary sheep in which both sexes are horned. But with 
domesticated sheep the presence or absence of horns is not 
a firmly fixed character; for a certain proportion of the 
merino ewes bear small horns, and some of the rams are 
hornless; and in most breeds hornless ewes are occasionally 

Dr. W. Marshall has lately made a special study of the 
protuberances so common on the heads of birds, J; and he 
comes to the following conclusion: that with those species 
in which they are confined to the males, they are developed 
late in life; whereas with those species in which they are 
common to the two sexes, they are developed at a very 
early period. This is certainly a striking confirmation of 
my two laws of inheritance. 

In most of the species of the splendid family of the 
pheasants, the males differ conspicuously from the females, 
and they acquire their ornaments at a rather late period of 

* I have been assured that the horns of the sheep in North Wales 
can always be felt, and are sometimes even an inch in length at 
birth. Youatt says ("Cattle," 1834, p. 277), that the prominence of 
the frontal bone in cattle penetrates the cutis at birth, and that the 
horny matter is soon formed over it. 

f I am greatly indebted to Prof. Victor Carus for having made 
inquiries for me, from the highest authorities, with respect to the 
merino sheep of Saxony. On the Guinea coast of Africa there is. 
however, a breed of sheep in which, as with merinos, the rams alone 
bear horns; and Mr. Winwood Reade inforuis me that in one case 
observed by him, a young ram, born on Feb, 10th, first showed horns 
on March 6th, so that in this instance, in conformity with rule, the 
development of the horns occurred at a later period of life than in 
Welsh sheep, in which both sexes are homed. 

X " Ueber die knSchermen Schadelhocker der Vflgel " in the " Ni©- 
derlandischen Archiv. fOr Zoologie," Baud I, Heft 2, 1872. 


life. The eared pheasant {Orossoptilon mirifum), however, 
olfers a remarkable exception, for both sexes possess the 
fine caudal plumes, the large ear- tufts and the crimson 
velvet about the head; I find that all these characters 
appear very early in life in accordance with rule. The 
adult male can, however, be distinguished from the adult 
female by the presence of spurs; and, conformably with 
our rule, these do not begin to be developed before the age 
of six months, as I am assured by Mr. Bartlett, and even 
at this age the two sexes can hardly be distinguished.* The 
male and female peacock differ conspicuously from each 
other in almost every part of their plumage, except m the 
elegant head-crest, which is common to both sexes; and this 
is developed very early in life, long before the other orna- 
ments which are confined to the male. The wild duck 
offers an analogous case, for the beautiful g/e«xi speculum 
on the wings is common to both sexes, though duller and 
somewhat smaller in the female, and it is developed early 
in life, while the curled tail-feathers and other ornaments 
of the male are developed later, f Between such extreme 
cases of close sexual resemblance and wide dissimilarity, as 
those of the Orossoptilon and peacock, many intermediate 

*In the common peacock (Pavo cristatus) the male alone possesses 
spurs, while both sexes of the Java Peacock (P. imitictis) 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, of both species, 
cotn})ared on April 23, 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 

pen informed if any difference in the rate of development had been 

userved subsequently. 

f In some other species of the Duck family the speculum differs in 
a greater degree in the two sexes; but I have not been able to dis- 
cover whether its full development occurs later in life in the males of 
such species, than in the males of the common duck, as ought to be the 
case according to our rule. With the allied Mergus ciicuUatus we 
have, however, a case of this kind: the two sexes differ conspicu- 
ously in general plumage, and to a considerable degree in the specu- 
lum, which is pure white in the male and grayish white in the 
female. Now the young males at first entirely resemble the females, 
and have a grayish-white speculum, which becomes pure white at an 
earlier age than that at which the adult male acquires his other and 
more strongly -marked sexual differences: see Audubon, *♦ Ornitholo- 
gical Biography," vol. iii, 1835, pp. 249-250. 


ones could be given, in which the characters follow our two 
rules in their order of development. 

As most insects emerge from the pupal state in a mature 
condition it is doubtful whether the period of development 
can determine the transference of their characters to one or 
to both sexes. But we do not know that the colored scales, 
for instance, in two species of butterflies, in one of which 
the sexes differ in color, while 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 devel- 
oped on the wings of the same species of butterfly, in 
which certain colored marks are confined to one sex, while 
others are common to both sexes. A difference of this kind 
in the period of development is not so improbable as it may 
at first appear; for with the Orthoptera, which assume their 
adult state, not by a single metamorphosis, but by a suc- 
cession of moults, the young males of some species at first 
resemble the females, and acquire their distinctive mascu- 
line characters only at a later moult. Strictly analogous 
cases occur at the successive moults of certain male 

We have as yet considered the transference of characters, 
relatively to their period of development, only in species in 
a natural state; we will now turn to domesticated animals, 
and first touch 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 con- 
genital, as is probably color-blindness — yet these peculiar- 
ities, and other similar ones, are often limited in their 
transmission to one sex; so that the rule that characters, 
developed at an early period, tend to be transmitted to both 
eexes, here wholly fails. But this rule, as before remarked, 
does not appear to be nearly so general as the converse one, 
namely, that characters which appear late in life in one sex 
are transmitted exclusively to the same sex. From the 
fact of the above abnormal peculiarities becoming attached 
to one sex, long before the sexual functions are active, we 
may infer that there must be some difference between the 
sexes at an extremely early age. With respect to sexually- 
limited diseases we know too little of the period at which 
they originate to draw any safe conclusion. Gout, however, 
eeei^is to fall under our rule, for it is generally caused by 


intemperance during manhood, and is transmitted from the 
father to his sons in a much more marked manner than to 
his daughters. 

In the various domestic breeds of sheep, goats, and 
cattle the males differ from their respective females in 
the shape or development of their horns, forehead, mane, 
dewlap, tail and hump on the shoulders; and these pecu- 
liarities, in accordance with our rule, are not fully devel- 
oped until a rather late period of life. The sexes of dogs 
do not differ, except that in certain breeds, especially in 
the Scotch deer-hound, the male is much larger and heavier 
than the female; and, as we shall see in a future chapter, 
the male goes on increasing in size to an unusually late 
period of life, which, according to rule, will account for 
his increased size being transmitted to his male offspring 
alonCc On the other hand, the tortoise-shell color, which 
is confined to female cats, is quite distinct at birth, and 
this case violates the rule. There is a breed of pigeons in 
which the males alone are streaked with black, and the 
streaks can be detected even in the nestlings; but they 
become more conspicuous at each successive moult, so that 
this case partly opposes and partly supports the rule. With 
the English carrier and Pouter pigeons, the full develop- 
ment of the wattle and crop occurs rather late in life, 
and conformably with the rule, these characters are trans- 
mitted in full perfection to the males alone. The follow- 
ing cases perhaps come within the class previously alluded 
tOj in wliich both sexes have varied in the same manner at 
a rather late period of life, and have consequently trans- 
ferred their new characters to both sexes at a corresponding 
late period, and if so, these cases are not opposed to our 
rule; there exist sub-breeds of the pigeon, described by 
J^'eumeister,* in wliich both sexes change their color during 
two or three moults (as is likewise the case with the Almond 
Tumbler); nevertheless, these changes, though occurring 
rather late in life, are common to both sexes. One variety 
of the canary-bird, namely, the London Prize, offers a 
nearly analogous case. 

With the breeds of the fowl the inheritance of various 
characters by one or both sexes seems generally determined 

* " Das Ganze der Taubenzuclit," 1837, ss. 21, 24. For tlie case of 
tbe streaked pigeons, see Dr. Chapuis. *' Le pigeon voyageur Beige," 
I860, p. 87, 


by the period at which such characters are developed. Thus 
iu all the many breeds in which the adult male differs 
greatly in color from the female, as well as from the wild 
parent-species, he differs also from the young male, so that 
the newly-acquired characters must have appeared at a 
rather late period of life. On the other hand, in most of 
the breeds in which the two sexes resemble each other, the 
young are colored in nearly the same manner as their 
parents, and this renders it probable that their colors first 
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, which 
leads to its transference to both sexes; for the males alone 
of many natural species are either black or white, the 
females being differently colored. With the so-called 
Cuckoo sub-breeds of the fowl in which the feathers are 
transversely penciled with dark stripes, both sexes and the 
chickens are colored in nearly the same manner. The 
laced plumage of the Sebright bantam is the same in both 
sexes, and in the young chickens the wing-feathers are dis- 
tinctly, though imperfectly, laced. Spangled Hamburgs, 
however, offer a partial exception ; for the two sexes, 
though not quite alike, resemble each other more closely 
than do the sexes of the aboriginal parent-species; yet they 
acquire their characteristic plumage late in life, for the 
chickens are distinctly penciled. With respect to other 
characters besides color, in the wild-parent species and in 
most of the domestic breeds the males alone possess a well- 
developed comb; but in the young of the Spanish fowl it 
is largely developed at a very early age, and, in accordance 
with this early development in the male, it is of unusual 
size in the adult female. In the game breeds pugnacity is 
developed at a wonderfully early age, of which curious 
proofs could be given; and this character is 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;* and in this breed the adnlts 

* For full particulars and references on all tliese points respecting 
the several breeds of the fowl, see " Variation of Animals and Plants 


of both sexes are characterized by a great bony protuber- 
ance and an immense crest. 

Finally, from what we have now seen of the relation 
which exists in many natural species and domesticated 
races between the period of the development of their char- 
acters 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 bear horns, in comparison 
with their much later growth in the other species in which 
the male alone bears horns — we may conclude that one, 
though not the sole cause of characters being exclusively 
inherited by one sex, is their development at a late age. 
And secondly, that one, though apparently a less effective 
cause of characters being inherited by both sexes, is their 
development at an early age, while the sexes differ but 
little in constitution. It appears, however, that some dif- 
ference must exist between the sexes even during a very 
early embryonic period, for characters developed at this 
age not rarely become attached to one sex. 

Summary and Concluding Remarks. — From the forego- 
ing discussion on the various laws of inheritance we learn 
that the chai'acters of the parents often, or even generally, 
tend to become developed in the offspring of the same sex, 
at the same age, and periodically at the same season of the 
year in which they first appeared in the parents. But 
these rules, owing to unknown causes, are far from being 
fixed. Hence, during the modification of a species the 
successive changes may readily be transmitted in different 
ways; some to one sex and some to both; some to the off- 
spring at one age and some to the offspring at all ages. 
Not only are the laws of inheritance extremely complex, 
but so are the causes which induce and govern variability. 
The variations thus induced are preserved and accumulated 
by sexual selection, which is in itself an extremely complex 
affair, depending as it does on the ardor of love, the cour- 
age and the rivalry of the males as well as on the powers 
of perception, the taste and will of the female. Sexual 
selection will also be largely dominated by natural selection 

under Domestication," vol. i, pp. 250, 256. In regard to the higher 
animals, the sexual differences which have arisen under domestica- 
tion are described in the same work under the head of each species. 


tending toward the general welfare of the species. Hence 
the manner in which the individuals of either or both 
sexes have been affected through sexual selection cannot 
fail to be complex in the highest degree. 

When variations occur late in life in one sex and are 
transmitted to the same sex at the same age the other sex 
and the young are left unmodified. When they occur late 
in life but are transmitted to both sexes at the same age 
the young alone are left unmodified. Variations, however, 
may occur at any period of life in one sex or in both, and 
be transmitted to both sexes at all ages, and then all the 
individuals of tlie species are similarly modified. In the 
following chapters it will be seen that all these cases fre- 
quently occur in nature. 

Sexual selection can never act on any animal before the 
age for reproduction arrives. From the great eagerness of 
the male it has generally acted on this sex and not on the 
females. The males have thus become provided with 
weapons for fighting with their rivals, with organs for dis- 
covering and securely holding the female andfor exciting 
or 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 did 
not generally occur much before the age for reproduction. 
Whenever some or many of the variations occurred early in 
life the young males would partake more or less of "the 
characters of the adult males; and differences of this kind 
between the old and young males may be observed in many 
species of animals. 

It is probable that young male animals have often tended 
to vary in a manner which would not only have been of no 
use to them at an ondy age, but would have been actually 
injurious — as by acquiring bright colors which would 
render them conspicuous to their enemies, or by acquiring 
structures, such as great horns, which would expend much 
vital force in their development. Variations of this kind 
occurring in the young males would almost certainly be 
eliminated through natural selection. With the adult and 
experienced males, on the other hand, the advantages 
derived from the acquisition of such characters would 
more than counterbalance some exposure to danger and 
some loss of vital force. 


As variations which give to the male a better chance of 
conquering other males or of finding, securing or charm- 
ing the opposite sex would, if they happened to arise in the 
female, be of no service to her, tliey would not be pre- 
served in her through sexual selection. We have also good 
evidence with dom.esticated animals that variations of all 
kinds are, if not carefully selected, soon lost through inter- 
crossing and accidental deaths. Consequently in a state 
of nature if variations of the above kind chanced to aiise 
in the female line, and to be transmitted exclusively in 
this line, they would be extremely liable to be lost. If, 
however, the females varied and transmitted their newly 
acquired characters to their offspring of both sexes the 
characters which were advantageous to the males would be 
preserved by them through sexual selection, {ind the two 
sexes would in cousequence be modified in the same man- 
ner, although such characters were of no use to the 
females; but I shall hereafter have to recur to these more 
intricate contingencies. Lastly, the feuiales may acquire 
and apparently have often acquired by transference char- 
acters from the male sex. 

As variations occurring late in life and transmitted to 
one sex alone have incessantly been taken advantage of and 
accumulated through sexual selection in relation to the 
reproduction of the species; therefore it appears, at first 
sight, an unaccountable fact that similar variations have 
not frequently been accumulated through natural selection, 
in relation to the ordinary habits of life. If this had 
occurred, the two sexes would often have been differently 
modified, for the sake, for instance, of capturing ]»rey or 
of escaping from danger. Differences of this kind between 
the two sexes do occasionally occur, especially in the lower 
classes. But this implies that the two sexes follow different 
habits in their struggles for existence, which is a rare cir- 
cumstance with the higher animals. Tiie case, however, is 
widely different with the reproductive functions, in which 
respect the sexes necessarily differ. For variations in 
.structure, which are related to these functions, have often 
proved of value to one sex, and from having arisen at a late 
period of life, have been transmitted to one sex alone; and 
such variations, thus preserved and transmitted, have given 
rise to secoiulary sexual characters. 

lu the following chapters I shall treat of the secondary 


sexual characters in animals of all classes, and shall 
endeavor in each case to apply the principles explained in 
the present chapter. The lowest classes will detain us for 
a very short time, but the higher animals, especially birds, 
must be treated at considerable length. It should be borne 
in mind that for reasons already assigned I intend to give 
only a few illustrative instances of the innumerable 
structures by the aid of which the male finds the female, 
or, when found, holds her. On the other hand, all 
structures and instincts by the aid of which the male con- 
quers other males, and by which he allures or excites the 
female, will be fully discussed, as these are in many ways 
the most interesting. 


As no one, as far as I can discover, has paid attention to 
the relative numbers of the two sexes throughout the 
animal kingdom, I will here give such materials as I have 
been able to collect, although they are extremely imperfect. 
Tliey consist in only a few instances of actual enumeration 
and the numbers are not very large. As the proportions 
are known with certainty only in mankind, 1 will first give 
them as a standard of comparison. 

Man. — In England during ten years (from 1857 to 1866) 
the average number of children born alive yearly was 
707,120, in the proportion of 104.5 males to 100 females. 
But in 1857 the male births throughout England wore as 
105.^, and in 1865 as 104 to 100. Looking to separate 
districts, in Buckinghamshire (where about 5,000 children 
are annually born) the mean proportion of male to female 
births during the whole period of the above ten years was 
as 102.8 to 100, while in N. AVales (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 avernge only 730), in 1864 the male 
births were #s 114.6, and in 1862 as only 97 to 100; but 
even in this small district the average of the 7,385 births 
during the whole ten years was as 104.5 to 100; that 


18 in the same ratio as throughout England.* The propor- 
tions 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, while 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, and 
in Philadelphia, in the United States, as 110.5 to 100. f The 
average for Europe, deduced by Bickes from about 70,000,- 
000 births, is 106 males to 100 females. On the other 
hand, with white children born at the Cape of Good Hope, 
the proportion of males is so low as to fluctuate during suc- 
cessive years between 90 and 99 mules for every 100 females. 
It is a singular fact that with Jews the proportion of male 
births is decidedly larger than with Christians ; thus in 
Prussia the proportion is as 113, in Breslau as 114, and in 
Livonia as 120 to 100; the Christian births in these coun- 
tries being the same as usual, for instance, in Livonia as 
104 to 100. t 

Prof. Faye remarks that " 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 we have in 
several countries from 134.6 to 144.9 still-born males. 
During the first four or five years of life, also, more male 
children die than females, for example in England, during 
the first year, 126 boys die for every 100 girls — a proportion 
which in France is still more unfavorable." § Dr. Stock- 

*" Twenty-ninth Annual Report of the Rsgistrar- General for 
1866." In this report (p. 12) a special decennial table is given. 

f For Norway and Russia, see abstract of Prof. Faye's researches 
in "British and Foreign Medico-Cbirurg. Review," April, 1867, pp. 
343,345. For France, the "Annuaire pour I'An, 1867," p. 213. 
For Philadelphia, Dr. Stockton Hough. *' Social Science Assoc," 
1874. For the Cape of Good Hope, Quetelet as quoted by Dr. H. H. 
Zouteveenin the Dutch translation of this work (vol. i, p. 417), where 
much information is given on the proportion of the sexes. 

:j: In regard to the Jews, see M. Thury, " La Loi de Production des 
Sexes," 1863, p. 25. 

§" British and Foreign Medico-Chirurg. Review," April, 1867, p. 
343. Dr. Stark also remarks (" Tenth Annual Report of Births, 


toil Hongh accounts for these facts in part by the more 
frequent defective development of males than of females. 
We have before seen that the male sex is more variable in 
structure thun the female ; and variations in important 
organs would generally be injurious. But the size of the 
body, and especially of the head, being greater in male 
than female infants is another cause; for the males are thus 
more liable to be injured during parturition. Consequently 
the still-born males are more numerous; and as a highly 
competent judge, Dr. Crichton Browne,* believes male 
infants often suffer in health for some years after birth. 
Owing to this excess in the death-rate of male children, 
both at birth and for some time subsequently, and owing to 
the exposure of grown men to various dangers and to their 
tendency to emigrate, the females in all old-settled coun- 
tries, where statistical records have been kept,f are found 
to preponderate considerably over the males. 

It seems at first sight a mysterious fact that in different 
nations, nnder different conditions and climates, in Naples, 
Prussia, Westphalia, Holland, France, England and the 
United States, the excess of male over female births is less 
when they are illegitimate than when legitimate.]; This 
has been explained by different writers in many different 
ways, as from the mothers being generally young, from the 
large proportion of first pregnancies, etc. But we have 

Deatlis, etc., in Scotland." 1867, p. 28) tliat "These examples may 
suffice to show that, at almost every stage of life, the males in Scot- 
land 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 consti- 
tutional peculiarity due to sex alone." 

* " West Riding Lunatic Asylum Reports." vol. i, 1871, p. 8. Sir 
J, Simpson has proved that the head of the male infant exceeds that 
of the female *>y three-eighths of an inch in circumference and by 
one eighth in transverse diameter. Quetelet has shown that woman 
is born smaller than man ; see Dr. Duncan, " Fecundity, Fertility, 
Sterility," 1871, p. 382. 

f With the savage Guaranys of Paraguay, according to the accu- 
rate Azara ('• Voyages dans TAmerique merid ," tom, ii, 1809, pp. 60, 
179) the women are to the men in the porportion of 14 to 13. 

ifBabbage. "Edinburgh Journal of Science," 1829, vol. i, p. 88; 
also p. 90, on still-born children. On illegitimate children in En- 
gland, see "Report of Registrar-General for 1866," p. 15. 


seen that male infants, from the large size of their heads, 
suffer more than female infants during parturition; and as 
the mothers of illegitimate children must be more liable 
than other women to undergo bad labors, from various 
causes, such as attempts at concealment by tight lacing, 
hard work, distress of mind, etc., their male infants would 
proportionately suffer. And this probably is the most effi- 
cient of all the causes of the proportion of males to females 
born alive being less among illegitimate children than 
among the legitimate. With most animals the greater size 
of the adult male than of the female is due to the stronger 
males having conquered the weaker in their struggles for 
the possesBion of the females, and no doubt it is owin^ to 
this fact that the two sexes of at least some animals differ 
in size at birth. Thus we have the curious fact that we 
rnay attribute the more frequent deaths of male than 
female infants, especially among the illegitimate, at least 
in part to sexual selection. 

It has often been supposed that the relative age of the 
two parents determines the sex of the offspring; and Prof. 
Leuckart * has advanced what he considers sufficient evi- 
dence, with respect to man and certain domesticated 
animals, that this is one important though not the sole 
factor in the result. So again the period of impregnation 
relatively to the state of the female has been thought by 
some to be the efficient cause; but recent observations dis- 
countenance this belief. According to Dr. Stockton 
Hough, t the season of the year, the poverty or wealth of 
the parents, residence in the country or in cities, the cross- 
ing of foreign immigrants, etc., all influence the proportion 
of the sexes. With mankind, polygamy has also been sup- 
posed to lead to the birth of a greater proportion of female 
infants; but Dr. J. Campbell J carefully attended to this 
subject in the harems of Siam, and concludes that the pro- 
portioji of male to female births is the same as from 
monogamous unions. Hardly any animal has been rendered 
so highly polygamous as the English race-horse, and we 
shall immediately see that his male and female offspring 

* Leuckart, in Wagner, " Handworterbuch der Pliys,," B.iv, 1853, 
s. 774. 
f Social Science Assoc, of Philadelphia, 1874. 
j " Anthropological Review," April, 1870, p. 108, 


are almost exactly equal in number. I will now give the 
facts which I have collected with respect to the proportional 
numbers of the sexes of various animals; and will then 
briefly discuss how far selection has come into play in 
determining the result. 

Horses. — Mr. Tegetmeier has been so kind as to tabulate for me 
from the " Racinij Calendar" the births of race-horses during a 
period of twenty-one years, viz., from 1846 to 1867; 1849 being 
omitted, as no returns were that year published. The total births 
were 25,560,* consisting of 12,763 males and 12,797 females, or in the 
proportion of 99.7 males to 100 females. As these numbers are tol- 
erably large, and as they are drawn from all parts of England, dur- 
ing 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 propor- 
tions during successive years are closely like those which occur with 
mankind, when a small and thinly populated area is considered; thus 
in 1856 the male horses were as 107.1, and in 1867 as only 92.6 to 
100 females. In the tabulated returns the proportions vary in cycles, 
for the males exceeded the females during six successive years; and 
the females exceeded the males during two periods each of four 
years; this, however, may be accidental; at least I can detect nothing 
of the kind with man in the decennial table in the Registrar's Report 
for 1866. 

Dogs. — During a period of twelve years, from 1857 to 1868, the 
births of a large number of greyhounds throughout England were 
sent to the "Field" newspaper; and I am again indebted to Mr. 
Tegetmeier for carefully tabulating the results. The recorded births 
were 6,878, consisting of 3,605 males and 3,273 females, that is, in 
the proportion of 110.1 males to 100 females. The greatest fluctua- 
tions occurred in 1864, when the proportion was as 95.3 males, and 
in 1867; as 116.3 males to 100 females. The above average propor- 
tion of 110.1 to 100 is probably nearly correct in the case of the grey- 
hound, but whether it would hold with other domesticated breeds is 
in some degree doubtful. Mr. Cupples has inquired from several 
great breeders of dogs, and finds that all without exception believe 
that females are produced in excess; but he suggests that this belief 
may have arisen from females being less valued, and from the 
consequent disappointment producing a stronger impression on the 

Sheep — The sexes of sheep are not ascertained by agriculturists 
until several months after birth, at the period when the males are 

* During eleven years a record was kept of the number of mares which 
proved barren or prematurely slipped their foals ; and it deserves notice, as 
Bhowinj? how infertile these highly nurtured and rather closely interhred ani- 
mals have become, that not far from one-third of the mares failed to produce 
living foals. Thus during 1866, 8<i9 maie colts and 816 female colts were born, 
and 743 mares failed to produce offspring. Dux-ing 1867, 836 males and 908 
female were born» and 794 mares failed. 


castrated; so that the following returns do not give the proportions 
at birth. Moreover, I find that several great breeders in Scotland, 
who annually raise some thousand sheep, are firmly convinced that 
a larger proportion of males than of females die during the first year 
or two. Therefore the proportion of males would be somewhat larger 
at birth than at the age of castration. This is a remarkable coiuci- 
dence with what, as we have seen, occurs with mankind, ahd both 
cases probably depend on the same cause. I have received returns 
from four gentlemen in England who have bred Lowland sheep, 
chiefly Leicesters, during the last ten to sixteen years; they amount 
altogether to 8,965 births, consisting of 4,407 males and 4,558 females; 
that is in the proportion of 96.7 males to 100 females. With respect 
to Cheviot and black-faced sheep bred in Scotland, I have received 
returns from six breeders, two of them on a large scale, chiefly for 
the years 1867-1869, but some of the returns extend back to 1862. 
The total number recorded amounts to 50,685, consisting of 25,071 
males and 25,614 females, or in the proportion of 97.9 males to 100 
females. If we take the English and Scotch returns together, the 
total number amounts to 59,650, consisting of 29,478 males and 30,172 
females, or as 97 7 to 100. So that with sheep at the age of castra- 
tion the females are certainly in excess of the males, but probably 
this would not hold good at birth.* 

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 tbe proportion of 94.4 males to 100 females. 
The Rev. VV. 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 
has inquired from several breeders of pigs, and most of them esti- 
mate the male to the female births as about 7 to 6. This same 
gentleman has bred rabbits for many years, and has noticed that a 
far greater number of bucks are produced than does. But estima- 
tions are of little value. 

Of mammalia in a state of nature I have been able to learn very 
little. In regard to the common rat, I have received conflicting 
statements. Mr. R. Elliot, of laighwood, informs me that a rat- 
catcher assured him that he had always found the males in great 
excess, even with the young in the nest. In consequence of this, 
Mr. Elliot himself subsequently examined some hundred old ones 
and found the statement true. Mr. F. Buckland has bred a large 
number of white rats, and he also believes that the males greatly 
exceed the females. In regard to moles, it is said that " the males 
are much more numerous than the females ;" f 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:): 

* 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 premature 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 large j^^tunis 
as to sheep. 

+ Bell, " History of British Quadrupeds," p. 100. 

X '' lUustratiouA of the Zoology of S. Africa,'' 1849, pL 29i 


{Kobus eUipsiprymnus), remarks, tliat in tlie herds of this and otheaf 
species, the males are few in number compared with the females ; 
the natives believe that tbey are born in tbis proportion; others 
believe tbat the younger males are expelled from the herds, and Sir 
A. Smith, says, tbat tlioagh he has himself never seen herds con- 
sisting of young males alone, otbers affirm tbat tbis doei? occur. It 
appearsprobable tbat the young when expelled from the herd would 
often fall a prey to the many beasts of prey of the country. 

Birds. — With respect to the fowl, I have received only one 
account, namely, that out of 1,001 chickens of a highly-bred stock of 
Cocbins, 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 eitbertbat the males are produced in excess, 
or that tbey live longer ; for these birds invariably pair, and single 
males, as Mr. Tegetmeier informs me, can always be purchased 
cheaper than females. Usually the two birds reared from the two 
eggs laid in the same nest are a male and a female; but Mr. Harrison 
Weir, who has been so large a breeder, says that he has often bred 
two cocks from the same nest, and seldom two bens ; 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 otbers* 
are convinced tbat the males are generally the more numerous ; and 
as the young males of many species resemble the females, tbe latter 
would naturally appear to be the more numerous. Large numbers 
of pbeasants are reared by Mr. Baker of licadenhall from eggs laid 
by wild birds, and be informs Mr. Jenner Weir that four or five 
males to one feirale are generally produced. An experienced 
observer remarks, f that in Scandinavia the broods of the capercailzie 
and black-cock contain more males than females ; and tbat with the 
Dal ripa (a kind of ptarmigan) more males tban females attend the 
leks or places of courtsbip ; 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 Wbite of Selborne,^ 
it seems clear that the males of tbe partridge must be in considerable 
excess in tbe soutb of England ; and I have been assured that this is 
the case in Scotland. Mr. Weir on inquiring from the dealers who 
receive at certain seasons large numbers of ruffs {Machetes pugnax), 
was told tbat the males are much the more numerous. This same 
naturalist bas also inquired for me from the bird-catchers, who annu- 
ally 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 cbaffinch the males 
are in large excess ; he thought as high as 2 males 
to 1 female, or at least as high as 5 to 3. § The males 

* Brehui (*' Illust Thierleben," B. iv. s. 990) comes to the same conclusion. 

t On tbe authority of L. Lloyd, " Game Birds of Sweden,'' 1837, pp. 12, 132 

t *' Nat. Hist, of Selborne," letter xxix. edit, of 1825, vol, i p 139. 

§Mr. Jenner Weir received similar information, on maklnsr inquiries 
durJnj? the following? year. To show the number of living chaffinches caui?b£ 
I may mention that in 18G9 there was a match between two experts and one 
man caufrht in a day 62, and another 40, male chaliinches. The greatest num- 
ber ever caught by one man in a singlrday was 7a 

PROFonrroN of tub sexes. 281 

of tlie V.acl^bird, lie likewise maintained, were hy far tLe more 
nunieroas, wbetber caught by traps or by netting at nig-bt. These 
statements may apparently be trusted, because this same man said 
that the sexes are about equal with the lark, the twite [Linavia 
montana), and goldfinch. On the other band, be is certain that with 
the comuion linnet, the females preponderate greatly, but unequally, 
during different years; during some years he has found the females 
to the males as 4 to 1. It should, however, be borne in mind, 
that the chief season for catching birds does not begin till September, 
so that with some species ]>artial migrations may have begun, and 
the flocks at this period often consist of hens ab^ne. Mr. Salvia 
paid particular attention to the sexes of the humming-birds mi Cen- 
tral America, and he is convinced that with most of the species the 
males are in excess; thus one year he procured 204 specimens belong- 
ing to ten species, and these consisted of 166 males and of only 38 
females. With two other species the females were in excess; but 
the proportions apparently vary either during different seasons or in 
different localities; for on one occasion tlie males of Campyloptei'us 
hemileuciirus were to the females as 5 to 2. and on another occasion* 
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 
chaffiuch keeping apart, and "the females by Car the most numer- 
ous;" while in Palestine, Mr. Tristram found "the male flocks 
api)earing greatly to exceed the female in number. "| So again 
with the Quiscaius major, Mr. G. Taylor^ says, that in Florida there 
were "very vew females in pro])ortion to the males," while in Hon- 
duras the proportion was the other way, the species there having the 
character of a polygamist. 

Fish. — With fish tlie proportional numbers of the sexes can be 
ascertained only by catching them in the adult or nearly adult state; 
and there are many difficulties in arriving at any just conclusion. i^ 
Infertile females might readily be mistaken for liiales, as Dr. Giiii- 
ther has remarked to me in regard to irout. With some species the 
males are believed to die soon after fertilizing the ova. With many 
species the males are of much smaller size than the females, go that 
a lai'ge number of males would escape from the same net by which 
the females were caught. M. Carbonnier,|| who has especially 
attended to the natural history of the pike {Elsox lucius), states that 
many males, owing to their small size, are devoured by the larger- 
females; and he believes that the males of almost all fish are exposed 
from this same cause to greater danger than the females. Neverthe- 
less, in the few cases in which the proportional numbers have been 
actually observed, the males appear to be largely in excess. Thus 
Mr. R. Buist, the superintendent of the Stormontfield experiments, 

*" Ibis," vol. ii, p. C60, as quoted in '"Gould's Trochilidas," ISfil, p. ?2. 
For the foregoing proportions. I am indebted to Mr. Salvia for a table of his 

t '• Ibis," 18(50. p. 1.37; and 1837, p. 369. 

X " Ibis," 18C-.>. p, 187. 

ILeuckart quotes Bloch (Wagner, *' Handworterbuch der Phvs.," B, iv, 
1853, 8. 77.b), that with fish there uro twice as many males as Jenaalea. 

J Quoted ia th© '' Farmer," Max-ca 18, 1869^ p. 869. 


says tliat in 1865, out of 70 salmon first landed for tlie purpose of 
obtaining the ova, upward of 60 were males. In 1867 Le 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," Afterward 
female> sufficient for obtaining ova were i)rocure<l. He adds. ** from 
the great proportion of the nuiles, »hey are constantly fightiv\g and 
tearing each other on the spawning-beds."* This disproportion, no 
donbt, can be accounted for in part, but whethbr wholly is doubtful, 
by the males ascending the rivers before tlie females. Mr. F. Buck- 
land remarks in regard to trout, that " it is a curious fact that the 
nuiles preponderate very largely m number over the females. It 
invaridbli/ happens that when the first rush of fish is made to the 
TiCt theve will be at least seven or eight males to one female found 
captive. I cannot quite account for this; either the males are more 
numerous than the females, or the latter seek safety by concealment 
rather than tlight." lie then adds, that by carefully searching the 
banks sufficient females for obtaining ova can be found. f Mr. H. 
Lee informs me that out of 212 trout taken for this purpose in Lord 
Poitsmouth's park, 150 were males and 62 females. 

The males of the Cyprinidse likewise seem to be in excess; but sev- 
eral members of this family, viz., the carp, tench, bream and min- 
now, appear reguhrly to follow the practice, rare in the animal king- 
dom, of polyandry; tor the female while spawning is always attended 
by two males, one on each side, and in the case of the bream by three 
or four males. This fact is so weii known that it is always recom- 
mended to stock a pond with two male tenches to one female, or at 
least with three males to two females. With the minnow, an excel- 
lent observer states, that on the spawning-beds the males are ten 
times as numerous as the females; when a female comes among the 
males, '• she is immediately pressed clo.selyljy a male on each side; 
and when they have been in that situation for a time are superseded 
by two other males.":}: 

Insects. — Tn this great class tbe Lepidoptera almost alone afford 
means for judging of the proportional numbers of the sexes; for they 
have been collected with special care by many good observers, and 
have been largely bred from the egg or caterpillar state. I had hoped 
that some breeders of silk-moths might have kept an exact record, 
but after writing to France and Italy, and consulting various 'reatises, 
1 cannot find that this has ever been done. The general opinion ap- 
pears to be that the sexes are nearly equal, but in Italy, as I hear 
from Prof. Canestrini, many breeders are convinced that the females 
are produced in excess. This same naturalist, however, informs me 
that in the two yearly broods of the Ailanthus silk-moth (Bombyx 
cyiUhiti), the males greatly preponderate in the first, while in the 
second the two sexes are nearly equal, or the females rather in 

*-The Stormontfield Piscicultural Experiments,'' 1866, p. 23. The 
*' Field '■ new.spaper. June 2^. 18:J7. 

t •• Land and Water," 18G8, . . A\. 

X YarreJl, *" Hist. British Fishes," vol. i, 1826, p. 807; on the Cyprinus carpio, 
p. 331; on the 7'i/ica vulgaris, p, ;S31; on the Abramls brama, p. 33(5. See, for the 
minnow iLeuciscus phoxinue), " Loudon's Mag. of Nat. Uist.," voL y, lB3Si, p. 682. 


In regard to butterflies in a state of nature, several observers bave 
been mucb struck by tbe apparently enormous preponderance of tbe 
males.* Tbus Mr. Bates. f in speaking of several species, about a 
hundred in number, wbicb inhabit the Upper Amazons, says that 
the males are much more numerous than the females, even in the 
proportion of 100 to 1. In North America, Edwards, who 
had great experience, estimates in the genus Papilio the males to the 
females as 4 to 1; and Mr. Walsh, w^ho informed me of this 
statement, says that with P. turrius this is certainly the case. In 
S. Africa, Mr. R. Trimen found the males in excess in nineteen spe- 
cies; X and in one of these, which swarms in open places, he estimated 
the number of males as 50 to 1 female. With another species, 
in which the males are numerous in certain localities, he collected 
only five females during seven years. In the Island of Bourbon, M. 
Maillard states that the males of one species of Papilio are twenty 
times as numerous as the females. § Mr. Trimen informs me that as 
far as he has himself seen, or heard from others, it is rare for the 
females of any butterfly to exceed the males in number; but three 
South African species perhaps offer an exception. Mr. W'allace|| 
states that the females of Ornithoptera crcesus, in the Malay Archi- 
pelago, are more common and more easily caught than the males; 
but this is a rare butterfly. I may here add that in Hyperythra, a 
genus of moths, Guenee says, that from four to five females are sent 
in collections from India for one male. 

When this subject of the proportional numbers of the sexes of 
insects was brought before the Entomological Society, 1[ 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 Avell known to occur 
with most Lepidoptera, as well as with other insects. So that, as M. 
Personnat remarks, tbe males of the domesticated Bomhyx Tamamai 
are useless at the beginning of the season, and the females at the 
end, from the want of mates.** I cannot, however, persuade myself 
that these causes suflSce to explain the great excess of males in the 
above cases of certain butterflies which are extremely common in 
their native countries. Mr. Stainton, who has paid venj»-close atten- 
tion during many years to the smaller moths, informs me that when 
he collected them in the imago state, he thought that the males were 
ten times as numerous as the females, but that since he has reared 
them on a large scale from the caterpillar state he is convinced that 
the females are the more numerous. Several entomologists concur 

* Leuekart quotes Meinecke (Wajirner, " Handworterbuch der Phys.," B. 
Iv. 1858, s. 775), that the males of butterflies are three or four times as numer- 
ous as the females. 

t •• The Naturalist on the Amazons." vol. ii, 1863, pp. 238, 347. 

% " Four of these cases are given by Mr. Trimen in his " Rhopalocera Africaa 

§ Quoted by Trimen, '• Transact. Ent. Soc," vol. v, part Iv, 1866, p. 880. 

i •• Transact. Linn. Soc.," vol. xxv, p. 37. 

^ •' Proc. Entomolog. Soc," Feb. 17, 1868. 

•♦Quoted by Dr. Wallace in ** Proc. Ent. Soc," 8d series, yoL y, 1867, p. 487. 


in tills view. Mr. Doubleday, however, and some otters, take an 
opposite view, and are conviuced tliat tliey Lave reared from tlie 
e^gs and caterpillars a larger proportion of males tlian of females. 

Besides the more active Labits of tlie males, their earlier emergence 
from the cocoon, and in some cases their frequenting more open 
stations, other causes may be assigned for an ap])arent or real differ- 
ence in the proportional numbers of the sexes of Lepidoptera, when 
captured in the imago state, and when reared from the egg or cater- 
pillar state. I hear from Prof. C'anestrini that it is believed by many 
breeders in Italy 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 piactice; 
but Dr. Wallace is sure that most collectors take all the speci- 
mens 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 Prof. Canestrini informs me 
that in Italy some breeders believe, though on insufficient evidence, 
that in the first broods of the Ailanthus silk-moth the wasps destroy 
a larger number of the female than of the male caterpillars. Dr. 
Wallace further remarks that female caterpillars, from being larger 
than the males, require more time for their development and con- 
sume more food and moisture; and thus they would be exposed 
during a longer time to danger from ichneumons, birds, etc., and in 
times of scarcity would perish in greater numbers. Hence it appears 
quite possible that in a state of nature, fewer female Lepidoptera 
may reach maturity than males; and for our special object we are 
concerned with their relative numbers at maturity, when the sexes 
are ready to propagate their kind. 

The manner in which the males of certain moths congregate in 
extraordinary numbers round a single female, apparently 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 twenty males may often be 
seen congregated round a female ElacMsta rufocinerea. It is well 
known that if a virgin Lasiocampa quercus or Saturnia 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. Mr. 
Doubleday believes that he has seen from fifty to a hundred males of 
both these species attracted in the course of a single day by a female 
in confinement. In the Isle of Wight, Mr. Trimen exposed a box in 
which a female of the Lasiocampa had been confined on the previous 
day, and five males soon endeavored to gain admittance. In Aus^ 
tralia, M. Verreaux, having placed the female of a small Bombyx in 
a box in his pocket, was followed by a crowd of males, so that about 
200 entered the house with him. * 

Mr. Doubleday has called my attention to M. Staudinger 'sf list 

* Blanchard, " Metamorphoses, Moeurs des Insectes," 186S, pp. 8^226. 
t " Lepidopteren-Poublettea Ligte," Berlin, Ko. x. IS&Q. 



of Lepidoptera, which gives the prices of the males and females of 
800 species or well-marlced varieties of butterflies (Khopalocera). 
The prices for both sexes of the very common species are of course 
the same; but in 114 of the rarer species they differ; the males 
being in all cases, excepting one, the cheaper. On an average of the 
prices of the 113 species, tiie price of the male to that of the 
female is as 100 to 149; and this apparently indicates that inversely 
the males exceed the females in the same proportion. About 
2,000 species or varieties of moths (Heterocera) are catalogued, 
those with wingless females being here excluded on account 
of the difference in habits between the two sexes: of these 
2,000 species, 141 differ in price according to sex, the males of 130 
being cheaper, and those of only 11 being dearer than the females. 
The average price of the males of the 130 species, to that of the 
females, is as 100 to 143. With respect to the butterflies in this 
price-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 number 
of the males. But I am bound to add that Dr. Staudinger informs 
me that he is himself of a different opinion. He thinks that the 
less active habits of the females and the earlier euiergence 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 cater[)illar 
state, Dr. Staudinger believes, as previously stated, that a greater 
number of females than of males die while confined in the cocoons. 
He adds that with certain species one sex seems to preponderate over 
the other during certain years. 

Of direct observations on the sexes of Lepidoptera, reared either 
from eggs or caterpillars, I have received only the few following 


Females , 

The Rev. J. Hellins * of Exeter reared, during 1868, imajjos 

of 73 species, which consisted of . . 

Mr. Albert Jones of Eltham reared, during 1868, imaffos of 

{) species, which consisted of 

Durinsj 1869 he reared imagos from 4 species, consisting 


Mr. Buckler of Emswrnth, Hants, during 1860, reared 

imagos from 74 species, consisting of 

Dr. Wallace of Colchester reared from one brood of Bom- 

bvx cvnthia 





Dr. Wallace raised, from cocoons of Bombyx Pernyi sent 

from China, durinjr ]8!iO 

Dr. Wallace raised, during 1808 and 1869, from two lots of 





♦ This natui-alist has been so kind as to send me some results from former 
years, in wliich the females seemed to preponderate ; but so many of the 
figures were estimates that I found it impossible to tabulate theca. 


So that in these eigLt 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 

On the whole, from these various sources of evidence, all pointing 
in the same direction, I infer that with most species of Lepidoptera 
the mature males generally exceed the fenjales in number, whatever 
the proportions may be at their first emergence from the egg. 

With reference to the other orders of insects, I have been able to 
collect very little reliable information. With the stag-beetle {Lu- 
canus cervus) " the males appear to be much more numerous than 
the females;" but when, as Cornelius remarked during 1867, an 
unusual number of these beetles appeared in one part of Germany, 
the females appeared to exceed the males as 6 to 1. With one 
of the Elateridse, the males are said to be much more numerous than 
the females, and "two or three are often found united with one 
female;* so that here polyandry seems to prevail." With Siagonium 
(Staphylinidse), in which the males are furnished with horns, "the 
females are far more numerous than the opposite sex." Mr. Jansou 
stated at the Entomological Society that the females of the bark- 
feeding Tomiciis villosus are so common as to be a plague, while the 
males are so rare as to be hardly known. 

It is hardly worth while saying anything about the proportion of 
the sexes in certain species and even groups of insects, for the males 
are unknown or very rare, and the females are parthenogenetic, 
that is, fertile without sexual union ; examples of this are 
afforded by several of the Cynipidae.f In all the gall-making 
Cynipidae 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 Cecidomyiidse (Diptera). With some common species 
of Saw-flies (Tenthredinae) Mr. F. Smith has reared hundreds of 
specimens from larvas of all sizes, but has never reared a single 
male; on the other hand, Curtis says,t that with certain species 
(Athalia) bred by him, the^ males were to the females as 6 to 1 ; 
while exactly the reverse occurred with the mature insects of the 
same species caught in the fields. In the family of bees, Hermann 
Mliller^ collected a large number of specimens of many species, and 
reared others from the cocoons, and counted the sexes. He found 
that the males of some species greatly exceeded the females in num- 
ber; in others the reverse occurred; and in' others the two sexes were 
nearly equal. But as in most cases the males emerge from the co- 
coons before the females, they gire at the commencement of the breed> 
ing season practically in excess. Miiller also observed that the rela- 
tive number of the two sexes in some species differed much in differ- 
ent localities. But as H. Miiller has himself remarked to me, these 
remarks must be received with some caution, as one sex might more 

* Gunther's " Record of Zoological Literature," 18';7. p. 2fi0. On the excess 
of female Lueanus, ibid. p. 2.5'>. On the males of Lucmiius in England, West- 
wood, " Modern Class of Insects," vol i. p. 187. On the Siagonium, ibid. p. 172. 

t Walsh in "The American Entomologist." vol. i, 18U9, p. 103. F. Smi'.h. 
"Record of Zoological Literature," 1807. p. 3.8. 

t " Farm Insects " pp. 4V-4G. 

§ " Anwendung der Darwinschen Lehre Verb. d. n. V. Jahrg.," xxiy. 


easily escape observation tlian the otlier. Tlius Lis brother Fritz 
Miiller Lai4 noticed in Brazil that tlie two sexes of tlie same species of 
bee sometimes frequent diiferent kinds of flowers. With respect to 
the Orthoptera, 1 know hardly anything about the relative number of 
the sexes; Koite,* however, says that out of 500 locusts %vhich he 
examined, the males were to the females as 5 to 6, With the 
Neuroptera, Mr. Walsh states tbat in many, but by no means In all 
tbe species of the Odonatous group, tbere is a great overplus of males; 
in the genus Hetaerina, also, the males are generally at least four 
times as numerous as tbe females. In certain species in the genus 
(Jomjdius tbe males are equally in excess, while in two other species 
tbe females are twice or thrice as numerous as the males. In some 
European species of Psocus thousands of lemales may be collected 
without a single male, while with other species of the same genus 
both sexes are common. f In England, Mr. MacLachlan has captured 
hundreds of the fen)ale Apatania mvUebris, but Las never seen the 
male; and of Boreas hyemalu only four or five males have been seen 
here.| With most of these species (excepting the Tentbredinse) there 
is at present no evidence that the females are subject to partheno- 
genesis; and thus we see bow ignorant we are of the causes of the 
apparent discrepancy in the proportion of the two sexes. 

In the other classes of the Articulata I have been able to collect 
still less information. With spiders, Mr. Blackwall, who has care- 
fully attended to this class during many years, writes to me that the 
males from their more erratic habits are more commonly seen, and 
therefore api)ear more numerous. This is actually the case with a 
few species; but he mentions several species m six genera, in which 
the females appear to be much more numerous than the males.§ The 
small size of the males in comparison with the females (a peculiarity 
which is sometimes carried to an extreme degree), and their widely 
different appearance, may account in some instances for their rarity 
in collections. |j 

Some of the lower Crustaceans are able to propagate their kind 
sexually, and this will account for the extreme rarity of the males; 
thus Von Siebold^ carefully examined no less than 13,000 specimens 
of Apus from twenty-one localities, and among these be found only 
319 males. With some other forms (as Tanais and Cypris), as Fritz 
Muller informs me, there is reason to believe that the males are much 
shorter-lived than the females; and this would ex])lain their scarcity, 
supposing the two sexes to be at tirst equal in number. On the other 
band, Miiller has invariably taken far more males than females of 
the Diastylidfe and of Cypridina on the shores of Brazil; thus with a 

* " Die Stricb, Zug oder Wanderheuschrecke." 1828, p. CO. 

+ " Observations on North American Neuroptera," by H. Haffen and B. D. 
Walsh, " Proc. Ent. Soc, Philadelphia," Oct., 18Gi, pp. U8, :C23, 239. 

X " Proc. Ent. Soc, London," Feb. 17, 18C8. 

§ Another great authority with respect to this class. Prof. Thorell. of Upsala 
("On European Spiders," )8G -18^0, part i, p. :iOo), speaks as if female spidera 
were generally commoner than the males. 

II See, on this subject, Mr. O. P. Cambridge, as quoted In " Quarterly Jour- 
nal of Science," 18C8. p. 429. 

^"Beitrage zur Parthenogenesis," p. 174. 


species in tLe latter g:enns, 63 specimens caught tlie same day included 
57 males; but lie suggests that this preponderance may be due to 
some unknown differeuce in the habits of the two sexes. With one 
of the higher Brazilian crabs, namely, a Gelasimus, Fritz Miiller 
found the males to be more numerous than the females. According 
to the large experience of Mr. C. Spence Bate, the reverse seems to 
be the case with six common British crabs, the names of which lie 
has given me. 

7Iie Proportion of the Sexes in delation to Natural 
Selection. — There is reason to suspect that in some cases 
man lias by selection indirectly influenced his own sex- 
producing powers. Certain women tend to produce during 
their whole lives more children of one sex than of the 
other; and the same holds good of many animals, for 
instance, cows and horses; thus Mr. AVright, of Yeldersley 
House, informs me that one of his Arab mares, though put 
seven times to different horses, produced seven fillies. 
Though I have very little evidence on this head, analogy 
would lead to the belief that the tendency to produce 
either sex would be inherited like almost every othei 
peculiarity, for instance, that of producing twins; and con- 
cerning the above tendency a good authority, Mr. J. 
Downing, has communicated to me facts which seem to 
prove that this does occur in certain families of short-horn 
cattle. Col. Marshall* has recently found on careful 
examination that the Todas, a hill tribe of India, consist 
of 112 males and 84 females of all ages — that is in a ratio 
of 133.3 males to 100 females. The Todas, who are poly- 
androus in their marriages, during former times invariably 
practiced female infanticide; but this practice has now 
been discontinued for a considerable period. Of the chil- 
dren born within late years the males are more numerous 
than the females in the proportion of 124 to 100. Col. 
Marshall accounts for this fact in the follovv^ing ingenious 
manner: '^ Let us for the purpose of illustration take three 
families as representing an average of the entire tribe; say 
that one mother gives birth to six daughters and no sons; 
a second mother has six sons only, while the third mother 
has three sons and three daughters. The first mother, fol- 
lowing the tribal custom, destroys four daughters and pre- 
serves two. The second retains her six sons. The third 
kills two daughters and keeps one, us also her three sons. 

*"Tbe Todas," 1873, pp. 100, HI, 104, 196. 



Wo liavc then from the three families nine sons and three 
daughters with which to continue the breed. But while 
the 'males belong to families in which the tendency to pro- 
duce sons is great the females are of those of a converse 
inclination. Thus the bias strengthens with each genera- 
tion until, as we find, families grow to have habitually 
more sons than daughters." 

That this result would follow from the above form of 
infanticide seems almost certain; that is if we assume that 
a sex-producing tendency is inherited. But as the above 
numbers are so extremely scanty I have searched for addi- 
tional evidence, but cannot decide whether what I have 
found is trustworthy; nevertheless the facts are, perhaps, 
worth giving. The Maories of New Zealand have long 
practiced infanticide ; and Mr. Fenton* states that he 
'* iias met with instances of women who have destroyed 
four, six and even seven children, mostly females. How- 
ever, the universal testimony of those best qualified to 
judge is conclusive that this custom has for many years 
been almost extinct. Probably the year 1835 may be 
named as the period of its ceasing to exist." Now 
among the New Zealanders, as with the Todas, male births 
are considerably in excess. Mr. Fenton remarks (p. 30) : 
*' One fact is certain, although the exact period of the 
commencement of this singular condition of the dispropor- 
tion of the sexes cannot be demonstratively fixed, it is quite 
clear that this course of decrease was in full operation 
during the years 1830 to 1844, when the non-adult pop- 
ulation of 1844 was being produced, and has continued 
with great energy up to the present time." The following 
statements are taken from Mr. Fenton (p. 20), but as the 
numbers are not large, and as the census was not accu- 
rate, uniform results cannot be expected. It should bo 
borne in mind in this and the following cases, that the 
normal state of every population is an excess of women, at 
least in all civilized countries, chieiiy owing to the greater 
mortality of the male sex during youth, and partly to acci- 
dents of all kinds later in life. In 1858, the native popula- 
tion of New Zealand was estimated as consisting of 31,007 
males and 24, 303 females of all ages, that is, in the ratio 

*" Aborigiualluhabitautsof New Zealand: Government lieport," 
1659, p. 30. 


of 130.3 males to 100 females. But during this same year 
and in certain limited districts, the numbers were ascer- 
tained with much care, and the males of all ages were here 
753 and the females GIG; that is in the ratio of 122.2 males 
to 100 females. It is more important for us that during 
this same year of 1858, the non-adiilt males within the 
same district were found to be 178, and the non-achiU 
females 142, that is in the ratio of 125.3 to 100. It may 
be added that in 1844, at which period female infanticide 
had only lately ceased, the non aduU males in one district 
were 281, and the nouadalt females only 194, that is in the 
ratio of 144.8 males to 100 females. 

. In the Sandwich Islands, the males exceed the females 
in number. Infanticide was formerly practiced there to a 
frightful extent, but was by no means confined to female 
infants, as is shown by Mr. Ellis,* and as I have been informed 
by Bishop Staley and the Rev. Mr. Coan. Nevertheless, 
another apparently trustworthy Avriter, Mr. Jarves,f whose 
observations apply to the whole archipelago, remarks: 
*' Numbers of women are to be found who confess to the 
murder of from throe to six or eight children,'" and he adds, 
'* females from being considered less useful than males 
were more often destroyed." From what is known to 
occur in other parts of the world this statement is 
probable; but must be received with much caution. The 
practice of infanticide ceased about the year 1819, when 
idolatry was abolished and missionaries settled in the 
islands. A careful census in 1839 of the adult and taxable 
men and women in the island of Kauai and in one district 
of Oahu (Jarves, p. 404), gives 4,723 males and 3,776 
females; that is in the ratio of 125.08 to 100. At the same 
time the number of males under fourteen years in Kauai 
and under eighteen in Oahu was 1,797, and of females of 
the same ages 1,429; and here we have the ratio of 125.75 
males to 100 females. 

In a census of all the islands in 1850, J the males of all 
ages amount to 36,272, and the females to 33,128, or as 
1U9.49 to 100. The males under seventeen years amounted 

* •' Narrative of a Tour througb Hawaii," 1826. p. 298. 
f •' History of liie Sandwich Islands," 1843. p. 93. 
X This is given in the Hev. H. T. CUeever's **Life ia the Sandwich 
Islands," 1851; p. 277. > 

rnoroRTioN of the sexes. 291 

to 10,773, and the females under the same age to 9,593, or 
as 112.3 to 100. From the census of 1872 tlie proportion 
of males of all ages (including half-castes) to females is as 
125.30 to 100. It must be borne in mind that all these 
returns for the Sandwich Islands give the proportion of 
living males to living females, and not of the births; and 
judging from all civilized countries the proportion of males 
would have been considerably higher if the numbers had 
referred to births.* 

From the several foregoing cases we have some reason to 
believe that infanticide practiced in the maimer above 
explained, tends to make a male-producing race; but I am 
far from supposing that this practice in the case of man, or 
some analogous process with other species, has been the sole 
determining cause of an excess of males. There may be 
some unknown law leading to this result in decreasing 

*Dr. Coulter, in describing ("Journal R. Geograpli. Soc," vol. v, 
1835, p. 67) the state of California about the year 1830, says tbat the 
natives, reclaimed by the Spanish missionaries, have nearly all per- 
ished, or are perishing, although well treated, not driven from their 
native land, and kept from the use of spirits. He attributes this, in 
great part, to the undoubted fact that the men greatly exceed the 
vi^omen in number; bu* he does not know whether this is due to a 
failure of female offspring, or to more females dying during early 
youth. The latter alternative, according to all analogy, is very 
improbable. He adds that "infanticide, properly so called, is not 
common, though very frequent resource is had to abortion." H Dr. 
Coulter is correct about infanticide, this case cannot be advanced in 
support of Col. Marshall's view. From the rapid decrease of the 
reclaimed natives, we may suspect that, as in the cases lately given, 
their fertility has been diminished from changed habits of life. I 
had hoped to gain some light on this subject from the breeding of 
dogs; inasmuch as in most breeds, with the exception, perhaps, of 
greyhounds, many more female puppies are destroyed than males, 
just as with the Toda infants. Mr. Cupples assures me that this is 
usual with Scotch deer-hounds. Unfortunately I know nothing of 
the proportion of the sexes in any breed, excepting greyhounds, and 
there the male births are to the females as 110.1 to 100. Now from 
inquiries made from many breeders, it seems that the females are in 
some respects more esteemed, though otherwise troublesome; and it 
does not appear that the female puppies of the best- bred dogs are 
systematically destroyed more than the males, though this does some- 
times take place to a limited extent. Therefore I am unable to 
decide whether we can, on the above principles, account for the pre- 
ponderance of male births in greyhounds. On the other hand, we 
have seen that with horses, cattle and sheep, which are too valuable 
for the young of either sex to be destroyed, if there is any difference, 
tlio females are slightly in excess. 


races which have already become eomewhat infertile. 
Besides the several causes previously alluded to, the greater 
facility of parturition among savages, and the less conse- 
quent injury to their male infants, would tend to increase 
the proportion of live-born males to females. There does 
not, however, seem to be any necessary connection between 
savage life and a marked excess of males; that is if we may 
judge by the character of the scanty offspring of the lately 
existing Tasmanians and of the crossed oflspring of the 
Tahitians now inhabiting Norfolk Island. 

As the males and females of many animals differ some- 
what in habits, and are exposed in different degrees to 
danger, it is probable that in many cases m.ore of one sex 
than of the other are habitually destroyed. But as far as I 
can trace out the complication of causes an indiscriminate 
though large destruction of either sex would not tend to 
modify the sex-producing power of the species. With 
strictly social animals, such as bees or ants, which produce 
a vast number of sterile and fertile females in comparison 
with the males, and to whom this preponderance is of para- 
mount importance, we can see that those communities 
would flourish best which contained females having a 
strong inherited tendency to produce more and more 
females; and in such cases an unequal sex-producing ten- 
dency would be ultimately gained through natural selection. 
With animals living in herds or troops in which the males 
come to the front and defend the herd, as with the bisons 
of North America and certain baboons, it is conceivable 
that a male-producing tendency might be gained by natural 
selection; for the individuals of the better defended herds 
would leave more numerous descendants. In the case of 
mankind the advantage arising from having a preponderance 
of men in the tribe is supposed to be one chief cause of 
the practice of female infanticide. 

In no case, as far as we can see, would an inherited ten- 
dency to produce both sexes in equal numbers or to produce 
one sex in excess, be a direct advantage or disadvantage to 
certain individuals more than to others; for instance, an 
individual with a tendency to produce more males than 
females would not succeed better in the battle for life than 
an individual with an opposite tendency; and therefore a 
tendency of this kind could not be gained through natural 
selection. Nevertheless, there are certain animals (for 


instance, fishes and cirripedes) in which two or more males 
appear to be necessary for the fertilization of the female; 
and the males accordingly largely preponderate, but it is 
by no means obvious how this male-producing tendency 
could have been acquired. I formerly thought that when 
a tendency to produce the two sexes in equal numbers was 
advantageous to the species it would follow from natural 
selection, but I now see that the whole problem is so intri- 
cate that it is safer to leave its solution for the futuie. 




Tliese cliaracters absent in tlie lowest classes — Brilliant colors — 
Mollusca — Annelids — Crustacea, secondary sexual characters 
strongly devoloped; dimorphism; color; characters not acquired 
before maturity — Spiders, sexual colors of; stridulatiou by the 
males — Myriapoda. 

With animals belonging to the lower classes, the two 
sexes are not rarely united in the same individual, and there- 
fore secondary sexual characters cannot be developed. In 
many cases where the sexes are sepai-ate both are perma- 
nently attached to some support, and the one cannot search 
or struggle for the other. Moreover it is almost certain 
that these animals have too imperfect senses and much too 
low mental powers to appreciate each other's beauty or 
other attractions, or to feel rivalry. 

Hence in these classes or sub-kingdoms, such as the Pro- 
tozoa, Ccelenterata, Echinodermata, Scolecida secondary 
sexual characters of the kind which we have to consider do 
not occur; and this fact agrees with the belief that such 
characters in the higher classes have been acquired through 
sexual selection, which depends on the will, desire and 
choice of either sex. Nevertheless some few apparent 
exceptions occur; thus, as I hear from Dr. Baird, the males 
of certain Entozoa or internal parasitic worms differ slightly 
in color from the females; but we have no reason to sup- 
pose that such differences have been augmented through 
sexual selection. Contrivances by which the male holda 
the female, and which are indispensable for the propaga- 
tion of the species, are independent of sexual selection, and 
have been acquired through ordinary selection. 

Many of the lower animals, whether hermaphrodites or 
with separate sexes, are ornamented with the most brilliant 
tints, or are shaded and striped in an elegant manner; for 
instance, many corals and sea-auemones (Actiniae), some 


3ell5^-fish (Medusae, Porpita, etc.), some Planarias, many 
star-fishes, Echini, Ascidians, etc.; but we may conclude 
from the reasons already indicated, namely, the union of 
the two sexes in some of these animals, the permanently 
affixed condition of others, and the low mental powers of 
all that such colors do not serve as a sexual attraction and 
have not been acquired through sexual selection. ^ It 
should be borne in mind that in no case have we sufficient 
evidence that colors have been thus acquired, except where 
one sex is much more brilliantly or conspicuously colored 
than the other, and where there is i^o difference in habits 
between the sexes sufficient to account for their different 
colors. But the evidence is rendered as complete as it can 
ever be only when the more ornamented individuals, almost 
always the males, voluntarily display their attractions 
before the other sex; for we cannot believe that such dis- 
play is useless, and if it be advantageous sexual selection 
will almost inevitably follow. We may, however, extend 
this conculsion to both sexes when colored alike if their 
colors are plainly analogous to those of one sex alone in 
certain other species of the same group. 

How, then, are we to account for the beautiful or even 
gorgeous colors of many animals in the lowest classes? It 
appears doubtful whether such colors often serve as a pro- 
tection; but that we may easily err on this head will be 
admitted by every one who reads Mr. Wallace's excellent 
essay on this subject. It would not, for instance, at first 
occur to any one that the transparency of the Medusae, or 
jelly-fish, is of the highest service to them as a protection; 
but when we are reminded by Iliickel that not only the 
Medusae but many floating mollusca, crustaceans and even 
small oceanic tishes partake of this same glass-like appear- 
ance, often accompanied by prismatic colors, we can hardly 
doubt that they thus escape the notice of pelagic birds and 
other enemies. M. Giard is also convinced* that the 
bright tints of certain sponges and ascidians serve as a pro- 
tection. Conspicuous colors are likewise beneficial to many 
animals as a warning to their would-be devourers that they 
are distasteful, or that they possess some special means of 
defense; but this subject will be discussed more conven- 
iently hereafter. 

We can in our ignorance of most of the lowest animals 

♦ *' Arcliivea de Zoolog. Exr)er. " Oct., 1872, p. 503. 


only say that their bright tints result either from the 
cliemical nature or the minute structure of tlieir tissues 
independently of any benetlt thus derived. Hardly any 
color is finer than that of arterial blood; but there is no 
reason to suppose that the color of the blood is in itself 
any advantage; and though it adds to the beauty of the 
maiden's cheek, no one will pretend that it has been 
acquired for this purpose. So again with many animals, 
especially the lower ones, the bile is richly colored; thus, as 
I am informed by Mr. Hancock, the extreme beauty cf the 
Eolidge (naked sea-slugs) is chiefly due to the biliary glands 
being seen through the translucent integuments — this 
beauty being probably of no service to these animals. The 
tints of the decaying leaves in an American forest are 
described by every one as gorgeous; yet no one supposes 
that these tints are of the least advantage to the trees. 
Bearing in mind how many substances closely analogous to 
natural organic compounds have been recently formed by 
chemists, and which exhibit the most splendid colors, it 
would have been a strange fact if substances similarly 
colored had not often originated, independently of any 
useful end thus gained, in the complex laboratory of living 

The Siih Kingdom of the Mollnslca. — Throughout this 
great division of the animal kingdom, as far as I can dis- 
cover, secondary sexual characters, such as we are here con- 
sidering, never occur. Nor could they be expected in the 
three lowest classes, namely, in the Ascidians, Polyzoa and 
Brachiopods (constituting the Molluscoida of some authors), 
for most of these animals are permanently affixed to a sup- 
port or have their sexes united in the same individual. In 
the Lamellibranchiata, or bivalve shells, hermaphroditism 
is not rare. In the next higher class of the Gasteropoda, 
or univalve shells, the sexes are either united or separate. 
But in the latter case the males never possess special organs 
for finding, securing, or charming the females, or for fight- 
ing with other males. As I am informed by Mr. Gwyn 
Jeffreys, the sole external difference between the sexes con- 
sists in the shell sometimes differing a little in form; for 
instance, the shell of the male periwinkle {Littorina 
lit tor ea) 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 repro- 
duction, or with the development of the ova. 

The Gasteropoda, though capable of locomotion and 
furnished with imperfect eyes, do not appear to be endowed 
with sufficient mental powers for the members of the same 
sex to struggle together in rivalry, and thus to acquire 
secondary sexual characters. Nevertheless with the pul- 
moniferous gasteropods, or land-snails, the pairing is pre- 
ceded by courtship; for these animals, though hermaphro- 
dites, are compelled by their structure to pair together. 
Agassiz remarks:* *' Quiconque a eu I'occasion d'observer 
les amours des limagons, ne saurait mettre en doute la 
seduction deployee dans les monvements et les allures qui 
preparent et accomplissent le double embrassemeut de ces 
hermaphrodites." 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-snails (Helix poniatia), 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 e::ploration, for both then started, 
along the same track and disappeared over the wall. 

Even in the highest class of the MoUuska, the Cephalo- 
poda or cuttle-tishes, in which the sexes are separate, 
secondary sexual characters of the present kind do not, as 
far as 1 can discover, occur. This is a surprising circum- 
stance, as these animals possess highly-developed sense- 
organs and have considerable mental powers, as will be 
admitted by everyone who has watched their artful endeav- 
ors to escape from an enemy, f Certain Cephalopoda, how- 
ever, are characterized by one extraordinary sexual charac- 
ter, namely that the male element collects within one of 
the arms or tentacles, which is then cast off, andclinging 
by its sucking-disks to the female, lives for a time an inde- 
pendent life. So completely does the cast-off arni resemble 
a separate animal, that it was described by Cuvier as a para- 

* " De I'Espece et de la Class," etc., 1869, p. 106. 
\ See, for instance, the account wliicli 1 liave given in my '* Jouj^ 
nal of teearclies," X845, p. 7. 


sitic worm nnder the name of Hectocotyle. But this mar- 
velous structure may be classed as a primary rather than ao 
a secondary sexual character. 

Althou2fh with the MoUuska sexual selection does not 
seem to liave come into play; yet many univalve and 
bivalve shells, such as volutes, cones, scallops, etc., :ire 
beautifully colored and shaped. The colors do not appear 
in most cases to be of any use as a protection; they aio 
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 be influential to a certain extent ; for 
although, as repeatedly stated by Mr. Gv/yn Jeffreys, the 
shells of some species living at a profound depth are brightly 
colored, yet we generally see the lower surfaces, as well as 
the parts covered by the mantle, less highly colored than 
the upper and exposed surfaces.* In some cases, as with 
shells living among corals or brightly tinted sea-weeds, the 
bright colors may serve as a protection.! But that many 
of the nudi-branch moUuska, or sea-slugs, are as beauti- 
fully colored as any shells, may be seen in Messrs. Aider 
and Hancock's magnificent work; and from information 
kindly given me by Mr. Hancock, it seems extremely 
doubtful whether these colors usually serve as a protection. 
With some species this may be the case, as with one kind 
which lives on the green leaves of algae, and is itself bright- 
green. But many brightly-colored, white, or otherwise 
conspicuous species, do not seek concealment; while again 
some equally conspicuous species, as well as other dull- 
colored kinds, live under stones and in dark recesses. So 
that with these nudibranch mollusks, color 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, 

*I liave given ("Geolog. Observations on Volcanic Islands," 1844, 
p. 53) a curious instance of the intiuence of liglit on the colors of a 
frondescent incrustation, deposited by the surf on the coast-rocks of 
Ascension, and formed by the solution of triturated sea-shells. 

f Dr. Morse has lately discussed this subject in his paper on the 
Adaptive Coloration of MoUuska, "Proc. Boston Soc. of "^aX. Hisit.,.** 
vol. xiv, April, 1871. 


attracted by each other's greater beauty, might unite 
and leave offspring wliich would inherit their parents' 
greater beauty. But with such lowly-organized creatures 
this is extremely improbable. Nor is it at all obvious how 
the oflspring from the more beautiful pairs of hermaphro- 
dites would have any advantage over the offspring of the 
less Deautiful, so as to increase in number, unless indeed 
vigor and beauty generally coincided. We have not here 
the case of a number of males becoming mature before 
the females, with the more beautiful males selected by the 
more vigorous females. If, indeed, brilliant colors were 
beneficial to a hermaphrodite animal in relation to its gen- 
eral habits of life, the more brightlj'-tinted individuals would 
succeed best and would increase in number; but this would 
be a case of natural and not of sexual selection. 

Suh - kingdom of the Vermes — Annelida (or Sea- 
worms). — In this class, although the sexes, when separate, 
sometimes differ from each other in characters of such im- 
portance 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 are often beautifully colored, but as the sexes do 
not differ iu this respect we are but little concerned with 
them. Even the Nemertians, though so lowly organized, 
" vie in beauty and variety of coloring with any other 
group in the vertebrate series;" yet Dr. Mcintosh * cannot 
discover that these colors are of any service. The sedentary 
annelids become duller-colored, according to M. Quatre- 
fage£,t after the period of reproduction; and this I pre- 
sume may be attributed to their less vigorous condition at 
that time. All these worm-like animals apparently stand 
too low in the scale for the individuals of either sex to exert 
any choice in selecting a partner, or for the individuals of 
the same sex to struggle together in rivalry. 

Sub 'kingdom of the Arthropoda — Crustacea. — In 
this great class we first meet with undoubted secondary 
Bexual characters, often developed in a remarkable manner. 

*See his beautiful monograph on "British Annelids," pari i, 1873, 
p. 3. 

fSee M. Perrier. " TOrigine de rHommed'aprds Darwin," "Revu© 
Scientifique," Feb., 1873, jk bOa. 


Unfortunately the habits of crustaceans are very imper- 
fectly 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 fur- 
nished with perfect legs, atennfe and sense- 
organs; the females being destitute of these organs, with 
their bodies often consisting of a mere distorted mass. But 
these extraordinary differences between the two sexes are no 
doubt related to their widely different habits of life, and 
consequently do not concern us. In various crustaceans, 
belonging to distinct families, the anterior attennas are fur- 
nished with peculiar thread-like bodies, which are believed 
to act as smelling-organs, and these are much more numerous 
in the males than in the females. As the males, without any 
unusual development of their olfactory organs, would almost 
certainly be able sooner or later to find the females, the 
increased number of thesmelling-threads has probably been 
acquired through sexual selection, by the better provided 
males having been the more successful in finding partners 
and in producing offspring. Fritz Miiller has described a 
remarkable dimorphic species of Tanais in which the male 
is represented by two distinct forms which never graduate 
into each other. In the one form the male is furnished 
with more numerous smelling-threads, and in the other 
form with more powerful and more elongated chelae or 
pincers which serve to hold the female. Fritz Miiller sug- 
gests that these differences between the two male forms of 
the same species may have originated in certain individuals 
having varied in the number of the smelling-threads, while 
other individuals varied in the shape and size of their 
chelae; so that of the former those which were best able to 
find the female, and of the latter those which were best 
able to hold her, have left the greatest number of progeny 
to inherit their respective advantages.* 

In some of the lower crustaceans the right anterior 
antenna of the male differs greatly in structure from the 
left, th^ latter resembling in its simple tapering joints the 
antennae of the female. In the male the modified antenna 
is either swollen in the middle or angularly bent or con- 

?^ ".Facts and Arguments for Darwin." English translat., 1869, p. 
20 See the previous discussion on the olfactory threads. Sars has 
descrihed a soinewlmt analogous case (as quoted in " Nature," 1870| 
p. 455) in a Norwegian crustacean, the PotUoporcia affiui^^ 



verted (Sg. 4) into an elegant and sometimes wonderfully 
complex prehensile organ.^ It serves, as I hear from Sir 
J. Lubbock, to hold the female, 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. 

In the higher crustaceans the 
anterior legs are developed into 
chelae or pincers; and these are gen- 
erally larger in the male than in the 
female — so much so that the market 
value of the male edible crab (Cancer 
pa(junit(), according to Mr. C. Spence 
Bate, is live times as great as that of 
the female. In many species the 
chelae are of unequal size on the 
opposite side of the body, the right- 
hand one being, as I am informed by 
Mr. Bate, generally though not 
invariably the largest. This ine- 
quality is also often much greater in 
the male than in the female. The 
two chelse of the male often differ 
in structure (figs. 5, 6 and 7), the 
smaller one resembling that of the 
female. AVhat advantage is gained 
by their inequality in size on the 
opposite sides of the body and by the 
inequality being much greater in the 
the male than in the female; and 
why when they are of equal size both 
are often much larger in the male 
than in the female is not known. As 
I hear from Mr. Bate, the chelae are 
sometimes of such length and size 
that they cannot possibly be used for 
carrying food to the mouth. In the male? of certain fresh 

Fig. 4. Labidocpra Dnrwinli 
(from Lubbock;. 

a. Part of rigrht anterior an- 

tenna of male, forming a 
preiiensile orjran. 

b. Posterior pair of tboracio 

lejrs of male. 

c. Ditto of female. 

* See Sir J. Lubbock in " Annals and INIag. of Nat. Hist.," vol. xi, 
1853, pi. i and x; and vol. xii, 1853, pi. vii. See also Lulibock la 
"Transact. Ent. Soc. ," vol iv, new series, 185j-1858, p. 8. Wiih 
respect to the zigzagged antennse mentioned below, see Fritz Miiller, 
♦ I'acts and Argameuts for Darwin," 1869, p. 40, foot note. 



water prawns (Palaemon) the right leg is actually longer than 
the whole body.* The great size of the one leg with its 
chelse may aid the male in fighting with his rivalsj but this 

rig. 5. Anterior part of body of Callianassa 'from Milne-Edwards), 
saowinjr the unequal and differentia -constructed rig-^ and 
left hand chelae of the male. 

N. B.— The artist by mistake has reversed the drawing, and made the 
left-hand chela the largest 

Ilg. 6. 

PIsr. 6. Second lee of male Orchestia Tucuratinga (from Fritz Muller). 
"Sig.l. Ditto of female. 

will not account for their inequality in the female on the 
opposite sides of the body. In Gelasimus, according to a 

*See a paper by Mr. C. Spence Bate, with figures in '* Proc. 
Zoolo<^. Soc," 1868. p. 363; and on the nomenclature of the genus, 
ibid. p. 585. I am greatly indebted to Mr. Spence Bate for nearly all 
the above statements with respect to the chelae of the higher 


Btatement quoted by Milne-Edwards, * the male and the 
female live in the same burrow, and this shows that they 
pair; the male closes the mouth of the burrow with one of 
its chela3, which is enormously developed; so that here it 
indirectly serves as a means of defense. Their main use, 
however, is probably to seize and to secure the female, and 
this in some instances, as with Gammarus, is known to be 
the case. The male of the hermit or soldier crab (Pagiirufi) 
for weeks together, carries about the shell inhabited by the 
female, f The sexes, however, of the common shore-crab 
(Carcinus mcenrnt), as Mr. Bate informs me, unite directly 
after the female has moulted her hard shell, when she is so 
soft that she would be injured if seized by the strong 
pincers of the male; but as she is caught and carried about 
by the male before moulting, she could then be seized with 

Fritz Miiller states that certain species of Melita are dis- 
tinguished from all other amphipods by the females having 
'* the coxal lamellai of the penultimate pair of feet pro- 
duced into hook-like processes, of which the males lay hold 
with the hands of the first pair." The development of 
these hook-like processes has probably followed from those 
females which were the most securely held during the act 
of reproduction, having left the largest number of offspring. 
Another Brazilian amphipod {Orchestia Darwinii, tig. 8) 
presents a case of dimorphism, like that of Tanais; for 
there are two male forms, which differ in the struc- 
ture of their chelse.J; As either chela would certainly suf- 
fice to hold the female — for both are now used for this pur- 
pose — the two male forms probably originated by some 
having varied in ons manner and some in another ; 
both forms having derived certain special, but nearly equal 
advantages, from their differently shaped organs. 

It is not known that male crustaceans fight together for 
the possession of the females, but it is probably the case ; 
for with most animals when the male is larger than the 
female, he seems to owe his greater size to his ancestors 

*"Hist. Nat. des Crust.," torn, ii, 1837, p. 50. 
+ Mr. C. Spence Bate, *' Brit. Assoc, Fourth Report on tlie Fauna 
of S. Devon." 

t Fritz Mailer, *' Facts and Arguments for Darwin," 1869, pp. 


having fought with other males during many generations. 
In most of the orders, especially in the highest or the 
Brachyura, the male is larger than the female ; the para- 
sitic genera, however, in which the sexes follow diiferent 

Fig. 8. Orcbestia Darwiryi (from Fiitz Muller\ showing the differently- 
constructed chelaj of the two male forms. 

habits of life, ami most of the Entomostraca must be 
excepted, The chelae of many crustaceans are weapons 
well adapted for fighting. Thus when a devil-crab {PoV' 
tiinns puber) was seen by a sou of Mr. Bate fighting with 
a Carcinus hkbikis, the latter was soon thrown on its back, 
and had every limb tcra from its body. AVhen several 


males of a Brazilian Gelasimus, a species furnished with 
immense pincers, were phiced together in a glass vessel by 
Fritz Muller, they mutilated and killed one another. Mr. 
Bate put a large male Carcimis mwims into a pan of 
water, inhabited by a female which was paired with a 
smaller male; but the latter was soon dispossessed. Mr, 
Bate adds, *Mf they fought, the victory was a bloodless 
one, for I saw no wounds.'' This same naturalist separated 
a male sand -skipper (so common on our sea-shores). Gam- 
marus viarinus, from its female, both of whom were 
imprisoned in the same vessel with many individuals of the 
same species. The female, when thus divorced, soou 
joined the others. After a time the male was put again 
into the same veseel; and he then, after swimming about 
for a time, dashed into the crowd, and without any fighting 
at once took away his wife. This fact shows that in the 
Amphipoda, an order low in the scale, the males and 
females recognize each other and are mutually attached. 

The mental powers of the Crustacea are probably higher 
than at first sight appears probable. Any one who tries to 
catch one of the shore-crabs, so common on tropical coasts, 
will perceive how wary and alert they are. There is a large 
crab {Birgiis latro), found on coral islands, which makes a 
thick bed of the picked fibers of the cocoanut, at the 
bottom of a deep burrow. It feeds on the fallen fruit of 
this tree by tearing off the husk, fiber by fiber; and it 
always begins at that end where the three eye-like depres- 
sions are situated. It then breaks through one of these 
eyes by hammering with its heavy front pincers, and, turn- 
ing round, extracts the albuminous core with its narrow 
posterior pincers. But these actions are probably instinct- 
ive, so that they would be performed as well by a young 
animal as by an old one. The following case, however, 
can hardly be so considered: a trustworthy naturalist, Mr. 
Gardner,* while watching a shore-crab (Gelasimus) making 
its burrow, threw some shells toward the hole. One rolled 
in, and three other shells remained within a few inches of 
the mouth. In about five minutes the crab brought out 
the shell which had fallen in, and carried it away to a dis- 

*" Travels in the Interior of Brazil," 1846, p. 111. I have given in 
ray "Journal of KesearcUes," p. 463, au account of tke liabita of the 


tance of a foot; it then saw the three other shells lying 
near, and, evidently thinking that they might likewise roll 
in, carried them to the spot where it had laid the first. It 
would, I think, be difficult to distinguish this act from one 
performed by man by the aid of reason. 

Mr. Bate does not know of any well-marked case of dif- 
ference of color in the two sexes of our British crustaceans, 
in which respect the sexes of the higher animals so often 
differ. In some cases, however, the males and fsmales differ 
slightly in tint, but Mr. Bate thinks not more than may be 
accounted for by their different habits of life; such as by 
the male wandering more about, and being thus more 
exposed to the light. Dr. Power tried to distinguish by 
color the sexes of the several species which inhabit the 
Mauritius but failed, except with one species of Sqnilla, 
probably *S'. stylifera, the male of which is described as 
being *^of a beautiful bluish-green," with some of the 
appendages cherry-red, while the female is clouded with 
brown and gray, '' with the red about her much less vivid 
than in the male." * In this case we may suspect the 
agency of sexual seleccion. From M. Bert's observation on 
Daphuia, whdn placed in a vessel illuminated by a prism, 
we have reason to believe that even the lowest crustaceans 
can distinguish colors. With Saphirina (an oceanic genus 
of Entomostraca), the males are furnished with minute 
shields or cell-like bodies, which exhibit beautiful changing 
colors; these are absent in the females, and in both sexes 
of one species. t It would, however, be extremely rash to 
conclude that these curious organs serve to attract the 
females. I am informed by Fritz Miiller, that in the 
female of a Brazilian species of Gelasimus the whole body 
is of a nearly uniform grayish-brown. In the male the 
posterior part of the cephalo-thorax is pure white, with the 
anterior part of a rich green, shading into dark brown; and 
it is remarkable that these colors are liable to change in the 
course of a few minutes — the white becoming dirty gray or 
even black, the green ^' losing much of its brilliancy." It 
deserves especial notice that the males do not acquire their 
bright colors until they become mature. They appear to 

*Mr. Ch. Eraser, in '' Proc. Zcolog. Soc," 18G9, p, 3. 1 am 
indebted to Mr. Bate for Dr. Power's btaieiiient. 
f Claus, "Die freilebendeu Copepoden," 1863, s. 35. 


be much more nnmerons than the females; they differ also 
in the larger size of their chelae. In some species of the 
genns, 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 proba- 
ble that the male in this species has become gayly orna- 
mented in order to attract or excite the female. 

It has just been stated that the male Gelasimus does not 
acquire his conspicuous colors until mature and nearly 
ready to breed. This seems a general rule in the whole 
class in respect to the many remarkable structural differ- 
ences between the sexes. We shall hereafter find the same 
law prevailing throughout the great sub-kingdom of the 
vertebrata; and in all cases it is eminently distinctive of 
characters which have been acquired through sexual selec- 
tion. Fritz Miiller * gives some striking instances of this 
law; thus the male sand-hopper (Orchestia) does not, until 
nearly full grown, acquire his large claspers, which are 
very differently constructed from those of the female; while 
young his claspers resemble those of the female. 

Arachiida (Spiders). — The sexes do not generally 
differ much in color, but the males are often darker than 
the females, as may be seen in Mr. Blackwnll's magnificent 
work.f In some species, however, the difference is con- 
ppicuous; tluis the female of Sparassus smaragdidus is 
dullish green, while the ad nit male has the abdomen of a fine 
yellow, with three longitudinal stripes of rich red. In 
certain species of Thoniisns the sexes closely resemble each 
other, in others they differ much; and nnalogous cases occur 
in many other genera. It is often difficnlt'to spy which of 
the two sexes departs most from the ordinnry coloration of 
the sfenus to which the species belong; but Mr. Blackwall 
thinks that, as a general rule, it isthe^male; and CanestriniJ 
remarks that in certain genera the males can be specifically 
distinguished with ease, but the females with great difficulty. 

* " Facts and Arguments," etc., p, 79. 

f " A History of tl.e Spiders of Great Britain," 1861-64. For tlie 
following facts, see i)p. 77. 88, 102. 

:J: This author lias recently published a valuable essay on tlie 
*'Caratteri sessuali secondarii de^ili Arachnioi," in tbe '* Atli delia 
See. Veueto-Treiitina di Sc. Mat. Padova," vol. i, Fasc. 3, 1873. 


I am informed by Mr. Blackwall that the sexes while yoinig 
usually resemble each other; and both often undergo great 
changes in color during their successive moults before 
arriving at maturity. In other cases the male alone appears to 
change color. Thus the male of the above bright-colored 
Sparassus at tirst resembles the female, and acquires his pecu- 
liar tints only when nearly adult. Spiders are possessed of 
acute senses, and exhibit much intelligence; as is well 
known, the females often show the strongest affection for 
their eggs, which they carry about enveloped in a silken 
web. The males search eagerly for the females, and have 
been seen by Canestrini and others to fight for possession of 
them. This same author says that the union of the two 
sexes has been observed in about twenty species; and he 
asserts positively that the female rejects some of the males 
who court her, threatens them with open mandibles 
and at last after long hesitation accepts the chosen one. 
From these several considerations, we may admit with some 
confidence that the well-marked differences in color between 
the sexes of certain species are the results of sexual selection, 
though we have not here the best kind of evidence — the 
display by the male of his ornaments. From the extreme 
variability of color in the male of some species, for instance 
of Theridion Uneatum, it would appear that these sexual 
characters of the males have not as yet become well fixed. 
Canestrini draws the same conclusion from the fact that the 
males of certain species present two forms, differing from 
each other in the size and length of their jaws; and this 
reminds us of the above cases of dimorphic crustaceans. 

The male is generally much smaller than the female, 
sometimes to an extraordinary degree,* and he is forced to 
be extremely cautious in making his advances, as tho 
female often carries her coyness to a dangerous pitch. 
De Geer saw a male that ^^in the midst of his preparatory 
caresses was seized by the object of his attentions, envel- 
oped by her in a web and then devoured, a sight which, as 

* Aug. Vinson (" Arantildes des lies de la Reunion," pi. vi, figs, 1 
and 2) gives a good instance of the small size of the male, in Epeira 
nigra, in this species, as 1 may 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 
("Quarterly Journal of Science," 1868, July, p. 429)} but I have not 
seen the original accounts. 


he adds, filled him with liorror and indignation/'* The Rev. 
0. P. Cambridget accounts in the following manner for 
the extreme smallness of the male in the genus Nephila: 
*' M. Vinson gives a graphic account of the agile way in 
whicli the diminutive male escapes from the ferocity of the 
female by gliding about and playing hide and seek over 
her body and along her gigantic limbs. In such a pursuit 
it is evident that the chances of escape would be in favor 
of the smallest males, while the larger ones would fall 
early victims; thus gradually a diminutive race of males 
would be selected, until at last they would dwindle to the 
smallest possible size compatible with the exercise of their 
generative functions — in fact, probaby to the size we now 
see them, ?. e., so small as to be a sort of parasite upon the 
female, and either beneath her notice or too agile and too 
small for her to catch without great difficulty." 

Westring has made the interesting discovery that the 
males of several species of TheridionJ have the power of 
making a stridulating sound, while the females are mute. 
The apparatus consists of a serrated ridge at the base of 
the abdomen, against which the hard hinder part of the 
thorax is rubbed; and of this structure not a trace can be 
detected in the females. It deserves notice that several 
writers, including the well known arachnologist Walck- 
enaer, have declared that spiders are attracted by 
music. § From the analogy of the Orthoptera and Homop- 
tera, to be described in the next chapter, we may feel 
almost sure that the stridulation serves, as Westring also 
believes, to call or to excite the female; and this is the first 
case known to me in the ascending scale of the animal 
kingdom of sounds emitted for this purpose. || 

*Kirby and Spence, "Introduction to Entomology," vol. i, 1818, 
p. 280. 

t " Proc. Zoolog. Soc." 1871, p. 621. 

X Theridioii {Amgena, Sund.) seri^atipeft, i-punctatum et guttatum; 
see Westring. in Kioyer. " Naturliist. Tidskrift," vol. iv, 1842-1843, 
p. 349; and vol. ii, 1846-1849, p. 342. See, also, for other species, 
" Araneae Siiecicae," p. 184. 

§ Dr. H. H. van Zouteveen, in Lis Dutch translation of this work 
(vol. 1, p. 444), has collected several cases. 

I Hilgendorf, howeve-, has lately called attention to an analogous 
structure in some of the higher crustaceans, which seems adapted to 
produce sound; see "Zoological Record," 1869, p. 603, 


Mijriapoda. — In neither of the two orders in this class, 
the millipedes and centipedes, can I find any well-marked 
instances of such sexual differences as more particularly 
concern us. In Glomeris limhata, however, and perhaps 
in some few other species, the males differ slightly m color 
from the females; but this Glomeris is a highly variable 
species. In the males of the Diplopoda, the legs belong- 
ing either to one of the anterior or of the posterior seg- 
ments of the body are modified into prehensile hooks 
which serve to secure the female. In some species of 
Inlas the tarsi of the male are furnished with membranous 
suckers for the same purpose. As we shall see when we 
treat of insects, it is a much more unusual circumstance, 
that it is the female in Lithobius, which is furnished with 
prehensile appendages at the extremity of her body for 
holding the male.* 

^Walckenaer et P. Gervais, "Hist. Nat. des Insectes; Apteres," 
torn, iv, 1847, pp. 17, 19, 68. 




Diversified structures possessed by tlie males for seizino; the females 
— DillVrences between the sexes, of whicb the meaning is not 
understood — Difference in size between the sexes — Tbysanura 
— Diptera — Hemiptera — Homoptera, musical powers possessed 
by tlie males alone — Orthoptera, musical insiruments of tbe 
niales, mucb diversified in structure; pugnacity; colors — Neu- 
roptera, sexual differences in color — Hymenoptera, pugnacity 
and colors — Coleoptera, colors; furnisbed witb great boms, 
ajiparently as an ornament; battles; stridulatiug organs gener- 
ally common to botb sexes. 

In the immense class of insects the sexes sometimes 
differ in their locomotive-organs, and often in their sense- 
organs, as in the pectinated and beautifully plumose anten- 
nae of the males of many species. In Chloeon, one of tho 
Ephemerae, the male has great pillared eyes, of which the 
female is entirely destitute* The ocelli are absent in tho 
females of certain insects, as in theMutillidae; and here the 
females are likewise wingless. But we are chiefly concerned 
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 contriv- 
ances, 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 abdomen, which ought per- 
haps to be ranked as primary organs, f ** 1 1 is ascouibina^, its 

*Sir J. Lubbock, *• Transact. Liunean Soc," vol. xxv, 186G, p. 
484. Witb respect to tbe Mutillidae see Westwood, "Modern Class, 
of Insects," vol. ii, p. 213. 

f Tbese organs in tbe male often differ in closely allied species 
and afford excellent specific characters. But their importance, from 
a functional point of view, as Mr. R. MacLacblan lias remarked to 
me. bas probably been overrated. It bas been suggested that slight 
differences in tbese organs would suffice to prevent tbe intercrossing 
of well-marked varieties or incipient species, and would tbua aid in 



Mr. B. D. Walsh* has remarked, *' how many different 
organs are worked in by nature for the seemingly insignifi- 
cant object of enabling the male to grasp the female 
firmly." The mandibles or jaws are sometimes nsed for 
this purpose; thus the male Corydalis cornutns (a neu- 
ropterous insect in some degree allied to the dragon flies, 

etc.) has immense curved jaws, 
many times longer than those of 
the female; and they are smooth 
instead of being toothed, so that 
he is thus enabled to seize her 
without injury, f One of the 
stag-beetles of North America 
(Lncanvs claphtts) 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 (AmmopJiila) the jaws in 
the two sexes are closely alike, 
but are used for widely difl'ercnt 
purposes; the males, as Prof. 
VVestwood observes, ^' are exceed- 
ingly ardent, seizing their part- 
ners round the neck with their 
sickle-shaped jaws;"J while the 
females use these organs for 
■"feuroSSe-iowSte^'eteX" burrowing in sand-banks aud 

making their nests. 
The tarsi of the front legs are dilated in many male 
beetles, or are furnished with broad cushions of hair; and 
in many genera of water beetles they are armed with a 

their development. That this can hardly be the casp, we may infer 
from the many recorded cases (see, for instance. Bronn, " Geschichte 
der Natnr," k ii, 1843, s. 164; and Westwood, "Transact, Ent. 
Soc," vol. ill, 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 Phryganidae, which present 
strongly pronounced differences of this kind, were confined togethei 
hy Dr. Aug. Mever, they coy pled, and one pair produced fertile ova. 

*" The Practical Entomologist," Phila., vol. ii, May, 1867, p. 88. 

t Mr. Walsh, ibid. p. 107. 

i" Modern Classification of Insects," vol. ii, 1840, pp. 205.206. 
Mr. Walsh, who called my attention to the double use of the jaws. 
Bays that lie has repeatedly observed this fact. 



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 (Dytis- 
cus) have their elytra deeply grooved, and in 
Acilius sulcatus thickly set with hairs as an 
aid to the male. The females of some other 
water beetles (Hydroporus) have their elytra 
punctured for the same purpose.* In the 
male of Crabro crihrarius (fig. 9) it is the 
tibia which is dilated into a broad horny 
plate with minute membraneous dots, giving 
to it a singular appearance like that of a 
riddle, f In the male of Penthe (a genus 
of beetles) a few of the middle joints of the 
antennae are dilated and furnished on the 
inferior surface with cushions of hair, ex- 
actly 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 in- 
finite 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 thick- 
ened, but this is by no means invariably a 
sexual character; or one pair, or all three 
pairs are elongated, sometimes to an extrava- 
gant length. I 

The sexes of many species in all the orders 
present differences, of which the meaning is 
not understood. One curious case is 

Fi^. 10. Tapliro- 
deres distortus 
(enlarged), Up- 

{)er figure, male; 
o wer figure, 

* We have here a curious and inexplicable case of dimorphism, for 
some of the females of four European species of Dysticus, and of 
certain species of Hydroporus, have their elytra smooth; and no 
intermediate gradations between the sulcated or punctured, and the 
•juite smooth elytra have been observed. See Dr. H. Schaum, as 
quoted in the " Zoologist," vols, v-vi, 1847-48, p. 1896. Also Kirby 
and Spence, "Introduction to Entomology," vol. iii, 1826, p. 305. 

f Westwood, "Modern Class.," vol. ii, p. 193. The following 
statement about Penthe, and others in inverted commas, are taken 
from Mr. Walsh, "Practical Entomologist," Phila., vol. iii, p. 88. 

X Kirby and Spence, ** Introduct.," »t^., vol. iii, pp. 38^336. 


that of the beetle (fig. 10), the male of which has 
left mandible much enlarged; so that the mouth is 
greatly distorted. In another Oarabidous beetle, Euryg- 
nathus,* we have the case, unique as far as known to Mr. 
Wollaston, of the head of the female being much broader 
and larger, though in a variable degree, than that of the 
male. Any number of such cases could be given. They 
abound in the Lepidoptera; one of the most extraordinary 
is that certain male butterflies have their fore legs more or 
less atrophied, with the tibiae and tarsi reduced to mere 
rudimentary knobs. The wings, also, in the two sexes 
often diifer in neuration,f and sometimes considerably in 
outline,, as in the Aricoj'is epittis, 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 excrescences on the 
disks of the posterior pair. I In several British butterflies, 
as shown by Mr. Wonfor, the males alone are in parts 
clothed with peculiar scales. 

The use of the bright light of the female glow-worm has 
been subject to much discussion. The male is feebly 
luminous, as are the larvae and even the eggs. It has been 
supposed by some authors that the light serves to frighten 
away enemies, and by others to guide the male to the 
female. At last Mr. Belt§ appears to have solved the 
difficulty; he finds that all the Lampyridae which he has 
tried are highly distasteful to insectivorous mammals and 
birds. Hence it is in accordance with Mr. Bates^ view, 
hereafter to be explained, that many insects mimic the 
Lampyridae closely, in order to be mistaken for them, and 
thus to escape destruction. He further believes that the 
luminous species profit by being at once recognized as 

* ** Insecta Maderensia," 1854, p, 20. 

f E. Doubleday, " Annals and Mag. of Nat. Hist," vol. i, 1848, p. 
379. I may add that the wings in certain Hymenoptera (see Shuck- 
ard, " Fossorial Hymenop.," 1837, pp. 39-43) differ in neuration 
according to sex. 

:J:H. W, Bates, in "Journal of Proc. Linn. Soc," vol. vi, 1862, p. 
74. Mr. Wonfor's observations are quoted in " Popular Science 
Review," 1868, p. 343. 

§ '* The Naturalist in Nicaragua," 1874, pp. 316-320. On the phos- 
phorescence of the eggs, see "Annals and Mag. of Nat. Hist.," 1871, 
Nov., p. 372. 


unpalatable. It is probable that the same explanation may 
be extended to the Elaters, both sexes of which are highly 
luminous. It is not known why the wings of the female 
glow-worm have not been developed; but in her present 
state she closely resembles a larva, and, as larvae are so 
largely preyed on by many animals, we can understand why 
she has been rendered so much more luminous and con- 
spicuous than the male; and why the larvae themselves are 
likewise luminous. 

Differ e7ice in Size Bekoeen the Sexes, — With insects of 
all kinds the males are commonly smaller than the females; 
and this difference can often be detected, even in the larval 
state. So considerable is the difference between the male 
and female cocoons of the silk-moth {Bomhyx mori), that 
in France they are separated by a particular mode of 
weighing.* In the lower classes of the animal kingdom 
the greater size of the females seems generally to depend 
on their developing an enormous number of ova; and this 
may to a certain extent hold good with insects. But Dr. 
Wallace has suggested a much more probable explanation. 
He finds, after carefully attending to the development of 
the caterpillars of Bomhyx cynthia and yamamai, and espe- 
cially to that of some dwarfed caterpillars reared from a 
second brood on unnatural food, ^'^that in proportion as 
the individual moth is finer, so is the time required for its 
metamorphosis longer; and for this reason the female, which 
is the larger and heavier insect, from having to carry her 
numerous eggs, will be preceded by the male, which is 
smaller and has less to mature, ^'f Now as most insects are 
short-lived, and as they are exposed to many dangers, it 
would manifestly be advantageous to the female to be im- 
pregnated 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, J through nat- 
ural 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, while 

*Robinet, "Vers a Sole," 1848, p. 207. 

f " Transact, Ent. Soc," 3d series, vol. v, p. 486. 

% " Journal of Proc. Ent. Soc," Feb. 4, 1867, p. 71. 


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 these exceptions 
are intelligible. Size and strength would be an advantage 
to the males, which fight for the possession of the females; 
and in these cases, as with the stag-beetle (Lucanus), the 
males are larger than the females. There are, however, 
other beetles which are not known to fight together, of which 
the males exceed the females in size; and the meaning of this 
fact is not known; but in some of these cases, as with the 
huge Dynastes and Megasoma, we can at least see that there 
would be no necessity for the males to be smaller than the 
females, in order to be matured before them, for these 
beetles are not short-lived, and there would be ample time 
for the pairing of the sexes. So again, male dragon-flies 
(Libellulidae) are sometimes sensibly larger, and never 
smaller, than the females;* and, as Mr. MacLachlan believes, 
they do not generally pair with the females until a week or 
fortnight has elapsed, and until they have assumed their 
proper masculine colors. But the most curious case show- 
ing on what complex and easily overlooked relations so 
trifling a character as 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 accordance with the general 
rule, are smaller than the females, and emerge about a 
week before them; but among the bees, the males of Apis 
melUjica, Antliiclium 7nanicatiim, and Anthophora acervo- 
rum, and among the Fossores the males of the Methoca 
ichneumonides are larger than the females. The explana- 
tion of this anomaly is that a marriage flight is absolutely 
necessary with these species, and the male requires great 
strength and size in order to carry the female through the 
air. Increased size has here been acquired in opposition to 
the usual relation between size and the period of develop- 
ment, 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 

* For this and other statements on the size of the sexes, see Kirby 
and Spence, ibid., vol. ill, p. 300; on the duration of life in insects, 
see p. 344. 



(butterflies and moths) will be retained for a separate 

Thysanura. — The members of this lowly organized 
order are wingless, dull-colored, minute insects, with ugly, 
almost misshapen heads and bodies. Their sexes do not 
dilf er, but they are interesting as showing us that the males 
pay sedulous court to the females even low down in the ani- 
mal scale. Sir J. Lubbock* says: '^it is very amusing to 
see these little creatures (Smynthurus hiteus) coquetting 
together. The male, which is much smaller than the 
female, runs round her, and they butt one another, stand- 
ing 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 antennaB, 
and seem to be all in all to one another.'' 

Diptera (Flies). — The sexes differ little in color. The 
greatest difference, known to Mr. F. Walker, is in the 
genus Bibio, in which the males are blackish or quite 
black, and the females obscure brownish-orange. The 
genus Elaphomyia, discovered by Mr. Wallace \ in New 
Guinea, is highly remarkable, as the males are furnished 
with horns, of which the females are quite destitute. The 
horns spring from beneath the eyes, and curiously resemble 
those of a stag, being either branched or palmated. In one 
of the species they equal the whole body in length. They 
might be thought to be adapted for fighting, but as in one 
species they are of a beautiful pink color, edged with black, 
with a pale central stripe, and as these insects have alto- 
gether a very elegant appearance it is perhaps more proba- 
ble that they serve as ornaments. That the males of some 
Diptera fight together is certain; Prof. WestwoodJ has 
several times seen this with the Tipulae. The males of 
other Diptera apparently try to win the females by their 

*" Transact. Linnean Soc," vol. xxvi, 1868, p. 296. 

f " The Malay Archipelago," vol. ii, 1869, p. 313. 

:^" Modern Classification of Insects," vol. ii. 1840. p. 526. 


music. H. Miiller* watched for some time two males of an 
Eristalis courting a female; they hovered above her, and 
flew from side to side making a high humming noise at the 
same time. Gnats and mosquitoes (Culicidae) also seem to 
attract each other by humming; and Prof. Mayer has 
recently ascertained that the hairs on the antennae of the 
male vibrate in unison with the notes of a tuning-fork 
within the range of the sounds emitted by the female. The 
longer hairs vibrate sympathetically with the graver notes, 
and the shorter hairs with the higher ones. Landois also 
asserts that he has repeatedly drawn down a whole swarm 
of gnats by uttering a particular note. It may be added 
that the mental faculties of the Diptera are probably higher 
than in most other insects, in accordance with their highly 
developed nervous system, f 

Hemiptera (Field Bugs). — Mr. J. W. Douglas, who has 
particularly attended to the British species, has kindly 
given me an account of their sexual differences. The 
males of some species are furnished with wings, while the 
females are wingless; the sexes differ in the form of their 
bodies, elytra, antennae and tarsi; but as the signification of 
these differences is unknown they may be here passed over. 
The females are generally larger and more robust than the 
males. With British and, as far as Mr. Douglas knows, 
with exotic species the sexes do not commonly differ much 
in color; but in about six British species the male is con- 
siderably darker than the female, and in about four other 
species the female is darker than the male. Both sexes of 
some species are beautifully colored; and as these insects 
emit an extremely nauseous odor their conspicuous colors 
may serve as a signal that they are unpalatable to insect- 
ivorous animals. In some few cases their colors appear to 
be directly protective ; thus Prof. Hoffmann informs me 
that he could hardly distinguish a small pink and green 
species from the buds on the trunks of lime-trees which 
this insect frequents. 

*Anwendung, etc., "Verli. d. n. V. Jalirg.," xxix, p. 80. Mayer, 
in "American Naturalist," 1874, p. 236. 

f See Mr. B. T. Lowne's interesting work, " On the Anatomy of the 
Blow-fly, Musca vomitoria," 1870, p. 14. He remarks (p. 33) that 
** the captured flies utter a peculiar plaintive note, and that this 
sound causes other flies to disappear." 

IN8EGT8. 310 

Some species of Reduvidae make a stridulating noise; and 
in the case of Pirates stridulus this is said* to be effected 
by the movement of the neck within the pro-thoracic 
cavity. According to Westring, Reduvhis personatus also 
stridulates. But I have no reason to suppose that this is a 
sexual character, excepting that with non-social insects 
there seems to be no use for sound-producing organs unless 
it be as a sexual call. 

Homoptera. — Every one who has wandered in a tropi- 
cal forest must have been astonished at the din made 
by the male Cicadas. 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 quainter of a mile from the shore of Brazil; 
and Capt. Hancock says it can be heard at the distance of a 
mile. The Greeks formerly kept, and the Chinese now 
keep, these insects in cages for the sake of their song, so 
that it must be pleasing to the ears of some men.f The 
Cicadidae usually sing during the day, while the Fulgoridas 
appear to be night-songsters. The sound, according to 
Landois,J: is produced by the vibration of the lips of the 
spiracles, which are set in motion by a current of air 
emitted from the tracheae; but this view has lately been dis- 
puted. Dr. Powell appears to have proved § that it is pro- 
duced by the vibration of a membrane set into action by a 
special muscle. In the living insect, while stridulating, 
this membrane can be seen to vibrate; and in the dead 
insect the proper sound is heard, if the muscle, when a little 
dried and hardened, is pulled with the point of a pin. In 
the female the whole complex musical apparatus is present, 
bat is much less developed than in the male, and is never 
used for producing sound. 

With respect to the object of the music. Dr. Hartman, in 
speaking of the Cicada septemdecim of the United States, 

* Westwood, "Modern Class, of Insects," vol. ii, p. 473. 

f These particulars are taken from Westwood's ** Modern Class, of 
Insects," vol. ii, 1840, p. 422. See also, on the Fulgoridae, Kirby 
and Spence, " Introduct.," vol. ii, p. 401. 

X "Zeitschrift fiir wissenschaft Zoolog.," B. xvii, 1867, ss. 152-158. 

§ "Transact. New Zealand Institute," vol. v, 1873, p. 286, 


says,* "the drums are now (June 6 and 7, 1851) heard in 
all directions. This I believe to be the marital su<mmons 
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 (August, 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 species 
with a particularly loud voice, seated at a considerable dis- 
tance from each other; as soon as one had finished his song 
another immediately began and then another. As there is 
so much rivalry between the males, it is probable that the 
females not only find them by their sounds, but that, like 
female birds, they are excited or allured by the male with 
the most attractive voice. 

I have not heard of any well-marked cases of ornamental 
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, while 
the females are pale-colored or obscure. 

Orthoptera (Crickets and Grasshoppers). — The males in 
the three saltatorial families in this order are remarkable 
for their musical powers, namely the Achetidse or crickets, 
the Locustidae, for which there is no equivalent English 
name, and the Acridiidae or grasshoppers. The stridula- 
tion produced by some of the Locustidas is so loud that 
it can be heard during the night at the distance of a 
mile;t 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 cage^. All observers agree that the 
sounds serve either to call or excite the mute females. 
With respect to the migratory locusts of Russia, Korte has 
given X an interesting case of selection by the female of a 

* I am indebted to Mr. Walsh for having sent me this extract from 
a ** Journal of the Doings of Cicada septemdecim," by Dr. Hartman. 

f L. Guilding, "Transact, Linn, Soc," vol, xv, p. 154. 

X I state this on the authority of Koppen, " Ueber die Heuschrecken 
in Siidrussland," 1866, p. 33, for I have in vain endeavored to pro 
cure Korte's work. 



male. The males of this, species {Pachytylus migraforius) 
while coupled with the female stridulate from anger or 
jealousy if approached by other males. The house-cricket 
when surprised at night uses its voice to warn its fellows.* 
In North America the Katydid [Platyphyllum concavum, 
one of the Locustidse) is described \ as mounting on the 
upper branches of a tree, and in the evening beginning 
^' his noisy babble, while rival notes issue from the neigh- 
the groves resound with the call of 
the live- 
Bates, in 





boring trees, 

Katy - did - she - di 

long night. ^' Mr. 

speaking of the 

field-cricket (one of the Ache- 

tidse), says '*^the male has been 

observed to place himself in 

the evening at the entrance 

of his burrow, and stridulate 

until a female approaches, 

when the louder notes are 

succeeded by a more subdued 

tone, while the successful 

musician caresses with his 

antennae the mate he has 

won.^t Dr. Scudder was able 

to excite one of these insects 

to answer him, by rubbing on 

a file with a quill. § In both 

sexes a remarkable auditory 

apparatus has been discovered 

by Von Siebold, situated in the front legs. 1| 

In the three families the sounds are differently produced. 
In the males of the Achetidse both wing-covers have the 
same apparatus; and this in the field-cricket (Gryllus 
campestris, fig, 11) consists, as described by Landois,!^ of 

♦Gilbert White, "Nat. Hist, of Selborne," vol. ii, 1825, p. 263- 

f Harris, " Insects of New England," 1842, p. 128. 

f The Naturalist on the Amazons," vol. i, 1863, p. 252. Mr. 
Bates gives a very interesting discussion on the gradations in the 
musical apparatus of the three families. See also West wood, " Mod- 
ern Class.," vol. ii, pp. 445, 453. 

§ " Proc. Boston Soc. of Nat. Hist.," vol. xi, April, 1868. 

|"Nouveau Manuel d'Anat. Comp." (French translat.), torn, i, 
1850, p. 587. 

t" Zeitschrift fur wissenschaft. Zoolog.," B. xvii, 1867, s. UX 

11. Gryllus 
Right-hand figure, under side of part 
of a wing-nervure, much magnified, 
showing the teeth, st. 
Left-hand figure, upper surface of 
wing-cover, with the projecting, 
smooth nervure, r, across which the 
teeth {st) are scraped. 


from 131 to 138 sharp, transverse 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 oppo- 
site wing. First one wing is rubbed over the other, and 
then the movement is reversed. Both wings are raised a 
little at the same time, so as to increase the resonance. In 
some species the wing-covers of the males are furnished at 
the base with a talc-like plate.* I here give a drawing 
(fig. 12) of the teeth on the under side of the nervure of 
another species of Gryllus, viz., G. domesticus. With 
respect to the formation of these teeth. Dr. Gruber has 
shown f that they have been developed by the aid of 
selection, from the minute scales and hairs 
with which the wings and body are covered, 
and I came to the same conclusion with 
respect to those of the Coleoptera. But Dr. 
Gruber further shows that their development 
is in part directly due to the stimulus from 
the friction of one wing over the other. 

In the Locustidse the opposite wing-covers 
differ from each other in structure (fig 13), 
■^NerviirJof Gryi- ^^^ ^^^^ action Cannot, as in the last family, 
1 u s domestipus be reversed. The left wing, which acts as the 

(from Landois). ^^^^ |.^g ^^^^ ^j^^ ^.^1^^ ^-^^^ which SCrVCS aS 

the fiddle. 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 Phasgonura viridissiina it 
appeared to me that the serrated nervure is rubbed against 
the rounded hind-corner of the opposite wing, the edge of 
which is thickened, colored brown, and very sharp. In 
the right wing, but not in the left, there is a little plate, as 
transparent as talc, surrounded by nervures, and called the 
speculum. In Epliippiger vitium, a member of this same 
family, we have a curious 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 

* Westwood, "Modern Class, of Insects," vol. i, p. 440. 
f ' ' Ueber der Tonapparat der Locustiden, ein Beitrag zum Darwin- 
isinus," "Zeitscli. ftir wissensch Zoolog.," B. xxii, 1873, p. 100. 


the wing-covers, and which has probably the effect of 
increasing the sound/^* 

We thus see that the musical apparatus is more dif- 
ferentiated or specialized in the Locustidae (which 
include, I believe, the most powerful performers in 

Hg. 18. ChlorocoelusTanana (from Bates), a, 6. Lobes of opposite wing-covers. 

the order), and in the Achetidae, in which both wing- 
covers have the same structure and the same function, f 
Landois, however, detected in one of the Locustidae, 
namely in Decticus, a short and narrow row of small 
teeth, mere rudiments, on the inferior surface of the 
right wing-cover, which underlies the other and is never 
used as the bow. I observed the same rudimentary 
structure on the under side of the right wing- 
cover in Phasgonura viridissima. Hence we may infer 
with confidence that the Locustidae are descended from a 
form in which, as in the existing Achetidae, both wing- 

*Westwood, •♦Modern Class, of Insects," vol. i, p. 453 

f Landois, " Zeitsch. f. wiss Zoolog." B. xvii, X867» ss. 131, 133. 



covers had serrated nervnres 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 division of labor, the one 
to act exclusively as the bow and the other as the fiddle. 
Dr. Gruber takes the same view, and has shown that rudi- 
mentary teeth are commonly found on the inferior surface 
of the right wing. By what steps the more simple appa- 
ratus in the Achetidse originated we do not know, but it is 
probable that the basal portions of the wing-covers origi- 
nally overlapped each other as they do at present; and that 

the friction of the nervures 
produced a grating sound as 
is now the case with the wing- 
covers of the females.* A 
grating sound thus occasion- 
ally and accidentally made by 
the males,if it served them ever 
so little as a love-call to the fe- 
males, might readily have been 
intensified through sexual se- 
lection by variations in the 
roughness of the nervures hav- 
ing been con tinually preserved . 
Fig. 14, Hind-leg of stenobothrus pra- ^"^ J^^e last and third family, 
torum. r, the striduiating ridge ; namely, the Acridudae or 
i?S'nSmagnifild%-oSl^^ grasshoppers, the stridulation 

is produced in a very differ- 
ent manner, and according to Dr. Scudder, is not so shrill 
as in the preceding families. The inner surface of the 
femur (fig. 14, r) is furnished with a longitudinal row of 
minute, elegant, lancet-shaped, elastic teeth from eighty- 
five to ninety-three in number;f and these are scraped 
across the sharp, projecting nervures on the wing-covers 
which are thus made to vibrate and resound. HarrisJ; 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 

*Mr. Walsh also informs me tliat lie has noticed that the female 
of the Platyphyllum concavuniy "when captured, makes a feeble 
grating noise by shuffling her wing-covers together." 

f Landois, ibid., s. 113. 

I " Insects of New England," 1842, p. 133. 



lodged in a furrow designed to receive it, and then draws 
the leg briskly up and down. He does not play both 
fiddles together, but alternately, first upon one and then 
on the other." In many species the base of the abdomen 
is hollowed out into a great cavity which is believed to act 
as a resounding board. In Pneumora (fig. 15), a S. Afri- 

Flg. 15. 

Pneumora (fTom specimens in the British Museum). Upper 
figure, male; lower figure, female. 

can genus belonging to the same family, we meet with a 
new and remarkable modification; in the males a small 
notched ridge projects obliquely from each side of the 
abdomen, against which the hind femora are rubbed.* As 
the male is furnished with wings (the female being wing- 

* Westwood, "Modem Classification," vol. 1, p. 462, 


less) it is remarkable that the thighs are not nibbed in the 
usual manner against the wing-covers; but this may per- 
haps be accounted for by the unusually small size of the 
hind legs. I have not been able to examine the inner sur- 
face 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 in the male the Avhole body 
has been converted into a musical instrument, being dis- 
tended with air like a great pellucid bladder so as to 
increase the resonance. Mr. Trimen informs me that at 
the Cape of Good Hope these insects make a wonderful 
noise during the night. 

In the three foregoing families the females are almost 
always destitute of an efficient musical apparatus. But there 
are a few exceptions to this rule, for Dr. Gruber has shown 
that both sexes of EjjJiippiger vitium are thus provided; 
though the organs differ in the male and female to a cer- 
tain extent. Hence we cannot suppose that they have been 
transferred from the male to the female, as appears to have 
been the case with the secondary sexual characters of many 
other animals. They must have been independently devel- 
oped in the two sexes, which no doubt mutually call to 
each other during the season of love. In most other Locus- 
tidae (but not according to Landois in Decticus) the females 
have rudiments of the stridulatory organs proper to the 
male; from whom it is probable that these have been trans- 
ferred. Landois also found such rudiments on the under 
surface of the wing-covers of the female Achetidas, and on 
the femora of the female Acridiidae. In the Homoptera, 
also, the females have the proper musical apparatus in a 
functionless state; and we shall hereafter meet, in other 
divisions of the animal kingdom, with many instances of 
structures proper to the male being present in a rudimentary 
condition in the female. 

Landois has observed another important fact, namely, 
that in the females of the Acridiidae, the stridulating teeth 
on the femora remain throughout life in the same condition 
in which they first appear during the larval state in both 
sexes. In the males, on the hand, they become further 
developed, and acquire their perfect structure at the last 
moult, when the insect is mature and ready to breed. 

Prom the facts now given we see that the meanfi by 


which the males of the Orthoptera produce their sounds are 
extremely diversified, and are altogether different from 
those employed by the Homoptera.* But throughout the 
animal kingdom we o'ften find the same object gained by 
the most diversified means; this seems due to the whole 
organization having undergone multifarious changes in the 
course of ages, and as part after part varied different varia- 
tions v/ere taken advantage of for the same general purpose. 
The diversity of means for producing sound in the three 
families of the Orthoptera and in the Homoptera, 
impresses the mind with the high importance of these 
structures to the males, for the sake of calling or alluring 
the females. We need feel no surprise at the amount of 
modification which the Orthoptera have undergone in this 
respect, as we new know, from Dr. Scudder's remarkable 
discovery,! that there has been more than ample time. 
This naturalist has lately found a fossil insect in the 
Devonian formation of New Brunswick, which is furnished 
with " the well-known tympanum or stridulating apparatus 
of the male Locustidse." The insect, though in most 
respects related to the Neuroptera, appears, as is so often 
the case with very ancient forms, to connect the two related 
orders of the Neuroptera and Orthoptera. 

I have but little more to say on the Orthoptera. Some 
of the species are very pugnacious; when two male field- 
crickets (Gryllus campestris) are confined together they 
fight till one kills the other; and the species of Mantis are 
described as maneuvering with their sword-like front limbs, 
like hussars with their sabers. The Chinese keep these 
insects in little bamboo cages, and match them like game- 
cocks. J AVith respect to color, some exotic locusts are 
beautifully ornamented; the posterior wings being marked 
with red, blue and black; but as throughout the order the 
sexes rarely differ much in color, it is not probable that 
they owe their bright tints to sexual selection. Conspicu- 

* Landois lias recently found in certain Ortlioptera rudimentary- 
structures closely similar to the sound-producing organs in the 
Homoptera; and tliis is a surprising fact. See "Zeitsclir. fiir wis- 
sensch. Zoolog.," B. xxii, Heft 3, 1871, p. 348. 

f " Transact. Ent. Soc," 3d series, vol. ii. (" Journal of Proceed- 
ings," p 117.) 

X West wood, " Modern Class of Insects,'* vol. i, p. 427; for crick- 
ets, p. 445. 


ous colors may be of use to these insects by giving notice 
that they are unpalatable. Thus it has been observed* that 
a bright-colored Indian locust was inyariably rejected when 
offered to birds and lizards. Some cases^ however, are 
known of sexual differences in color in this order. The 
male of an American cricket f is described as being as 
white as ivory, while 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 Phasmidae) 
** is of a shining brownish-yellow color; the adult female 
being of a dull, opaque, cinereous brown; the young of 
both sexes being green. ^' Lastly, I may mention that the 
male of one curious kind of cricket J; is furnished with ^'^a 
long membranous appendage, which falls over the face like 
a veil;" but what its use may be is not known. 

Neuroptera, — Little need here be said, except as to color. 
In the Ephemeridse the sexes often differ slightly in their 
obscure tints ;§ but it is not probable that the males are 
thus rendered attractive to the females. The Libellulidae 
or dragon-flies are ornamented with splendid green, blue, 
yellow, and vermilion metallic tints; and the sexes often 
differ. Thus, as Prof. Westwood remarks, || the males 
of some of the Agrionidae, *' are of a rich blue with black 
wings, while the females are fine green with colorless 
wings." But in Agrion Ramhurii these colors are exactly 
reversed in the two sexes. 1^ In the extensive North Ameri- 
can genus of Hetaerina, the males alone have a beautiful 
carmine spot at the base of each wing. In A^iax 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 color. In closely-allied 

*Mr. Ch. Home, in "Proc. Ent. Soc," May 3, 1869, p. 13. 

f The (Ecanthus nivalis. Harris, " Insects of New England," 1842, 
p. 124. The two sexes of the CE. pellucidus of Europe differ, as I 
hear from Victor Carus, in nearly the same manner. 

:|: Platyblemnus; Westwood, "Modern Class.," vol. i, p. 447. 

§ B. D. Walsh, the " Pseudoneuroptera of Illinois," in " Proc. Ent. 
Soc. of Philadelphia," 1862, p. 361. 

I " Modern Class.," vol. ii, p. 37. 

Tf Walsh, ibid., p. 381. I am indebted to this naturalist for the fol- 
lowing facts on Hetaerina, Anax and Gomphus. 


forms throughout the animal kingdom similar cases of the 
sexes differing greatly, or very little, or not at all, are of 
frequent occurrence. Although there is so wide a diifer- 
ence in color between the sexes of many Libellulidse, it is 
often difficult to say which is the more brilliant; and the 
ordinary coloration of the two sexes is reversed, as we have 
just seen, in one species of Agrion. It is not probable that 
their colors in any case have been gained as a protection. 
Mr. MacLachlan, who has closely attended to this family, 
writes to me that dragon-flies — the tyrants of the insect- 
world — are the least liable of any insect to be attacked by 
birds or other enemies, and he believes that their bright 
colors serve as a sexual attraction. Certain dragon-flies 
apparently are attracted by particular colors; Mr. Patterson 
observed* that the Agrionidae, of which the males are blue, 
settled in numbers on the blue float of a fishing line; while 
two other species were attracted by shining white colors. 

It is an interesting fact, first noticed by Schelver, that, 
in several genera belonging to two sub-families, the males 
on first emergence from the pupal state, are colored exactly 
like the females ; but that their bodies in a short time 
assume a conspicuous milky-blue tint, owing to the exuda- 
tion of a kind of oil, soluble in ether and alcohol. Mr. 
MacLachlan believes that in the male of Lihellula depressa 
this change of color does not occur until nearly a fortnight 
after the metamorphosis, when the sexes are ready to pair. 

Certain species of Neurothemis present, according to 
Brauer,f a curious case of dimorphism, some of the 
females having ordinary wings, while others have them 
" very richly netted, as in the males of the same species.'^ 
Brauer '^ explains the phenomenon on Darwinian principles 
by the supposition that the close netting of the veins is a 
secondary sexual character in the males, which has been 
abruptly transferred to some of the females, instead of, as 
generally occurs, to all of them." Mr. MacLachlan 
informs me of another instance of dimorphism in sev- 
eral species of Agrion, in which some individuals are 
of an orange color, and these are invariably females. 
This is probably a case of reversion ; for in the 
true Libellulae, when the sexes differ in color, the females 

♦"Transact. Ent. Soc," vol. i, 1836, p. 81. 

f See abstract in the •' Zoological Record " for 1867, p. 450. 


are orange or yellow; so that supposing Agrion to be 
descended from some primordial form which resembled the 
typical Libullulse in its sexual characters, it would not be 
surprising that a tendency to vary in this manner should 
occur in the females alone. 

Although many dragon-flies are large, powerful and fierce 
insects, the males have not been observed by Mr. Mac- 
Lachlan to fight together, excepting, as he believes, in some 
of the smaller species of Agrion. In another group in this 
order, namely, the Termites or white ants, both sexes at 
the time of swarming may be seen running about, ^-the 
male after the female, sometimes two chasing one female, 
and contending with great eagerness who shall win the 
prize.^^* The Atropos pulsatoriiis is said to make a noise 
with its jaws, which is answered by other individuals, f 

Hymenoptera. — That inimitable observer, M. rabre,J: in 
describing the habits of Cerceris, a wasp-like insect, 
remarks that '^ fights frequently ensue between the males 
for the possession of some particular female, who sits an 
apparently unconcerned beholder of the struggle for suprem- 
acy, and when the victory is decided, quietly flies away in 
company with the conqueror." AVestwood § says that the 
males of one of the saw-flies (Tenthredin^) *^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 mind that 
insects belonging to this order have the power of recogniz- 
ing 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 recognized and caressed one 
another with their antennae. Had they been strangers they 
would have fought together. Again, when two commu- 
nities engage in a battle the ants on the same side some- 

* Kirby and Spence, *' Introduct. to Entomology," vol. ii, 1818, 
p. 85. 

f Houzeau, " Les Facultes Mentales," etc., torn, i, p. 104. 

:f See an interesting article, "The Writings of Fabre," in "Nat 
Hist. Review," April, 1862. p. 122. 

I "Journal of Proc. of Entomolog. Soc," Sept. 7, 1863, p. 169, 


times attack each other in the general confusion, but they 
soon pepceive their mistake, and the one ant soothes the 

In this order slight differences in coloi;, 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 colored — for instance in Chrysis, in which ver- 
milion and metallic greens prevail — that we are tempted to 
attribute the result to sexual selection. In the Ichneu- 
monidae, according to Mr. Walsh, f the males are almost 
universally lighter-colored than the females. On the other 
hand, in the Tenthredinidae the males are generally darker 
than the females. In the Siricidae the sexes frequently 
differ; thus the male of Sir ex juvencus is banded with 
orange, while the female is dark purple; but it is difficult 
to say which sex is the more ornamented. In Tremex 
columbcB the female is much brighter colored than the 
male. I am informed by Mr. F. Smith that the male 
ants of several species are black, the females being 

In the family of bees, especially in the solitary species, 
as I hear from the same entomologist, the sexes often differ 
in color. The males are generally the brighter, and in 
Bombus as well as in Apathus, much more variable in color 
than the females. In Anthophora retusa the male is of a 
rich fulvous-brown, while the female is quite black; so are 
the females of several species of Xylocopa, the males being 
bright yellow. On the other hand the females of some 
species, as of Andrmna fulva, are much brighter colored 
than the males. Such differences in color can hardly oe 
accounted for by the males being defenseless and thus 
requiring protection, while the females are well defended 
by their stings. H. Muller,J: who has particularly attended 
to the habits of bees, attributes these differences in color in 
chief part to sexual selection. That bees have a keen per- 
ception of color is certain. He says that the males search 
eagerly and fight for the possession of the females; and he 

*P. Huber, " Reclierclies sur les Moeurs des Fourmis," 1810, pp, 
150, 165. 

f *' Proc. Entomolog. Soc. of Philadelphia," 1866, pp. 238, 239. 

X " Anwendung der Darwinschen Lehre auf Bienen." Verb. d. n 
(Jabrg., xxix. 


accounts through such contests for the mandibles of the 
males being in certain species larger than those- of the 
females. In some cases the males are far more numerous 
than the females, either early in the season, or at all times 
and places, or locally; whereas the females in other cases 
are apparently in excess. In some species the more beauti- 
ful males appear to have been selected by the females; and 
in others the more beautiful females by the males. Conse- 
quently in certain genera (Miiller, p. 42) the males of the 
several species differ much in appearance, while the females 
are almost indistinguishable; in other genera the reverse 
occurs. H. Miiller believes (p. 82) that the colors gained 
by one sex through sexual selection have often been trans- 
ferred in a variable degree to the other sex, just as the 
pollen-collecting apparatus of the female has often been 
transferred to the male, to whom it is absolutely useless.* 

Mutilla Europcea makes a stridulating noise; and accord- 
ing to Goureau \ both sexes have this power. He attributes 
the sound to the friction of the third and preceding 
abdominal segments, and I find that these surfaces are 
marked with very fine concentric ridges; but so is the pro- 
jecting thoracic collar into which the head articulates, and 
this collar, when scratched with the point of a needle, 
emits the proper sound. It is rather surprising that both 
sexes should have the power of stridulating, as the male is 

*M. Perrier in his article " la Selection sexuelle d'apres Darwin" 
("Revue Scientifique," Feb., 1873, p. 868), without apparently having 
reflected much on the subject, objects that as the males of social bees 
are known to be produced from unfertilized ova, they could not trans- 
mit new characters to their male offspring. This is an extraordinary 
objection. A female bee fertilized by a male, which presented some 
character facilitating the union of the sexes, or rendering him more 
attractive to the female, would lay eggs which would produce only 
females; but these young females would next year produce males ; 
and will it be pretended that such males would not inherit the char- 
acters of their male grandfathers ? To take a case with ordinary ani- 
mals as nearly parallel as possible; if a female of any white quad- 
ruped or bird were crossed by a male of a black breed, and the male 
and female offspring were paired together, will it be pretended that 
the grandchildren would not inherit a tendency to blackness from 
their male grandfather ? The acquirement of new characters by the 
sterile worker-bees is a much more difficult case, but I have endeav- 
ored to show in my " Origin of Species " how these sterile beings are 
subjected to the power of natural selection. 

\ Quoted by Westwood, " Modern Class, of Insects/' voL ii, p. 214 


winged and the female wingless. It is notorious that bees 
express certain emotions, as of anger, by the tone of their 
humming; and according to H. Miiller (p. 80) the males 
of some species make a peculiar singing noise while pursu- 
ing the females. 

Coleoptera (Beetles). — Many beetles are colored so as to 
resemble the surfaces which they habitually frequent, and 
they thus escape detection by their enemies. Other species, 
for instance diamond-beetles, are ornamented with splendid 
colors, which are often arranged in stripes, spots, crosses 
and other elegant patterns. Such colors can hardly serve 
directly as a protection except in the case of certain flower- 
feeding species; but they may serve as a warning or means 
of recognition on the same principle as the phosphorescence 
of the glow-worm. As with beetles the colors of the two 
sexes are generally alike, we have no evidence that they 
have been gained through sexual selection; but this is at 
least possible, for they may have been developed in one sex 
and then transferred to the other; and this view is even in 
some degree probable in those groups which possess other 
well-marked secondary sexual characters. Blind beetles, 
which cannot of course behold each other^s beauty, never, 
as I hear from Mr. Waterhouse, Jr,, exhibit bright colors, 
though they often have polished coats; but the explanation 
of their obscurity may be that they generally inhabit caves 
and other obscure stations. 

Some Longicorns, especially certain Prionidae, oifer an 
exception to the rule that the sexes of beetles do not differ 
in color. Most of these insects are large and splendidly 
colored. The males in the genus Pyrodes,* which I saw 

* Pyrodes pulcherrimuSy in whicli the sexes differ conspicuously, 
lias 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 color between the sexes of beetles. Kirby and Spence 
("Introduct. to Entomology," vol. iii, p. 301) mention a Cantharis, 
Meloe, Rhagium, and the Leptura testacea ; 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 family of Longi- 
corns. Messrs. R. Trimen and Waterhouse junior inform me of two 
Lamellicorns, viz., a Peritrichia and Trichius, the male of the latter 
being more obscurely colored than the female. In Tillus elongatus 
the male is biack, and the female always, as it is believed, of a dark 
blue color, with a red thorax. The male, also, of Orsodacna atra, as 
I hear from Mr. Walsh, is black, the female (the so called 0. rvficol. 
lis) having a rufous thorax. 



in Mr. Bates' collection, are generally redder but rather 
duller than the females, the latter being colored of a more 
or less splendid golden-green. On the other hand, in one 
species the male is golden-green, the female being richly 
tinted with red and purple. In the genus Esmeralda the 
sexes differ so greatly in color that they have been ranked 
as distinct species; in one species both are of a beautiful 
shining green, but the male has a red thorax. On the 
whole, as far as I could judge, the females of those 
Prionidae, in which the sexes differ, are colored more richly 
than the males, and this does not accord with the common 
rule in regard to color when acquired through sexual 

A most remarkable distinction between the sexes of many 
beetles is presented by the great horns which rise from the 
head, thorax and clypeus of the males; and in some few 
cases from the under surface of the body. These horns 
in the great family of the Lamellicorns, resemble those of 
various quadrupeds, such as stags, rhinoceroses, etc, and 
are wonderiui both from their size and diversified shapes. 
Instead of iescribing them, I have given figures of the 
males and females of some of the more remarkable forms. 
(Figs. 16 to 20.) The females generally exhibit rudiments 

Frg. 16. Chaloosoma atlas. Upper figure, male (reducetl); lower figure, f«mal9 
Caatural size>. 



PhansBus f auuus. 

Fig. 19. 

Dipelicus cantori; 

Fig. SO. Ontliophagus rangif er, enlarged 


of the horns in the form of small knobs or ridges; but some 
are destitute of even the slightest rudiment. On the other 
hand^ the horns are nearly as well developed in the female 
as in the male of Phanceus lancifer; and only a little less 
well developed in the females of some other species of this 
genus and of Copris. I am informed by Mr. Bates that 
the horns do not differ in any manner corresponding with 
the more important characteristic differences between the 
several subdivisions of the family; thus within the same 
section of the genus Onthophagus, there are species which 
have a single horn and others which have two. 

In almost all cases the horns are remarkable from their 
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 distinguished from the 
females. Mr. Walsh* found that in Plianmus carnifex the 
horns were thrice as long in some males as in others. Mr. 
Bates, after examining above a hundred males of Oiitlio- 
phagus rangifer (fig. 20), thought that he had at last dis- 
covered a species in which the horns did not vary; but 
further research proved the contrary. 

The extraordinary size of the horns and their widely dif- 
ferent structure in closely-allied forms indicate that they 
have been formed for some purpose; but their excessive 
variability in the males of the same species leads to the 
inference that this purpose cannot be of a definite nature. 
The horns do not show marks of friction, as if used for any 
ordinary work. Some authors suppose f that as the males 
wander about much more than the females, they require 
horns as a defense against their enemies; but as the horns 
are often blunt, they do not seem well adapted for defense. 
The most obvious conjecture is that they are used by the 
males for fighting together; but the males have never been 
observed to fight; nor could Mr. Bates, after a careful 
examination of numerous species, find any sufficient evi- 
dence, in their mutilated or broken condition, of their 
having been thus used. If the males had been habitual 
fighters, the size of their bodies would probably have been 
increased through sexual selection, so as to have exceeded 
that of the females; but Mr, Bates, after comparing the 

* '* Proc. Entomolog, Soc. of Pliiladelphia," 1864, p. 228. 

f Kirbj^ and Spence, ' ■ Introduct. Entomology.," vol. iii, p. 300. 



two sexes in above a hundred species of the Copridae, did 
not tiud any marked difference in this respect among well- 
developed individuals. In Lethrus, moreover, a beetle 
belonging to the same great division of the Lamelli corns, 
the males are known to fight, but are not provided with 
horns, though their mandibles are much larger than those of 
the female. 

The conclusion that the horns have been acquired as 
ornaments is that which best agrees with the fact of their 
having been so immensely, yet not fixedly, developed — as 
shown by their extreme variability in the same species, and 
by their extreme diversity in closely-allied species. This 
view will at first appear extremely improbable; but we shall 

Fig. 21. Fig. 22. 

Fig. 21. Onitis furcifer, male viewed from beneath. 

Fig. 22. Left-hand figure, male of Onitis furcifer, viewed laterally. Right- 
hand figure, female, a. Rudiment of cephalic horn. h. Trace of 
thoracic horn or crest. 

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. 21), and of some other 
species of the genus 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. Judging from 
other insects, these may aid the male in clinging to the 
female. Although the males have not even a trace of a horn 
on the upper surface of the body, yet the females plainly ex- 
hibit a rudiment of a single horn on the head (fig. 22, a) and 
of a crest {h) on the thorax. That the slight thoracic crest 
in the 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 genus which 


comes next to Onitis) has a similar slight crest on tlie 
thorax, and the male bears a great projection in the same 
situation. So, again, there can hardly be a doubt that the 
little point {a) on the head of the female Onitis furcifer, 
as well as on the head of the females of two or three allied 
species, is a rudimentary representative of the cephalic 
horn, which is common to the males of so many Lamelli- 
corn beetles, as in Phanaeus (fig. 18). 

The old belief that rudiments have been created to com- 
plete the scheme of nature is here so far from holding 
good, that we have a complete inversion of the ordinary 
state of things in the family. AVe may reasonably suspect 
that the males originally bore horns and transferred them 
to the females in a rudimentary condition, as in so many 
other Lamellicorns. Why the males subsequently lost their 
horns, we know not; but this may have been caused through 


Fig. 23. Bledius taurus, magnified. Left-hand figure, male; right-hand figure, 


the principle of compensation, owing to the development of 
the large horns and projections on the lower surface; and 
as these are confined to the males, the rudiments of the 
upper horns on the females would not have been thus 

The cases hitherto given refer to the Lamellicorns, but 
the males of some few other beetles, belonging to two 
widely distinct groups, namely, the Curculionidae and 
Staphylinidae, are furnished with horns — in the former on 
the lower surface of the body,* in the latter on the upper 
surface of the head and thorax. In the Staphylinidae, the 
horns of the males are extraordinarily variable in the same 
species, just as we have seen with the Lamellicorns. In 
Siagonium we have a case of dimorphism, for the males 
can be divided into two sects, differing greatly in the size 
of their bodies and in the development of tlieir horns, with- 
out intermediate gradations. In a species of Bledius (fig. 
23), also belonging to the Staphylinidae, Prof. West wood 

*Kirby and Spence, " Introduct. Entomolog.," vol. iii, p. 329, 


states that, '' male specimens can be found in the same 
locality in Avhich the central horn of the thorax is very 
large, but the horns of the head quite rudimental ; and 
others, in which the thoracic horn is much shorter, while 
the protuberances on the head are long."* Here we appar- 
ently have a case of compensation, which throws light on 
that just given, of the supposed loss of the upper horns by 
the males of Onitis. 

Law of Battle. — Some male beetles, which seem ill-fitted 
for fighting, nevertheless engage in conflicts for the posses- 
sion of the females. Mr. Wallace \ saw two males of 
Leptorhyiichus 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 vanquished." In some few 
cases male beetles are well adapted for fighting, by possess- 
ing great toothed mandibles, 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 season they engage in fierce conflicts. When Mr. A. 
H. Davis I inclosed two males with one female in a box 
the larger male severely pinched the smaller one until he 
resigned his pretensions. A friend informs me that when a 
boy he often put the males together to see them fight, and 
he noticed that they were much bolder and fiercer than the 
females, as with the higher animals. The males would 
seize hold of his finger if held in front of them, but not so 
the females, although they have stronger jaws. The males 
of many of the Lucanidae, as well as of the above-men- 

* "Modern Classification of Insects," vol. i, p. 172; Siagonium, p. 
172. In tlie British Museum I noticed one male specimen of Siago- 
nium in an intermediate condition, so that the dimorphism is not 

t " The Malay Archipelago," vol. ii, 1869, p. 276. Riley, Sixth 
"Report on Insects of Missouri," 1874, p. 115. 

X " Entomological Magazine," vol. i, 1833, p. 82. See also on the 
conflicts of this species, Kirby and Spence, ibid., vol. iii, p. 314; and 
West wood, ibid., vol. i, p. 187. 


tioned Leptorliynchus, are larger and more powerful insects 
than the females. The two sexes of Lethrus cephalotes 
(one of the Lamellicorns) inhabit the same burrow; and 
the male has larger mandibles than the female. If, during 
the breeding season, a strange 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; and the 
battle lasts until the aggressor is killed or runs aAvay. * The 
two sexes of another Lamellicorn beetle, the Ateuchtis 
cicatricosus, live in pairs, and seem much attached to each 
other; the male excites the females 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 f believes, would 
remain on the same spot until she died. 

The great mandibles of the male Lucanida? are extremely 
variable both in size and structure, and in this respect 
resemble the horns on the head and thorax of many male 
Lamellicorns and Staphylinidae. A perfect 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 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 they 
are used by the Luccmus elaphus of North America for 
seizing the female. As they are so conspicuous and so 
elegantly branched, and as owing to their great length 
they are not well adapted for pinching, the suspicion has 
crossed my mind that they may in addition serve as an 
ornament, like the horns on the head and thorax of the 
various species above described. The male Chiasognathus 
Grantii of S. Chili — a splendid beetle belonging to the 
same family — has enormously developed mandibles (fig. 24) ; 
he is bold and pugnacious; when threatened he faces round, 
opens his great jaws, and at the same time stridulates 
loudly. But the mandibles were not strong enough to pinch 
my finger so as to cause actual pain. 

* Quoted from Fischer, in "Diet. Class. d'Hist. Nat.," torn, x^, p. 

f '* Ann. Soc. Entomolog. France,'' 1866, as quoted in "Journal of 
Travel," by A. Murray, 1868, p. 135. 



Sexual selection, wliicli implies the possession of con- 
siderable perceptive powers and of strong passions, seems to 
have been more effective with the 
Lamellicorns than with any other 
family of beetles. With some species 
the males are provided with weapons 
for fighting; some live in pairs and 
show mutual aifection; many have 
the power of stridulating when ex- 
cited; many are furnished with the 
most extraordinary horns, apparently 
for the sake of ornament; and some, 
which are diurnal in their habits, are 
gorgeously colored. Lastly, several 
of the largest beetles in the world 
belong to this family, which was 
placed by Linnseus and Fabricius at 
the head of the order.* 

Stridulating Organs, — Beetles be- 
longing to many and widely distinct 
families possess these organs. The 
sound thus produced can sometimes 
be heard at the distance of several 
feet or even yards, f but it is not 
comparable with that made by the 
Orthoptera. The rasp generally con- 
sists of a narrow, slightly raised sur- 
face, crossed by very fine, parallel 
ribs, sometimes so fine as to cause 
iridescent colors, and having a very 
elegant appearance under the micro- 
scope. In some cases, as with Ty- 
phoeus, minute, bristly or scale-like 
prominences, with which the whole 
surrounding surface is covered in 
approximately parallel lines, could 
be traced passing into the ribs of the 
rasp. The transition takes place 

Fig. 24. Chiasognathus Gran^ 
tii, reduced. Upper figure, 
male; lower figure, female. 

* Westwood; " Modern Class.," vol. i, p. 184. 
fWollaston, "On Certain Musical Curculionid», 
Ms^. of Nat. Hist.," vol. vi, 1860, p> 14. 

Annals and 



by their becoming confluent and straight, and at the 
same time more prominent and smooth. A hard ridge 
on an adjoining part of the body serves as the scraper 
for the rasp, but this scraper in some cases has been spe- 
cially modified for the purpose. It is rapidly moved across 
the rasp, or conversely the rasp across the scraper. 


^ — 

pi^^HO ;v 


'^Sbl ^ 

^- — 

-^Sm " ^ 




^^^|o eO 





— ^So * 


— T^^Q t) 


^ ~. 

^^H** ^ c 



-^^go II 

Fig. 25. Necrophorus (from Landois). r. The two rasps. Left-hand 
figure, part of the rasp highly magnified. 

These organs are situated in widely different positions. 
In the carrion - beetles (Necrophorus) two parallel rasps 
(r, fig. 25) stand on the dorsal surface of the fifth abdomi- 
nal segment, each rasp* consisting of 126 to 140 fine ribs. 
These ribs are scraped against the posterior margins of the 
elytra, a small portion of which projects beyond the gen- 
eral outline. In many Crioceridae, and in Clythra 4:-pimc- 
tata (one of the Chrysomelidae), and in some Tenebrionidae, 
etc.,f the rasp is seated on the dorsal apex of the abdomen, 
on the pygidium or pro-pygidium, and is scraped in the 
same manner by the elytra. In Heterocerus, which belongs 
to another family, the rasps are placed on the sides of the 
first abdominal segment and are scraped by ridges on the 

* Landois, " Zeitsclirift fiir wiss. Zoolog.," B. xvii, 1867, s. 127. 

f I am greatly indebted to Mr. G. R. Crotcli for having sent me 
many prepared specimens of various beetles belonging to these three 
families and to others, as well as for valuable information. He be- 
lieves that the power of stridulation in the Clythra has not been pre- 
viously observed. 1 am also much indebted to Mr. E. W. Janson, 
for information and specimens. I may add that my son,, Mr. F. 
Darwin, finds that D&rmestes murimus 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 Maga- 
zine," vol. vi, p. 130. 



femora.* In certain Ciirculionidae and Carabidaef the 
parts are completely reversed in position, for the rasps are 
seated on the interior 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 Dytiscidae or water-beetles) a strong 
ridge runs parallel and near to the sutural margin of the 
elytra and is crossed by ribs, coarse in the middle part, but 
becoming gradually finer at both ends, especially at the 
upper end; when this insect is held under water or in the 
air a stridulating noise is produced by the 
extreme horny margin of the abdomen being 
scraped against the rasps. In a great num- 
ber of long-horned beetles (Longicornia) the 
organs are situated quite otherwise, the rasp 
being on the meso-thorax, which is rubbed 
against the pro-thorax. Landois counted 238 
very fine ribs on the rasp of Cerambyx heros. 
Many Lamellicorns have the power of 
stridulating, and the organs differ greatly in 
position. Some species stridulate very 
loudly, BO that when Mr. F. Smith caught a 
Trox sahulosus, a gamekeeper who stood by 
thought he had caught a mouse; but I 
failed to discover the proper organs in this 
beetle. In Geotrupes and Typhoeus a narrow 
ridge runs obliquely across {r, fig. 26) the coxa 
of each hind leg (having in G. stercorarius 84 
ribs), which is scraped by a specially project- 
ing part of one of the abdominal segments. 
In the nearly allied Oo2)ris lunaris an excessively narrow 
fine rasp runs along the sutural margin of the elytra with 
another short rasp near the basal outer margin; but in 
some other Ooprini the rasp is seated, according to 

Fig. 26. Hind leg 
of Geotrupes 
From Landois 

r. Rasp. c. Coxa. 

/. Femur, t. Tibia. 

tr. Tarsi. 

* Scliiodte, translated in "Annals and Mag. of Nat. Hist.," vol. xx, 
1867, p. 37. 

f West ring has described (Kroyer, " Naturhist. Tidskrift," B. ii, 
1848-1849, p. 334) the stridulating organs in these two, as well as in 
other families. In the Carabidae I have examined Klaphrus uligi- 
no8U8 and Blethisa muUipunctata, sent to me by Mr. Crotch. In 
Blethisa the transverse ridges on the furrowed border of the abdom- 
inal segment do not, as far as I could judge, come into play in scrap- 
ing the rasps on the elytra. 


Leconte,* on the dorsal surface of tlie abdomen. In 
Oryctes it is seated on the propygidiiim; and, according 
to the same entomologist, in some other Dynastini on the 
nnder surface of the elytra. Lastly, Westring states that 
in OmalojMa hrunnea the rasp is placed on the pro-sternum 
and the scraper on the meta-sternum, the parts thus occu- 
pying the under surface of the body instead of the upper 
surface, as in the Longicorns. 

We thus see that in the different coleopterous families 
the stridulating organs are wonderfully diversified in 
position, but not much in structure. Within the same 
family some species are provided with these organs, and 
others are destitute of them. This diversity is intelligible, 
if we suppose that originally various beetles made a shuf- 
fling or hissing noise by the rubbing together of any hard 
and rough parts of their bodies, which happened to be in 
contact; and that from the noise thus produced being in 
some way useful, the rough surfaces were gradually devel- 
oped into regular stridulating organs. Some beetles as they 
move now produce, either intentionally or unintentionally, 
a shuffling noise without possessing any proper organs for 
the purpose. Mr. Wallace informs me that the Euchirus 
lo7igimanits (a Lamellicorn, with the anterior legs wonder- 
fully elongated in the male) ^' makes, while 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 like- 
wise make the grating sound by rubbing the shagreened sur- 
face of the femur against the granulated margin of the cor- 
responding elytron; but I could not here detect any proper 
rasp; nor is it likely that I could have overlooked it in so 
large an insect. After examining Cychrus, and reading 
what Westring has written about this beetle, it seems very 
doubtful whether it possesses any true rasp, though it has 
the power of emitting a sound. 

From the analogy of the Orthoptera and Homoptera, I 
expected to find the stridulating organs in the Colpeotera 
differing according to sex; but Landois, who has carefully 

* I am indebted to Mr. Walsh, of Illinois, for liaving sent me ex- 
tracts from Leconte*s " Introduction to Entomology," pp. 101, 143. 


examined several species, obsen^ed no sucli difference; nor 
did Westring; nor did Mr. G. R. Crotch in preparing the 
many specimens which he had the kindness to send me. 
Any difference in these organs, if slight, would, however, 
be difficult to detect, on account of thoir great variability. 
Thus, in the first pair of specimens of Necrophorus 
humator and of Pelohius which I examined, the rasp 
was considerably larger in the male than in the female; 
but not so with succeeding specimens. In Geotrupes 
stercorarius the rasp appeared to me thicker, opaquer 
and more prominent in three males than in the same 
number of females ; in order, therefore, to discover 
whether the sexes differed in their power of stridulat- 
ing, my son, Mr. F. Darwin, collected fifty-seven living 
specimens, which he separated into two lots, according as 
they made a greater or lesser noise, when held in the same 
manner. He then examined all these specimens and found 
that the males were very nearly in the same proportion 
to the females in both the lots. Mr. F. Smith has kept 
alive numerous specimens of Monoynchus pseudacori (Our- 
culionidse), and is convinced that both sexes stridulate, 
and apparently in an equal degree. 

Nevertheless, the power of stridulating is certainly a 
sexual character in some few Ooleoptera. Mr. Crotch dis- 
covered that the males alone of two species of Heliopathes 
(Tenebrionidse) possess stridulating organs. I examined 
five males of ^. gMus, and in all these there was a well- 
developed rasp, partially divided into two, on the dorsal 
surface of the terminal abdominal segment; while 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. cribratostriaius 
the male has a similar rasp, excepting that it is not par- 
tially divided into two portions, and the female is com- 
pletely destitute of this organ; the male in addition has on 
the apical margins of the elytra, on each side of the suture, 
three or four short longitudinal ridges, which are crossed 
by extremely fine ribs, parallel to and resembling those on 
the abdominal rasp; whether these ridges serve as an inde- 
pendent rasp or as a scraper for the abdominal rasp, I could 
not decide ; the female exhibits no trace of this latter 

Again, in three species of the Lamellicom genus Oryc- 


tes, we have a nearly parallel case. In the females of 0. 
gryphus 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 sur- 
face of this segment, when held in the proper light, is seen 
to be clothed with hairs, which are absent or are repre- 
sented 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. senegaleiisis the difference be- 
tween the sexes is more strongly marked, and this is best 
seen when the proper abdominal segment is cleaned and 
viewed as a transparent object. In the female the whole 
surface is covered with little separate crests bearing spines; 
while in the male these crests, in proceeding toward the 
apex, become more and more confluent, regular and naked; 
so that three-fourths of the segment is covered with ex- 
tremely fine parallel ribs, which are quite absent in the 
female. In the females, however, of all three species of 
Oryctes, a slight grating or stridulating sound is produced 
when the abdomen of a softened specimen is pushed back- 
ward and forward. 

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 stridu- 
lation apparently serves both sexes as a mutual call. 
Beetles stridulate under various emotions, in the same 
manner as birds use their voices for many purposes besides 
singing to their mates. The great Chiasognathus stridu- 
lates in anger or defiance; many species do the same from 
distress or fear, if held so that they cannot escape ; by 
striking the hollow stems of trees in the Canary Islands, 
Messrs. Wollaston and Crotch were able to discover the 
presence of beetles belonging to the genus Acalles by their 
stridulation. Lastly, the male Ateuchus stridulates to en- 
courage the female in her work, and from distress when she 
is removed.* Some naturalists believe that beetles make 
this noise to frighten away their enemies; but I cannot 
think that a quadruped or bird, able to devour a large 
beetle, would be frightened by so slight a sound. The 
belief that the stridulation serves as a sexual call is sup- 

•M. P. de la Brulerie, as quoted in " Jouraal of Travel,** A. Mi 
ray, vol. I, 1868, p. 135. 


ported by the fact that death-ticks {Anohium tessellatum) 
are well known to answer each other's ticking, and, as I 
have myself observed, a tapping noise artificially made. 
Mr. Doubleday also informs me that he has sometimes ob- 
served a female ticking,* and in an hour or two afterward 
has found her united with a male, and on one occasion sur- 
rounded by several males. Finally, At is 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 hard parts of their 
bodies; and that as those males or females which made the 
greatest noise succeeded best in finding partners, rugosities 
on various parts of their bodies were gradually developed 
by means of sexual selection into true stridulating organs. 

* According to Mr. Doubleday, "the noise is produced by the 
insect raising itself on its legs as high as it can, and then striking its 
thorax five or six times in rapid succession against the substance 
upon which it is sitting." For references on this subject see Landois, 
" Zeitschrift 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 mstXe, obedi- 
ent to this call, soon attends her, and they pair." 



INSECTS, continued. — ordee lepidoptera. 

(butterflies and moths.) 

Courtship of butterflies — Battles — Ticking noise — Colors common to 
both sexes, or more brilliant in the males — Examples— Not due 
to the direct action of the conditions of life— Colors adapted for 
protection-T-Colors of moths — Display — Perceptive powers of the 
Lepidoptera — Variability — Causes of the difference in color 
between the males and females — Mimicry, female butterflies more 
brilliantly colored than the males — Bright colors of caterpillars — 
Summary and concluding remarks on the secondary sexual char- 
acters of insects — Birds and insects compared. 

In this great order the most interesting points for us are 
the differences in color between the sexes of the same 
species, and 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 pur- 
suing and crowding round the same female. Their court- 
Bhip appears to be a prolonged affair, for 1 have frequently 
watched one or more males pirouetting round a female 
until I was tired, without seeing the end of the courtship. 
Mr. A. G. Butler also informs me that he has several times 
"watched a male courting a female for a full quarter of an 
hour; but she pertinaciously refused him, and at last set- 
tled on the ground and closed her wings, so as to escape 
from his addresses. 

Although butterflies are weak and fragile creatures, they 
are pugnacious, and an Emperor butterfly* has been capt- 
ured with the tips of its wings broken from a conflict with 
another male. Mr. Oollingwood, in speaking of the fre- 
quent battles between the butterflies of Borneo, says: " They 

* Apatura Iris: " The Entomologist's Weekly Intelligence," 18-59, 
p. 139. For the Bornean Butterflies, see C. Colling wood, " Ramble;? 
of a Naiuraliert," 1868, pw 183. 


whirl round each other with the greatest rapidity, and 
appear to be incited by the greatest ferocity." 

The Agercnia fe\ onia makes a noise like that produced 
by a toothed wheel passing under a spring catch, and 
which can be heard at the distance of several yards; I 
noticed this sound at Rio de Janeiro, only when two of 
these butterflies were chasing each other in an irregular 
course, so that it is probably made during the courtship of 
the sexes.* 

Some moths also produce sounds; for instance, the males 
of Thecopliora fovea. On two occasions Mr. F. Buchanan 
White t heard a sharp quick noise made by the male of 
Hylophila prasinana, and which he believes to be produced, 
as in Cicada, by an elastic membrane, furnished with a 
muscle. He quotes, also, Guenee, that Setina produces a 
sound like the ticking of a watch, apparently by the aid of 
'^ two large tympaniform vesicles, situated in the pectoral 
region;" and these *^are much more developed in the male 
than in the female." Hence the sound-producing organs in 
the Lepidoptera appear to stand in some relation with the 
sexual functions. I have not alluded to the well-known 
noise made by the Death's Head Sphinx, for it is generally 
heard soon after the moth has emerged from its cocoon. 

Giard has always observed that the musky odor, which 
is emitted by two species of Sphinx moths, is peculiar to 
the males; J and in the higher classes we shall meet with 
many instances of the males alone being odoriferous. 

Every one must have admired the extreme beauty of 
many butterflies and of some moths; and it may be asked, 
are their colors and diversified patterns the result of the 
direct action of the physical conditions to which these 
insects have been exposed, without any benefit being thus 
derived? Or have successive variations been accumulated 
and determined as a protection, or for some unknown pur- 
pose, or that one sex may be attractive to the other? And, 

* See my "Journal of Researches," 1845, p. 33. Mr. Doubleday 
lias detected ("Proc. Ent. Soc," March 3, 1845, p. 123) a peculiar 
membranous sac at the base of the front win^s, which is probably 
connected with the production of the sound. For the case of Theco- 
phora, see " Zoological Record," 1869, p. 401. For Mr. Buchanan 
White's observations, " The Scottish Naturalist," July, 1872, p. 214. 

t "The Scottish Naturalist," July, 1872, p. 213. 

X ** Zoological Record," 1869, p. 347. 


again, what is the meaning of the colors being widely dif- 
ferent in the males and females of certain species, and 
alike in the two sexes of other species of the same genus? 
Before attempting to answer these questions a body of 
facts must be given. 

With our beautiful English butterflies, the admiral, pea- 
cock, and painted lady (Vanessae), as well as many others, 
the sexes are alike. This is also the case with the magnifi- 
cent Heliconidse, and most of the Danaidae in the tropics. 
But in certain other tropical groups, and in some of our 
English butterflies, as the purple emperor, orange-tip, etc. 
{Apatura Iris and Anthocharis cardamines), the sexes 
difler either greatly or slightly in color. No language suf- 
fices to describe the splendor of the males of some tropical 
species. Even within the same genus we often find species 
presenting extraordinary dift'erences between the sexes, 
while others have their sexes closely alike. Thus in the 
South American genus Epicalia, Mr. Bates, to whom I am 
indebted for most of the following facts, and for looking 
over this whole discussion. 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 
which, therefore, cannot have been diiferently affected by 
external conditions.* In nine of these twelve species the 
males rank among the most brilliant of all butterflies, and 
differ so greatly from the comparatively plain females that 
they were formerly placed in distinct genera. The females 
of these nine species resemble each other in their general 
type of coloration; and they likewise resemble both sexes 
of the species in several allied genera found in various parts 
of the world. Hence we may infer that these nine species, 
and probably all the others of the genus, are descended 
from an ancestral form which was colored in nearly the 
same manner. In the tenth species the female still retains 
the same general coloring, but the male resembles her, so 
that he is colored in a much less gaudy and contrasted 
manner than the males of the previous species. In the 
eleventh and twelfth species the females depart from the 
usual type, for they are gayly decorated almost like the 

* See also Mr, Bates' paper in " Proc. Ent. Soc. of Philadelphia," 
1865, p. 206. Also Mr. Wallace on the same subject, in regard to 
Piadema, in 'Transact. Entomolog, Soc. of London," 1869, p. 278. 


males, but in a somewhat less degree. Hence in these two 
latter species the bright colors of the males seem to have 
been transferred to the females; while in the tenth species 
the male has either retained or recovered the plain colors of 
the female, as well as of the parent-form of the genus. The 
sexes in these three cases have thus been rendered nearly 
alike, though in an opposite manner. In the allied genus 
Eubagis, both sexes of some of the species are plain-colored 
and nearly alike; while the greater number of the males are 
decorated with beautiful metallic tints in a diversified 
manner, and differ much from their females. The females 
throughout the genus retain the same general style of 
coloring, so that they resemble one another much more 
closely than they resemble their own males. 

In the genus Papilio all the species of the ^neas group 
are remarkable for their conspicuous and strongly con- 
trasted colors, and they illustrate the frequent tendency 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 either a little 
brighter, or very much more superb than the females. The 
genus Junonia, allied to our Vanessae, offers a nearly 
parallel case, for although the sexes of most of the species 
resemble each other, and are destitute of rich colors, yet in 
certain species, as in J. cenone, the male is rather more 
bright - colored than the female, and in a few (for 
instance /. andremiaja) the male is so different from the 
female that he might be mistaken for an entirely distinct 

Another striking case was pointed out to me in the Brit- 
ish Museum by Mr. A. Butler, namely, one of the tropical 
American Theclse, in which both sexes are nearly alike and 
wonderfully splendid; in another species the male is colored 
in a similarly gorgeous manner, while the whole upper 
surface of the female is of a dull uniform brown. Our 
common little English blue butterflies of the genus Lycaena 
illustrate the various differences in color between the sexes 
almost afi well, though not in so striking a manner, as the 
above exotic genera. In Lyccena agestis both sexes have 
wings of a brown color, bordered with small ocellated 
orange spots and are thus alike. In L. oegon the wings of 
the male are of a fine blue bordered with black, while 
those of the female are brown with a similar border closely 


resembling the wings of L. agestis. Lastly, in L. arion 
both sexes are of a blue color and are very like, though in 
the female the edges of the wings are rather duskier with 
the black spots plainer; and in a bright-blue Indian species 
both sexes are still more alike. 

I have given the foregoing details in order to show, in 
the first place, that when the sexes of butterflies differ the 
male as a general rule is the more beautiful and departs 
more from the usual type of coloring of the group to which 
the species belongs. Hence in most groups the females of 
the several species resemble each other much more closely 
than do the males. In some • cases, however, to which I 
shall hereafter allude, the females are colored more splen- 
didly than the males. In the second place, these details 
have been given to bring clearly before the mind that 
within the same genus the two sexes frequently present 
every gradation from no difference in color to so great a 
difference that it was long before the two were placed by 
entomologists in the same genus. In the third place, we 
have seen that when the sexes nearly resemble each other 
this appears due either to the male having transferred his 
colors to the female, or to the male having retained or per- 
haps recovered the primordial colors of the group. It also 
deserves notice that in those groups in which the sexes 
differ the females usually somewhat resemble the males, 
so that when the males are beautiful to an extraordinary 
degree the females almost invariably exhibit some degree 
of beauty. From the many cases of gradation in the 
amount of difference between the sexes, and from the prev- 
alence of the same general type of coloration throughout 
the whole of the same group, we may conclude that the 
causes have generally been the same which have determined 
the brilliant coloring of the males alone of some species, 
and of both sexes of other species. , 

As so many gorgeous butterflies inhabit the tropics it 
has often been supposed that they owe their colors to the 
great heat and moisture of these zones; but Mr. Bates* has 
shown by the comparison of various closely-allied groups of 
insects from the temperate and tropical regions that this 
view cannot be maintained; and the evidence becomes con- 
clusive when brilliantly colored males and plain colored 

* "The Naturalist on the Amazons," vol. i, 1863, p. 19. 


females of the same species inhabit the same district, feed 
on the same food and follow exactly the same habits of 
life. Even wheil the sexes resemble each other we can 
hardly believe that their brilliant and beautifully arranged 
colors are the purposeless result of the nature of the tissues 
and of the action of the surrounding conditions. 

With animals of all kinds, whenever color has been 
modified for some special purpose, this has been, as far as 
we can judge, either for direct or indirect protection, or as 
an attraction between the sexes. With many species of 
butterflies the upper surfaces of the wings are obscure; and 
this in all probability leads' to their escaping observation 
and danger. But butterflies would be particularly liable 
to be attacked by their enemies when at rest; and most 
kinds while resting raise their wings vertically over their 
backs, so that the lower surface alone is exposed to view. 
Hence it is this side which is often colored so as to imitate 
the objects on which these insects commonly rest. Dr. 
Eossler, I believe, first noticed the similarity of the closed 
wings of certain Vanessse and other butterflies to the 6ark 
of trees. Many analogous and striking facts could be given. 
The most interesting one is that recorded by Mr. Wallace* 
of a common Indian and Sumatran butterfly (Kallima), 
which disappears like magic when it settles on a bush; for 
it hides its head and antennae between its closed wings, 
which, in form, color and veining, cannot be distinguished 
from a withered leaf with its footstalk. In some other 
cases the lower surfaces of the wings are brilliantly colored, 
and yet are protective; thus in Thecla ruM the wings when 
closed are of an emerald green and resemble the young 
leaves of the bramble, on which in spring this butterfly 
may often be seen seated. It is also remarkable that in very 
many species in which the sexes differ greatly in color on 
their upper surface, the lower surface is closely similar or 
identical in both sexes, and serves as a protection, f 

Although the obscure tints both of the upper and under 
sides of many butterflies no doubt serve to conceal them, yet 
we cannot extend this view to the brilliant and conspicuous 
colors on the upper surface of such species as our admiral and 

* See the interesting article in the "Westminster Eeview," July, 
1867, p. 10. A wood-cut of the Kallima is given by Mr. WaJlace in 
"Hardwicke's Science Gossip," Sept., 1867, p. 196. 

tMr. a. Fraser, in "Nature," April, 1871, p. 489. 


peacock Vanessae, our white cabbage-butterflies (Pieris), or 
the great swallow-tail Papilio which haunts the open fens — 
for these butterflies are thus rendered visible to every living 
creature. In these species both sexes are alike; but in the 
common brimstone butterfly ( Gonepteryx rlimnni), the male 
is of an intense yellow, while the female is much paler; and 
in the orange-tip {Atitliocliaris cardanmies) the males alone 
have their wings tipped with bright orange. Both the 
males and females in these cases are conspicuous, and it is 
not credible that their difference in color should stand in 
any relation to ordinary protection. Prof. Weismann 
remarks * that the female of one of the Lycaense expands 
her brown wings when she settles on the ground, and is 
then almost invisible; the male, on the other hand, as if 
aware of the danger incurred from the bright blue of the 
upper surface of his wings, rests with them closed; and this 
shows that the blue color cannot be in any way protective. 
Nevertheless, it is probable that conspicuous colors are 
indirectly beneficial to many species, as a warning that they 
are unpalatable. For in certain other cases, beauty has 
been gained through the imitation of other beautiful 
species, which inhabit the same district and enjoy an im- 
munity from attack by being in some way offensive to their 
enemies; but then we have to account for the beauty of the 
imitated species. 

As Mr. Walsh has remarked to me, the females of our 
orange-tip butterfly, above referred to, and of an American 
species (Anth. genutia) probably show us the primordial 
colors of the parent-species of the genus; for both sexes of 
four or five widely-distributed species are colored in nearly 
the same manner. As in several previous cases, we may 
here infer that it is the males of Anth. cardamines and 
genidia which have departed from the usual type of the 
genus. In the Anth. sara from California, the orange tips 
to the wings have been partially developed in the female ; 
but they are paler than in the male, and slightly different 
in some other respects. In an allied Indian form, the 
Iphias glaucippe, the orange-tips are fully developed in 
both sexes. In this Iphias, as pointed out to me by Mr. A. 
Butler, the under surface of the wings marvelously resem- 
bles a pale-colored leaf; and in our English orange-tip, the 

♦•• JEinfluss der Isolirung auf di. Artbildun^," 1873, p. 63. 


under surface resembles the flower-head of the wild parsley, 
on which the butterfly often rests at night.* The same 
reason which compels us to believe that the lower surfaces 
have here been colored for the sake of protection, leads us 
to deny that the wings have been tipped with bright orange 
for the same purpose, especially when this character is con- 
fined to the males. 

Most moths rest motionless during the whole or greater 
part of the day with their wings depressed; and the whole 
upper surface is often shaded and colored in an admirable 
manner, as Mr. Wallace has remarked, for escaping detec- 
tion. The front- wings of the Bombycidas and Noctuidae,f 
when at rest, generally overlap and conceal the hind wings; 
so that the latter might be brightly colored without much 
risk; and they are in fact often thus colored. During 
flight, moths would often be able to escape from their ene- 
mies; nevertheless, as the hind wings are then fully exposed 
to view, their bright colors must generally have been 
acquired at some little risk. But the following fact shows 
how cautious we ought to be in drawing conclusions on this 
head. The common yellow under wings (Triphaena) often 
fly about during the day or early evening, and are then 
conspicuous from the color of their hind wings. It would 
naturally be thought that this would be a source of danger; 
but Mr. J. Jenner Weir believes that it actually serves 
them as a means of escape, for birds strike at these brightly 
colored and fragile surfaces, instead of at the body. For 
instance, Mr. Weir turned into his aviary a vigorous speci- 
men of Triphcena 'pronu'ba, which was instantly pursued by 
a robin : but the bird's attention being caught by the col- 
ored wings, the moth was not captured until after about 
fifty attempts, and small portions of the wings were repeat- 
edly broken off. He tried the same experiment in the 
open air, with a swallow and T, fimbria ; but the large 
size of this moth probably interfered with its capture. | 
We are thus reminded of a statement made by Mr. Wal- 

* See the interesting observations by Mr. T. W. Wood, ** The 
Student," Sept., 1868, p. 81. 

t Mr. Wallace in " Hardwicke's Science Gossip," Sept., 1867, p. 193. 

X See also on this subject, Mr. Weir's paper in " Transact. Ent. 
Soc." 1869, p. 23. 


lace,* namely, that in the Brazilian forests and Malayan 
islands, many common and highly-decorated butterflies 
are weak flyers, though furnished with a broad expanse of 
wing; and they '^^are often captured with pierced and 
broken wings, as if they had been seized by birds, from 
which they had escaped; if the wings had been much 
smaller in proportion 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 colors of many butterflies and of 
some moths are specially arranged for display, so that they 
may be readily seen. During the night colors are not vis- 
ible, and there can be no doubt that the nocturnal moths, 
taken as a body, are much less gayly decorated than butter- 
flies, all of which are diurnal in their habits. But the 
moths of certain families, such as the Zygaenidae, several 
Sphingidae, Uraniidas, some Arctiidae and Saturniidge, fly 
about during the day or early evening, and many of these 
are extremely beautiful, being far brighter-colored than the 
strictly nocturnal kinds. A few exceptional cases, how- 
ever, of bright - colored nocturnal species have been 
recorded, f 

There is evidence of another kind in regard to display. 
Butterflies, as before remarked, elevate their wings when 
at rest, but while basking in the sunshine often alternately 
raise and depress them, thus exposing both surfaces to full 
view; and although the lower surface is often colored in an 
obscure manner as a protection, yet in many species it is as 
highly decorated as the upper surface, and sometimes in a 
very different manner. In some tropical species the lower 
surface is even more brilliantly colored than the upper. | 
In the English fritillaries {Argynnis) the lower surface 

* " Westminster Review," July, 1867, p. 16. 

f For instance, Litliosia; but Prof. Westwood ("Modern Class, of 
Insects," vol. ii, p. 390) seems surprised at this case. On the relative 
colors of diurnal and nocturnal Lepidoptera, see ibid., pp. 333, 392; 
also Harris, " Treatise on the Insects of New England," 1842, p. 315. 

X 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 Papilionidae of the Malayan 
Region," in "Transact. Linn. Soc," vol. xxv, part i, 1865. 


alone is oruamented with shining silver. Nevertheless, as 
a general rule, the upper surface, which is probably more 
fully exposed, is colored more brightly and diversely than 
the lower. Hence the lower surface generally affords to 
entomologists the more useful character for detecting the 
affinities of the various species. Fritz Miiller informs me 
that three species of Castnia are found near his house in 
S. Brazil; of two of them the hind wings are obscure, and 
are always covered by the front wings when these butter- 
flies are at rest; but the third species has black hind wings, 
beautifully spotted with red and white, and these are fully 
expanded and displayed whenever the butterfly rests. Other 
such cases could be added. 

If we now turn to the enormous group of moths which, 
as I hear from Mr. Stainton, do not habitually expose the 
under surface of their wings to full view, we find this side 
very rarely colored with a brightness greater than, or even 
equal to, that of the upper side. Some exceptions to the 
rule, either real or apparent, must be noticed, as the case of 
Hypopyra.* Mr. Trimen informs me that in Guenee's 
great work three moths are figured, in which the under sur- 
face is much the more brilliant. For instance, in the Aus- 
tralian Gastrophora the upper surface of the fore wing is 
pale grayish-ochreous, while the lower surface is magnifi- 
cently ornamented by an ocellus of cobalt-blue, placed in 
the midst of a black mark, surrounded by orange-yellow, 
and this by bluish-white. But the habits of these three 
moths are unknown; so that no explanation can be given 
of their unusual style of coloring. Mr. Trimen also 
informs me that the lower surface of the wings in certain 
other Geometrsef and quadrifid Noctuae are either more 
variegated or more brightly-colored 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 the 
under surface to view. Other species, when settled on the 
ground or herbage, now and then suddenly and slightly lift 

*See Mr. Wormald on this moth; " Proc. Ent. Soc," March 2, 

f See also an account of the South American genus Erateina (one 
of the Geometrse) in "Transact. Ent. Soc." new series, vol. v, pis 
XV and xvi. 


up their wings. Hence the lower surface of the wings 
being brighter than the upper surface in certain moths is 
not so anomalous as it at first appears. The Saturniidae 
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* 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 dis- 
play, which is more characteristic of diurnal than of 
nocturnal Lepidoptera.'' 

It is a singlar fact that no British moths which are 
brilliantly colored, and, as far as I can discover, hardly any 
foreign species, differ much in color according to sex; 
though this is the case with many brilliant butterflies. The 
male, however, of one American moth, the Saturnia lo, is 
described as having its fore wings deep yellow, curiously 
marked with purplish-red spots; while the wings of the 
female are purple-brown, marked with gray lines. \ The 
British moths which difter sexually in color are all brown, 
or of various dull yellow tints, or nearly white. In several 
species the males are much darker than the females, J and 
these belong to groups which generally fly about during 
the afternoon. On the other hand, in many genera, as 
Mr. Stainton informs me, the males have the hind wings 
whiter than those of the female — of which fact Agrotis 
exclamationis offers a good instance. In the Ghost Moth 
(Hepialus humuli) the difference is more strongly 
marked; the males being white and the females yellow 

*"Proc. Ent. Soc. of London," July 6, 1868, p. 27. 

f Harris, "Treatise," etc., edited by Flint, 1862, p 395. 

X For instance, I observe in my son's cabinet that the males are 
darker than the females in the Ladocampa quercus, Odonestis pota- 
toria, Hypogymna dispar, DasycMra pudihunda and Gycnia mendica. 
In this latter species the diiference in color between the two sexes is 
strongly marked ; and Mr. Wallace informs me that we here have, as 
he believes, an instance of protective mimicry confined to one sex, as 
will hereafter be more fully explained. The white female of the 
Cycnia resembles the very common Spilosoma menthrasti, both sexes 
of which are white; and Mr. Stainton observed that this latter moth 
was rejected with utter disgust by a whole brood of young turkeys, 
which were fond of eating other moths; so that if the Cycnia was 
commonly mistaken by British birds for the Spilosoma, it would es- 
cape being devoured, and its white, deceptive color would thus be 
lughly beneficial. 

mSEGTS. 359 

with darker markings.* It is probable that in these 
cases the males are thus rendered more conspicuous, and 
more easily seen by the females while flying about in the 

From the several foregoing facts it is impossible to admit 
that the brilliant colors of butterflies, and of some few 
moths, have commonly been acquired for the sake of pro- 
tection. We have seen that their colors and elegant pat- 
terns are arranged and exhibited as if for display. Hence 
I am led to believe that the females prefer or are most 
excited by the more brilliant males; for on any other sup- 
position the males would, as far as we can see, be orna- 
mented to no purpose. We know that ants and certain 
Lamellicorn beetles are capable of feeling an attachment 
for each other, and that ants recognize their fellows after 
an interval of several months. Hence there is no abstract 
improbability in the Lepidoptera, which probably stand 
nearly or quite as high in the scale as these insects, having 
sufficient mental capacity to admire bright colors. They 
certainly discover flowers by color. The humming-bird 
sphinx may often be seen to swoop down from a distance 
on a bunch of flowers in the midst of green foliage; and I 
have been assured by two persons abroad that these moths 
repeatedly visit flowers painted on the walls of a room and 
vainly endeavor to insert their proboscis into them. Fritz 
Miiller informs me that several kinds of butterflies in 
S. Brazil show an unmistakable preference for certain 
colors over others. He observed that they very often 
visited the brilliant red flowers of five or six genera of 
plants, but never the white or yellow flowering species of 
the same and other genera growing in the same garden; 
and I have received other accounts to the same effect. As 
I hear from Mr. Doubleday, the common white butterfly 
often flies down to a bit of paper on the ground, no doubt 
mistaking it for one of its own species. Mr. Collingwoodf 

* It is remarkable that in tlie Shetland Islands the male of this 
moth, instead of differing widely from the female, frequently resem- 
bles her closely in color (see Mr. MacLachlan, " Transact. Ent. Soc," 
vol. ii, 1866, p. 459). Mr. G. Fraser suggests ("Nature," April, 
1871, p. 489) that at the season of the year when the ghost-moth ap- 
pears in these northern islands, the whiteness of the males would 
not be needed to render them visible to the females in the twilight 

f " Rambles of a Naturalist in the Chinese Seas," 1808, p. 183, 


in speaking of the difficulty in collecting certain butter- 
flies in the Malay Archipelago^ states that " a dead speci- 
men pinned upon a conspicuous twig will often arrest an 
insect of the same species in its headlong flight and bring 
it down within easy reach of the net, especially if it be of 
the opposite sex." 

The courtship of butterflies is, as before remarked, a 
prolonged affair. The males sometimes fight together in 
rivalry; and many maybe seen pursuing or crowding round 
the same female. Unless, then, the females prefer one 
male to another the pairing must be left to mere chance, 
and this does not appear probable. If, on the other hand, 
the females habitually, or even occasionally, prefer the 
more beautiful males, the colors of the latter will have been 
rendered brighter by degrees, and will have been trans- 
mitted to both sexes or to one sex, according to the law of 
inheritance which has prevailed. The process of sexual 
selection will have been much facilitated, if the conclusion 
can be trusted, arrived at from various kinds of evidence 
in the supplement to the ninth chapter; namely, that the 
males of many Lepidoptera, at least in the imago state, 
greatly exceed the females in number. 

Some facts, however, are opposed to the belief that female 
butterflies prefer the more beautiful males; thus, as I have 
been assured by several collectors, fresh females may fre- 
quently be seen paired with battered, faded, or dingy males; 
but this is a circumstance which could hardly fail often to 
follow from the males emerging from their cocoons earlier 
than the females. With moths of the family of the Bom- 
bycidge, the sexes pair immediately after assuming the 
imago state; for they cannot feed, owing to the rudiment- 
ary 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 great experi- 
ence in breeding Bomhyx cyntliia, is convinced that the 
females evince no choice or preference. He has kept above 
three hundred of these moths together, and has often found 
the most vigorous females mated with stunted males. The 
reverse appears to occur seldom; for, as he believes, the 
jnore vigorous males pass over the weakly females, and are 


attracted by those endowed with most vitality. Never- 
theless, the Bombycidse, though obscurely colored, are 
often beautiful to our eyes from their elegant and mottled 

I have as yet only referred to the species in which the 
males are brighter colored than the females, and I have 
attributed their beauty to the females for many generations 
having chosen and paired with the more attractive males. 
But converse cases occur, though rarely, in which the 
females are more brilliant than the males; and here, as I 
believe, the males have selected the more beautiful females, 
and have thus slowly added to their beauty. We do not 
know why in various classes of animals the males of some 
few species have selected the more beautiful females instead 
of having gladly accepted any female, as seems to be the 
general rule in the animal kingdom; but if, contrary to 
what generally occurs with the Lepidoptera, the females 
were much more numerous than the males, the latter would 
be likely to pick out the more beautiful females. Mr. But- 
ler showed me several species of Oallidryas in the British 
Museum, in some of which the females equaled, and in 
others greatly surpassed, the males in beauty ; for the 
females alone have the borders of their wings suffused with 
crimson and orange and spotted with black. The plainer 
males of these species closely resemble each other, showing 
that here the females have been modified; whereas in those 
cases, where the males are the more ornate, it is these which 
have been modified, the females remaining closely alike. 

In England we have some analogous cases, though not so 
marked. The females alone of two species of Thecla have 
a bright purple or orange patch on their fore wings. In 
Hipparchia the sexes do not differ much ; but it is the 
female of H. jmiira which has a conspicuous light brown 
patch on her wings; and the females of some of the other 
species are brighter colored than their males. Again, 
the females of Colias echisa and hyale have "orange or 
yellow spots on the black marginal border, represented in 
the males only by thin streaks;" and in Pieris it is the 
females which "are ornamented with black spots on the 
fore wings, and these are only partially present in the 
males." Now the males of many butterflies are known to 
support the females during their marriage flight; but in 
the species just named it is the females which support the 



males; so that the part which the two sexes play is reversed, 
as is tlieir relative beauty. Throughout the animal king- 
dom the males commonly take the more active share in 
wooing, and their beauty seems to have been increased by 
the females having accepted the more attractive individuals; 
but with these butterflies the females take the more active 
part in the final marriage ceremony, so that we may sup- 
pose that they likewise do so in the wooing; and in this case 
we can understand how it is that they have been rendered 
the more beautiful. Mr. Meldola, from whom the fore- 
going statements have been taken, says in conclusion: 
" Though I am not convinced of the action of sexual selec- 
tion in producing the colors of insects, it cannot be denied 
that these facts are strikingly corroborative of Mr. Darwin's 

As sexual selection primarily depends on variability, a 
few words must be added on this subject. In respect to 
color there is no difficulty, for any number of highly variable 
Lepidoptera could be named. One good instance will suffice. 
Mr. Bates showed me a whole series of specimens of Papilio 
sesostris and P. childrenm; in the latter the males varied 
much in the extent of the beautifully enameled green patch 
on the fore wings, and in the size of the white mark, and 
of the splendid crimson stripe on the hind wings; so that 
there was a great contrast among the males between the 
most and the least gaudy. The male of Papilio sesostris 
is much less beautiful than of P. childrence; and it like- 
wise varies a little in the size of the green patch on the 
fore wings, and in the occasional appearance of the small 
crimson stripe on the hind wings, borrowed, as it would 
seem, from its own female; for the females of this and of 
many other species in the JEneas group possess this crimson 
stripe. Hence between the brightest specimens of P. ses- 
ostris and the dullest of P. childrenm there was but a small 
interval; and it was evident that as far as mere variability 
is concerned, there would be no difficulty in permanently 
increasing the beauty of either species by means of selec- 
tion. The variability is here almost confined to the male 

* "Nature," April 27, 1871, p 
in "Soc. Ent. de France," 1837, 

while pairing. See also Mr. G. Fraser, in " Nature," April 20, 1871, 
p. 489, on the sexual differences of several British butterflies, 

508. Mr. Meldola quotes Donzel, 
p. 77, on the flight of butterflies 


sex; but Mr. Wallace and Mr. Bates have shown * that the 
females of some species are extremely variable, the males 
being nearly constant. In a future chapter I shall have 
occasion to show that the beautiful eye-like spots, or ocelli, 
found on the wings of many Lepidoptera are eminently 
variable. I may here add that these ocelli offer a difficulty 
on the theory of sexual selection; for though appearing to 
us so ornamental, they are never present in one sex and 
absent in the other, nor do they ever differ much in the 
two sexes. t This fact is at present inexplicable; but if it 
should hereafter be found that the formation of an ocellus 
is due to some change in the tissues of the wings, for 
instance, occurring at a very early period of development, 
we might expect, from what we know of the laws of inherit- 
ance, that it would be transmitted to both sexes, though 
arising and perfected in one sex alone. 

On the whole, although many serious objections may be 
urged, it seems probable that most of the brilliantly-colored 
species of Lepidoptera owe their colors to sexual selection, 
excepting in certain cases, presently to be mentioned, in 
which conspicuous colors have been gained through mimicry 
as a protection. From the ardor of the male throughout 
the animal kingdom he is generally willing to accept any 
female; and it is the female which usually exerts a choice. 
Hence, if sexual selection has been efficient with the 
Lepidoptera, the male, when the sexes differ, ought to be 
the more brilliantly colored, and this undoubtedly is the 
case. When both sexes are brilliantly colored and resemble 
each other the characters acquired by the males appear to 
have been transmitted to both. We are led to this conclu- 
sion by cases, even within the same genus, of gradation 
from an extraordinary amount of difference to identity in 
color between the two sexes. 

But it may be asked whether the differences in color 
between the sexes may not be accounted for by other means 

* Wallace on the Papilionidse of the Malayan Region, in "Trans- 
act. Linn. Sec," vol. xxv, 1865, pp. 8, 36. A striking case of a rare 
variety, strictly intermediate between two other well-marked female 
varieties, is given by Mr. Wallace. See also Mr. Bates, in " Proc. 
Entomolog. Soc," Nov. 19, 1866, p. 40. 

f Mr. Bates was so kind as to lay this subject before the Entomo- 
logical Society, and I have received answers to this effect from several 


besides sexual selection. Thus the males and females of the 
same species of butterfly are in several cases known* 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,! as 
in the adult state they are exposed to different conditions 
during a very short period ; and the larvae of both are 
exposed to the same conditions. Mr. Wallace believes that 
the difference between the sexes is due not so much to the 
males having been modified, as to the females having in all 
or almost all cases acquired dull colors for the sake 
of protection. It seems to me, on the contrary, far 
more probable that it is the males which have been 
chiefly modified through sexual selection, the females having 
been comparatively little changed. We can thus under- 
stand how it is that the females of allied species generally 
resemble one another so much more closely than do the 
males. They thus show us approximately the primordial 
coloring of the parent-species of the group to which they 
belong. They have, however, almost always been somewhat 
modified by the transfer to them of some of the successive 
variations, through the accumulation of which the males 
were rendered beautiful. But I do not wish to deny that 
the females alone of some species may have been specially 
modified for protection. In most cases the males and 
females of distinct species will have been exposed during 
their prolonged larval state to different conditions, and 
may have been thus affected ; though with the males any 
slight change of color thus caused will generally have been 
masked by the brilliant tints gained through sexual selec- 
tion. When we treat of birds, I shall have to discuss the 
whole question, as to how far the differences in color 
between the sexes are due to the males having been modi- 
fied through sexual selection for ornamental purposes, or 
to the females having been modified through natural selec- 
tion for the sake of protection, so that I will here say but 
little on the subject. 

In all the cases in which the more common form of equal 

*H. W. Bates, " The Naturalist on tlie Amazons," vol. ii, 1863, p. 
228. A. R. Wallace, in " Transact. Linn. Soc," vol. xxv, 1865, p. 10. 

f On this whole subject see " The Variation of Animals and Plants 
under Domestication," 1868, vol. ii, chap, xxiii. 


inheritance by both sexes has prevailed, the selection of 
bright-colored males would tend to make the females 
bright colored ; and the selection of dull-colored females 
would tend to make the males dull. If both processes 
were carried on simultaneously, they would tend to coun- 
teract each other ; and the final result would depend on 
whether a greater number of females from being well pro- 
tected by obscure colors, or a greater number of males by 
being brightly colored and thus finding partners, succeeded 
in leaving more numerous offspring. 

In order to account for the frequent transmission of char- 
acters to one sex alone, Mr. Wallace expresses his belief that 
the more common form of equal inheritance by both sexes 
can be changed through natural selection into inheritance 
by one sex alone, but in favor of this view I can discover 
no evidence. We know from what occurs under domestica- 
tion that new characters often appear, which from the first 
are transmitted to one sex alone ; and by the selection of 
such variations there would not be the slightest difficulty 
in giving bright colors to the males alone, and at the same 
time or subsequently, dull colors to the females alone. In 
this manner the females of some butterflies and moths 
have, it is probable, been rendered inconspicuous for the 
sake of protection, and widely different from their males. 

I am, however, unwilling without distinct evidence to 
admit that two complex processes of selection, each requir- 
ing the transference of new characters to one sex alone, 
have been carried on with a multitude of species — that the 
males have been rendered more brilliant by beating their 
rivals, and the females more dull colored by having escaped 
from their enemies. The male, for instance, of the common 
brimstone butterfly (Gronepteryx), is of a far more intense 
yellow than the female, though she is equally conspicuous; 
and it does not seem probable that she specially acquired 
her pale tints as a protection, though it is probable that 
the male acquired his bright colors as a sexual attraction. 
The female of Antliocharis cardamines does not possess 
the beautiful orange wing-tips of the male ; consequently 
she closely resembles the white butterflies (Pieris) so com- 
mon in our gardens; but we have no evidence that this 
resemblance is beneficial to her. As, on the other hand, she 
resembles both sexes of several other species of the genus 
inhabiting various quarters of the world, it is probable that 


she has simply retained to a large extent her primordial 

Finally, as we have seen, various considerations lead to the 
conclusion that with the greater number of brilliantly col- 
ored Lepidoptera it is the male which has been chiefly 
modified through sexual selection; the amount of difference 
between the sexes mostly depending on the form of inherit- 
ance which has prevailed. Inheritance is governed by so 
many unknown laws or conditions that it seems to us to act 
in a capricious manner;* and we can thus, to a certain ex- 
tent, understand how it is that with closely allied species 
the sexes either differ to an astonishing degree, or are iden- 
tical in color. As all the successive steps in the process of 
variation are necessarily transmitted through the female, a 
greater or less number of such steps might readily become 
developed in her; and thus we can understand the frequent 
gradations from an extreme difference to none at all between 
the sexes of allied species. These cases of gradation, it 
may be added, are much too common to favor the supposi- 
tion that we here see females actually undergoing the 
process of transition and losing their brightness for the 
sake of protection; for we have every reason to conclude 
that at any one time the greater number of species are in a 
fixed condition. 

Mimicry. — This principle was first made clear in an ad- 
mirable paper by Mr. Bates, f who thus threw a flood of 
light on many obscure problems. It had previously been 
observed that certain butterflies in South America belong- 
ing to quite distinct families resembled the Heliconidae so 
closely in every stripe and shade of color that they could 
not be distinguished save by an experienced entomologist. 
As the Heliconidae are colored in their usual manner, while 
the others depart from the usual coloring of the groups to 
which they belong, it is clear that the latter are the imi- 
tators, and the Heliconidae the imitated. Mr. Bates further 
observed that the imitating species are comparatively rare, 
while the imitated abound, and that the two sets live min- 
gled together. From the fact of the Heliconidae being 

* *• The Variation of Animals and Plants under Domestication," vol. 
ii, chap, xii, p. 17. 

f " Transact. Unn. Soc," vol. xxiii, 1863, p. 495. 


conspicuous and beautiful insects, yet so numerous in indi- 
viduals and species, he concluded that they must be pro- 
tected from the attacks of enemies by some secretion or 
odor; and this conclusion has now been amply confirmed,* 
especially by Mr. Belt. Hence Mr. Bates inferred that the 
butterflies which imitate the protected species have acquired 
their present marvelously deceptive 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 colors of 
the imitated, but only of the imitating butterflies. We 
must account for the colors of the former in the same gen- 
eral manner as in the cases previously discussed in this 
chapter. Since the publication of Mr. Bates' paper similar 
and equally striking facts have been observed by Mr. Wal- 
lace in the Malayan region, by Mr. Trimen in S. Africa, 
and by Mr. Riley in the United States, f 

As some writers have felt much difficulty in understand- 
ing how the first steps in the process of mimicry could 
have been effected through natural selection, it may be well 
to remark that the process probably commenced long ago 
between forms not widely dissimilar in color. In this case 
even a slight variation would be beneficial if it rendered 
the one species more like the other; and afterward the 
imitated species might be modified to an extreme degree 
through sexual selection or other means, and if the changes 
were gradual the imitators might easily be led along the 
same track, until they differed to an equally extreme degree 
from their original condition; and they would thus ulti- 
mately assume an appearance or coloring /wholly unlike 
that of the other members of the group to which they 
belonged. It should also be remembered that many species 
of Lepidoptera are liable to considerable and abrupt varia- 
tions in color. A few instances have been given in this 
chapter; and many more may be found in the papers of 
Mr. Bates and Mr. Wallace. 

*"Proc. Ent. Soc," Dec. 3, 1866, p. 45. 

f Wallace, "Transact. Linn. Soc," vol. xxv, 1865, p. 1; also 
*' Transact. Ent. Soc," vol. iv (3d series), 1867, p. 301. Trimen, 
" Linn. Transact.," vol. xxvi, 1869, p. 497. Riley, " Third Annual 
Report on the Noxious Insects of Missouri," 1871, pp. 163-168. This 
latter essay is valuable, as Mr. Riley here discusses all the objections 
which have been raised against Mr. Bates' theory. 


With several species the sexes are alike, and imitate the 
two sexes of another species. But Mr. Trimen gives, in 
the paper already referred to, three cases in which the sexes 
of the imitated form differ from each other in color, and 
the sexes of the imitating form differ in a like manner. 
Several cases have also been recorded where the females 
alone imitate brilliantly-colored and protected species, the 
males retaining ^' the normal aspect of their immediate con- 
geners.^" It is here obvious that the successive variations 
by which the female has been modified have been trans- 
mitted to her alone. It is, however, probable that some of 
the many successive variations would have been transmitted 
to, and developed in, the males had not such males been 
eliminated by being thus rendered less attractive to the 
females; so that only those v^ariations were preserved which 
were from the first strictly limited in their transmission to 
the female sex. We have a partial illustration of these 
remarks in a statement by Mr. Belt; * that the males of 
some of the Leptalides, which imitate protected species, 
still retain in a concealed manner some of their original 
characters. Thus in the males '^ the upper half of the 
lower wing is of a pure white, while all the rest of the wings 
is barred and spotted with black, red and yellow, like the 
species they mimic. The females have not this white 
patch, and the males usually conceal it by covering it with 
the upper wing, so that I cannot imagine its being of any 
other use to them than as an attraction in courtship, when 
they exhibit it to the females, and thus gratify their deep- 
seated preference for the normal color of the order to which 
the Leptalides belong."' 

Bright Colors of Caterpillars. — While reflecting on the 
beauty of many butterflies it occurred to me that some 
caterpillars were splendidly colored; and as sexual selection 
could not possibly have here acted, it appeared rash to 
attribute the beauty of the mature insect to this agency, 
unless the bright colors of their larvae could be somehow 
explained. In the first place, it may be observed that the 
colors of caterpillars do not stand in any close correlation 
with those of the mature insect. Secondly, their bright 
colors do not serve in any ordinary manner as a protection. 

* ♦* The Naturalist in Nicaragua," 1874, p. 385, 


Mr. Bates informs me, as an instance of this, 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 one who passed by, even at the 
distance of many yards, and no doubt that of every passing 

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 colored green like the leaves on 
which they feed, or being curiously like the twigs of the trees 
on which they live.'^ Another instance of protection, fur- 
nished me by Mr. J. Mansel Weale, may be added, namely, 
that there is a caterpillar of a moth which lives on the 
mimosas in S. Africa, and fabricates for itself a case quite 
indistinguishable from the surrounding thorns. From 
such considerations Mr. Wallace thought it probable that 
conspicuously colored caterpillars were protected by having 
a nauseous taste; but as their skin is extremely 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. Wal- 
lace 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 recognized as unpalatable by all birds and other 
animals. Thus the most gaudy colors would be service- 
able, and might have been gained by variation and the 
survival of the most easily recognized individuals. 

This hypothesis appears at first sight very bold, but 
when it was brought before the Entomological Society* it 
was supported by various statements; and Mr. J. Jenner 
Weir, who keeps a large number of birds in an aviary, 
informs me that he has made many trials and finds no 

* " Proc. Entomolog. Soc," Dec. 3, 1866, p. 45, and March 4, 1867, 


exception to the rule that all caterpillars of nocturnal and 
retiring habits with smooth skins, all of a green color and 
all which imitate twigs are greedily devoured by his birds. 
The hairy and spinose kinds are invariably rejected, as 
were four conspicuously colored species. When the birds 
rejected a caterpiller they plainly showed by shaking their 
heads and cleansing their beaks that they were disgusted 
by the taste.* Three conspicuous kinds of caterpillars and 
moths were also given to some lizards and frogs by Mr. A. 
Butler and were rejected, though other kinds were eagerly 
eaten. Thus the probability of Mr. Wallace's view is con- 
firmed, namely, that certain caterpillars have been made 
conspicuous for their own good, so as to be easily recog- 
nized by their enemies, on nearly the same principle that 
poisons are sold in colored bottles by druggists for the good 
of man. We cannot, however, at present thus explain the 
elegant diversity in the colors of many caterpillars; but 
any species which had at some former period acquired a 
dull, mottled or striped appearance, either in imitation of 
surrounding objects or from the direct action of climate, 
etc., almost certainly would not become uniform in color 
when its tints were rendered intense and bright; for in 
order to make a caterpillar merely conspicuous there would 
be no selection in any definite direction. 

Summary and Concluding Remarhs on Insects. — Looking 
back to the several orders we see that the sexes often differ 
in various characters, the meaning of which is not in the 
least understood. The sexes, also, often differ in their 
organs of sense and means of locomotion, so that the males 
may quickly discover and reach the females. They dift'er 
still oftener in the males possessing diversified contrivances 
for retaining the females when found. We are, however, 
here concerned only in a secondary degree with sexual dif- 
ferences of these kinds. 

In almost all the orders the males of some species, even 
of weak and delicate kinds, are known to be highly pug- 

* See Mr, J, Jenner Weir's paper on Insects and Insectivorous 
Birds, in "Transact. Ent. Soc," 1869, p. 21; also Mr. Butler's paper, 
ibid., p. 27. Mr. Riley has given analogous facts in the "Third 
Annual Report on the Noxious Insects of Missouri," 1871, p. 148. 
Some opposed cases are, however, given by Dr. Wallace and M. H. 
d'Orville; see "Zoological Record," 1869, p. 349. 


nacious; and some few are furnished with special weapons 
for fighting with their rivals. But the law of battle does 
not prevail nearly so widely with insects as with the higher 
animals. Hence it probably arises that it is in only a 
few cases that the males have been rendered larger and 
stronger than the females. On the contrary, they are 
usually smaller, so that they may be developed within a 
shorter time, to be ready in large numbers for the emerg- 
ence of the females. 

In two families of the Homoptera and in three of the 
Orthoptera, the males alone possess sound-producing organs 
in an efficient state. These are used incessantly during the 
breeding-season, not only for calling the females, but ap- 
parently for charming or exciting them in rivalry with 
other males. No one who admits the agency of selection 
of any kind, will, after reading the above discussion, dis- 
pute that these musical instruments have been acquired 
through sexual selection. In four other orders the mem- 
bers of one sex, or more commonly of both sexes, are pro- 
vided with organs for producing various sounds, which ap- 
parently serve merely as call-notes. When both sexes are 
thus provided the individuals which were able to make the 
loudest or most continuous noise would gain partners before 
those which were less noisy, so that their organs have proba- 
bly been gained through sexual selection. It is instructive 
to reflect on the wonderful diversity of the means for pro- 
ducing sound possessed by the males alone, or by both 
sexes in no less than six orders. We thus learn how effectual 
sexual selection has been in leading to modifications which 
sometimes, as with the Homoptera, relate to important 
parts of the organization. 

From the reasons assigned in the last ch?.pter, it is proba- 
ble that the great horns possessed by th^ males of many 
Lamellicorn, and some other beetles, have been acquired as 
ornaments. From the small size of insects we are apt to 
undervalue their appearance. If we could imagine a male 
Chalcosoma (see fig. 16), with its polished bronzed coat of mail 
and its vast complex horns, magnified to the size of a 
horse, or even of a dog, it would be one of the most impos- 
ing animals in the world. 

The coloring of insects is a complex and obscure subject. 
When the male differs slightly from th^ female, and 
neither are brilliantly colored, it is probable that the sex^s 


have varied in a slightly different manner, and that the 
variations have been transmitted by each sex to the same, 
without any benefit or evil thus accruing. When the 
male is brilliantly colored and differs conspicuously from 
the female, as with some dragon-flies and many butterflies, 
it is probable that he owes his colors to sexual selection , 
while the female has retained a primordial or very ancient 
type of coloring, slightly modified by the agencies before 
explained. But in some cases the female has apparently 
been made obscure by variations transmitted to her alone, 
as a means of direct protection; and it is almost certain 
that she has sometimes been made brilliant, so as to imitate 
other protected species inhabiting the same district. When 
the sexes resemble each other and both are obscurely colored 
there is no doubt that they have been in a multitude of 
cases so colored for the sake of protection. So it is in some 
instances when both are brightly colored, for they thus imi- 
tate protected species, or resemble surrounding objects such 
as flowers; or they give notice to their enemies that they 
are unpalatable. In other cases in which the sexes resem- 
ble each other and are both brilliant, especially when the 
colors are arranged for display, we may conclude that they 
have been gained by the male sex as an attraction, and have 
been transferred to the female. We are more especially led 
to this conclusion whenever the same type of coloration pre- 
vails throughout a whole group, and we find that the males 
of some species differ widely in color from the females, 
while others differ slightly or not at all with intermediate 
gradations connecting these extreme states. 

In the same manner as bright colors have often been par- 
tially transferred from the males to the females, so it has 
been with the extraordinary horns of many Lamellicorn 
and some other beetles. So, again, the sound-producing 
organs proper to the males of the Homoptera and Orthop- 
tera have generally been transferred in a rudimentary, or 
even in a nearly perfect condition, to the females ; yet not 
sufficiently perfect to be of any use. It is also an interest- 
ing fact, as bearing on sexual selection, that the stridu- 
lating organs of certain male Orthoptera are not fully 
developed until the last moult; and that the colors of cer- 
tain male dragon-flies are not fully developed until some 
little time after their emergence from the pupal state, and. 
>vhen they are ready to breed. 


Sexual selection implies that the more attractive indi- 
viduals are preferred by the opposite sex ; and as with 
insects, when the sexes differ, it is the male which, with 
some rare exceptions, is the more ornamented, and departs 
more from the type to which the species belongs; and as it 
is the male which searches eagerly for the female, we must 
suppose that the females habitually or occasionally prefer 
the more beautiful males, and that these have thus acquired 
their beauty. That the females in most or all the orders 
would have the power of rejecting any particular male, is 
probable from the many singular contrivances possessed by 
the males, such as great jaws, adhesive cushions, spines, 
elongated legs, etc., for seizing the female; for these con- 
trivances show that there is some difficulty in the act, 
so that her concurrence would seem necessary. Judging 
from what we know of the perceptive powers and affections 
of various insects, there is no antecedent improbability in 
sexual selection having come largely into play; but we have 
as yet no direct evidence on this head, and some facts are 
opposed to the belief. Nevertheless, when we see many 
males pursuing the same female, we can hardly believe that 
the pairing is left to blind chance — that the female exerts 
no choice, and is not influenced by the gorgeous colors or 
other 07'naments with which the male is decorated. 

If we admit that the females of the Homoptera and 
Orthoptera appreciate the musical tones of their male part- 
ners, and that the various instruments have been perfected 
through sexual selection, there is little improbability in the 
females of other insects appreciating beauty in form or 
color, and consequently in such characters having been 
thus gained by the males. But from the circumstance of 
color being so variable, and from its having been so often 
modified for the sake of protection, it is difficult to decide 
in how large a proportion of cases sexual selection has 
played a part. This is more especially difficult in those 
orders, such as Orthoptera, Hymenoptera, and Coleoptera, 
in which the two sexes rarely differ much in color; for we 
are then left to mere analogy. With the Coleoptera, how- 
ever, 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 be- 
tween the sexes, that we find the males of some species pos- 
sessing 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. With butterflies 
we have the best evidence, as the males sometimes take 
pains to display their beautiful colors; and we cannot be- 
lieve that they would act thus, unless the display was of 
use to them in their courtship. 

When we treat of birds we shall see that they present in 
their secondary sexual characters the closest analogy with 
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 colors, all evidently for 
the sake of display. We shall find that, as with insects, 
both sexes in certain groups are equally beautiful, and are 
equally provided with ornaments which are usually confined 
to the male sex. In other groups both sexes are equally 
plain-colored and unornamented. Lastly, in some few 
anomalous cases the females are more beautiful than the 
males. We shall often find, in the same group of birds, 
every gradation from no difference between the sexes to an 
extreme difference. We shall see that female birds, like 
female insects, often possess more or less plain traces or 
rudiments of characters which properly belong to the males 
and are of use only to them. The analogy, indeed, in all 
these respects between birds and insects is curiously close. 
Whatever explanation applies to the one class probably 
applies to the other; and this explanation, as we shall here- 
after attempt to show in further detail, is sexual selection. 

FISHES. 375 



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

We have now arrived at the great sub-kingdom of the 
Vertebrata, and will commence with the lowest class, that 
of fishes. The males of Plagiostomous fishes (sharks, rays) 
and of Chimaeroid fishes are provided with claspers which 
serve to retain the female, like the various structures 
possessed by many of the lower animals. Besides the 
claspers, the males of many rays have clusters of strong 
sharp spines on their heads and several rows along *'the 
upper outer surface of their pectoral fins.'' These are 
present in the males of some species, which have other 
parts of their bodies smooth. They are only temporarily 
developed during the breeding-season ; and Dr. (Jiinther 
suspects that they are brought into action as prehensile 
organs by the doubling inward and downward of the two 
sides of the body. It is a remarkable fact that the females 
and not the males of some species, as of Raia clavata, have 
their backs studded with large hook-formed spines.* 

The males alone of the capelin (Mallotus villosus, one of 

*Yarrell's "Hist, of British Fishes," vol. ii, 1836, pp. 417, 425, 
436. Dr. Gtinther informs me that the spines in M clavata are 
peculiar to the female. 


Salmonidae) are provided with a ridge of closely-set, brush- 
like scales, by the aid of which two males, one on each side, 
hold the female, while she runs with great swiftness on 
the sandy beach and there deposits her spawn.* The 
widely distinct Mo7iacantJius scopas presents a somewhai 
analogous structure. The male, as Dr. Giinther informs 
me, has a cluster of stiff, straight spines, like those of a 
comb, on the sides of the tail ; and these in a specimen 
six inches long were nearly one and a half inches in 
length; the female has in the same place a cluster of bristles, 
which may be compared with those of a toothbrush. In 
another species, M. peroniiy the male has a brush like that 
possessed by the female of the last species, while the sides 
of the tail in the female are smooth. In some other 
species of the same genus the tail can be perceived to 
be a little roughened in the male and perfectly smooth in 
the female; and lastly in others, both sexes have smooth 

The males of many fish fight for the possession of the 
females. Thus the male stickleback ( Gasterosteus leiurus) 
has been described as ^' mad with delight " when the female 
comes out of her hiding-place and surveys the nest which 
he has made for her. '^ He darts round her in every direc- 
tion, then to his accumulated materials for the nest, then 
back again in an instant; and as she does not advance he 
endeavors to push her with his snout, and then tries to pull 
her by the tail and side-spine to the nest.^'f The males are 
said to be polygamists; I they are extraordinarily bold and 
pugnacious, while '*^the females are quite pacific.^^ Their 
battles are at times desperate; "for these puny combatants 
fasten tight on each other for several seconds, tumbling 
over and over again, until their strength appears completely 
exhausted." With the rough-tailed stickleback (G. trachu- 
rus) the males while fighting swim round and round each 
other, biting and endeavoring to pierce each other with 
their raised lateral spines. The same writer adds,§ ''the 
bite of these little furies is very severe. They also use their 

*** The American Naturalist," April, 1871, p. 119. 
f See Mr. R. Warington's interesting articles in "Annals and Mag 
of Nat. Hist.," Oct., 1852, and Nov., 1855. 
I Noel Humphreys, " River Gardens," 1857. 
§ Loudon's "Mag. of Nat. History," vol. iii, 1830, p. 331. 

FISHES. 877 

lateral spines with such fatal effect that I have seen ono 
during a battle absolutely rip his opponent quite open, so 
that he sank to the bottom and died." When a fish is con- 
quered, *' his gallant bearing forsakes him; his gay colors 
fade away; and he hides his disgrace among his peaceable 
companions, but is for some time the constant object of hi3 
conquerer's persecution." 

The male salmon is as pugnacious as the little stickle- 
back; and so is the male trout, as I hear from Dr. Giinther. 
Mr. Shaw saw a violent contest between two male salmon 
which lasted the whole day; and Mr. R. Buist, Superin- 
tendent of Fisheries, informs me that he has often watched 
from the bridge at Perth the males driving away their 
rivals whil^ the females were spawning. The males "are 
constantly fighting and tearing each other on the spawning- 
beds, and many so injure each other as to cause the death 
of numbers, many being seen swimming near the banks of 
the river in a state of exhaustion, and apparently in a 
dying state." * Mr. Buist informs me that in June, 1868, 
the keeper of the Stormontfield Breeding-Ponds visited the 
northern Tyne and found about 300 dead salmon, all of 
which with one exception were males; and he was convinced 
that they had lost their lives by fighting. 

The most curious point about the male salmon is that 
during the breeding-season, besides a light change in color, 
''the lower jaw elongates, and a cartilaginous pro- 
jection turns upwar 1 from the point, which, when the 
jaws are closed, occupies a deep cavity between the inter- 
maxillary bones of the upper jaw."t (I^^igs- 27 and 28.) 
In our salmon this change of structure lasts only during 
the breeding-season; but in the Salmo lycaodon oi North- 
western America the change, as Mr. J. K. Lord J believes, 
is permanent and best marked in the older males which have 
previously ascended the rivers. In these old males the 
jaw becomes developed into an immense hook-like projec- 
tion and the teeth grow into regular fangs, often more than 

*"The Field," June 29, 1867. For Mr. Sliaw's statement, see 
" Edinburgli Review," 1843. Another experienced observer (Scrope's 
"Days of Salmon Fishing," p. 60) remarks that like the slag, the 
male would, if he could, keep all other males away. 

f Yarrell, " History of British Fishes," vol. ii, 1836, p. 10. 

% " The Naturalist in Vancouver's Island," vol. i, 1866, p. 64 


half an inch in length. With the European salmon, 
according to Mr. Lloyd,* the temporary hook-like structure 

Kg. {W. Head of male common salmon (,Scdmo solar) during the breeding- 

[This drawing, as well as all the others in the present chapter, have been exe- 
cuted by the well-known artist, Mr. G. Ford, from specimens in the British 
Museum, under the kind superintendence of Dr. Gunther.] 

serves to strengthen and protect the jaws, when one male 
charges another with wonderful violence; hut the greatly 
developed teeth of the male American salmon may be com- 

• " Scandinavian Aaventures/' vol. \, 1854, pp. 100, 104 

FISHES. 379 

pared with the tusks of many male mammals, and they 
indicate an offensive rather than a protective purpose. 

The salmon is not the only fish in which the teeth differ 
in the two sexes; as this is the case with many rays. In 

Pig. 28. Head of female salmon. 

the thornback (Raia Clavata) the adult male has sharp, 
pointed teeth, directed backward, while those of the female 
are broad and flat, and form a pavement; so that these 
teeth differ in the two sexes of the same species more than 
is usual in distinct genera of the same family. The teeth 
of the male become sharp only when he is adult; while 
young they are broad and flat like those of the female. A^ 


BO frequently occurs with secondary sexual characters, both 
sexes of some species of rays (for instance R. batis), when 
adult, possess sharp, pointed teeth; and here a character, 
proper to and primarily gained by the male, appears to have 
been transmitted to the offspring of both sexes. The teeth 
are likewise pointed in both sexes of R. maculata, but only 
when quite adult; the males acquiring them at an earlier 
age than the females. AVe shall hereafter meet with anal- 
ogous cases in certain birds, in which the male acquires the 
plumage common to both sexes when adult, at a somewhat 
earlier age than does the female. With other species of 
rays the males even when old never possess sharp teeth, and 
consequently the adults of both sexes are provided with 
broad, flat teeth like those of the young, and like those of 
the mature females of the above-mentioned species.* As 
the rays are bold, strong and voracic 3 fish, we may suspect 
that the males require their sharp teeth for fighting with 
their rivals; but as they possess many parts modified and 
adapted for the jDrehension of the female, it is possible that 
their teeth may be used for this purpose. 

In regard to size, M. Car onnierf maintains that the 
female of almost all fishes is larger than the male; and Dr. 
Giinther does not know of a single instance in which the 
male is actually larger than the female. With some 
Cyprinodonts the male is not even half as large. As in 
many kinds of fishes the males habitually fight together, it 
is surprising that they have not generally become larger 
and stronger than the females through the effects of sexual 
selection. The males suffer from their small size, for, 
according to M. Carbonnier, they are liable to be devoured 
by the females of their own species when carnivorous, and 
no doubt by other species. Increased size must be in some 
manner of more importance to the females than strength 
and size are to the males for fighting with other males; 
and this perhaps is to allow of the production of a vast 
number of ova. 

In many species the male alone is ornamented with 
bright colors; or these are much brighter in the male than 
the female. The male, also, is sometimes provided with 

* See Yarrell's account of the rays in his " Hist, of British Fishes/ 
vol. ii, 1836, p. 416, with an excellent figure, and pp. 423, 433. 

f As quoted in " The Farmer," 1868, p. 369. 

FI8EE8. 881 

appendages which appear to be of no more use to him for 
the ordinary purposes of life than are the tail feathers to 
the peacock. I am indebted for most of the following 
facts to the kindness of Dr. Giinther. There is reason 
to suspect that many tropical fishes differ sexually in color 
and structure; and there are some striking cases with our 
British fishes. The male Callionymns lyra has been called 
the gemmeous dragonet " from its brilliant gem-like colors/' 

Fig. 29. Callionyjmis lyra Upper figure, male ; lower figure, female. 
N. B.— The lower figure is more reduced than the upper. 

When fresh caught from the sea the body is yellow of 
various shades, striped and spotted with vivid blue on the 
head; the dorsel fins are pale brown with dark longitudinal 
bands; the ventral, caudal and anal fins being bluish-black. 
The female, or sordid dragonet, was considered bjr Lin- 
naeus and by many subsequent naturalists as a distinct 
species; it is of a dingy reddish-brown with the dorsal fin 
brown and the other fins white. The sexes differ also in 
the proportional size of the head and mouth and in the 
position of the eyes;* but the most striking difference is 
the extraordinary elongattion in the male (fig. 29) of the 

*I have drawn up this description from Yarrell's "British 
Fishes," vol. i, 1836, pp. 261, 266. 


dorsal fin. Mr. W. Saville Kent remarks that this '^ sin- 
gular appendage appears from my observations of the 
species in confinement to be subservient to the same end 
as the wattles, crests and other abnormal adjuncts of the 
male in gallinaceous birds for the purpose of fascinating 
their mates. '^* The young males resemble the adult 
females in structure and color. Throughout the genus 
Callionymusf the male is generally much more brightly 
spotted than the female, and in several species, not only 
the dorsal, but the anal fin is much elongated in the males. 

The male of the Cottus scorpins, or sea-scorpion, is 
slenderer and smaller than the female. There is also a 
great difference in color between them. It is difficult, as 
Mr. Lloyd| remarks, " for any one who has not seen this 
fish during the spawning season when its hues are brighest 
to conceive the admixture of brilliant colors with which it, 
in other respects so ill-favored, is at that time adorned." 
Both sexes of the Labrus mixtus, although very different 
in color, are beautiful; the male being orange with bright 
blue stripes and the female bright red with some black 
spots on the back. 

In the very distinct family of the Cyprinodontidae — 
inhabitants of the fresh waters of foreign lands — the sexes 
sometimes differ much in various characters. In the male 
of the Mollienesia petenensis,% the dorsal fin is greatly de- 
veloped and is marked with a row of large, round, ocellated, 
bright-colored spots; while the same fin in the female is 
smaller, of a different shape, and marked only with irregu- 
larly curved brown spots. In the male the basal margin of 
the anal fin is also a little produced and dark colored. In 
the male of an allied form, the Xipliophorus Hellerii (fig. 
30), the inferior margin of the caudal fin is developed into 
a long filament, which, as I hear from Dr. Giinther, is 
striped with bright colors. This filament does not contain 
any muscles, and apparently cannot be of any direct use to 
the fish. As in the case of the Callionymus, the males 

*" Nature," July, 1873, p. 264. 

f " Catalogue of Acanth. Fishes in the British Museum," by Dr. 
Giinther, 161, pp. 138-151. 

X "Game Birds of Sweden," etc., 1867, p. 466. 

§ With respect to this and the following species I am indebted to 
Dr. Giinther for information; see also his paper on the " Fishes of 
Central America," in "Transact. Zoolog. Soc," vol. vi, 1868, p. 485. 

FISHES. 883 

while young resemble the adult females in color and struct- 
ure. Sexual differences such as these may be strictly com- 
pared with those which are so frequent with gallinaceous 

In a siluroid fish, inhabiting the fresh waters of South 
America, the Plecostomiis l)ar'batus\ (fig. 31), the male has 
its mouth and inter-operculum fringed with a beard of stiff 
hairs, of which the female shows hardly a trace. These 

Fig. 30. Xiphophonis Hellerii. Upper figure, male ; lower figure, female. 

hairs are of the nature of scales. In another species of the 
same genus, soft flexible tentacles project from the front 
part of the head of the male, which are absent in the 
female. These tentacles are prolongations of the true skin, 
and therefore are not homologous with the stiff hairs of the 
former species; but it can hardly be doubted that both 
serve the same purpose. What this purpose may be it is 
difficult to conjecture; ornament does not here seem prob- 
able, but we can hardly suppose that stiff hairs and flexible 

*Dr. Giintlier makes this remark; "Catalogue of Fislies in the 
British Museum," vol. iii, 1861, p. 141. 

f See Dr. Gtinther on this genus, in *' Proc. Zoolog. See," 1868, p. 



Fig. 31. Plecostomus barbatus. Upper figure, head of male ; lower figure, 

FISHES. 385 

filainents can be useful in any ordinary way to the males 
alone. In that strange monster, the Chimcera monstrosa, 
the male has a hook-shaped bone on the top of the head, 
directed forward, with its end rounded and covered with 
sharp spines ; in the female '^ this crown is altogether 
absent," but what its use may be to the male is utterly 

The structures as yet referred to are permanent in the 
male after he has arrived at maturity; but with some Blen- 
nies, and in another allied genus, f a crest is developed on 
the head of the male only during the breeding season, and 
the body at the same time becomes more brightly colored. 
There can be little doubt that this crest serves as a tem- 
porary sexual ornament, for the female does not exhibit a 
trace of it. In other species of the same genus both sexes 
possess a crest, and in at least one species neither sex is 
thus provided. In many of the ChromidaB, for instance in 
Geophagus and especially in Cichla, the males, as I hear 
from Prof. Agassiz,]; have a conspicuous protuberance on 
the forehead which is wholly wanting in the females and 
in the young males. Prof. Agassiz adds: ^'1 have often 
observed these fishes at the time of spawning when the 
protuberance is largest, and at other seasons when it is 
totally wanting, and the two sexes show no difference 
whatever in the outline of the profile of the head. I 
never could ascertain that it subserves any special func- 
tion, and the Indians on the Amazon know nothing about 
its use." These protuberances resemble in their periodical 
appearance the fleshy carbuncles on the heads of certain 
birds; but whether they serve as ornaments must remain at 
present doubtful. 

I hear from Prof. Agassiz and Dr. Giinther that the 
males of those fishes which differ permanently in color 
from the females often become more brilliant during 
the breeding season. This is likewise the case with a 
multitude of fishes, the sexes of which are identical in 

*F. Buckland in " Land and Water," July, 1868, p. 377, with a 
figure. Many other cases could be added of structures peculiar to 
the male, of which the uses are not known. 

f Dr. Giinther, "Catalogue of Fishes," vol. iii, pp. 221 and 240. 

X Sea also •' A Journey in Brazil," by Prof, and Mrs. Agassiz, 1868, 
p. 230. 


color at all other seasons of the year. The tench, roach 
and perch may be given as instances. The male salmon 
at this season is '' marked on the cheeks with orange- 
colored stripes, which give it the appearance of a Labrus, 
and the body partakes of a golden-orange tinge. The 
females are dark in color, and are commonTy called black- 
fish.^^* An analogons and even greater change takes place 
with the Salmo eriox or bull trout ; the males of the char 
{S. umhla) are likewise at this season rather brighter in 
color than the females, f The colors of the pike ( Esox 
reticulatus) of the United States, especially of the male, 
become, during the breeding-season, exceedingly intense, 
brilliant, and iridescent.]; Another striking instance out 
of many is afforded by the male stickleback ( Gasterosteus 
leiurus), which is described by Mr. Warington,§ as being 
then ^^ beautiful beyond description." The back and eyes 
of the female are simply brown and the belly white. The 
eyes of the male, on the other hand, are '' of the most 
splendid green, having a metallic luster like the green 
feathers of some humming-birds. The throat and belly are 
of a bright crimson, the back of an ashy-green, and the 
whole fish appears as though it were somewhat translucent 
and glowed with an internal incandescence." After the 
breeding-season these colors all change, the throat and 
belly become of a paler red, the back more green, and the 
glowing tints subside. 

With respect to the courtship of fishes, other cases have 
been observed since the first edition of this book appeared, 
besides that already given of the stickleback. Mr. W. S.* 
Kent says that the male of the Labrus mixtuSy which, as 
we have seen, differs in color from the female, makes " a 
deep hollow in the sand of the tank, and then endeavors in 
the most persuasive manner to induce a female of the same 
species to share it with him, swimming backward and for- 
ward between her and the completed nest, and plainly 
exhibiting the greatest anxiety for her to follow." The 
males of Cantharus Uneatus become, during the breeding- 

* Yarrell, "British Fishes," vol. ii, 1836, pp. 10, 12, 35. 
fW. Thompson, in "Annals and Mag. of Nat. History," vol. vi, 
1841, p. 440. 
t " The American Agriculturist," 1868, p. 100. 
§ " Annals and Mag. of Nat. Hist.," Oct., 1858. 

FISHES. 387 

season, of deep leaden-black; they then retire from the 
shoal, and excavate a hollow as a nest. ^' Each male now 
monnts vigilant guard over his respective hollow, and vig- 
orously attacks and drives away any other fish of the same 
sex. Toward his companions of the opposite sex his con- 
duct is far different; many of the latter are now distended 
with spaAvn, and these he endeavors by all the means in his 
power to lure singly to his prepared hollow, and there to 
deposit the myriad ova with which they are laden, which 
he then protects and guards with the greatest care."* 

A more striking case of courtship, as well as of display, 
by the males of a Chinese Macropus has been given by M. 
Carbonnier, who carefully observed these fishes under con- 
finement, t The males are most beautifully colored, more 
so than the females. During the breeding-season they con- 
tend for the possession of the females ; and, in the act of 
courtship, expand their fins, which are spotted and orna- 
mented with brightly colored rays, in the same manner, 
according to M. Carbonnier, as the peacock. They 
then also bound about the females with much vivacity, and 
appear by ^^Tetalage de leurs vives couleurs chercher a 
attirer Tattention des femelles, lesquelles ne paraissaient 
indifferentes a ce manege, elles nageaient avec une molle 
lenteur vers les mdles et semblaient se complaire dans leur 
voisinage." After the male has won his bride he makes a 
little disk of froth by blowing air and mucus out of his 
mouth. He then collects the fertilized ova dropped by the 
female in his mouth; and this caused M. Carbonnier much 
alarm, as he thought that they were going to be devoured. 
But the male soon deposits them in the disk of froth, after- 
ward guarding them, repairing the froth, and taking care 
of the young when hatched. I mention these particulars 
because, as we shall presently see, there are fishes the males 
of which hatch their eggs in their mouths; and those who 
do not believe in the principle of gradual evolution might 
ask how could such a habit have originated; but the diffi- 
culty is much diminished when we know that there are 
fishes which thus collect and carry the eggs; for if delayed 
by any cause in depositing them, the habit of hatching 
them in their mouths might have been acquired. 

* "Nature," May, 1873, p. 25. 

t *' Bull, de la Soc. d'Acclimat.," Paris, July, 1869, and Jan. 1870. 


To return to our more immediate subject. The case 
stands thus; female fishes, as far as I can learn, never will- 
ingly spawn except in the presence of the males; and the 
males never fertilize the ova except in the presence of the 
females. The males fight for the possession of the females. 
In many species the males while young resemble the females 
in color; but when adult become much more brilliant, and 
retain their colors throughout life. In other species the 
males become brighter than the females and otherwise more 
highly ornamented, only during the season of love.' The 
males sedulously court the females, and in one case, as we 
have seen, take pains in displaying their beauty before 
them. Can it be believed that they w^ould thus act to no 
purpose during their courtship? And this would be the case 
unless the females exert some choice and select those males 
which please or excite them most. If the female exerts 
such choice, all the above facts on the ornamentation of 
the males become at once intelligible by the aid of sexual 

We have next to inquire whether this view of the bright 
colors of certain male fishes having been acquired through 
sexual selection can, through the law of the equal trans- 
mission of characters to both sexes, be extended to those 
groups in which the mules and females are brilliant in the 
same, or nearly tlie same, degree and manner. In such a 
genus as Labrus, wliicli includes some of the most splendid 
fishes in the world — for instance, the Peacock Labrus {L. 
pavo), described,* with pardonable exaggeration, as formed 
of polished scales of gold, incrusting lapis-lazuli, rubies, 
sapphires, emeralds and amethysts — we may, with much 
probability, accept this belief, for we have seen that the 
sexes in at least one species of the genus differ greatly in 
color. Witn some fishes, as witli many of the lowest ani- 
mals, splendid colors may be the direct result of the nature 
of their tissues and of the surrounding conditions, without 
tlie aid of selection of any kind. The gold-fish {Cyprinus 
miratus), judging from the analogy of the golden variety 
of tlie common carp, is perhaps a case in point, as it may 
owe its splendid colors to a single abrupt variation, due to 
the conditions to which this fish has been subjected under 

*Bory de Saint Vincent, in "Diet. Class. d'Hist. Nat.," torn, ix, 
1826, p. 151. 

FISHES, 889 

confinement. It is, however, more probable that these 
colors have been intensified through artificial selection, as 
this species has been carefully bred in China from a remote 
period.* Under natural conditions it does not seem prob- 
able that beings so highly organized as fishes, and which 
live under such complex relations, should become brilliantly 
colored without suffering some evil or receiving some bene- 
fit from so great a change, and consequently without the 
intervention of natural selection. 

AVhat, then, are we to conclude in regard to the many 
fishes, both sexes of which are splendidly colored? Mr. 
AVallace f believes that the species which frequent reefs, 
where corals and other brightly-colored organisms abound, 
are brightly colored in order to escape detection by their 
enemies; but according to my recollection they were thus 
rendered highly conspicuous. In the fresh waters of the 
tropics there are no brilliantly-colored corals or other 
organisms for the fishes to resemble; yet many species in 
the Amazons are beautifully colored, and many of the car- 
nivorous Cyprinidas in India are ornamented with " bright 
longitudinal lines of various tints." X Mr. McClelland, in 
describing these fishes, goes so far as to suppose that " the 
peculiar brilliancy of their colors" serves as "a better 
mark for king-fishers, terns, and other birds which are 
destined to keep the number of these fishes in check;" but 
at the present day few naturalists will admit that any 
animal has been made conspicuous as an aid to its own 
destruction. It is possible that certain fishes may have 
been rendered conspicuous in order to warn birds and beasts 
of prey that they were unpalatable, as explained when 
treating of caterpillars; but it is not, I believe, known that 

* Owing to some remarks on this subject made in my work " On 
the Variation of Animals under Domestication," Mr. W. F. Mayers 
("Chinese Notes and Queries," Aug. 1868, p. 123) has searched the 
ancient Chinese encyclopedias. He finds that gold-fish were first 
reared in confinement during the Sung Dynasty which commenced 
A. D. 960. In the year 1129 these fishes abounded. In another 
place it is said that since the year 1548 there has been " produced at 
Hangchow's a variety called the fire-fish, from its intensely red color. 
It is universally admired and there is not a household where it is not 
cultivated, in rivalry as to its color, and as a source of profit." 

y Westminster Review," July, 1867, p. 7. 

t *' Indian Cyprinidse," by Mr. M'Clelland, " Asiatic Besearclies," 
vol. xix, part u, 1839, p. 230. 


an J fish, at least any fresh-water fish, is rejected from 
being distasteful to fish-devouring animals. On the wliolo, 
the most probable view in regard to the fishes, of which 
both sexes are brilliantly colored, is that their colors were 
acquired by the males as a sexual ornament, and were 
transferred equally, or nearly so, to the other sex. 

We have now to consider whether, when the male differs 
in a marked manner from the female in color or in other 
ornaments, he alone has been modified, the variations being 
inherited by his male offspring alone ; or whether the 
female has been specially modified and rendered inconspicu- 
ous for the sake of protection, such modifications being 
inherited only by the females. It is impossible to doubt 
that color has been gained by many fishes as a protection; no 
one can examine the speckled upper surface of a flounder 
and overlook its resemblance to the sandy bed of the sea on 
which it lives. Certain fishes, moreover, can through the 
action of the nervous system change their colors in adapta- 
tion to surrounding objects, aud that within a short time.* 
One of the most striking instances ever recorded of an 
animal being protected by its color (as far as it can be 
judged of in preserved specimens), as well as by its form, 
is that given by Dr. Giintherf of a pipe-fish, which, with 
its reddish streaming filaments, is hardly distinguishable 
from the sea- weed to which its clings with its prehensile 
tail. But the question now under consideration is whether 
the females alone have been modified for this object. We 
can see that one sex will not be modified through natural 
selection for the sake of protection more than the other, 
supposing both to vary, unless one sex is exposed for a 
longer period to danger, or has less power of escaping from 
such danger than the other; and it does not appear that 
with fishes the sexes differ in these respects. As far as 
there is any difference the males, from being generally 
smaller and from wandering more about, are exposed to 
greater danger than the females; and yet when the sexes 
differ the males are almost always the more conspicuously 
colored. The ova are fertilized immediately after being 
deposited; and when this process lasts for several days, as 
in the case of the salmon, J; the female during the whole 

* G. Pouchet, L'Institut, Nov. 1, 1871, p. 134. 

f " Proc. Zoolog. Soc," 1865, p. 327, pi. xiv and xv. 

j Yarrell, ** Britisli Fishes," vol. ii, p. 11. 

FI8HE8. 391 

time is attended by the male. After the ova are fertilized 
they are, in most cases, left unprotected by both parents, 
so that the males and females, as far as oviposition is con- 
cerned, are equally exposed to danger, and both are equally 
important for the production of fertile ova; consequently 
the more or less brightly colored individuals of either 
sex would be equally liable to be destroyed or preserved, 
and both would have an equal influence on the colors of 
their offspring. 

Certain fishes, belonging to several families, make nests, 
and some of them take care of their young when hatched. 
Both sexes of the bright-colored Crenilnbrus massa and 
melops work together in building their nests with sea-weed, 
shells, etc.* But the males of certain fishes do all the 
work and afterward take exclusive charge of the young. 
This is the case with the dull-colored gobies, f in which the 
sexes are not known to differ in color, and likewise with 
the sticklebacks (Gasterosteus), in which the males become 
brilliantly colored during the spawning season. The male 
of the smooth-tailed stickleback ( 0. leiurus) performs the 
duties of a nurse with exemplary care and vigilance during 
a long time, and is continually employed in gently leading 
back the young to the nest when they stray too far. He 
courageously drives away all enemies, including the females 
of his own species. It would indeed be no small relief to 
the male if the female after depositing her eggs were 
immediately devoured by some enemy, for he is forced 
incessantly to drive her from the nest. J 

The males of certain other fishes inhabiting South Amer- 
ica and Ceylon, belonging to two distinct orders, have the 
extraordinary habit of hatching within their mouths, or 
branchial cavities, the eggs laid by the females. § I am 
informed by Prof. Agassiz that the males of the Amazonian 

* According to the observations of M. Gerbe; see Giinther's 
" Record of Zoolog. Literature," 1865, p. 194. 

fCuvier, " Regne Animal," vol. ii, 1829, p. 242. 

X See Mr. Warington's most interesting description of the habits of 
the Gasterosteus leiurus in "Annals and Mag. of Nat. Hist./' Nov., 

§Prof. Wyman, in "Proc. Boston Soc. of Nat. Hist.," Sept. 15, 
1857. Also Prof. Turner, in "Journal of Anatomy and Phys.," 
Nov. 1, 1866, p. 78. Dr. Giinther has likewise described other 


species wliicli follow this habit, *' not only are generally 
brighter than the females, but the difference is greater at 
the spawning-season than at any other time." The species 
of Geophagus act in the same manner; and in this genus, a 
conspicuous protuberance becomes developed on the fore- 
head of the males during the breeding- season. With the 
various species of Chromids, as Prof. Agassiz likewise 
informs me, sexual differences in color may be observed, 
*' whether they lay their eggs in the water among aquatic 
plants or deposit them in holes, leaving them to come out 
without further care; or build shallow nests in the river 
mud, over which they sit, as our Pomotis does. It ought 
also to be observed that these sitters are among the bright- 
est species in their respective families; for instance, Hygro- 
gonus is bright green with large black ocelli, encircled 
with the most brilliant red." Whether with all the species 
of Chromids it is the male alone which sits on the eggs is 
not known. It is, however, manifest that the fact of the 
eggs being protected or unprotected by the parents, has had 
little or no influence on the differences in color between the 
sexes. It is further manifest in all the cases in which the 
males take exclusive charge of the nests and young, that 
the destruction of the brighter-colored males would be far 
more influential on the character of the race than the 
destruction of the brighter-colored females; for the death 
of the male during the period of incubation or nursing 
would entail the death of the young, so that they could not 
inherit his peculiarities; yet in many of these very cases 
the males are more conspicuously colored than the females. 
In most of the Lophobranchii (Pipe-fish, Hippocampi, 
etc.) the males have either marsupial sacks or hemispherical 
depressions on the abdomen, in which the ova laid by the 
female are hatched. The males also show great attachment 
to their young.* The sexes do not commonly differ much 
in color; but Dr. Gunther believes that the male Hippo- 
campi are rather brighter than the females. The genus 
Solenostoma, however, offers a curious exceptional case,t 
for the female is much more vividly colored and spotted 

*Yarrell, " Hist, of British Fishes," vol. ii, 1836, pp. 829, 338. 

f Dr. Gunther, since publishing an account of this species in " The 
Fishes of Zanzibar," by Col. Playfair, 1866, p. 137, has re-examine4 
the specimens and has given me the above inf ormatioxu 

FISHES. 893 

than the male, and she alone has a marsupial sack and 
hatches the eggs; so that the female of Solenostoma differs 
from all the other Lophobranchii in this latter respect, and 
from almost all other fishes, in being more brightly colored 
than the male. It is improbable that this remarkable 
double inversion of character in the female should be 
an accidental coincidence. As the males of several fishes, 
which take exclusive charge of the eggs and young, are 
more brightly colored than the females, and as here the 
female Solenostoma takes the same charge and is brighter 
than the male, it might be argued that the conspicuous colors 
of that sex which is the more important of the two for the 
welfare of the offspring, must be in some manner pro- 
tective. But from the large number of fishes, of which the 
males are either permanently or periodically brighter than 
the females, but whose life is not at all more important for 
the welfare of the species than that of the female, this 
view can hardly be maintained. AYhen we treat of birds 
we shall meet with analogous cases, where tliere has been a 
complete inversion of the usual attributes of the two sexes, 
and we shall tlien give wliat appears to be the probable 
explanation, namely, that the males have selected the more 
attractive females, instead of the latter having selected, in 
accordance with the usual rule tliroughout the animal 
kingdom, the more attractive males. 

On the whole we may conclude, that with most fishes, in 
which tlie sexes differ in color or in other ornamental cliar- 
acters, the males originally varied, with their variations 
transmitted to the same sex, and accumulated through 
sexual selection by attracting or exciting the females. In 
many cases, however, sucli cliaracters have been transferred, 
either partially or completely, to the females. In other 
cases, again, both sexes have been colored alike for the sake 
of protection; but in no instance does it appear that the 
female alone lias had her colors or other characters specially 
modified for this latter purpose. 

The last point which need be noticed is that fishes are 
known to make various noises, some of which are described 
as being musical. Dr. Dufosse, who has especially attended 
to tliis subject, says that the sounds are voluntarily pro- 
duced in several ways by different fishes; by the friction of 
the pharyngeal bones — by the vibration of certain muscles 
attached to tlie swim-bladder, which serves as a resoundinir 


board — and by the vibration of the intrinsic muscles of the 
swim-bladder. By this latter means the Trigla producoB 
pure and long-drawn sounds which range over nearly an 
octave. But the most interesting case for us is that of two 
species of Ophidium, in which the males alone are provided 
with a sound-producing apparatus, consisting of small mov- 
able bones, with proper muscles, in connection with the 
swim-bladder.* The drumming of the Umbrinas in the 
European seas is said to be audible from a depth of twenty 
fathoms; and the fisherman of Rochelle assert '^^that the 
males alone make the noise during the spawning- time; and 
that it is possible by imitating it to take them without 
bait."f From this statement, and more especially from 
the case of Ophidium, it is almost certain that in this, the 
lowest class of the Vertebrata, as with so many insects and 
spiders, sound-producing instruments have, at least in some 
cases, been developed through sexual selection, as a means 
for bringing the sexes together. 


Urodela. — I will begin with the tailed amphibians. The 
sexes of salamanders or newts often diifer much both in 
color and structure. In some species prehensile claws 
are developed on the fore legs of the males during 
the breeding-season ; and at this sisason in the male Triton 
palmipes the hind feet are provided with a swimming-web, 
which is almost completely absorbed during the winter; so 
that their feet then resemble those of the female. I This 
structure no doubt aids the male in his eager search and 
pursuit of the female. While courting her he rapidly 
vibrates the end of his tail. With our common newts 
{Triton punctatus and cristatus) a deep, much indented 
crest is developed along the back and tail of the male 
during the breeding-season, which disappears during tlie 

* "Comptes Rendus." Tom, xlvi, 1858, p. 353. Tom. xlvii, 1858, 
p. 916. Tom. liv, 1863, p. 393. The noise made by the Umbrinas 
{Scicena aquila), is said by some authors to be more like that of a 
tiiite or organ, than drumming: Dr. Zouteveen, in the Dutch trans- 
lation of this work (vol. ii, p. 36), gives some further particulars on 
the sounds made by fishes. 

f The Rev, C, Kingsley, in " Nature," May, 1870, p. 40. 

;Bell "History of British Reptiles," 2nd edit. 1849, pp. 166-159. 



winter. Mr. St. George Mivart informs me that it is not 
t'urnislied with muscles, and therefore cannot be used for 
locomotion. As during the season of courtship it becomes 
edged with bright colors, there can hardly be a doubt that 
it is a masculine ornament. In many species the body pre- 
sents strongly contrasted, though lurid tints, and these 
become more vivid during the breeding-season. The male, 
for instance, of our common little newt {IViton pu7ictatus) 
is " brownish-gray above, passing into yellow beneath, 
which in the spring becomes a rich bright orange, marked 
everywhere with round dark spots. ^' The edge of the crest 

Fig. 32. Triton cristatus (tialf natural size, from Bell's " British Reptiles ")• 
Upper figure, male during the breeding-season; lower figure, female. 

also is then tipped with bright red or violet. The female 
is usually of a yellowish-brown color with scattered brown 
dots, and the lower surface is often quite plain.* The 
young are obscurely tinted. The ova are fertilized during 
the act of deposition, and are not subsequently tended by 
either parent. We may therefore conclude that the males 
have acquired their strongly-marked colors and ornamental 
appendages through sexual selection; these being transmit- 
ted either to the male offepring alone, or to both sexes. 

Anura or BatracMa. — With many frogs and toads the 
colors evidently serve as a protection, such as the bright 

*Bell, "History of British Reptiles," 2d edit., 1849, pp. 146, 151, 


green tints of tree frogs and the obscure mottled shades of 
many terrestrial species. The most conspicuously-colored 
toad which I ever saw, the Phryniscns nigricans,^ had the 
whole upper surface of the body as black as ink, with the 
soles of the feet and parts of the abdomen spotted with the 
brightest vermilion. It crawled about the bare sandy or 
open grassy plains of La Plata under a scorching sun, and 
could not fail to catch the eye of every passing creature. 
These colors are probably beneficial by making this animal 
known to all birds of prey as a nauseous mouthful. 

In Nicaragua there is a little frog '' dressed in a bright 
livery of red and blue^' which does not conceal itself like 
most other species, but hops about during the daytime, and 
Mr. Belt says f that as soon as he saw its happy sense of 
security he felt sure that it was uneatable. After several 
trials he succeeded in tempting a young duck to snatch up 
a young one, but it was instantly rejected; and the duck 
" went about jerking its head as if trying to throw off some 
unpleasant taste." 

With respect to sexual differences of color Dr. Giinther 
does not know of any striking instance either with frogs 
or toads; yet he can often distinguish the male from the 
female by the tints of the former being a little more intense. 
Nor does he know of any striking difference in external 
structure between the sexes, excepting the prominences which 
become developed during the breeding-season on the front 
legs of the male, by which he is enabled to hold the female. J; 
It is surprising that these animals have not acquired more 
strongly- marked sexual characters; tor though cold-blooded 
their passions are strong. Dr. Giinther informs me that he 
has several times found an unfortunate female toad dead 
and smothered from having been so closely embraced by 
three or four males. Frogs have been observed by Prof. 
Hoffman in Giessen fighting all day long during the breed- 
ing season, and with so much violence that one had its body 
ripped open. 

* "Zoology of tlie Voyage of the 'Beagle,' " 1843. Bell, ibid, p. 

f " The Naturalist in Nicaragua," 1874, p. 321. 

X The male alone of the Bufo sikimmensifi (Dr. Anderson, ** Proo. 
Zoolog. Soc," 1871, p. 204) has two plate like callosities on the 
thorax and certain rugosities on the fingers, which perhaps subserve 
the same end as the above mentioned prominences. 


Frogs and toads offer one interesting sexual difference, 
namely, in the musical powers possessed by the males; but 
to speak of music, when applied to the discordant and 
overwhelming sounds emitted by male bull-frogs and some 
other species seems, according to our taste, a singularly 
inappropriate expression. Nevertheless, certain frogs sing 
in a decidedly pleasing manner. Near Eio Janeiro I used 
often to sit in the evening to listen to a number of little 
Hylae perched on blades of grass close to the water, which 
sent forth sweet chirping notes in harmony. The various 
sounds are emitted chiefly by the males during the breed- 
ing-season, as in the case of the croaking of our common 
frog.* In accordance with this fact the vocal organs of the 
males are more highly developed than those oi the females. 
In some genera the males alone are provided with sacs 
which open into the larynx, f For instance, in the edible 
frog {Rana esculenta) *nhe sacs are peculiar to the males, 
and become, when filled with air in the act of croaking, 
large globular bladders, standing out one on each side of 
the head near the corners of the mouth." The croak of 
the male is thus rendered exceedingly powerful; while that 
of the female is only a slight groaning noise. J In the sev- 
eral genera of the family the vocal organs differ considerably 
in structure, and their development in all cases may be 
attributed to sexual selection. 


Clielonia. — Tortoises and turtles do not offer well-marked 
sexual differences. In some species the tail of the male is 
longer than that of the female. In some the plastron or 
lower surface of the shell of the male is slightly concave in 
relation to the back of the female. The male of the mud- 
turtle of the United States (Chrysemys picta) has claws on 
its front feet twice as long as those of the female; and 
these are used when the sexes unite. § With the huge 
tortoise of the Galapagos Islands ( Testudo nigra) the males 

*Bell, "History of Biitisli Reptiles," 1849, p. 93. 

+ J. Bishop, in "Todd's Cyclop, of Anat. and Phys.," voL iv, p. 

tBell, ibid, pp. 112-114. 

§Mr. C. J. Maynard, "The American Naturalist," Dec. 


are said to grow to a larger size than the females. During 
the pairing season, and at no other time, the male utters a 
hoarse, bellowing noise which can be heard at the distance 
of more than a hundred yards; the female, on the other 
hand, never uses her voice. * 

With the Testudo elegans of India it is said " that the 
combats of the males may be heard at some distance from 
the noise they produce in butfcing against each other/^f 

Crocodilia. — The sexes apparently do not differ in color; 
nor do I know that the males fight together, though this 
is probable, for some kinds make a prodigious display 
before the females. BartramJ describes the male alligator 
as striving to win the female by splashing and roaring in 
the midst of a lagoon, " swollen to an extent ready to 
burst, with its head and tail lifted up, he springs or twirls 
round on the surface of the water like an Indian chief 
rehearsing his feats of war." During the season of love a 
musky odor is emitted by the submaxiliary glands of the 
crocodile and pervades their haunts. § 

OpMdia. — Dr. Giinther informs me that the males are 
always smaller than the females, and generally have longer 
and slenderer tails; but he knows of no other difference in 
external structure. In regard to color, he can almost 
always distinguish the male from the female by his more 
strongly pronounced tints; thus the black zigzag band on 
the back of the male English viper is more distinctly 
defined than in the female. The difference is much plainer 
in the rattlesnakes of North America, the male of which, 
as the keeper in the Zoological Gardens showed me, can at 
once be distinguished from the female by having more 
lurid yellow about its whole body. In S. Africa the 
Bucephalus capensis presents an analogous difference, for 
the female " is never so fully variegated with yellow on the 
sides as the male. || The male of the Indian Dipsas cynodon, 

* See my " Journal of Researches during the Voyage of the 
'Beagle,'" 1845, p. 384. 
f Dr. Giinther, " Reptiles of British India," 1864, p. 7. 
X " Travels through Carolina," etc., 1791, p. 128. 
^Owen, " Anatomy of Vertebrates," vol. i, 1866, p. 615. 
I Sir Andrew Smith, " Zoolog. of S. Africa: Reptilia," 1849, pi. x. 


on the other hand, is blackish-brown, with the belly partly 
black, while the female is reddish or yellowish-olive, with 
the belly either uniform yellowish or marbled with black. 
In the Tragops dispar of the same country the male is 
bright green and the female bronze colored.* No doubt 
the colors of some snakes are protective, as shown by the 
green tints of tree-snakes and the various mottled shades 
of the species which live in sandy places; but it is doubtful 
whether the colors of many kinds, for instance of the 
common English snake and viper, serve to conceal them; 
and this is still more doubtful with the many foreign 
species which are colored with extreme elegance. The 
colors of certain species are very diiferent in the adult and 
young states. \ 

During the breeding-season the anal scent-glands of 
snakes are in active function; J and so it is with the same 
glands in lizards, and as we have seen with the submaxillary 
glands of crocodiles. As the males of most animals search 
for the females, these odoriferous glands probably serve to 
excite or charm the female, rather than to guide her to the 
spot where the male may be found. Male snakes, though 
appearing so sluggish, are amorous; for many have been 
observed crowding round the same female, and even round 
her dead body. They are not known to fight together from 
rivalry. Their intellectual powers are higher than might 
have been anticipated. In the Zoological Gardens they 
soon learn not to strike at the iron bar with which their 
cages are cleaned; and Dr. Keen, of Philadelphia, informs 
me that some snakes which he kept learned after four or 
five times to avoid a noose, with which they were at first 
easily caught. An excellent observer in Ceylon, Mr. E. 
Layard,§ saw a cobra thrust its head through a narrow hole 
and swallow a toad. '^^With this incumbrance he could 
not withdraw himself; finding this, he reluctantly dis- 
gorged the precious morsel, which began to move off; this 

*Dr. A. Giintlier, ** Reptiles of British India," Ray Soc, 1864, pp. 
304, 308. 

f Dr. Stoliczka, ** Journal of Asiatic Soc. of Bengal," voL xxxix, 
1870, pp. 205, 211. 

X Owen, " Anatomy of Vertebrates,*' vol. 1, 1866, p. 615. 

§ '• Rambles in Ceylon," in "Annals and Mag. of Nat. Hist./* 2(i 
series, vol. ix, 1852, p. 333. 


was too much for snake philosophy to bear, and the toad 
was again seized, and again was the snake, after violent 
efforts to escape, compelled to part with its prey. This 
time, however, a lesson had been learned, and the toad was 
seized by one leg, withdrawn, and then swallowed in 

The keeper in the Zoological Gardens is positive that 
certain snakes, for instance Crotalus and Python, distin- 
guish him from all other persons. Cobras kept together in 
the same cage apparently feel some attachment toward each 

It does not, however, follow because snakes have some 
reasoning power, strong passions and mutual affection, 
that they should likewise be endowed with sufficient taste 
to admire brilliant colors in their partners, so as to lead to 
the adornment of the species through sexual selection. 
Nevertheless, it is difficult to account in any other manner 
for the extreme beauty of certain species; for instance, of 
the coral-snakes of South America, which are of a rich red 
with black and yellow transverse bands. I well remember 
how much surprise I felt at the beauty of the first coral- 
snake which I saw gliding across a path in Brazil. Snakes 
colored in this peculiar manner, as Mr. Wallace states on 
the authority of Dr. Gunther,f are found nowhere else in 
the world except in South America, and here no less than 
four genera occur. One of these, Elaps, is venomous; a 
second and widely-distinct genus is doubtfully venomous, 
and the two otliers are quite harmless. The species belong- 
ing to these distinct genera inhabit the same districts, and 
are so like each other that no one '^but a naturalist would 
distinguish the harmless from the poisonous kinds.'^ Hence, 
as Mr. Wallace believes, the innocuous kinds have proba- 
bly acquired their colors as a protection, on the principle of 
imitation; for they would naturally be thought dangerous 
by their enemies. The cause, however, of the bright 
colors of the venomous Elaps remains to be explained, and 
this may perhaps be sexual selection. 

Snakes produce other sounds besides hissing. The 
deadly Echis carinata has on its sides some oblique rows of 
scales of a peculiar structure with serrated edges ; and 

*Dr. Glintber. " Reptiles of British India," 1864, p. 340. 
\ " Westminster Review," July 1, 1867, p. 33. 


when this snake is excited these scales are rubbed against 
each other, which produces "a curious prolonged, almost 
hissing sound/^ * AVith respect to the rattling of the 
rattlesnake, we have at last some definite information; for 
Prof essor Aughey states,! that on two occassons, being him- 
self unseen, he watched from a little distance a rattlesnake 
coiled up with head erect, which continued to rattle at 
short intervals for half an hour; and at last he saw another 
snake approach, and when they met they paired. Hence 
he is satisfied that one of the uses of the rattle is to bring 
the sexes together. Unfortunately he did not ascertain 
whether it was the male or the female which remained 
stationary and called for the other. But it by no means 
follows from the above fact that the rattle may not be of 
use to these snakes in other ways, as a warning to animals 
which would otherwise attack them. Nor can I quite dis- 
believe the several accounts which have appeared of their 
thus paralyzing their prey with fear. Some other snakes 
also make a distinct noise by rapidly vibrating their tails 
against the surrounding stalks of plants ; and I have 
myself heard this in the case of a Trigonocephalus in South 

Lacertilia. — The males of some, probably of many kinds 
of lizards, fight together from rivalry. Thus the arboreal 
Anolis crista felhis of South America is extremely pugna- 
cious: '^During the spring and early part of the summer, 
two adult males rarely meet without a contest. On first 
seeing one another, they nod their heads up and down 
three or four times, and at the same time expanding the 
frill or pouch beneath the throat; their eyes glisten with 
rage, and after waving their tails from side to side for a 
few seconds, as if to gather energy, they dart at each other 
furiously, rolling over and over, and holding firmly with 
their teeth. The conflict generally ends in one of the com- 
batants losing his tail, which is often devoured by the 
victor.'^ The male of this species is considerably larger 
than the female;^ and this, as far as Dr. Giinther has been 

*Dr. Anderson, "Proc. Zoolog. Soc," 1871, p. 196. 
f " Tlie American Naturalist," 1873, p. 85. 

X Mr. N. L. Austen kept these animals alive for a considerable 
time; see *' Land and Water," July, 1867, p. 0. 



able to ascertain, is the general rule with lizards of all kinds. 
The male alone of the Uyrtodadylus rubidus of the Anda- 
man Islands possesses pre-anal pores; and these pores, judg- 
ing from analogy, probably serve to emit an odor.* 

The sexes often differ greatly in various external charac- 
ters. The male of the above-mentioned Anolis is furnished 
with a crest which runs along the back and tail, and 
can be erected at pleasure ; but of this crest the 
female does not exhibit a trace. In the Indian 
Cophotis ceylanica the female has a dorsal crest, though 
much less developed than in the male; and so it is, as Dr. 

Giinther informs me, with the 
females of many Iguanas, 
Chameleons and other lizards. 
In some species, however, 
the crest is equally developed 
in both sexes, as in the Iguana 
tuberculata. In the genus 
Sitana, the males alone are 
furnished with a large throat- 
pouch (fig. 33), which can be 
folded up like a fan, and is 
Fiff. 33. Sitana minor. Male with colored blue, black and red; 

but these splendid colors are 
exhibited only during the pair- 
ing-season. The female does not possess even a rudi- 
ment of this appendage. In the Anolis cristatellus accord- 
ing to Mr. Austen, the throat pouch, which is bright red 
marbled with yellow, is present in the female, though in a 
rudimental condition. Again, in certain other lizards, 
both sexes are equally well provided with throat pouches. 
Here we see with species belonging to the same group, as 
in so many previous cases, the same character either con- 
fined to the males or more largely developed in them than 
in the females, or again equally developed in both sexes. 
The little lizards of the genus Draco, which glide through 
the air on their rib-supported parachutes, and which in the 
beauty of their colors baffle description, are furnished with 
skinny appendages to the throat *' like the wattles of gall- 
inaceous birds. ^' These become erected when the animal 

the gular pouch expanded (from 
Qunther's '' Reptiles of India".) 

* Stoliczka, "Journal of Asiatic Soc. of Bengal,' 
p. 106. 

vol. xxxiv, 1870, 


is excited. They occur in both sexes, but are best devel- 
oped when the male arrives at maturity, at which age the 
middle appendage is sometimes twice as long as the head. 
Most of the species likewise have a low crest running along 
the neck; and this is much more developed in the full-grown 
males than in the females or young males.* 

A Chinese species is said to live in pairs during the 
spring; '•^and if one is caught the other falls from the tree 
to the ground, and allows itself to be captured with im- 
punity, I presume from despair, f 

There are other and much more 
remarkable differences between 
the sexes of certain lizards. The 
male of Ceratophora aspera bears 
on the extremity of his snout an 
appendage half as long as the head. 
It is cylindrical, covered with 
scales, flexible and apparently 
capable of erection; in the female 
it is quite rudimental. In a second 
species of the same genus a ter- 
minal scale forms a minute horn 
on the summit of the flexible 

appendage; and in a third species . , , ,, .. 

d Stoddartii (fig. 34), the whole %?'er°1l|i?l;''m1ae;*iSwer 
appendage is converted into a horn, figure, female, 
which is usually of a white color, 

but assumes a purplish tint when the animal is excited. In 
the adult male of this latter species the horn is half an inch 
in length, but it is of quite minute size in the female and in 
the young. These appendages, as Dr. Giinther has 
remarked to me, may be compared with the combs of gall- 
inaceous birds, and apparently serve as ornaments. 

In the genus Chameleon we come to the acme of differ- 
ence between the sexes. The upper part of the skull of the 
male C. hifurcus (fig. 35), an inhabitant of Madagascar, is 
produced into two great, solid, bony projections, covered 

* All the foregoing statements and quotations in regard to Copho- 
tis, Sitana and Draco, as well as the following facts in regard to 
Ceratophora and ChamaBleon, are from Dr. Giinther himself, or from 
his magnificent work on the "Reptiles of British India," Ray See, 
1864, pp. 122, 130, 135. 

f Mr. Swinhoe, "Proc. Zoolog. Soc," 1870, p. 240. 



with scales like tne rest of the head; and of this wonderful 
modification of structure the female exhibits only a rudi- 
ment. Again, in Chamceleo Oiuenii (fig. 36), from the 
vesi coast of Africa, the male bears on his snout and fore- 

ITg. 85. Chamaeleo bifurcus. Upper figure, male ; lower figure, female. 

head three curious horns, of which the female has not a 
trace. These horns consist of an excrescence of bone 
covered with a smooth sheath, forming part of the general 
integuments of the body, so that tliey are identical in 
structure with those of a bull, goat, or other sheath-horned 
ruminant. Although the three horns differ so much in 
appearance from the two great prolongations of the skull 



in 0. Mfurcus, we can hardly doubt that they serve the 
same general purpose in the economy of these two animals. 
The first conjecture, which will occur to every one, is that 
they are used by the males for fighting together; and as 
these animals are very quarrelsome,* this is probably a cor- 
rect view. Mr. T. W. Wood also informs me that ne once 
watched two individuals of C. pumilus fighting violently 
on the branch of a tree; they flung their heads about and 
tried to bite each other; they then rested for a time and 
afterward continued their battle. 

Fig. 88. ChamsBleo Owenll. Upper figure, male; lower figure, female. 

^ With many lizards the sexes differ slightly in color, the 
tints and stripes of the males being brighter and more dis- 
tinctly defined than in the females. This, for instance, is 
the case with the above Cophotis and with the AcantJio- 
dactylus capensis of S. Africa. In a Cordylus of the latter 
country, the male is either much redder or greener than 
the female. In the Indian Calotes nigrilahris there is a 
still greater difference; the lips also of the male are black, 
while those of the female are green. In our common little 
viviparous lizard {Zootoca vivipara) '* the under side of the 
body and base of the tail in the male are bright orange, 

*Dr. Bucholz, " Monatsbericht K. Preuss. Akad.," Jan., 1874. p 
78. . > f 


spotted with black; in the female these parts are pale gray- 
ish green without spots/^ * We have seen tliat the mafes 
alone of Sitana possess a throat-pouch; and this is splen- 
didly tinted with blue, black and red. In the Proctotretus 
tenuis of Chili the male alone is marked with spots of blue, 
green and coppery red. \ In many cases the males retain 
the same colors throughout the year, but in others they 
become much brighter during the breeding-season; I may 
give as an additional instance the Calotes onaria, which at 
this season has a bright red head, the rest of the body being 
green. I 

Both sexes of many species are beautifully colored exactly 
alike; and there is no reason to suppose that such colors are 
protective. No doubt with the briglit-green kinds which 
live in the midst of vegetation, this color serves to conceal 
them; and in N". Patagonia I saw a lizard {Proctotretus 
multimacAilatus) which, when frightened, flattened its body, 
closed its eyes, and then from its mottled tints was hardly 
distinguishable from the surrounding sand. But the bright 
colors with which so many lizards are ornamented, as well 
as their various curious appendages, were probably acquired 
by the males as an attraction, and then transmitted either 
to their male offspring alone, or to both sexes. Sexual 
selection, indeed, seems to have played almost as important 
a part with reptiles as with birds; and the less conspicuous 
colors of the females in comparison with the males cannot 
be accounted for, as Mr. Wallace believes to be the case 
with birds, by the greater exposure of the females to danger 
during incubation. 

*Bell, "History of British Reptiles," 2d edit., 1849, p. 40. 

f For Proctotretus see " Zoology of the Voyage of the ' Beagle ; ' 
Reptiles," by Mr. Bell, p. 8, For the lizards of S. Africa, see 
" Zoology of S. Africa: Reptiles," by Sir Andrew Smith, pi. 25 and 
39. For the Indian Calotes, see " Reptiles of British India," by Dr. 
Giinther, p. 143. 

tGiintherin "Proc. Zoolog. Soc," 1870, p. 778, with a colored 

BIRDS. 407 



Sexual differences — Law of battle — Special weapons — Vocal organs 
— Instrumental music — Love-antics and dances — Decorations 
permanent and seasonal — Double and single annual moults — 
Display of ornaments by tbe males. 

Secondary sexual characters are more diversified and 
conspicuous in birds, though not perhaps entailing more 
important changes of structure, than in any other class of 
animals. I shall, therefore, treat the subject at consider- 
able length. Male birds sometimes, though rarely, possess 
special weapons for fighting with each other. They charm the 
female by vocal or instrumental music of the most varied 
kinds. They are ornamented by all sorts of combs, wattles, 
protuberances, horns, air-distended sacks, top-knots, naked 
shafts, plumes and lengthened feathers gracefully spring- 
ing from all parts of the body. The beak and naked skin 
about the head and the feathers are often gorgeously col- 
ored. The males sometimes pay their court by dancing or 
by fantastic antics performed either on the ground or in 
the air. In one instance, at least, the male emits a musky 
odor, which we may suppose serves to charm or excite the 
female; for that excellent observer, Mr. Ramsay,* says of 
the Australian musk duck {Biziura lohata) that *^the 
smell which the male emits during the summer months is 
confined to that sex, and in some individuals is retained 
throughout the year. I have never, even in the breeding- 
season, shot a female which had any smell of musk." So 
powerful is this odor during the pairing-season that it can 
be detected long before the bird can be seen.f On the 
whole, birds appear to be the most aesthetic of all animals, 
excepting of course man, and they have nearly the same 

* "Ibis," vol. ill (new series), 1867, p. 414. 

•I Gould, "Hand book to the Birds of Australia," 1865, Yol. ii, p. 
383. ■ *^ 


taste for the beautiful as we have. This is shown by onr 
enjoyment of the singing of birds, and by our women,, both 
civilized and savage, decking their heads with borrowed 
plumes and using gems which are hardly more brilliantly 
colored than the naked skin and wattles of certain birds. 
In man, however, when cultivated the sense of beauty is 
manifestly a far more complex feeling and is associated 
with various intellectual ideas. 

Before treating of the sexual characters with which we 
are here more particularly concerned, I may just allude to 
certain differences between the sexes which apparently 
depend on differences in their habits of life; for such 
cases, though common in the lower, are rare in the higher 
classes. Two humming - birds belonging to the genus 
Eustephanus, which inhabit the Island of Juan Fernandez, 
were long thought to be specifically distinct, but are 
now known, as Mr. Gould informs me, to be the male 
and female of the same species, and they differ slightly 
in the form of the beak. In another genus of hum- 
ming-birds ( Grypus) the beak of the male is serrated along 
the margin and hooked at the extremity, thus differing 
much from that of the female. In the Neomorpha of New 
Zealand, there is, as we have seen, a still wider difference 
in the form of the beak in relation to the manner of feed- 
ing of the two sexes. Something of the same kind has 
been observed with the goldfinch (Carcluelis elegans), for I 
am assured by Mr. Jenner Weir that the bird-catchers 
can distinguish the males by their slightly longer beaks. 
The flocks of males are often found feeding on the seeds of 
the teazle (Dipsacus), which they can reach with their 
elongated beaks, while the females more commonly feed on 
the seeds of the betou}' or Scrophularia. AVith a slight 
difference of this kind as a foundation we can see how the 
beaks of the two sexes might be made to differ greatly 
through natural selection. In some of the above cases, 
however, it is possible that the beaks of the males may 
have been first modified in relation to their contests with 
other males; and that this afterward led to slightly changed 
habits of life. 

Lmo of Battle. — Almost all male birds are extremely 
pugnacious, using their beaks, wings, and legs for fighting 
together. We see this every spring with our robins and 

BIRDS, 409 

span*ows. ^\}ie smallest of all birds, namely., the humming- 
bird, is one of the most quarrelsome. Mr. Gosse* describes 
a battle in which a pair seized hold of each other's beaks, 
and whirled round and round till they almost fell to the 
ground; and M. Montes de Oca, in speaking of another 
genus of humming-bird, says that two males rarely meet 
without a fierce aerial encounter; when kept in cages " their 
fighting has mostly ended in the splitting of the tongue of 
one of the two, which then surely dies from being unable 
to f eed. '' t With Waders, the males of the common water- 
lien (GaUinula chloroptis) '^when pairing, fight violently 
for the females; they stand nearly upright in the water and 
Hiirike with their feet." Two were seen to be thus engaged 
for half an hour, until one got hold of the head of the 
other, which would have been killed had not the observer 
interfered; the female all the time looking on as a quiet 
spectator, j Mr. Blyth informs me that the males of an 
allied bird ( f-raUicrex cristatus) are a third larger than the 
females, and are so pugnacious during the breeding-season 
that they are kept by the natives of Eastern Bengal for the 
sake of fighting. Various other birds are kept in India for 
the fjame purpose, for instance, the bulbuls (Pucnonotus 
hcemorrhons) which '' fight with great spirit." § 

The polygamous ruif, Maclietes pugnax (fig. 37), is 
notorious for his extreme pugnacity; and in the spring, the 
males, which are considerably larger than the females, con- 
gregate day after day at a particular spot, where the females 
propose to lay their eggs. The fowlers discover these spots 
by the turf being trampled somewhat Here they fight 
very much like game-cocks, seizing each other with their 
beaks and striking with their wings. The great ruff of 
feathers round the neck is then erected, and according to 
Col. Montagu " sweeps the ground as a shield to defend 
the more tender parts;" and this is the only instance known 
to me in the case of birds of any structure serving as a 
shield. The ruif of feathers, however, from its varied and 

* Quoted by Mr. Gould, "Introduction to the Trocliilidae," 1861, 
p. 29. 

t Gould, ibid, p. 53. 

:tW. Thompson, " Na* Hist, of Ireland; Birds," vol. il, 1850, p. 

g Jsrdon, "Birds of India," 18C3. vol. ii, p. 96. 



rich colors probably serves in chief part as an ornament. 
Like most pugnacious birds, they seem always ready to 

fight, and when closely confined often kill each other; but 
Mcntagu observed that their pugnacity becomes greater 
dining the spring, when the long feathers on their necks 
are fully developed; and at this period the least movement 

BIRDS, 411 

by any one bird provokes a general battle.* Of the pug- 
nacity of web-footed birds, two instances will suffice : m 
Guiana " bloody fights occur during the breeding-season 
between the males of the wild musk-duck (Cairina mo- 
schata); and where these fights have occurred the " river is 
covered for some distance with feathers." f Birds which 
seem ill-adapted for fighting engage in fierce conflicts; thus 
the stronger males of the pelican drive away the weaker 
ones, snapping with their huge beaks and giving heavy 
blows with their wings. Male snipe fight together, ** tug- 
ging and pushing each other with their bills in the most 
curious manner imaginable." Some few birds are believed 
never to fight; this is the case, according to Audubon, with 
one of the woodpeckers of the United States (Picu sau- 
ratus), although "''the hens are followed by even half a 
dozen of their gay suitors." X 

The males of many birds are larger than the females, 
and this no doubt is the result of the advantage gained by 
the larger and stronger males over their rivals during many 
generations. The difference in size between the two sexes 
is carried to an extreme point in several Australian species; 
thus the male musk-duck (Biziura) and the male Cinclor- 
amphus cmralis (allied to our pipits) are by measure- 
ment actually twice as large as their respective females. § 
With many other birds the females are larger than the 
males; and, as formerly remarked, the explanation often 
given, namely, that the females have most of the work in 
feeding their young, will not suffice. In some few cases, 
as we shall hereafter see, the females apparently have 
acquired their greater size and strength for the sake of con- 
quering other females and obtaining possession of the 

The males of many gallinaceous birds, especially of the 
polygamous kinds, are furnished with special weapons foi 
fighting with their rivals, namely spurs, which can be used 

* Macgillivray, *'Hist. Brit. Birds," vol. iv, 1852. pp. 177-181. 

f Sir R. Sclioniburgk, in " Journal of R. Geograph. Soc," vol. xili, 
1843. p. 31. 

I "Ornithological Biography," vol. i, p. 191. For pelicans and 
snipes, see vol. iii. pp 138, 477. 

§ Gould, "Hand-book of Birds of Australia," vol. i, p. 395; voL ii, 
p. 38a 


with fearful effect. It has been recorded by a trustworthy 
writer* that in Derbyshire a kite struck at a game-hen 
accompanied by her chickens, when the cock rushed to the 
rescue, and drove his spur right through the eye and skull 
of the aggressor. The spur was with difficulty drawn from 
the skull, and as the kite, though dead, retained his grasp, 
the two birds were firmly locked together ; but the cock 
when disentangled was very little injured. The invincible 
courage of the game-cock is notorious ; a gentleman who 
long ago witnessed the brutal scene, told me that a bird 
had both its legs broken by some accident in the cock-pit, 
and tha owner laid a wager that if the legs could be spliced 
BO that the bird could stand upright, he would continue 
fighting. This was effected on the spot, and the bird 
fought with undaunted courage until he received his death- 
stroke. In Ceylon a closely allied, wild species, the Gnllus 
Staiileyi, is known to fight desperately " in defense of his 
seraglio," so that one of the combatants is frequently found 
dead.f An Indian partridge {Ortygornis gularis), the 
male of which is furnished Avith strong and sharp spurs, is 
so quarrelsome ' ' that the scars of former fights disfigure 
the breast of almost every bird you kill. "J 

The males of almost all gallinaceous birds, even those 
which are not furnished with spurs, engage during the 
breeding-season in fierce conflicts. The Capercailzie and 
Black-cock {Tetrao urog alius and T. tetrix) which are 
both polygamists, have regular appointed places, where 
during many weeks they congregate in numbers to fight 
together and to display their charms before the females. 
Dr. W. Kovalevsky informs me that in Russia he has seen 
the snow all bloody on the arenas where the capercailzie 
have fought; and the black-cocks *^ make the feathers fly 
in every direction," when several ^' engage in a battle 
royal." The elder Brehm gives a curious account of the 
Balz, as the love-dances and love-songs of the black-cock 
are called in Germany. The bird utters almost contin- 
uously the strangest noises: **he holds his tail up and 
spreads \i out like a fan, he lifts up his head and neck with 
all the feathers erect, and stretches his wings from the 

*Mt. Hewitt in the "Poultry Book by Tegetmeier," 1866, p. 137. 
f Layard, "Annals and Mag. of Nat. Hist.," vol. xiv, 1854, p. 63 
J Jerdon, " Birds of India," vol. iii, p. 574 

BIBDS, 418 

body. Then he takes a few jumps in different direc- 
tions, sometimes in a circle, and presses the under part 
of his beak so hard against the ground that the 
chin feathers are rubbed oft*. During these move- 
ments he beats his wings and turns round and 
round. The more ardent he grows the more lively he 
becomes, until at last the bird appears like a frantic creat- 
ure.^' At such times the black-cocks are so absorbed that 
they become almost blind and deaf, but less so than the 
capercailzie; hence bird after bird may be shot on the same 
spot, or even caught by the hand. After performing these 
antics the males begin to light; and the same black-cock, 
in order to prove his strength over several antagonists, will 
visit in the course of one morning several Balz-places, which 
remain the same during successive years.* 

The peacock with his long train appears more like a 
dandy than a warrior, but he sometimes engages in fierce 
contests; the Rev. \V. Darwin Fox informs me that at some 
little distance from Chester two peacocks became so excited 
while fighting that they flew over the whole city, still 
engaged, until they al'ghted on the top of St. John's tower. 

The spur, in those gallinaceous birds which are thus pro- 
vided, is generally single; but Polyplectron (see fig. 51) 
has two or more on each leg; and one of the blood-pheas- 
ants {Ithaginis cruentus) has been seen with five spurs. 
The spurs are generally confined to the male, being repre- 
sented by mere knobs or rudiments in the female; but the 
females of the Java peacock (Pavo muticus) and, as I am 
informed by Mr. Blyth, of the small fire-backed pheasant 
{Euplocawus erythroptJialmus) possess spurs. In Galloper- 
dix it is usual for the males to have two spurs, and for the 
females to have only one on each leg.f Hence spurs may 
be considered