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+The Project Gutenberg EBook of The Descent of Man, by Charles Darwin
+
+This eBook is for the use of anyone anywhere at no cost and with almost
+no restrictions whatsoever. You may copy it, give it away or re-use
+it under the terms of the Project Gutenberg License included with this
+eBook or online at www.gutenberg.org
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+
+Title: The Descent of Man
+
+Author: Charles Darwin
+
+Posting Date: January 6, 2013 [EBook #2300]
+First Posted: November 28, 1999
+Last Updated: October 9, 2017
+
+Language: English
+
+Character set encoding: ISO-8859-1
+
+*** START OF THIS PROJECT GUTENBERG EBOOK THE DESCENT OF MAN ***
+
+
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+
+Produced by Sue Asscher
+
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+
+THE DESCENT OF MAN
+
+AND
+
+SELECTION IN RELATION TO SEX
+
+
+Works by Charles Darwin, F.R.S.
+
+Life and Letters of Charles Darwin. With an Autobiographical Chapter.
+Edited by Francis Darwin. Portraits. 3 volumes 36s. Popular Edition.
+Condensed in 1 volume 7s 6d.
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+Naturalist's Journal of Researches into the Natural History and
+Geology of Countries Visited during a Voyage Round the World. With
+100 Illustrations by Pritchett. 21s. Popular Edition. Woodcuts. 3s 6d.
+Cheaper Edition, 2s. 6d. net.
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+Origin of Species by means of Natural Selection; or, The Preservation of
+Favoured Races in the Struggle for Life. Large Type Edition, 2 volumes
+12s. Popular Edition, 6s. Cheaper Edition with Portrait, 2s. 6d.
+
+Various Contrivances by which Orchids are Fertilized by Insects.
+Woodcuts. 7s. 6d.
+
+Variation of Animals and Plants under Domestication. Illustrations. 15s.
+
+Descent of Man, and Selection in relation to Sex. Illustrations. Large
+Type Edition, 2 volumes 15s. Popular Edition, 7s 6d. Cheaper Edition,
+2s. 6d. net.
+
+Expression of the Emotions in Man and Animals. Illustrations. 12s.
+
+Insectivorous Plants. Illustrations. 9s.
+
+Movements and Habits of Climbing Plants. Woodcuts. 6s.
+
+Cross and Self-Fertilization in the Vegetable Kingdom. Illustrations.
+9s.
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+Different Forms of Flowers on Plants of the Same Species. Illustrations.
+7s. 6d.
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+Formation of Vegetable Mould through the Action of Worms. Woodcuts. 6s.
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+The above works are Published by John Murray.
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+Structure and Distribution of Coral Reefs. Smith, Elder, & Co.
+
+Geological Observations on Volcanic Islands and Parts of South America.
+Smith, Elder, & Co.
+
+Monograph of the Cirripedia. Illustrations. 2 volumes. 8vo. Ray Society.
+
+Monograph of the Fossil Lepadidae, or Pedunculated Cirripedes of Great
+Britain. Palaeontographical Society.
+
+Monograph of the Fossil Balanidae and Verrucidae of Great Britain.
+Palaeontographical Society.
+
+
+
+
+THE DESCENT OF MAN
+
+AND
+
+SELECTION IN RELATION TO SEX
+
+BY
+
+CHARLES DARWIN, M.A., F.R.S.
+
+
+Uniform with this Volume
+
+The Origin of Species, by means of Natural Selection; or, The
+Preservation of Favoured Races in the Struggle for Life. Popular
+Edition, with a Photogravure Portrait. Large Crown 8vo. 2s. 6d. net.
+
+A Naturalist's Voyage. Journal of Researches into the Natural History
+and Geology of the Countries visited during the Voyage of H.M.S.
+"Beagle" round the World, under the Command of Capt. Fitz Roy, R.N.
+Popular Edition, with many Illustrations. Large Crown 8vo. 2s. 6d. net.
+
+
+PREFACE TO THE SECOND EDITION.
+
+During the successive reprints of the first edition of this work,
+published in 1871, I was able to introduce several important
+corrections; and now that more time has elapsed, I have endeavoured to
+profit by the fiery ordeal through which the book has passed, and have
+taken advantage of all the criticisms which seem to me sound. I am
+also greatly indebted to a large number of correspondents for the
+communication of a surprising number of new facts and remarks. These
+have been so numerous, that I have been able to use only the more
+important ones; and of these, as well as of the more important
+corrections, I will append a list. Some new illustrations have been
+introduced, and four of the old drawings have been replaced by better
+ones, done from life by Mr. T.W. Wood. I must especially call attention
+to some observations which I owe to the kindness of Prof. Huxley (given
+as a supplement at the end of Part I.), on the nature of the differences
+between the brains of man 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 selection of such variations as are
+often called spontaneous; whereas, even in the first edition of the
+'Origin of Species,' I distinctly stated that great weight must be
+attributed to the inherited effects of use and disuse, with respect both
+to the body and mind. I also attributed some amount of modification
+to the direct and prolonged action of changed 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 organisation 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, however, a tolerably
+clear sketch of this principle in the first edition of the 'Origin of
+Species,' and I there stated that it was applicable to man. This subject
+of sexual selection has been treated at full length in the present work,
+simply because an opportunity was here first afforded me. I have been
+struck with the likeness of many of the half-favourable 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 accepted; and it has already been fully and favourably received
+by several capable judges.
+
+DOWN, BECKENHAM, KENT, September, 1874.
+
+First Edition February 24, 1871. Second Edition September, 1874.
+
+
+CONTENTS.
+
+
+INTRODUCTION.
+
+
+PART I. THE DESCENT OR ORIGIN OF MAN.
+
+
+CHAPTER I.
+
+The Evidence of the Descent of Man from some Lower Form.
+
+Nature of the evidence bearing on the origin of man--Homologous
+structures in man and the lower animals--Miscellaneous points
+of correspondence--Development--Rudimentary structures, muscles,
+sense-organs, hair, bones, reproductive organs, etc.--The bearing of
+these three great classes of facts on the origin of man.
+
+
+CHAPTER II.
+
+On the Manner of Development of Man from some Lower Form.
+
+Variability of body and mind in man--Inheritance--Causes of
+variability--Laws of variation the same in man as in the lower
+animals--Direct action of the conditions of life--Effects of
+the 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.
+
+
+CHAPTER III.
+
+Comparison of the Mental Powers of Man and the Lower Animals.
+
+The difference in mental power between the highest ape and the
+lowest savage, immense--Certain instincts in common--The
+emotions--Curiosity--Imitation--Attention--Memory--Imagination--Reason--Progressive
+improvement --Tools and weapons used by animals--Abstraction,
+Self-consciousness--Language--Sense of beauty--Belief in God, spiritual
+agencies, superstitions.
+
+
+CHAPTER IV.
+
+Comparison of the Mental Powers of Man and the Lower Animals--continued.
+
+The moral sense--Fundamental proposition--The qualities of social
+animals--Origin of sociability--Struggle between opposed instincts--Man
+a social animal--The more enduring social instincts conquer other less
+persistent instincts--The social virtues alone regarded by savages--The
+self-regarding virtues acquired at a later stage of development--The
+importance of the judgment of the members of the same community on
+conduct--Transmission of moral tendencies--Summary.
+
+
+CHAPTER V.
+
+On the Development of the Intellectual and Moral Faculties during
+Primeval and Civilised times.
+
+Advancement of the intellectual powers through natural
+selection--Importance of imitation--Social and moral faculties--Their
+development within the limits of the same tribe--Natural selection as
+affecting civilised nations--Evidence that civilised nations were once
+barbarous.
+
+
+CHAPTER VI.
+
+On the Affinities and Genealogy of Man.
+
+Position of man in the animal series--The natural system
+genealogical--Adaptive characters of slight value--Various small points
+of resemblance between man and the Quadrumana--Rank of man in the
+natural system--Birthplace and antiquity of man--Absence of fossil
+connecting-links--Lower stages in the genealogy of man, as inferred
+firstly from his affinities and secondly from his structure--Early
+androgynous condition of the Vertebrata --Conclusion.
+
+
+CHAPTER VII.
+
+On the Races of Man.
+
+The nature and value of specific characters--Application to the races of
+man--Arguments in favour of, and opposed to, ranking the so-called
+races of man as distinct species--Sub-species--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.
+
+
+PART II. SEXUAL SELECTION.
+
+
+CHAPTER VIII.
+
+Principles of Sexual Selection.
+
+Secondary sexual characters--Sexual selection--Manner of action--Excess
+of males--Polygamy--The male alone generally modified through sexual
+selection--Eagerness of the male--Variability of the
+male--Choice exerted by the female--Sexual compared with natural
+selection--Inheritance at corresponding periods of life, at
+corresponding seasons of the year, and as limited by sex--Relations
+between the several forms of inheritance--Causes why one sex and the
+young are not modified through sexual selection--Supplement on the
+proportional numbers of the two sexes throughout the animal kingdom--The
+proportion of the sexes in relation to natural selection.
+
+
+CHAPTER IX.
+
+Secondary Sexual Characters in the Lower Classes of the Animal Kingdom.
+
+These characters are absent in the lowest classes--Brilliant
+colours--Mollusca--Annelids--Crustacea, secondary sexual characters
+strongly developed; dimorphism; colour; characters not acquired
+before maturity--Spiders, sexual colours of; stridulation by the
+males--Myriapoda.
+
+
+CHAPTER X.
+
+Secondary Sexual Characters of Insects.
+
+Diversified structures possessed by the males for seizing the
+females--Differences between the sexes, of which the meaning is
+not understood--Difference in size between the
+sexes--Thysanura--Diptera--Hemiptera--Homoptera, musical powers
+possessed by the males alone--Orthoptera, musical instruments of the
+males, much diversified in structure; pugnacity; colours--Neuroptera,
+sexual differences in colour--Hymenoptera, pugnacity and
+odours--Coleoptera, colours; furnished with great horns, apparently
+as an ornament; battles; stridulating organs generally common to both
+sexes.
+
+
+CHAPTER XI.
+
+Insects, continued.--Order Lepidoptera.
+
+(Butterflies and Moths.)
+
+Courtship of Butterflies--Battles--Ticking noise--Colours common to both
+sexes, or more brilliant in the males--Examples--Not due to the
+direct action of the conditions of life--Colours adapted for
+protection--Colours of moths--Display--Perceptive powers of the
+Lepidoptera--Variability--Causes of the difference in colour between the
+males and females--Mimicry, female butterflies more brilliantly coloured
+than the males--Bright colours of caterpillars--Summary and concluding
+remarks on the secondary sexual character of insects--Birds and insects
+compared.
+
+
+CHAPTER XII.
+
+Secondary Sexual Characters of Fishes, Amphibians, and Reptiles.
+
+Fishes: Courtship and battles of the males--Larger size of the
+females--Males, bright colours and ornamental appendages; other strange
+characters--Colours and appendages acquired by the males during
+the breeding-season alone--Fishes with both sexes brilliantly
+coloured--Protective colours--The less conspicuous colours 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 colour between the sexes--Vocal organs.
+REPTILES: Chelonians--Crocodiles--Snakes, colours in some cases
+protective--Lizards, battles of--Ornamental appendages--Strange
+differences in structure between the sexes--Colours--Sexual differences
+almost as great as with birds.
+
+
+CHAPTER XIII.
+
+Secondary Sexual Characters of Birds.
+
+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 the males.
+
+
+CHAPTER XIV.
+
+Birds--continued.
+
+Choice exerted by the female--Length of courtship--Unpaired
+birds--Mental qualities and taste for the beautiful--Preference or
+antipathy shewn by the female for particular males--Variability of
+birds--Variations sometimes abrupt--Laws of variation--Formation of
+ocelli--Gradations of character--Case of Peacock, Argus pheasant, and
+Urosticte.
+
+
+CHAPTER XV.
+
+Birds--continued.
+
+Discussion as to why the males alone of some species, and both sexes
+of others are brightly coloured--On sexually-limited inheritance,
+as applied to various structures and to brightly-coloured
+plumage--Nidification in relation to colour--Loss of nuptial plumage
+during the winter.
+
+
+CHAPTER XVI.
+
+Birds--concluded.
+
+The immature plumage in relation to the character of the plumage in both
+sexes when adult--Six classes of cases--Sexual differences between the
+males of closely-allied or representative species--The female assuming
+the characters of the male--Plumage of the young in relation to the
+summer and winter plumage of the adults--On the increase of beauty in
+the birds of the world--Protective colouring--Conspicuously coloured
+birds--Novelty appreciated--Summary of the four chapters on birds.
+
+
+CHAPTER XVII.
+
+Secondary Sexual Characters of Mammals.
+
+The law of battle--Special weapons, confined to the males--Cause of
+absence of weapons in the female--Weapons common to both sexes, yet
+primarily acquired by the male--Other uses of such weapons--Their
+high importance--Greater size of the male--Means of defence--On the
+preference shewn by either sex in the pairing of quadrupeds.
+
+
+CHAPTER XVIII.
+
+Secondary Sexual Characters of Mammals--continued.
+
+Voice--Remarkable sexual peculiarities in seals--Odour--Development
+of the hair--Colour of the hair and skin--Anomalous case of the female
+being more ornamented than the male--Colour and ornaments due to sexual
+selection--Colour acquired for the sake of protection--Colour,
+though common to both sexes, often due to sexual selection--On the
+disappearance of spots and stripes in adult quadrupeds--On the colours
+and ornaments of the Quadrumana--Summary.
+
+
+PART III. SEXUAL SELECTION IN RELATION TO MAN, AND CONCLUSION.
+
+
+CHAPTER XIX.
+
+Secondary Sexual Characters of Man.
+
+Differences between man and woman--Causes of such differences, and of
+certain characters common to both sexes--Law of battle--Differences in
+mental powers, and voice--On the influence of beauty in determining
+the marriages of mankind--Attention paid by savages to ornaments--Their
+ideas of beauty in women--The tendency to exaggerate each natural
+peculiarity.
+
+
+CHAPTER XX.
+
+Secondary Sexual Characters of Man--continued.
+
+On the effects of the continued selection of women according to a
+different standard of beauty in each race--On the causes which interfere
+with sexual selection in civilised and savage nations--Conditions
+favourable to sexual selection during primeval times--On the manner of
+action of sexual selection with mankind--On the women in savage tribes
+having some power to choose their husbands--Absence of hair on the body,
+and development of the beard--Colour of the skin--Summary.
+
+
+CHAPTER XXI.
+
+General Summary and Conclusion.
+
+Main conclusion that man is descended from some lower form--Manner of
+development--Genealogy of man--Intellectual and moral faculties--Sexual
+selection--Concluding remarks.
+
+
+SUPPLEMENTAL NOTE.
+
+
+INDEX.
+
+
+
+THE DESCENT OF MAN; AND SELECTION IN RELATION TO SEX.
+
+...
+
+INTRODUCTION.
+
+The nature of the following work will be best understood by a brief
+account of how it came to be written. During many years I collected
+notes on the origin or descent of man, without any intention of
+publishing on the subject, but rather with the 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
+ind�pendante et de toutes pi�ces, des esp�ces," it is manifest that
+at least a large number of naturalists must admit that species are the
+modified descendants of other species; and this especially holds good
+with the younger and rising naturalists. The greater number accept the
+agency of natural selection; though some urge, whether with justice the
+future must decide, that I have greatly overrated its importance. Of
+the older and honoured chiefs in natural science, many unfortunately are
+still opposed to evolution in every form.
+
+In consequence of the views now adopted by most naturalists, and which
+will ultimately, as in every other case, be followed by others who are
+not scientific, I have been led to put together my notes, so as to
+see how far the general conclusions arrived at in my former works were
+applicable to man. This seemed all the more desirable, as I had never
+deliberately applied these views to a species taken singly. When we
+confine our attention to any one form, we are deprived of the weighty
+arguments derived from the nature of the affinities which connect
+together whole groups of organisms--their geographical distribution in
+past and present times, and their geological succession. The homological
+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 appears to me, ample and conclusive evidence in favour 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 development; 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 subject which has been fully
+described in many valuable works. The high antiquity of man has recently
+been demonstrated by the labours 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 shewn 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 conclusion 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, Buchner, Rolle, etc.
+(1. As the works of the first-named authors are so well known, I need
+not give the titles; but as those of the latter are less well known
+in England, I will give them:--'Sechs Vorlesungen �ber die Darwin'sche
+Theorie:' zweite Auflage, 1868, von Dr L. Buchner; translated into
+French under the title 'Conf�rences sur la Th�orie 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, page 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 ape."), and especially by Haeckel. This last
+naturalist, besides his great work, 'Generelle Morphologie' (1866),
+has recently (1868, with a second edition in 1870), published his
+'Nat�rliche Sch�pfungsgeschichte,' in which he fully discusses the
+genealogy of man. If this work had appeared before my essay had been
+written, I should probably never have completed it. Almost all the
+conclusions at which I have arrived I find confirmed by this naturalist,
+whose knowledge on many points is much fuller than mine. Wherever I
+have added any fact or view from Prof. Haeckel's writings, I give his
+authority in the text; other statements I leave as they originally stood
+in my manuscript, occasionally giving in the foot-notes references to
+his works, as a confirmation of the more doubtful or interesting points.
+
+During many years it has seemed to me highly probable that sexual
+selection has played an important part in differentiating the races of
+man; but in my 'Origin of Species' (first edition, page 199) I contented
+myself by merely alluding to this belief. When I came to apply this
+view to man, I found it indispensable to treat the whole subject in full
+detail. (2. Prof. Haeckel 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 works.) Consequently
+the second part of the present work, treating of sexual selection, has
+extended to an inordinate length, compared with the first part; but this
+could not be avoided.
+
+I had intended adding to the present volumes an essay on the expression
+of the various emotions by man and the lower animals. My attention was
+called to this subject many years ago by Sir Charles Bell's admirable
+work. This illustrious anatomist maintains that man is endowed with
+certain muscles solely for the sake of expressing his emotions. As this
+view is obviously opposed to the belief that man is descended from some
+other and lower form, it was necessary for me to consider it. I likewise
+wished to ascertain how far the emotions are expressed in the same
+manner by the different races of man. But owing to the length of the
+present work, I have thought it better to reserve my essay for separate
+publication.
+
+
+PART I. THE DESCENT OR ORIGIN OF MAN.
+
+
+CHAPTER I.
+
+THE EVIDENCE OF THE DESCENT OF MAN FROM SOME LOWER FORM.
+
+Nature of the evidence bearing on the origin of man--Homologous
+structures in man and the lower animals--Miscellaneous points
+of correspondence--Development--Rudimentary structures, muscles,
+sense-organs, hair, bones, reproductive organs, etc.--The bearing of
+these three great classes of facts on the origin of man.
+
+He who wishes to decide whether man is the modified descendant of some
+pre-existing form, would probably first enquire whether man varies,
+however slightly, in bodily structure and in mental faculties; and
+if so, whether the variations are transmitted to his offspring in
+accordance with the laws which prevail with the lower animals. 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 malconformations, the result of arrested development,
+of reduplication of parts, etc., and does he display in any of his
+anomalies reversion to some former and ancient type of structure?
+It might also naturally be enquired whether man, like so many other
+animals, has given rise to varieties and sub-races, differing but
+slightly from each other, or to 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 points.
+
+The enquirer would next come to the important point, whether man
+tends to increase at so rapid a rate, as to lead to occasional severe
+struggles for existence; and consequently to beneficial variations,
+whether in body or mind, being preserved, and injurious ones eliminated.
+Do the races or species of men, whichever term may be applied, encroach
+on and replace 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, must be answered 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 shews traces, more or less plain, of his
+descent from some lower form. In succeeding chapters the mental
+powers of man, in comparison with those of the lower animals, will be
+considered.
+
+THE BODILY STRUCTURE OF MAN.
+
+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 viscera. The brain, the most
+important of all the organs, follows the same law, as shewn by Huxley
+and other anatomists. Bischoff (1. 'Grosshirnwindungen des Menschen,'
+1868, s. 96. The conclusions of this author, as well as those of
+Gratiolet and Aeby, concerning the brain, will be discussed by Prof.
+Huxley in the Appendix alluded to in the Preface to this edition.), who
+is a hostile witness, admits that every chief fissure and fold in the
+brain of man has its analogy in that of the orang; but he adds that
+at no period of development do their brains perfectly agree; nor could
+perfect agreement be expected, for otherwise their mental powers would
+have been the same. Vulpian (2. 'Lec. sur la Phys.' 1866, page 890, as
+quoted by M. Dally, 'L'Ordre des Primates et le Transformisme,'
+1868, page 29.), remarks: "Les diff�rences r�elles qui existent entre
+l'encephale de l'homme et celui des singes sup�rieurs, sont bien
+minimes. Il ne faut pas se faire d'illusions a cet �gard. L'homme est
+bien plus pr�s des singes anthropomorphes par les caract�res anatomiques
+de son cerveau que ceux-ci ne le sont non seulement des autres
+mammif�res, mais m�me de certains quadrumanes, des guenons et des
+macaques." But it would be superfluous here to give further details on
+the correspondence between man and the higher mammals in the structure
+of the brain and all other parts of the body.
+
+It may, however, be worth while to specify a few points, not directly
+or obviously connected with structure, by which this correspondence or
+relationship is well shewn.
+
+Man is liable to receive from the lower animals, and to communicate to
+them, certain diseases, as hydrophobia, variola, the glanders, syphilis,
+cholera, herpes, etc. (3. Dr. W. Lauder Lindsay has treated this subject
+at some length in the 'Journal of Mental Science,' July 1871; and in
+the 'Edinburgh Veterinary Review,' July 1858.); and this fact proves
+the close similarity (4. A Reviewer has criticised ('British Quarterly
+Review,' Oct. 1st, 1871, page 472) what I have here said with much
+severity and contempt; but as I do not use the term identity, I cannot
+see that I am greatly in error. There appears to me a strong analogy
+between the same infection or contagion producing the same result, or
+one closely similar, in two distinct animals, and the testing of two
+distinct fluids by the same chemical reagent.) of their tissues and
+blood, both in minute structure and composition, far more plainly than
+does their comparison under the best microscope, or by the aid of
+the best chemical analysis. Monkeys are liable to many of the same
+non-contagious diseases as we are; thus Rengger (5. 'Naturgeschichte der
+S�ugethiere von Paraguay,' 1830, s. 50.), who carefully observed for
+a long time the Cebus Azarae in its native land, found it liable to
+catarrh, with the usual symptoms, and which, when often recurrent, led
+to consumption. These monkeys suffered also from apoplexy, inflammation
+of the bowels, and cataract in the eye. The younger ones when shedding
+their milk-teeth often died from fever. Medicines produced the same
+effect on them as on us. Many kinds of monkeys have a strong taste for
+tea, coffee, and spiritous liquors: they will also, as I have myself
+seen, smoke tobacco with pleasure. (6. 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 taste for rum, and for smoking tobacco.) Brehm asserts that
+the natives of north-eastern Africa catch the wild baboons by exposing
+vessels with strong beer, by which they are made drunk. He has seen some
+of these animals, which he kept in confinement, in this state; and he
+gives a laughable account of their behaviour and strange grimaces. On
+the following morning they were very cross and dismal; they held their
+aching heads with both hands, and wore a most pitiable expression:
+when beer or wine was offered them, they turned away with disgust, but
+relished the juice of lemons. (7. Brehm, 'Thierleben,' B. i. 1864, s.
+75, 86. On the Ateles, s. 105. For other analogous statements, see s.
+25, 107.) An American monkey, an Ateles, after getting drunk on brandy,
+would never touch it again, and thus was wiser than many men. These
+trifling facts prove how similar the nerves of taste must be in monkeys
+and man, and how similarly their whole nervous system is affected.
+
+Man is infested with internal parasites, sometimes causing fatal
+effects; and is plagued by external parasites, all of which belong to
+the same genera or families as those infesting other mammals, and in
+the case of scabies to the same species. (8. Dr. W. Lauder Lindsay,
+'Edinburgh Vet. Review,' July 1858, page 13.) Man is subject, like other
+mammals, birds, and even insects (9. With respect to insects see Dr.
+Laycock, "On a General Law of Vital Periodicity," 'British Association,'
+1842. Dr. Macculloch, 'Silliman's North American Journal of Science,'
+vol. XVII. page 305, has seen a dog suffering from tertian ague.
+Hereafter I shall return to this subject.), to that mysterious law,
+which causes certain normal processes, such as gestation, as well as the
+maturation and duration of various diseases, to follow lunar periods.
+His wounds are repaired by the same process of healing; and the stumps
+left after the amputation of his limbs, especially during an early
+embryonic period, occasionally possess some power of regeneration, as
+in the lowest animals. (10. I have given the evidence on this head in my
+'Variation of Animals and Plants under Domestication,' vol. ii. page 15,
+and more could be added.)
+
+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 (11. Mares e diversis generibus Quadrumanorum
+sine dubio dignoscunt feminas humanas a maribus. Primum, credo, odoratu,
+postea aspectu. Mr. Youatt, qui diu in Hortis Zoologicis (Bestiariis)
+medicus animalium erat, vir in rebus observandis cautus et sagax, hoc
+mihi certissime probavit, et curatores ejusdem loci et alii e ministris
+confirmaverunt. Sir Andrew Smith et Brehm notabant idem in Cynocephalo.
+Illustrissimus Cuvier etiam narrat multa de hac re, qua ut opinor, nihil
+turpius potest indicari inter omnia hominibus et Quadrumanis communia.
+Narrat enim Cynocephalum quendam in furorem incidere aspectu feminarum
+aliquarem, sed nequaquam accendi tanto furore ab omnibus. Semper
+eligebat juniores, et dignoscebat in turba, et advocabat voce
+gestuque.), to the birth and nurturing of the young. Monkeys are born in
+almost as helpless a condition as our own infants; and in certain genera
+the young differ fully as much in appearance from the adults, as do our
+children from their full-grown parents. (12. This remark is made with
+respect to Cynocephalus and the anthropomorphous apes by Geoffroy
+Saint-Hilaire and F. Cuvier, 'Histoire Nat. des Mammif�res,' tom. i.
+1824.) It has been urged by some writers, as an important distinction,
+that with man the young arrive at maturity at a much later age than with
+any other animal: but if we look to the races of mankind which inhabit
+tropical countries the difference is not great, for the orang is
+believed not to be adult till the age of from ten to fifteen years. (13.
+Huxley, 'Man's Place in Nature,' 1863, p. 34.) 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.
+
+EMBRYONIC DEVELOPMENT.
+
+[Fig. 1. Shows a human embryo, from Ecker, and a dog embryo, from
+Bischoff. Labelled in each are:
+
+a. Fore-brain, cerebral hemispheres, etc. b. Mid-brain, corpora
+quadrigemina. c. Hind-brain, cerebellum, medulla oblongata. d. Eye.
+e. Ear. f. First visceral arch. g. Second visceral arch. H. Vertebral
+columns and muscles in process of development. i. Anterior extremities.
+K. Posterior extremities. L. Tail or os coccyx.]
+
+Man is developed from an ovule, about the 125th of an inch in diameter,
+which differs in no respect from the ovules of other animals. The embryo
+itself at a very early period can hardly be distinguished from that of
+other members of the vertebrate kingdom. At this period the arteries run
+in arch-like branches, as if to carry the blood to branchiae which are
+not present in the higher Vertebrata, though the slits on the sides of
+the neck still remain (see f, g, fig. 1), marking their former position.
+At a somewhat later period, when the extremities are developed, "the
+feet of lizards and mammals," as the illustrious Von Baer remarks, "the
+wings and feet of birds, no less than the hands and feet of man, all
+arise from the same fundamental form." It is, says Prof. Huxley (14.
+'Man's Place in Nature,' 1863, p. 67.), "quite in the later stages of
+development that the young human being presents marked differences from
+the young ape, while the latter departs as much from the dog in its
+developments, as the man does. Startling as this last assertion may
+appear to be, it is demonstrably true."
+
+As some of my readers may never 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. (15.
+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 Bischoff,
+'Entwicklungsgeschichte des Hunde-Eies,' 1845, tab. xi. fig. 42B. This
+drawing is five times magnified, the embryo being twenty-five days old.
+The internal viscera have been omitted, and the uterine appendages in
+both drawings removed. I was directed to these figures by Prof. Huxley,
+from whose work, 'Man's Place in Nature,' the idea of giving them
+was taken. Haeckel has also given analogous drawings in his
+'Schopfungsgeschichte.')
+
+After the foregoing statements made by such high authorities, it would
+be superfluous on my part to give a number of borrowed details, shewing
+that the embryo of man closely resembles that of other mammals. It may,
+however, be added, that the human embryo likewise resembles 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,
+"extending considerably beyond the rudimentary legs." (16. Prof. Wyman
+in 'Proceedings of the American Academy of Sciences,' vol. iv. 1860, p.
+17.) In the embryos of all air-breathing vertebrates, certain glands,
+called the corpora Wolffiana, correspond with, and act like the kidneys
+of mature fishes. (17. Owen, 'Anatomy of Vertebrates,' vol. i. p. 533.)
+Even at a later embryonic period, some striking resemblances between
+man and the lower animals may be observed. Bischoff says that "the
+convolutions of the brain in a human foetus at the end of the seventh
+month reach about the same stage of development as in a baboon when
+adult." (18. 'Die Grosshirnwindungen des Menschen,' 1868, s. 95.) The
+great toe, as Professor Owen remarks (19. 'Anatomy of Vertebrates,'
+vol. ii. p. 553.), "which forms the fulcrum when standing or walking, is
+perhaps the most characteristic peculiarity in the human structure;" but
+in an embryo, about an inch in length, Prof. Wyman (20. 'Proc. Soc. Nat.
+Hist.' Boston, 1863, vol. ix. p. 185.) 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 (21. 'Man's Place in Nature,' p. 65.) who
+after asking, does man originate in a different way from a dog, bird,
+frog or fish? says, "the reply is not doubtful for a moment; without
+question, the mode of origin, and the early stages of the development
+of man, are identical with those of the animals immediately below him in
+the scale: without a doubt in these respects, he is far nearer to apes
+than the apes are to the dog."
+
+RUDIMENTS.
+
+This subject, though not intrinsically more important than the two last,
+will for several reasons be treated here more fully. (22. I had written
+a rough copy of this chapter before reading a valuable paper, "Caratteri
+rudimentali in ordine all' origine dell' uomo" ('Annuario della Soc. d.
+Naturalisti,' Modena, 1867, p. 81), by G. Canestrini, to which paper
+I am considerably indebted. Haeckel has given admirable discussions on
+this whole subject, under the title of Dysteleology, in his 'Generelle
+Morphologie' and 'Sch�pfungsgeschichte.') Not one of the higher animals
+can be named which does not bear some part in a rudimentary condition;
+and man forms no exception to the rule. Rudimentary organs must be
+distinguished from those that are nascent; though in some cases the
+distinction is not easy. The former are either absolutely useless, such
+as the mammae of male quadrupeds, or the incisor teeth of ruminants
+which never cut through the gums; or they are of such slight service
+to their present possessors, that we 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
+developed, are of high service to their possessors, and are capable of
+further development. Rudimentary organs are eminently variable; and
+this is partly intelligible, as they are useless, or nearly useless, and
+consequently are no longer subjected to natural selection. They often
+become wholly suppressed. When this occurs, they are nevertheless liable
+to occasional reappearance through reversion--a circumstance well worthy
+of attention.
+
+The chief agents in causing organs to become rudimentary seem to have
+been disuse at that period of life when the organ is chiefly used
+(and this is generally during maturity), and also inheritance at a
+corresponding period of life. The term "disuse" does not relate merely
+to the lessened action of muscles, but includes a diminished flow of
+blood to a part or organ, from being subjected to fewer alternations of
+pressure, or from becoming in any way less habitually active. Rudiments,
+however, may occur in one sex of those parts which are normally present
+in the other sex; and such rudiments, as we shall hereafter see, have
+often originated in a way distinct from those here referred to. In some
+cases, organs have been reduced by means of natural 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 compensation and economy of growth; but the later stages of
+reduction, after disuse has done all that can fairly be attributed to
+it, and when the saving to be effected by the economy of growth would be
+very small (23. Some good criticisms on this subject have been given by
+Messrs. Murie and Mivart, in 'Transact. Zoological Society,' 1869,
+vol. vii. p. 92.), 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 can come into play, is
+perhaps intelligible by the aid of the hypothesis of pangenesis. But
+as the whole subject of rudimentary organs has been discussed and
+illustrated in my former works (24. 'Variation of Animals and Plants
+under Domestication,' vol. ii pp. 317 and 397. See also 'Origin of
+Species,' 5th Edition p. 535.), I need here say no more on this head.
+
+Rudiments of various muscles have been observed in many parts of the
+human body (25. For instance, M. Richard ('Annales des Sciences Nat.,'
+3rd series, Zoolog. 1852, tom. xviii. p. 13) describes and figures
+rudiments of what he calls the "muscle pedieux de la main," which he
+says is sometimes "infiniment petit." Another muscle, called "le tibial
+posterieur," is generally quite absent in the hand, but appears from
+time to time in a more or less rudimentary condition.); and not a few
+muscles, which are regularly present in some of the lower animals can
+occasionally be detected in man in a greatly reduced condition. Every
+one must have noticed the power which many animals, especially horses,
+possess of moving or twitching their skin; and this is effected by the
+panniculus carnosus. Remnants of this muscle in an efficient state are
+found in various parts of our bodies; for instance, the muscle on the
+forehead, by which the eyebrows are raised. The platysma myoides, which
+is well developed on the neck, belongs to this system. Prof. Turner,
+of Edinburgh, has occasionally 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 shewn (26. Prof. W. Turner, 'Proceedings of
+the Royal Society of Edinburgh,' 1866-67, p. 65.) that the musculus
+sternalis or sternalis brutorum, which is not an extension of the rectus
+abdominalis, but is closely allied to the panniculus, occurred in the
+proportion of about three per cent. in upwards of 600 bodies: he adds,
+that this muscle affords "an excellent illustration of the statement
+that occasional and rudimentary structures are especially liable to
+variation in 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,
+grandfather, and his three children possess the same power to the same
+unusual degree. This family became divided eight generations ago into
+two branches; so that the head of the above-mentioned branch is cousin
+in the seventh degree to the head of the other branch. This distant
+cousin resides in another part of France; and on being asked whether he
+possessed the same faculty, immediately exhibited his power. This case
+offers a good illustration how persistent may be the transmission of an
+absolutely useless faculty, probably derived from our remote semi-human
+progenitors; since many monkeys have, and frequently use the power, of
+largely moving their scalps up and down. (27. See my 'Expression of the
+Emotions in Man and Animals,' 1872, p. 144.)
+
+The extrinsic muscles which serve to move the external ear, and the
+intrinsic muscles which move the different parts, are in a rudimentary
+condition in man, and they all belong to the system of the panniculus;
+they are also variable in development, or at least in function. I have
+seen one man who could draw the whole ear forwards; other men can draw
+it upwards; another who could draw it backwards (28. Canestrini quotes
+Hyrtl. ('Annuario della Soc. dei Naturalisti,' Modena, 1867, p. 97) to
+the same effect.); and from what one of these persons told me, it is
+probable that most of us, by often touching our ears, and thus directing
+our attention towards them, could recover some power of movement by
+repeated trials. The power of erecting and directing the shell of the
+ears to the various points of the compass, is no doubt of the highest
+service to many animals, as they thus perceive the direction of danger;
+but I have never heard, on sufficient evidence, of a man who possessed
+this power, the one which might be of use to him. The whole external
+shell may be considered a rudiment, together with the various folds and
+prominences (helix and anti-helix, tragus and anti-tragus, etc.) which
+in the lower animals strengthen and support the ear when erect, without
+adding much to its weight. Some authors, however, suppose that the
+cartilage of the shell serves to transmit vibrations to the acoustic
+nerve; but Mr. Toynbee (29. '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.), 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. (30. Prof. A.
+Macalister, 'Annals and Magazine of Natural History,' vol. vii. 1871,
+p. 342.) I am also assured by the keepers in the Zoological Gardens that
+these animals never move or erect their ears; so that they are in an
+equally rudimentary condition with those of man, as far as function is
+concerned. Why these animals, as well as the 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 lengthened period moved their ears but little, and thus
+gradually lost the power of moving them. This would be a parallel case
+with that of those large and heavy birds, which, from inhabiting oceanic
+islands, have not been exposed to the attacks of beasts of prey, and
+have consequently lost the power of using their wings for flight. The
+inability to move the ears in man and several apes is, however, partly
+compensated by the freedom with which they can move the head in a
+horizontal plane, so as to catch sounds from all directions. It has been
+asserted that the ear of man alone possesses a lobule; but "a rudiment
+of it is found in the gorilla" (31. Mr. St. George Mivart, 'Elementary
+Anatomy,' 1873, p. 396.); and, as I hear from Prof. Preyer, it is not
+rarely absent in the negro.
+
+[Fig. 2. Human Ear, modelled and drawn by Mr. Woolner. The projecting
+point is labelled a.]
+
+The celebrated sculptor, Mr. Woolner, informs me of one little
+peculiarity in the external ear, which he has often observed both in
+men and women, and of which he perceived the full significance. His
+attention was first called to the subject whilst at work on his figure
+of Puck, to which he had given pointed ears. He was thus led to examine
+the ears of various monkeys, and subsequently more carefully those of
+man. The peculiarity consists in a little blunt point, projecting from
+the inwardly folded margin, or helix. When present, it is developed at
+birth, and, according to Prof. Ludwig Meyer, more frequently in man than
+in woman. Mr. Woolner made an exact model of one such case, and sent
+me the accompanying drawing. (Fig. 2). These points not only project
+inwards towards the centre of the ear, but often a little outwards from
+its plane, so as to be visible when the head is viewed from directly in
+front or behind. They are variable in size, and somewhat in position,
+standing either a little higher or lower; and they sometimes occur on
+one ear and not on the other. They are not confined to mankind, for I
+observed a case in one of the spider-monkeys (Ateles beelzebuth) in our
+Zoological Gardens; and Mr. E. Ray Lankester informs me of another case
+in a chimpanzee in the gardens at Hamburg. The helix obviously consists
+of the extreme margin of the ear folded inwards; and this folding
+appears to be in some manner connected with the whole external ear being
+permanently pressed backwards. In many monkeys, which do not stand high
+in the order, as baboons and some species of macacus (32. See also some
+remarks, and the drawings of the ears of the Lemuroidea, in Messrs.
+Murie and Mivart's excellent paper in 'Transactions of the Zoological
+Society,' vol. vii. 1869, pp. 6 and 90.), the upper portion of the ear
+is slightly pointed, and the margin is not at all folded inwards; but
+if the margin were to be thus folded, a slight point would necessarily
+project inwards towards the centre, and probably a little outwards 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 (33. '�ber das Darwin'sche Spitzohr,' Archiv fur Path. Anat.
+und Phys., 1871, p. 485.), 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 instances, as in those figured by Prof. Meyer, in
+which there are several minute points, or the whole margin is sinuous.
+I have myself seen, through the kindness of Dr. L. Down, the ear of a
+microcephalous idiot, on which there is a projection on the outside of
+the helix, and not on the inward folded edge, so that this point can
+have no relation to a former apex of the ear. Nevertheless in some
+cases, my original view, that the points are vestiges of the tips of
+formerly erect and pointed ears, still seems to me probable. I think
+so from the frequency of their occurrence, and from the general
+correspondence in position with that of the tip of a pointed ear. In
+one case, of which a photograph has been sent me, the projection is so
+large, that supposing, in accordance with Prof. Meyer's view, the ear to
+be made perfect by the equal development of the cartilage throughout the
+whole extent of the margin, it would have covered fully one-third of the
+whole ear. Two cases have been communicated to me, one in North America,
+and the other in England, in which the upper margin is not at all folded
+inwards, but is pointed, so that it closely resembles the pointed ear of
+an ordinary quadruped in outline. In one of these cases, which was that
+of a young child, the father compared the ear with the drawing which I
+have given (34. 'The Expression of the Emotions,' p. 136.) of the ear
+of a monkey, the Cynopithecus niger, and says that their outlines are
+closely similar. If, in these two cases, the margin had been folded
+inwards in the normal manner, an inward projection must have been
+formed. I may add that in two other cases the outline still remains
+somewhat pointed, although the margin of the upper part of the ear is
+normally folded inwards--in one of them, however, very narrowly. [Fig.3.
+Foetus of an Orang(?). Exact copy of a photograph, shewing the form of
+the ear at this early age.] The following woodcut (No. 3) is an accurate
+copy of a photograph of the foetus of an orang (kindly sent me by Dr.
+Nitsche), in which it may be seen how different the pointed outline
+of the ear is at this period from its adult condition, when it bears a
+close general resemblance to that of man. It is evident that the folding
+over of the tip of such an ear, unless it changed greatly during its
+further development, would give rise to a point projecting inwards. On
+the whole, it still seems to me probable that the points in question are
+in some cases, both in man and apes, vestiges of a former condition.
+
+The nictitating membrane, or third eyelid, with its accessory muscles
+and other structures, is especially well developed in birds, and is of
+much functional importance to them, as it can be rapidly drawn across
+the whole eye-ball. It is found in some 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
+admitted by all anatomists, as a mere rudiment, called the semilunar
+fold. (35. Muller's 'Elements of Physiology,' Eng. translat. 1842, vol.
+ii. p. 1117. Owen, 'Anatomy of Vertebrates,' vol. iii. p. 260; ibid. on
+the Walrus, 'Proceedings of the Zoological Society,' November 8, 1854.
+See also R. Knox, 'Great Artists and Anatomists,' p. 106. This rudiment
+apparently is somewhat larger in Negroes and Australians than in
+Europeans, see Carl Vogt, 'Lectures on Man,' Eng. translat. p. 129.)
+
+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 coloured races
+of men, in whom it is much more highly developed than in the white and
+civilised races. (36. The account given by Humboldt of the power of
+smell possessed by the natives of South America is well known, and
+has been confirmed by others. M. Houzeau ('�tudes sur les Facult�s
+Mentales,' etc., tom. i. 1872, p. 91) asserts that he repeatedly made
+experiments, and proved that Negroes and Indians could recognise
+persons in the dark by their odour. Dr. W. Ogle has made some curious
+observations on the connection between the power of smell and the
+colouring 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-coloured races having a finer sense of smell than the white races.
+See his paper, 'Medico-Chirurgical Transactions,' London, vol. liii.
+1870, p. 276.) Nevertheless it does not warn them of danger, nor guide
+them to their 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 power in an enfeebled and so far rudimentary
+condition, from some early progenitor, to whom it was highly
+serviceable, and by whom it was continually used. In those animals
+which have this sense highly developed, such as dogs and horses, the
+recollection of persons and of places is strongly associated with their
+odour; and we can thus perhaps understand how it is, as Dr. Maudsley
+has truly remarked (37. 'The Physiology and Pathology of Mind,' 2nd ed.
+1868, p. 134.), 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, whilst in others they bear thick tufts of hair. (38. Eschricht,
+�ber die Richtung der Haare am menschlichen K�rper, Muller's 'Archiv fur
+Anat. und Phys.' 1837, s. 47. I shall often have to refer to this very
+curious paper.) There can be little doubt that the hairs thus scattered
+over the body are the rudiments of the uniform hairy coat of the lower
+animals. This view is rendered all the more probable, as it is known
+that fine, short, and pale-coloured hairs on the limbs and other parts
+of the body, occasionally become developed into "thickset, long, and
+rather coarse dark hairs," when abnormally nourished near old-standing
+inflamed surfaces. (39. Paget, 'Lectures on Surgical Pathology,' 1853,
+vol. i. p. 71.)
+
+I am informed by Sir James Paget that often several members of a family
+have a few hairs in their eyebrows much longer than the others; so that
+even this slight peculiarity seems to be inherited. These hairs, too,
+seem to have their representatives; for in the chimpanzee, and in
+certain species of Macacus, there are scattered hairs of considerable
+length rising from the naked skin above the eyes, and corresponding to
+our eyebrows; similar long hairs project from the hairy covering of the
+superciliary ridges in some baboons.
+
+The fine wool-like hair, or so-called lanugo, with which the human
+foetus during the sixth month is thickly covered, offers a more curious
+case. It is first developed, during the fifth month, on the eyebrows and
+face, and especially round the mouth, where it is much longer than that
+on the head. A moustache of this kind was observed by Eschricht (40.
+Eschricht, ibid. s. 40, 47.) 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 variability. The whole surface, including even the forehead and
+ears, is thus thickly clothed; but it is a significant fact that the
+palms of the hands and the soles of the feet are quite naked, like the
+inferior surfaces of all four extremities in most of the lower animals.
+As this can hardly be an accidental coincidence, the woolly covering of
+the foetus probably represents the first permanent coat of hair in those
+mammals which are born hairy. Three or four cases have been recorded of
+persons born with their whole bodies and faces thickly covered with fine
+long hairs; and this strange condition is strongly inherited, and
+is correlated with an abnormal condition of the teeth. (41. See my
+'Variation of Animals and Plants under Domestication,' vol. ii. p. 327.
+Prof. Alex. Brandt has recently sent me an additional case of a father
+and son, born in Russia, with these peculiarities. I have received
+drawings of both from Paris.) Prof. Alex. Brandt informs me that he
+has compared the hair from the face of a man thus characterised, 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 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 civilised 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. (42. Dr. Webb, 'Teeth in Man and the Anthropoid Apes,' as quoted
+by Dr. C. Carter Blake in Anthropological Review, July 1867, p. 299.)
+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.
+(43. Owen, 'Anatomy of Vertebrates,' vol. iii. pp. 320, 321, and 325.)
+Prof. Schaaffhausen accounts for this difference between the races by
+"the posterior dental portion of the jaw being always shortened" in
+those that are civilised (44. 'On the Primitive Form of the Skull,' Eng.
+translat., in 'Anthropological Review,' Oct. 1868, p. 426), and this
+shortening may, I presume, be attributed to civilised 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. (45. 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 civilised races they are on the road towards atrophy or
+elimination.)
+
+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 diverticulum of the intestine, ending in a
+cul-de-sac, and is extremely long in many of the lower vegetable-feeding
+mammals. In the marsupial koala it is actually more than thrice as long
+as the whole body. (46. Owen, 'Anatomy of Vertebrates,' vol. iii. pp.
+416, 434, 441.) It is sometimes produced into a long gradually-tapering
+point, and is sometimes constricted in parts. It appears as if, in
+consequence of changed diet or habits, the caecum had become much
+shortened in various animals, the vermiform appendage being left as a
+rudiment of the shortened part. That this appendage is a rudiment,
+we may infer from its small size, and from the evidence which Prof.
+Canestrini (47. 'Annuario della Soc. d. Nat.' Modena, 1867, p. 94.) 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 sometimes the
+cause of death, of which fact I have lately heard two instances: this
+is due to small hard bodies, such as seeds, entering the passage, and
+causing inflammation. (48. M. C. Martins ("De l'Unit� Organique," in
+'Revue des Deux Mondes,' June 15, 1862, p. 16) and Haeckel ('Generelle
+Morphologie,' B. ii. s. 278), have both remarked on the singular fact of
+this rudiment sometimes causing death.)
+
+In some of the lower Quadrumana, in the Lemuridae and Carnivora, as
+well as in many marsupials, there is a passage near the lower end of
+the humerus, called the supra-condyloid foramen, through which the
+great nerve of the fore limb 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 (49.
+With respect to inheritance, see Dr. Struthers in the 'Lancet,' Feb. 15,
+1873, and another important paper, ibid. Jan. 24, 1863, p. 83. Dr. Knox,
+as I am informed, was the first anatomist who drew attention to this
+peculiar structure in man; see his 'Great Artists and Anatomists,' p.
+63. See also an important memoir on this process by Dr. Gruber, in the
+'Bulletin de l'Acad. Imp. de St. Petersbourg,' tom. xii. 1867, p.
+448.), who has closely attended to the subject, has now shewn that this
+peculiarity is sometimes inherited, as it has occurred in a father, and
+in no less than four out of his seven children. When present, the great
+nerve invariably passes through it; and this clearly indicates that
+it is the 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 anthropoid and other apes (50. Mr. St.
+George Mivart, 'Transactions Phil. Soc.' 1867, p. 310.), 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. Busk (51. "On the Caves of Gibraltar," 'Transactions
+of the International Congress of Prehistoric Archaeology,' Third
+Session, 1869, p. 159. Prof. Wyman has lately shewn (Fourth Annual
+Report, Peabody Museum, 1871, p. 20), that this perforation is present
+in thirty-one per cent. of some human remains from ancient mounds in
+the Western United States, and in Florida. It frequently occurs in the
+negro.) 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 'Cimeti�re 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. Dupont found thirty per cent.
+of perforated bones in the caves of the Valley of the Lesse, belonging
+to the Reindeer period; whilst M. Leguay, in 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 nearer in the long line of descent to their remote
+animal-like progenitors.
+
+In man, the os coccyx, together with certain other vertebrae hereafter
+to be described, though functionless 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 (52. Quatrefages has lately
+collected the evidence on this subject. 'Revue des Cours Scientifiques,'
+1867-1868, p. 625. In 1840 Fleischmann exhibited a human foetus bearing
+a free tail, which, as is not always the case, included vertebral
+bodies; and this tail was critically examined by the many anatomists
+present at the meeting of naturalists at Erlangen (see Marshall in
+Niederlandischen Archiv f�r Zoologie, December 1871).), to form a small
+external rudiment of a tail. The os coccyx is short, usually including
+only four vertebrae, all anchylosed together: and these are in a
+rudimentary condition, for they consist, with the exception of the basal
+one, of the centrum alone. (53. Owen, 'On the Nature of Limbs,' 1849, p.
+114.) They are furnished with some small muscles; one of which, as I am
+informed by Prof. Turner, has been expressly described by Theile as a
+rudimentary repetition of the extensor of the tail, a muscle which is so
+largely developed in many mammals.
+
+The spinal cord in man extends only as far downwards as the last
+dorsal or first lumbar vertebra; but a thread-like structure (the filum
+terminale) runs down the axis of the sacral part of the spinal canal,
+and even along the back of the coccygeal bones. The upper part of this
+filament, as Prof. Turner informs me, is undoubtedly homologous with the
+spinal cord; but the lower part apparently consists merely of the pia
+mater, or vascular investing membrane. Even in this case the os coccyx
+may be said to possess a vestige of so important a structure as
+the spinal cord, though no longer enclosed within a bony canal. The
+following fact, for which I am also indebted to Prof. Turner, shews
+how closely the os coccyx corresponds with the true tail in the lower
+animals: Luschka has recently discovered at the extremity of the
+coccygeal bones a very peculiar convoluted body, which is continuous
+with the middle sacral artery; and this discovery led Krause and Meyer
+to examine the tail of a monkey (Macacus), and of a cat, in both
+of which they found a similarly convoluted body, though not at the
+extremity.
+
+The reproductive system offers various rudimentary structures; but these
+differ in one important respect from the foregoing cases. Here we are
+not concerned with the vestige of a part which does not belong to the
+species in an efficient state, but with a part efficient in the one
+sex, and represented in the other by a mere rudiment. Nevertheless, the
+occurrence of such rudiments is as difficult to explain, on the belief
+of the separate creation of each species, as in the foregoing cases.
+Hereafter I shall have to recur to these rudiments, and shall shew that
+their presence generally depends merely on inheritance, that is, on
+parts acquired by one sex having been partially transmitted to the
+other. I will in this place only give some instances of such rudiments.
+It is well known that in the males of all mammals, including man,
+rudimentary mammae exist. These in several instances have become well
+developed, and have yielded a copious supply of milk. Their essential
+identity in the two sexes is likewise shewn by their occasional
+sympathetic enlargement in both during an attack of the measles. The
+vesicula prostatica, which has been observed in many male mammals, is
+now universally acknowledged to be the homologue of the female uterus,
+together with the connected passage. It is impossible to read Leuckart's
+able description of this organ, and his reasoning, without admitting
+the justness of his conclusion. This is especially clear in the case
+of those mammals in which the true female uterus bifurcates, for in
+the males of these the vesicula likewise bifurcates. (54. Leuckart, in
+Todd's 'Cyclopaedia of Anatomy' 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.) Some other rudimentary structures belonging to the
+reproductive system might have been here adduced. (55. See, on this
+subject, Owen, 'Anatomy of Vertebrates,' vol. iii. pp. 675, 676, 706.)
+
+The bearing of the three great classes of facts now given is
+unmistakeable. But it would be superfluous fully to recapitulate
+the line of argument given in detail in my 'Origin of Species.' The
+homological construction of the whole frame in the members of the
+same class is intelligible, if we admit their descent from a common
+progenitor, together with their subsequent adaptation to diversified
+conditions. On any other view, the similarity of pattern between the
+hand of a man or monkey, the foot of a horse, the flipper of a seal, the
+wing of a bat, etc., is utterly inexplicable. (56. Prof. Bianconi, in
+a recently published work, illustrated by admirable engravings ('La
+Th�orie Darwinienne et la cr�ation dite ind�pendante,' 1874), endeavours
+to shew that homological structures, in the above and other cases, can
+be fully explained on mechanical principles, in accordance with their
+uses. No one has shewn 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 metaphysical principle, namely, the preservation
+"in its integrity of the mammalian nature of the animal." In only a few
+cases does he discuss rudiments, and then only those parts which are
+partially rudimentary, such as the little hoofs of the pig and ox, which
+do not touch the ground; these he shews clearly to be of service to the
+animal. It is unfortunate that he did not consider such cases as the
+minute teeth, which never cut through the jaw in the ox, or the mammae
+of male quadrupeds, or the wings of certain beetles, existing under
+the soldered wing-covers, or the vestiges of the pistil and stamens in
+various 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 structures are inexplicable on the
+principle of mere adaptation.) It is no scientific explanation to assert
+that they have all been formed on the same ideal plan. With respect to
+development, we can clearly understand, on the principle of 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 marvellous 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 rudimentary organs, we have only
+to suppose that a former progenitor possessed the parts in question in a
+perfect state, and that under changed habits of life they became greatly
+reduced, either from simple disuse, or through the natural selection of
+those individuals which were least encumbered with a superfluous part,
+aided by the other means previously indicated.
+
+Thus we can understand how it has come to pass that man and all other
+vertebrate animals have been constructed on the same general model, why
+they pass through the same early stages of development, and why they
+retain certain rudiments in common. Consequently we ought frankly to
+admit their community of descent: to take any other view, is to admit
+that our own 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
+consider the evidence derived from their affinities or classification,
+their geographical distribution and geological succession. It is only
+our natural prejudice, and that arrogance which made our forefathers
+declare that they were descended from demi-gods, which leads us to demur
+to this conclusion. But the time will 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.
+
+
+CHAPTER II.
+
+ON THE MANNER OF DEVELOPMENT OF MAN FROM SOME LOWER FORM.
+
+Variability of body and mind in man--Inheritance--Causes of
+variability--Laws of variation the same in man as in the lower
+animals--Direct action of the conditions of life--Effects of
+the 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 variability. No two
+individuals of the same race are quite alike. We may compare millions
+of faces, and each will be distinct. There is an equally great amount of
+diversity in the proportions and dimensions of the various parts of the
+body; the length of the legs being one of the most variable points. (1.
+'Investigations in Military and Anthropological Statistics of American
+Soldiers,' by B.A. Gould, 1869, p. 256.) Although in some quarters
+of the world an elongated skull, and in other quarters a short skull
+prevails, yet there is great diversity of shape even within the
+limits of the same race, as with the aborigines of America and South
+Australia--the latter a race "probably as pure and homogeneous in
+blood, customs, and language as any in existence"--and even with the
+inhabitants of so confined an area as the Sandwich Islands. (2. 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.) An eminent dentist assures me that there is nearly
+as much diversity in the teeth as in the features. The chief arteries
+so frequently run in abnormal courses, that it has been found useful for
+surgical purposes to calculate from 1040 corpses how often each course
+prevails. (3. 'Anatomy of the Arteries,' by R. Quain. Preface, vol. i.
+1844.) The muscles are eminently variable: thus those of the foot
+were found by Prof. Turner (4. 'Transactions of the Royal Society of
+Edinburgh,' vol. xxiv. pp. 175, 189.) not to be strictly alike in any
+two out of fifty bodies; and in some the deviations were considerable.
+He adds, that the power of performing the appropriate movements must
+have been modified in accordance with the several deviations. Mr. J.
+Wood has recorded (5. 'Proceedings Royal Society,' 1867, p. 544; also
+1868, pp. 483, 524. There is a previous paper, 1866, p. 229.) 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 descriptions of the muscular
+system given in anatomical text books." A single body presented the
+extraordinary number of twenty-five distinct abnormalities. The same
+muscle sometimes varies in many ways: thus Prof. Macalister describes
+(6. 'Proc. R. Irish Academy,' vol. x. 1868, p. 141.) no less than twenty
+distinct variations in the palmaris accessorius.
+
+The famous old anatomist, Wolff (7. 'Act. Acad. St. Petersburg,' 1778,
+part ii. p. 217.), insists that the internal viscera are more variable
+than the external parts: Nulla particula est quae non aliter et aliter
+in aliis se habeat hominibus. He has even written a treatise on
+the choice of typical examples of the viscera for representation. A
+discussion on the beau-ideal of the liver, lungs, kidneys, etc., as of
+the human face divine, sounds strange in our ears.
+
+The variability or diversity of the mental faculties in men of the same
+race, not to mention the greater differences between the men of distinct
+races, is so notorious that not a word need here be said. So it is with
+the lower animals. All who have had charge of menageries admit this
+fact, and we see it plainly in our dogs and other domestic animals.
+Brehm especially insists that each individual monkey of those which
+he kept tame 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 intelligence. Rengger,
+also, insists on the diversity in the various mental characters of
+the monkeys of the same species which he kept in Paraguay; and this
+diversity, as he adds, is partly innate, and partly the result of
+the manner in which they have been treated or educated. (8. Brehm,
+'Thierleben,' B. i. ss. 58, 87. Rengger, 'S�ugethiere von Paraguay,' s.
+57.)
+
+I have elsewhere (9. 'Variation of Animals and Plants under
+Domestication,' vol. ii. chap. xii.) so fully discussed the subject of
+Inheritance, that I need here add hardly anything. A greater number of
+facts have been collected with respect to the transmission of the most
+trifling, as well as of the most important characters in man, than
+in any of the lower animals; though the facts are copious enough
+with respect to the latter. So in regard to mental qualities, their
+transmission is manifest in our dogs, horses, and other domestic
+animals. Besides special tastes and habits, general intelligence,
+courage, bad and good temper, etc., are certainly transmitted. With man
+we see similar facts in almost every family; and we now know, through
+the admirable labours of Mr. Galton (10. 'Hereditary Genius: an Inquiry
+into its Laws and Consequences,' 1869.), that genius which implies
+a wonderfully complex combination of high faculties, tends to be
+inherited; and, on the other hand, it is too certain that insanity and
+deteriorated mental powers likewise run in families.
+
+With respect to the causes of variability, we are in all cases very
+ignorant; but we can see that in man as in the lower animals, they
+stand in some relation to the conditions to which each species has been
+exposed, during several generations. Domesticated animals vary more
+than those in a state of nature; and this is apparently due to the
+diversified and changing nature of the conditions to which they have
+been subjected. In this respect the different races of man resemble
+domesticated animals, and so do the individuals of the same race, when
+inhabiting a very wide area, like that of America. We see the influence
+of diversified conditions in the more civilised nations; for the
+members belonging 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. (11. 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 nostrils, and obliquity of eyes.") 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" (12.
+Blumenbach, 'Treatises on Anthropology.' Eng. translat., 1865, p. 205.)
+than any other animal. Some savage races, such as the Australians, are
+not exposed to more diversified conditions than are many species which
+have a wide range. In another and much more important respect, man
+differs widely from any strictly domesticated animal; for his breeding
+has never long been controlled, either by methodical or unconscious
+selection. No race or body of men has been so completely subjugated by
+other men, as that certain individuals should be preserved, and thus
+unconsciously selected, from somehow excelling in utility to their
+masters. Nor have certain 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.
+(13. Mitford's 'History of Greece,' vol. i. p. 282. It appears also from
+a passage in Xenophon's 'Memorabilia,' B. ii. 4 (to which my attention
+has been called by the Rev. J.N. Hoare), that it was a well recognised
+principle with the Greeks, that men ought to select their wives with
+a view to the health and vigour of their children. The Grecian poet,
+Theognis, who lived 550 B.C., clearly saw how important selection, if
+carefully applied, would be for the improvement of mankind. He
+saw, likewise, that wealth often checks the proper action of sexual
+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 everything:  for money's sake,
+    Men marry:  women are in marriage given
+    The churl or ruffian, that in wealth has thriven,
+    May match his offspring with the proudest race:
+    Thus everything is mix'd, noble and base!
+    If then in outward manner, form, and mind,
+    You find us a degraded, motley kind,
+    Wonder no more, my friend! the cause is plain,
+    And to lament the consequence is vain."
+
+(The Works of J. Hookham Frere, vol. ii. 1872, p. 334.))
+
+If we consider all the races of man as forming a single species,
+his range is enormous; but some separate races, as the Americans
+and Polynesians, have very wide ranges. It is a well-known law that
+widely-ranging species are much more variable than species with
+restricted ranges; and the variability of man may with more truth
+be compared with that of widely-ranging species, than with that of
+domesticated animals.
+
+Not only does variability appear to be induced in man and the 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 detail by Godron and Quatrefages, that I need here only refer
+to their works. (14. Godron, 'De l'Esp�ce,' 1859, tom. ii. livre
+3. Quatrefages, 'Unit� de l'Esp�ce Humaine,' 1861. Also Lectures on
+Anthropology, given in the 'Revue des Cours Scientifiques,' 1866-1868.)
+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 shewn by Isidore
+Geoffroy St.-Hilaire. (15. 'Hist. Gen. et Part. des Anomalies de
+l'Organisation,' in three volumes, tom. i. 1832.) In my work on the
+variation of domestic animals, I have attempted to arrange in a rude
+fashion the laws of variation under the following heads:--The direct and
+definite action of changed conditions, as exhibited by all or nearly all
+the individuals of the same species, varying in the same 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. All these so-called laws
+apply equally to man and the lower animals; and most of them even to
+plants. It would be superfluous here to discuss all of them (16. I have
+fully discussed these laws in my 'Variation of Animals and Plants under
+Domestication,' vol. ii. chap. xxii. and xxiii. M. J.P. Durand has
+lately (1868) published a valuable essay, 'De l'Influence des Milieux,'
+etc. He lays much stress, in the case of plants, on the nature of the
+soil.); 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 favour of this conclusion; and
+valid reasons may be urged on the other side, at least as far as the
+innumerable structures are concerned, which are adapted for special
+ends. There can, however, be no doubt that changed conditions induce an
+almost indefinite amount of fluctuating variability, by which the whole
+organisation is rendered in some degree plastic.
+
+In the United States, above 1,000,000 soldiers, who served in the late
+war, were measured, and the States in which they were born and
+reared were recorded. (17. 'Investigations in Military and Anthrop.
+Statistics,' etc., 1869, by B.A. Gould, pp. 93, 107, 126, 131, 134.)
+From this astonishing number of observations it is proved that local
+influences of some kind act directly on stature; and we further learn
+that "the State where the physical growth has in great measure taken
+place, and the State of birth, which indicates the ancestry, seem
+to exert a marked influence on the stature." For instance, it is
+established, "that residence in the Western States, during the years of
+growth, tends to produce increase of stature." On the other hand, it is
+certain that with sailors, their life delays growth, as shewn "by the
+great difference between the statures of soldiers and sailors at the
+ages of seventeen and eighteen years." Mr. B.A. Gould endeavoured to
+ascertain the nature of the influences which thus act on stature; but
+he arrived only at negative results, namely that they did not relate to
+climate, the elevation of the land, soil, nor even "in any controlling
+degree" to the abundance or the need of the comforts of life. This
+latter conclusion is directly opposed to that arrived at by Villerme,
+from the statistics of the height of the conscripts in different parts
+of France. When we compare the differences in stature between the
+Polynesian chiefs and the lower orders within the same islands, or
+between the inhabitants of the fertile volcanic and low barren coral
+islands of the same ocean (18. For the Polynesians, see Prichard's
+'Physical History of Mankind,' vol. v. 1847, pp. 145, 283. Also Godron,
+'De l'Esp�ce,' tom. ii. p. 289. There is also a remarkable difference
+in appearance between the closely-allied Hindoos inhabiting the Upper
+Ganges and Bengal; see Elphinstone's 'History of India,' vol. i. p.
+324.) 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 shew how
+difficult it is to arrive at any precise result. Dr. Beddoe has lately
+proved that, with the inhabitants of Britain, residence in towns and
+certain occupations have a deteriorating influence on height; and he
+infers that the result is to a certain extent inherited, as is likewise
+the case in the United States. Dr. Beddoe further believes that wherever
+a "race attains its maximum of physical development, it rises highest in
+energy and moral vigour." (19. 'Memoirs, Anthropological Society,' vol.
+iii. 1867-69, pp. 561, 565, 567.)
+
+Whether external conditions produce any other direct effect on man is
+not known. It might have been expected that differences of climate
+would have had a marked influence, inasmuch as the lungs and kidneys are
+brought into activity under a low temperature, and the liver and skin
+under a high one. (20. Dr. Brakenridge, 'Theory of Diathesis,' 'Medical
+Times,' June 19 and July 17, 1869.) It was formerly thought that the
+colour 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 well known that use strengthens the muscles in the individual, and
+complete disuse, or the destruction of the proper nerve, weakens them.
+When the eye is destroyed, the optic nerve often becomes atrophied. When
+an artery is tied, the lateral channels increase not only in diameter,
+but in the thickness and strength of their coats. When one kidney ceases
+to act from disease, the other increases in size, and does double work.
+Bones increase not only in thickness, but in length, from carrying
+a greater weight. (21. I have given authorities for these several
+statements in my 'Variation of Animals and Plants under Domestication,'
+vol. ii. pp. 297-300. Dr. Jaeger, "�ber das Langenwachsthum der
+Knochen," 'Jen�ischen Zeitschrift,' B. v. Heft. i.) Different
+occupations, habitually followed, lead to changed proportions in
+various parts of the body. Thus it was ascertained by the United States
+Commission (22. 'Investigations,' etc., by B.A. Gould, 1869, p. 288.)
+that the legs of the sailors employed in the late war were longer by
+0.217 of an inch than those of the soldiers, though the sailors were
+on an average shorter men; whilst their arms were shorter by 1.09 of
+an inch, and therefore, out of proportion, shorter in relation to their
+lesser height. This shortness of the arms is apparently due to their
+greater use, and is an unexpected result: but sailors chiefly use their
+arms in pulling, and not in supporting weights. With sailors, the
+girth of the neck and the depth of the instep are greater, whilst the
+circumference of the chest, waist, and hips is less, than in soldiers.
+
+Whether the several foregoing modifications would become hereditary, if
+the same habits of life were followed during many generations, is not
+known, but it is probable. Rengger (23. 'S�ugethiere von Paraguay,'
+1830, s. 4.) attributes the thin legs and thick arms of the Payaguas
+Indians to successive generations having passed nearly their whole lives
+in canoes, with their lower extremities motionless. Other writers have
+come to a similar conclusion in analogous cases. According to Cranz
+(24. 'History of Greenland,' Eng. translat., 1767, vol. i. p. 230.),
+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 labourers are at birth larger than those of
+the gentry. (25. 'Intermarriage,' by Alex. Walker, 1838, p. 377.) From
+the correlation which exists, at least in some cases (26. 'The
+Variation of Animals under Domestication,' vol. i. p. 173.), between the
+development of the extremities and of the jaws, it is possible that in
+those classes which do not labour much with their hands and feet, the
+jaws would be reduced in size from this cause. That they are generally
+smaller in refined and civilised men than in hard-working men or
+savages, is certain. But with savages, as Mr. Herbert Spencer (27.
+'Principles of Biology,' vol. i. p. 455.) 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; (28. Paget,
+'Lectures on Surgical Pathology,' vol. ii, 1853, p. 209.) and it can
+hardly be doubted that this is due to the inherited effects of pressure
+during a long series of generations.
+
+It is familiar to every one that watchmakers and engravers are liable
+to be short-sighted, whilst men living much out of doors, and especially
+savages, are generally long-sighted. (29. It is a singular and
+unexpected fact that sailors are inferior to landsmen in their mean
+distance of distinct vision. Dr. B.A. Gould ('Sanitary Memoirs of the
+War of the Rebellion,' 1869, p. 530), has proved this to be the case;
+and he accounts for it by the ordinary range of vision in sailors being
+"restricted to the length of the vessel and the height of the masts.")
+Short-sight and long-sight certainly tend to be inherited. (30.
+'The Variation of Animals under Domestication,' vol. i. p. 8.) 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 (31. 'S�ugethiere von
+Paraguay,' s. 8, 10. I have had good opportunities 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 collected ('Revue des Cours Scientifiques,'
+1870, p. 625) a large and valuable body of evidence proving that the
+cause of short-sight, "C'est le travail assidu, de pr�s.") 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 Mongolians
+of the plains of northern Asia, according to Pallas, have wonderfully
+perfect senses; and Prichard believes that the great breadth of their
+skulls across the zygomas follows from their highly-developed sense
+organs. (32. Prichard, 'Physical History of Mankind,' on the authority
+of Blumenbach, vol. i. 1851, p. 311; for the statement by Pallas, vol.
+iv. 1844, p. 407.)
+
+The Quechua Indians inhabit the lofty plateaux of Peru; and Alcide
+d'Orbigny states (33. Quoted by Prichard, 'Researches into the Physical
+History of Mankind,' vol. v. p. 463.) that, from continually breathing
+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. 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 informs
+me (34. Mr. Forbes' valuable paper is now published in the 'Journal of
+the Ethnological Society of London,' new series, vol. ii. 1870, p.193.)
+that they differ conspicuously from the men of all other races seen by
+him in the circumference and length of their bodies. In his table of
+measurements, the stature of each man is taken at 1000, and the other
+measurements are reduced to this standard. It is here seen that the
+extended arms of the Aymaras are shorter than those of Europeans, and
+much shorter than 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; whilst 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 compensation in relation with the greatly
+increased length of the trunk. The Aymaras present some other singular
+points of structure, for instance, the very small projection of the
+heel.
+
+These men are so thoroughly acclimatised to their cold and lofty abode,
+that when formerly carried down by the Spaniards to the low eastern
+plains, and when now tempted down by high wages to the gold-washings,
+they suffer a frightful rate of mortality. Nevertheless Mr. Forbes found
+a few pure families which had survived during two generations: and he
+observed that they still inherited their characteristic peculiarities.
+But it was manifest, even without measurement, that these peculiarities
+had all decreased; and on measurement, their bodies were found not to be
+so much elongated as those of the men on the high plateau; whilst their
+femora had become somewhat lengthened, as had their tibiae, although
+in a less degree. The actual measurements may be seen by consulting
+Mr. Forbes's memoir. From these observations, there can, I think, be no
+doubt that residence during many generations at a great elevation tends,
+both directly and indirectly, to induce inherited modifications in
+the proportions of the body. (35. Dr. Wilckens ('Landwirthschaft.
+Wochenblatt,' No. 10, 1869) has lately published an interesting essay
+shewing how domestic animals, which live in mountainous regions, have
+their frames modified.)
+
+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 shew that his liability in this respect has not been lost; and
+we positively know that the same law holds good with the lower animals.
+Consequently we may infer that when at a remote epoch the progenitors of
+man were in a transitional state, and were changing from quadrupeds into
+bipeds, natural selection would probably have been greatly aided by the
+inherited effects of the increased or diminished use of the different
+parts of the body.
+
+ARRESTS OF DEVELOPMENT.
+
+There is a difference between arrested development and arrested growth,
+for parts in the former state continue to grow whilst still retaining
+their early condition. Various monstrosities come under this head; and
+some, as a cleft palate, are known to be occasionally inherited. It will
+suffice for our purpose to refer to the arrested brain-development of
+microcephalous idiots, as described in Vogt's memoir. (36. 'M�moire sur
+les Microcephales,' 1867, pp. 50, 125, 169, 171, 184-198.) Their skulls
+are smaller, and the convolutions of the brain are less complex than in
+normal men. The frontal sinus, or the projection over the eye-brows,
+is largely developed, and the jaws are prognathous to an "effrayant"
+degree; so that these idiots somewhat resemble the lower types of
+mankind. Their intelligence, and most of their mental faculties, are
+extremely feeble. They cannot acquire the power of speech, and
+are wholly incapable of prolonged attention, but are much given to
+imitation. They are strong and remarkably active, continually gambolling
+and jumping about, and making 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 shewn by almost all boys in climbing
+trees; and this again reminds us how lambs and kids, originally alpine
+animals, delight to frisk on any hillock, however small. Idiots also
+resemble the lower animals in some other respects; thus several cases
+are recorded 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, whilst hunting for lice. They are often filthy in their habits,
+and have no sense of decency; and several cases have been published
+of their bodies being remarkably hairy. (37. Prof. Laycock sums up the
+character of brute-like idiots by calling them "theroid;" 'Journal of
+Mental Science,' July 1863. Dr. Scott ('The Deaf and Dumb,' 2nd ed.
+1870, p. 10) has often observed 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 in an idiot.)
+
+REVERSION.
+
+Many of the cases to be here given, might have been introduced under the
+last heading. When a structure is arrested in its development, but still
+continues growing, until it closely resembles a corresponding structure
+in some lower and adult member of the same group, it may in one sense be
+considered as a case of reversion. The lower members in a group give us
+some idea how the common 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 ultimately to perform
+its proper function, unless it had acquired such power during some
+earlier state of existence, when the present exceptional or arrested
+structure was normal. The simple brain of a microcephalous idiot, in as
+far as it resembles that of an ape, may in this sense be said to offer a
+case of reversion. (38. In my 'Variation of Animals under Domestication'
+(vol. ii. p. 57), I attributed the not very rare cases of supernumerary
+mammae in women to reversion. I was led to this as a probable
+conclusion, by the additional mammae being generally placed
+symmetrically on the breast; and more especially from one case, in which
+a single efficient mamma occurred in the inguinal region of a woman,
+the daughter of another woman with supernumerary mammae. But I now find
+(see, for instance, Prof. Preyer, 'Der Kampf um das Dasein,' 1869, s.
+45) that mammae erraticae, occur in other situations, as on the back, in
+the armpit, and on the thigh; the mammae in this latter instance having
+given so much milk that the child was thus nourished. The probability
+that the additional mammae are due to reversion is thus much 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 that some Lemurs normally
+have two pairs of mammae on the breast. Five cases have been recorded
+of the presence of more than a pair of mammae (of course rudimentary) in
+the male sex of mankind; see 'Journal of Anat. and Physiology,' 1872, 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 to by
+Dr. Bartels, a man bore five mammae, one being medial and placed
+above the navel; Meckel von Hemsbach thinks that this latter case is
+illustrated by a medial mamma occurring in certain Cheiroptera. On
+the whole, we may well doubt if additional mammae would ever have been
+developed in both sexes of mankind, had not his early progenitors been
+provided with more than a single pair.
+
+In the above work (vol. ii. p. 12), I also attributed, though with
+much hesitation, the frequent cases of polydactylism in men and various
+animals to reversion. I was partly led to this through Prof. Owen's
+statement, that some of the Ichthyopterygia possess more than five
+digits, and therefore, as I supposed, had retained a primordial
+condition; but Prof. Gegenbaur ('Jenaischen Zeitschrift,' B. v. Heft 3,
+s. 341), disputes Owen's conclusion. On the other hand, according to
+the opinion lately advanced by Dr. Gunther, on the paddle of Ceratodus,
+which is provided with articulated bony rays on both sides of a central
+chain of bones, there seems no great difficulty in admitting that six
+or more digits on one side, or on both sides, might reappear through
+reversion. I am informed by Dr. Zouteveen that there is a case on record
+of a man having twenty-four fingers and twenty-four toes! I 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 vertebrata. But I have
+explained in the second edition of my Variation under Domestication
+why I now place little reliance on the recorded cases of such regrowth.
+Nevertheless it deserves notice, inasmuch as arrested development and
+reversion are intimately related processes; 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 Geoffroy St.-Hilaire. But
+at present it is the safest course to give up altogether the idea that
+there is any relation between the development of supernumerary digits
+and reversion to some lowly organised progenitor of man.) There
+are other cases which come more strictly under our present head of
+reversion. Certain structures, regularly occurring in the lower members
+of the group to which man belongs, occasionally make their appearance
+in him, though not found in the normal human embryo; or, if normally
+present in the human embryo, they become abnormally developed, although
+in a manner which is normal in the lower members of the group. These
+remarks will be rendered clearer by the following illustrations.
+
+In various mammals the uterus graduates from a double organ with two
+distinct orifices and two passages, as in the marsupials, into a single
+organ, which is in no way double except from having a slight internal
+fold, as in the higher apes and man. The rodents exhibit a perfect
+series of gradations between these two extreme states. In all mammals
+the uterus is developed from two simple primitive tubes, the inferior
+portions of which form the cornua; and it is in the words of Dr. 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 middle portion or body exists, the cornua remain ununited. As the
+development of the uterus proceeds, the two cornua become gradually
+shorter, until at length they are lost, or, as it were, absorbed into
+the body of the uterus." The angles of the uterus are still produced
+into cornua, even in animals 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 instance of a simple arrest of embryonic development, with
+subsequent growth and perfect functional development; for either side of
+the partially double uterus is capable of performing the proper office
+of gestation. In other and rarer cases, two distinct uterine cavities
+are formed, each having its proper orifice and passage. (39. 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. Professor Turner, in 'Edinburgh Medical Journal,'
+February, 1865.) No such stage is passed through during the ordinary
+development of the embryo; and it is difficult to believe, though
+perhaps not impossible, that the two simple, minute, primitive tubes
+should know how (if such an expression may be used) to grow into two
+distinct uteri, each with a well-constructed orifice and passage, and
+each furnished with numerous muscles, nerves, glands and vessels, if
+they had not formerly passed through a similar course of development, as
+in the case of existing marsupials. No one will pretend that so perfect
+a structure as the abnormal double uterus in woman could be the result
+of mere chance. But the principle of reversion, by which a long-lost
+structure is called back into existence, might serve as the guide for
+its full development, even after the lapse of an enormous interval of
+time.
+
+Professor Canestrini, after discussing the foregoing and various
+analogous cases, arrives at the same conclusion as that just given. He
+adduces another instance, in the case of the malar bone (40. 'Annuario
+della Soc. dei Naturalisti,' Modena, 1867, p. 83. Prof. Canestrini gives
+extracts on this subject from various authorities. Laurillard remarks,
+that as he has found a complete similarity in the form, proportions,
+and 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 remarks that it more frequently occurs in
+prognathous skulls, not of the Aryan race, than in others. 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 reviewer, without any grounds or scruples, has thrown doubts on
+my statements.), 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 afterwards became fused together. In man the frontal
+bone consists of a single piece, but in the embryo, and in children, and
+in almost all the lower 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 approaching the lower animals in certain characters more
+frequently than do the modern races, appears to be, that the latter
+stand at a somewhat greater distance in the long line of descent from
+their early semi-human progenitors.
+
+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. (41. A whole series of cases is given by Isidore Geoffroy
+St.-Hilaire, 'Hist. des Anomalies,' tom, iii, p. 437. A reviewer
+('Journal of Anatomy 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
+development, is not only a means to an end, but once was an end in
+itself." This does not seem to me necessarily to hold good. Why should
+not variations occur during an early period of development, having
+no relation to reversion; yet such variations might be preserved and
+accumulated, if in any 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?)
+
+In man, the canine teeth are perfectly efficient instruments for
+mastication. But their true canine character, as Owen (42. 'Anatomy of
+Vertebrates,' vol. iii. 1868, p. 323.) remarks, "is indicated by the
+conical form of the crown, which terminates in an obtuse point, is
+convex outward and flat or sub-concave within, at the base of which
+surface there is a feeble prominence. The conical form is best expressed
+in the Melanian races, especially the Australian. The canine is
+more deeply implanted, and by a stronger fang than the incisors."
+Nevertheless, this tooth no longer serves man as a special weapon for
+tearing his enemies or prey; it may, therefore, as far as its proper
+function is concerned, be considered as rudimentary. In every large
+collection of human skulls some may be found, as Haeckel (43. 'Generelle
+Morphologie,' 1866, B. ii. s. clv.) observes, with the canine teeth
+projecting considerably beyond the others in the same manner as in the
+anthropomorphous apes, but in a less degree. In these cases, open spaces
+between the teeth in the one jaw are left for the reception of the
+canines of the opposite jaw. An inter-space of this kind in a Kaffir
+skull, figured by Wagner, is surprisingly wide. (44. Carl Vogt's
+'Lectures on Man,' Eng. translat., 1864, p. 151.) Considering how few
+are the ancient skulls which have been examined, compared to recent
+skulls, it is an interesting fact that in at least three cases the
+canines project largely; and in the Naulette jaw they are spoken of
+as enormous. (45. C. Carter Blake, on a jaw from La Naulette,
+'Anthropological Review,' 1867, p. 295. Schaaffhausen, ibid. 1868, p.
+426.)
+
+Of the anthropomorphous apes the males alone have their canines fully
+developed; but in the female gorilla, and in a less degree in the female
+orang, these teeth project considerably beyond the others; therefore
+the fact, of which I have been assured, that women sometimes have
+considerably projecting canines, is no serious objection to the belief
+that their occasional great development in man is a case of reversion
+to an ape-like progenitor. He who rejects with scorn the belief that
+the shape of his own canines, and their occasional great development in
+other men, are due to our early forefathers having been provided with
+these formidable weapons, will probably reveal, by sneering, the line of
+his descent. For though he no longer intends, nor has the power, to
+use these teeth as weapons, he will unconsciously retract his "snarling
+muscles" (thus named by Sir C. Bell) (46. The Anatomy of Expression,
+1844, pp. 110, 131.), 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. Professor Vlacovich (47. Quoted by Prof.
+Canestrini in the 'Annuario della Soc. dei Naturalisti,' 1867, p. 90.)
+examined forty male subjects, and found a muscle, called by him the
+ischio-pubic, in nineteen of them; in three others there was a ligament
+which represented this muscle; and in the remaining eighteen no trace of
+it. In only two out of thirty female subjects was this muscle developed
+on both sides, but in three others the rudimentary ligament was present.
+This muscle, therefore, appears to be much more common in the male than
+in the female sex; and on the belief in the descent of man from some
+lower form, the fact is intelligible; for it has been detected in
+several of the lower animals, and in all of these it serves exclusively
+to aid the male in the act of reproduction.
+
+Mr. J. Wood, in his valuable series of papers (48. These papers deserve
+careful study by any one who desires to learn how frequently our muscles
+vary, and in varying come to resemble those of the Quadrumana. The
+following references relate to the few points touched on in my text:
+'Proc. Royal Soc.' vol. xiv. 1865, pp. 379-384; vol. xv. 1866, pp. 241,
+242; vol. xv. 1867, p. 544; vol. xvi. 1868, p. 524. I may here add that
+Dr. Murie and Mr. St. George Mivart have shewn in their Memoir on the
+Lemuroidea ('Transactions, Zoological Society,' 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.), has minutely described a vast number of
+muscular variations in man, which resemble normal structures in the
+lower animals. The muscles which closely resemble those regularly
+present in our nearest allies, the Quadrumana, are too numerous to be
+here even specified. In a single male subject, having a strong bodily
+frame, and well-formed skull, no less than seven muscular variations
+were observed, all of which plainly represented muscles proper to
+various kinds of apes. This man, for instance, had on both sides of his
+neck a true and powerful "levator claviculae," such as is found in all
+kinds of apes, and which is said to occur in about one out of sixty
+human subjects. (49. See also Prof. Macalister in 'Proceedings, Royal
+Irish Academy,' vol. x. 1868, p. 124.) Again, this man had "a special
+abductor of the metatarsal bone of the fifth digit, such as Professor
+Huxley and Mr. Flower have shewn to exist uniformly in the higher and
+lower apes." I will give only two additional cases; the acromio-basilar
+muscle is found in all mammals below man, and seems to be correlated
+with a quadrupedal gait, (50. Mr. Champneys in 'Journal of Anatomy and
+Physiology,' Nov. 1871, p. 178.) and it occurs in about one out of sixty
+human subjects. In the lower extremities Mr. Bradley (51. Ibid. May
+1872, p. 421.) found an abductor ossis metatarsi quinti in both feet of
+man; this muscle had not up to that time been recorded in mankind, but
+is always present in the anthropomorphous 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. (52. 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.) Such resemblances are either perfect or imperfect; yet in the
+latter case they are manifestly of a transitional nature. Certain
+variations are more common in man, and others in woman, without our
+being able to assign any reason. Mr. Wood, after describing numerous
+variations, makes the following pregnant remark. "Notable departures
+from the ordinary type of the muscular structures run in grooves or
+directions, which must be taken to indicate some unknown factor, of
+much importance to a comprehensive knowledge of general and scientific
+anatomy." (53. The Rev. Dr. Haughton, after giving ('Proc. R. Irish
+Academy,' June 27, 1864, p. 715) a remarkable case of variation in the
+human flexor pollicis longus, adds, "This remarkable example shews
+that man may sometimes possess the arrangement of tendons of thumb and
+fingers characteristic of the macaque; but whether such a case should
+be regarded as a macaque passing upwards into a man, or a man passing
+downwards into a macaque, or as a congenital freak of nature, I cannot
+undertake to say." It is satisfactory to hear so capable an anatomist,
+and so embittered an opponent of evolutionism, admitting even the
+possibility of either of his first propositions. Prof. Macalister has
+also described ('Proceedings Royal Irish Academy,' vol. x. 1864, p.
+138) variations in the flexor pollicis longus, remarkable from their
+relations to the same muscle in the Quadrumana.)
+
+That this unknown factor is reversion to a former state of existence
+may be admitted as in the highest degree probable. (54. Since the first
+edition of this book appeared, Mr. Wood has published another memoir
+in the Philosophical Transactions, 1870, p. 83, on the varieties of
+the muscles of the human neck, shoulder, and chest. He here shews 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
+shewing 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 this department of anatomical
+science.") It is quite incredible that a man should through mere
+accident abnormally resemble certain apes in no less than seven of his
+muscles, if there had been no genetic connection between them. On the
+other hand, if man is descended from some ape-like creature, no valid
+reason can be assigned why certain muscles should not suddenly reappear
+after an interval of many thousand generations, in the same manner as
+with horses, asses, and mules, dark-coloured stripes suddenly reappear
+on the legs, and shoulders, after an interval of hundreds, or more
+probably of thousands 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 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; whilst others, such
+as the supracondyloid foramen, only occasionally appear, and therefore
+might have been introduced under the head of reversion. These several
+reversionary structures, as well as the strictly rudimentary ones,
+reveal the descent of man from some lower form in an unmistakable
+manner.
+
+CORRELATED VARIATION.
+
+In man, as in the lower animals, many structures are so intimately
+related, that when one part varies so does another, without our being
+able, in most cases, to assign any reason. We cannot say whether the
+one part governs the other, or whether both are governed by some
+earlier developed part. Various monstrosities, as I. Geoffroy repeatedly
+insists, are thus intimately connected. Homologous structures are
+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 colour of the skin and of the hair, colour and
+constitution, are more or less correlated. (55. The authorities for
+these several statements are given in my 'Variation of Animals under
+Domestication,' vol. ii. pp. 320-335.) Professor Schaaffhausen first
+drew attention to the relation apparently existing between a muscular
+frame and the strongly-pronounced supra-orbital ridges, which are so
+characteristic of the lower races of man.
+
+Besides the variations which can be grouped with more or less
+probability under the foregoing heads, there is a large class of
+variations which may be provisionally called spontaneous, for to our
+ignorance they appear to arise without any exciting cause. It can,
+however, be shewn that such variations, whether consisting of slight
+individual differences, or of strongly-marked and abrupt deviations of
+structure, depend much more on the constitution of the organism than on
+the nature of the conditions to which it has been subjected. (56.
+This whole subject has been discussed in chap. xxiii. vol. ii. of my
+'Variation of Animals and Plants under Domestication.')
+
+RATE OF INCREASE.
+
+Civilised populations have been known under favourable conditions, as
+in the United States, to double their numbers in twenty-five years; and,
+according to a calculation, by Euler, this might occur in a little over
+twelve years. (57. See the ever memorable 'Essay on the Principle of
+Population,' by the Rev. T. Malthus, vol. i. 1826. pp. 6, 517.) At
+the former rate, the present population of the United States (thirty
+millions), would in 657 years cover the whole terraqueous globe so
+thickly, that four men would have to stand on each square yard of
+surface. The primary or fundamental check to the 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 civilised 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
+miserable houses, at all ages. The effects of severe epidemics and wars
+are soon counterbalanced, and more than counterbalanced, in nations
+placed under favourable 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 civilised
+races. We know nothing positively on this head, for with savages
+no census has been taken; but from the concurrent testimony of
+missionaries, and of others who have long resided with such people, it
+appears that their families are usually small, and large ones rare. This
+may be partly accounted for, as it is believed, by the women suckling
+their infants 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 civilised men, would be actually less prolific. I
+have shewn in a former work (58. 'Variation of Animals and Plants under
+Domestication,' vol ii. pp. 111-113, 163.), that all our domesticated
+quadrupeds and birds, and all our cultivated plants, are more fertile
+than the corresponding species in a state of nature. It is no valid
+objection to this conclusion that animals suddenly supplied with an
+excess of food, or when 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 civilised men, who in one
+sense are highly domesticated, would be more prolific than wild men. It
+is also probable that the increased fertility of civilised nations would
+become, as with our domestic animals, an inherited character: it is
+at least known that with mankind a tendency to produce twins runs in
+families. (59. Mr. Sedgwick, 'British and Foreign Medico-Chirurgical
+Review,' July 1863, p. 170.)
+
+Notwithstanding that savages appear to be less prolific than civilised
+people, they would no doubt rapidly increase if their numbers were not
+by some means rigidly kept down. The Santali, or hill-tribes of India,
+have recently afforded a good illustration of this fact; for, as shewn
+by Mr. Hunter (60. 'The Annals of Rural Bengal,' by W.W. Hunter, 1868,
+p. 259.), 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 shew 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 civilised people, for all tribes periodically suffer
+from severe famines. At such times savages are forced to devour much bad
+food, and their health can hardly fail to be injured. Many accounts have
+been published of their protruding 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. Savages,
+when hard pressed, encroach on each other's territories, and war is the
+result; but they are indeed almost always at war with their neighbours.
+They are liable to many accidents on land and water in their search for
+food; and in some countries they suffer much from the larger beasts of
+prey. Even in India, districts have been depopulated by the ravages of
+tigers.
+
+Malthus has discussed these several checks, but he does not lay
+stress enough on what is probably the most important of all, namely
+infanticide, especially of female infants, and the habit of procuring
+abortion. These practices now prevail in many quarters of the world;
+and infanticide seems formerly to have prevailed, as Mr. M'Lennan (61.
+'Primitive Marriage,' 1865.) has shewn, on a still more extensive scale.
+These practices appear to have originated in savages recognising the
+difficulty, or rather the impossibility of supporting all the infants
+that are born. Licentiousness may also be added to the foregoing checks;
+but this does not follow from failing means of subsistence; though
+there is reason to believe that in some cases (as in Japan) it has been
+intentionally encouraged as a means of keeping down the population.
+
+If we look back to an extremely remote epoch, before man had arrived at
+the dignity of manhood, he would have been guided more by instinct and
+less by reason than are the lowest savages at the present time. Our
+early semi-human progenitors would not have practised infanticide or
+polyandry; for the instincts of the lower animals are never so perverted
+(62. 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 shews that the
+instincts of the higher animals are far nobler than the habits of
+savage 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?") 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; 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 reproduction in the wild
+horses and cattle of America, was at first in any sensible degree
+increased; or that, as each district became fully stocked, this same
+power was diminished. No doubt, in this case, and in all others, many
+checks concur, and different checks under different circumstances;
+periodical dearths, depending on unfavourable seasons, being probably
+the most important of all. So it will have been with the early
+progenitors of man.
+
+NATURAL SELECTION.
+
+We have now seen that man is variable in 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 (63. See some good remarks
+to this effect by W. Stanley Jevons, "A Deduction from Darwin's Theory,"
+'Nature,' 1869, p. 231.), 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. (64. Latham, 'Man and his
+Migrations,' 1851, p. 135.) The early progenitors of man must also have
+tended, like all other animals, to have increased beyond their means of
+subsistence; they must, therefore, occasionally have been exposed to
+a struggle for existence, and consequently to the rigid law of natural
+selection. Beneficial variations of all kinds will thus, either
+occasionally or habitually, have been preserved and injurious ones
+eliminated. I do not refer to strongly-marked deviations of structure,
+which occur only at long intervals of time, but to mere individual
+differences. We know, for instance, that the muscles of our hands and
+feet, which determine our powers of movement, are liable, like those of
+the lower animals, (65. 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.) to incessant
+variability. If then the progenitors of man inhabiting any district,
+especially one undergoing some change in its conditions, were divided
+into two equal bodies, the one half which included all the individuals
+best adapted by their powers of movement for gaining subsistence, or for
+defending themselves, would on an average survive in greater numbers,
+and procreate more offspring than the other and less well endowed half.
+
+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 organised form: and all others have yielded before
+him. He manifestly owes this immense superiority to his intellectual
+faculties, to his social habits, which lead him to aid and defend his
+fellows, and to his corporeal structure. The supreme importance of these
+characters has been proved by the final arbitrament of the battle for
+life. Through his powers of intellect, articulate language has been
+evolved; and on this his wonderful advancement has mainly depended. As
+Mr. Chauncey Wright remarks (66. Limits of Natural Selection, 'North
+American Review,' Oct. 1870, p. 295.): "a psychological analysis of
+the faculty of language shews, that even the smallest proficiency in
+it might require more brain power than the greatest proficiency in any
+other direction." He has invented 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 neighbouring fertile islands. He has
+discovered the art of making fire, by which hard and stringy roots can
+be rendered digestible, and poisonous roots or herbs innocuous. This
+discovery of fire, probably the greatest ever made by man, excepting
+language, dates from before the dawn of history. These several
+inventions, by which man in the rudest state has become so 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 (67. '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 re-published. The 'Essay on
+Man,' has been ably criticised by Prof. Claparede, one of the most
+distinguished zoologists in Europe, in an article published in the
+'Bibliotheque Universelle,' June 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,'
+originally published in the 'Anthropological Review,' May 1864, p.
+clviii. I cannot here resist quoting a most just remark 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 independently, and
+published it, though not with the same elaboration, at the same time.")
+maintains, that "natural selection could only have endowed the savage
+with a brain a little superior to that of an ape."
+
+Although the intellectual powers and social habits of man are of
+paramount importance to him, we must not underrate the importance of his
+bodily structure, to which subject the remainder of this chapter will
+be devoted; the development of the intellectual and social or moral
+faculties 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 defending himself, or in killing birds, requires the
+most consummate 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 flint into the rudest tool, or to form
+a barbed spear or hook from a bone, demands the use of a perfect hand;
+for, as a most capable judge, Mr. Schoolcraft (68. 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.), remarks, the shaping fragments of stone into knives, lances,
+or arrow-heads, shews "extraordinary ability and long practice." This
+is to a great extent proved by the fact that primeval men practised a
+division of labour; each man did not manufacture his own flint tools or
+rude pottery, but certain individuals appear to have devoted themselves
+to such work, no doubt 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 sufficiently perfect to throw a stone with precision, or to form
+a flint into a rude tool, could, with sufficient practice, as far
+as mechanical skill alone is concerned, make almost anything which a
+civilised man can make. The structure of the hand in this respect may be
+compared with that of the vocal organs, which in the apes are used for
+uttering various signal-cries, or, as in one 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. (69. Owen, 'Anatomy of
+Vertebrates,' vol. iii. p. 71.) 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 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-shells with the two thumbs. With their fingers they pull out
+thorns and burs, and hunt for each other's parasites. They roll down
+stones, or throw them at their enemies: nevertheless, they are clumsy in
+these various actions, and, as I have myself seen, are quite unable to
+throw a stone with precision.
+
+It seems to me far from true that because "objects are grasped clumsily"
+by monkeys, "a much less specialised organ of prehension" would have
+served them (70. 'Quarterly Review,' April 1869, p. 392.) 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 suspect that a hand as perfect as that of man would have
+been disadvantageous for climbing; for the most arboreal monkeys in the
+world, namely, Ateles in America, Colobus in Africa, and Hylobates in
+Asia, are either thumbless, or their toes partially cohere, so that
+their limbs are converted into mere grasping hooks. (71. In Hylobates
+syndactylus, as the 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 genera, I do not know. It
+deserves notice that the feet of the sloths, the most arboreal animals
+in the world, are wonderfully hook-like.
+
+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 to 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 (72. Brehm, 'Thierleben,' B. i. s. 80.); and they have acquired
+almost the gait of a dog. Man alone has become a biped; and we can, I
+think, partly see how he has come to assume his erect attitude, which
+forms one of his most conspicuous 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 C. Bell (73. 'The Hand,' etc., 'Bridgewater Treatise,' 1833,
+p. 38.) insists that "the hand supplies all instruments, and by its
+correspondence with the intellect gives him universal dominion." But
+the hands and arms could hardly have become perfect enough to have
+manufactured weapons, or to have hurled stones and spears with a
+true aim, as long as they were habitually used for locomotion and for
+supporting the whole weight of the body, or, as 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 prehension. It accords with the principle of the division of
+physiological labour, prevailing throughout the animal kingdom, that as
+the hands became perfected for prehension, the feet should have become
+perfected for support and locomotion. With some savages, however, the
+foot has not altogether lost its prehensile power, as shewn by their
+manner of climbing trees, and of using them in other ways. (74. Haeckel
+has an excellent discussion on the steps by which man became a
+biped: 'Nat�rliche Sch�pfungsgeschichte,' 1868, s. 507. Dr. Buchner
+('Conf�rences sur la Th�orie 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 subject.)
+
+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 animal could not
+have been gradually converted from a quadruped into a biped, as all
+the individuals in an intermediate condition would have been miserably
+ill-fitted for progression. But we know (and this is well worthy of
+reflection) that 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 move awkwardly, and much less securely
+than man. We see, in short, in existing monkeys a manner of progression
+intermediate between that of a quadruped and a biped; but, as an
+unprejudiced judge (75. Prof. Broca, La Constitution des Vert�bres
+caudales; 'La Revue d'Anthropologie,' 1872, p. 26, (separate copy).)
+insists, the anthropomorphous apes approach in structure more nearly to
+the bipedal 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 the same time transformed for firm support
+and progression, endless other changes of structure would have become
+necessary. The pelvis would have to be broadened, the spine peculiarly
+curved, and the head fixed in an altered position, all which changes
+have been attained by man. Prof. Schaaffhausen (76. 'On the Primitive
+Form of the Skull,' translated in 'Anthropological Review,' Oct. 1868,
+p. 428. Owen ('Anatomy of Vertebrates,' vol. ii. 1866, p. 551) on the
+mastoid processes in the higher apes.) maintains that "the powerful
+mastoid 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 gorilla than in man. Various other
+structures, which appear connected with man's erect position, might here
+have been added. It is very difficult to decide how far these correlated
+modifications are the result of natural selection, and how far of the
+inherited effects of the increased use of certain parts, or of the
+action of one part on another. No doubt these means of change often
+co-operate: thus when certain muscles, and the crests of bone to which
+they are attached, become enlarged by habitual use, this shews that
+certain actions are habitually performed and must be serviceable. Hence
+the individuals which performed them best, would tend to survive in
+greater numbers.
+
+The free use of the arms and hands, partly the cause and partly the
+result of man's erect position, appears to have led in an indirect
+manner to other modifications of structure. The early male 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 habit of
+fighting with their incisor teeth and hoofs.
+
+In the adult male anthropomorphous apes, as Rutimeyer (77. 'Die Grenzen
+der Thierwelt, eine Betrachtung zu Darwin's Lehre,' 1868, s. 51.),
+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 physiognomy." Therefore, as the jaws and teeth in man's
+progenitors gradually become reduced in size, the adult skull would
+have come to resemble more and more that of existing man. As we shall
+hereafter see, a great reduction of the canine teeth in the males would
+almost certainly affect the teeth of the females through inheritance.
+
+As the various mental faculties gradually developed themselves the brain
+would almost certainly become larger. No one, I 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 ganglia are of
+extraordinary dimensions, and in all the Hymenoptera these ganglia are
+many times larger than in the less intelligent orders, such as beetles.
+(78. Dujardin, 'Annales des Sciences Nat.' 3rd series, Zoolog., tom.
+xiv. 1850, p. 203. See also Mr. Lowne, 'Anatomy and Phys. of the Musca
+vomitoria,' 1870, p. 14. My son, Mr. F. Darwin, dissected for me
+the cerebral ganglia of the Formica rufa.) On the other hand, no one
+supposes that the intellect of any two animals or of any two men can be
+accurately gauged by the cubic contents of their skulls. It is certain
+that there may be extraordinary mental activity with an extremely
+small absolute mass of nervous matter: thus the wonderfully diversified
+instincts, mental powers, and 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
+marvellous 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 civilised races,
+of ancient and modern people, and by the analogy of the whole
+vertebrate series. Dr. J. Barnard Davis has proved (79. 'Philosophical
+Transactions,' 1869, p. 513.), by many careful measurements, that the
+mean internal capacity of the skull in Europeans is 92.3 cubic inches;
+in Americans 87.5; in Asiatics 87.1; and in Australians only 81.9 cubic
+inches. Professor Broca (80. 'Les Selections,' M. P. Broca, 'Revue
+d'Anthropologies,' 1873; see also, as quoted in C. Vogt's 'Lectures on
+Man,' Engl. translat., 1864, pp. 88, 90. Prichard, 'Physical History
+of Mankind,' vol. i. 1838, p. 305.) found that the nineteenth century
+skulls from graves in Paris were larger than those from vaults of
+the twelfth century, in the proportion of 1484 to 1426; and that the
+increased size, as ascertained by measurements, was exclusively in
+the frontal part of the skull--the seat of the intellectual faculties.
+Prichard is persuaded that the present inhabitants of Britain have "much
+more capacious brain-cases" than the ancient inhabitants. Nevertheless,
+it must be admitted that some skulls of very high antiquity, such as the
+famous one of Neanderthal, are well developed and capacious. (81. In
+the interesting article just referred to, Prof. Broca has well remarked,
+that in civilised nations, the average capacity of the skull must be
+lowered by the preservation of a considerable number of individuals,
+weak in mind and body, who would have been promptly eliminated in the
+savage state. On the other hand, with savages, the average includes
+only the more capable individuals, who have been able to survive under
+extremely hard conditions of life. Broca thus explains the otherwise
+inexplicable fact, that the mean capacity of the skull of the ancient
+Troglodytes of Lozere is greater than that of modern Frenchmen.) With
+respect to the lower animals, M.E. Lartet (82. 'Comptes-rendus des
+Sciences,' etc., June 1, 1868.), 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 shewn
+(83. The 'Variation of Animals and Plants under Domestication,' vol.
+i. pp. 124-129.) 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 generations, 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 supporting spinal column, more
+especially whilst he was becoming erect. As this change of position was
+being brought about, the internal pressure of the brain will also have
+influenced the form of the skull; for many facts shew how easily the
+skull is thus affected. Ethnologists believe that it is modified by the
+kind of cradle in which infants sleep. Habitual spasms of the muscles,
+and a cicatrix from a severe burn, have permanently modified the facial
+bones. In young persons whose heads have become fixed either sideways
+or backwards, owing to disease, one of the two eyes has changed its
+position, and the shape of the skull has been altered apparently by the
+pressure of the brain in a new direction. (84. Schaaffhausen gives
+from Blumenbach and Busch, the cases of the spasms and cicatrix,
+in 'Anthropological 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.) I have shewn
+that with long-eared rabbits 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 certainly
+be altered. I infer this from my observations on domestic rabbits, some
+kinds of which have become very much larger than the wild animal, whilst
+others have retained nearly the same size, but in both cases the brain
+has been much reduced relatively to the size of the body. Now I was at
+first much surprised 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. (85. 'Variation of Animals and Plants under Domestication,' vol.
+i. p. 117, on the elongation of the skull; p. 119, on the effect of the
+lopping of one ear.) 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" (86. Quoted by
+Schaaffhausen, in 'Anthropological Review,' Oct. 1868, p. 419.); and
+tall men may be compared with the larger and longer-bodied rabbits, all
+of which have elongated skulls or are dolichocephalic.
+
+From these several facts we can understand, to a certain extent, the
+means by which the great size and more or less rounded form of the
+skull have been acquired by man; and these are characters eminently
+distinctive of him in comparison with the lower 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 hippopotamus are naked; and this may be advantageous
+to them for gliding through the water; nor would it be injurious to
+them from the loss of warmth, as the species, which inhabit the colder
+regions, are protected by a thick layer of blubber, serving the same
+purpose as the fur of seals and otters. Elephants and rhinoceroses are
+almost hairless; and as certain extinct species, which formerly lived
+under an Arctic climate, were covered with long wool or hair, it would
+almost 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 (87. Owen, 'Anatomy of Vertebrates,' vol. iii. p. 619.) 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, favours
+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 it is thickly clothed with hair. The
+fact, however, that the other members of the order of Primates, to which
+man belongs, although inhabiting various hot regions, are well clothed
+with hair, generally thickest on the upper surface (88. Isidore Geoffroy
+St.-Hilaire remarks ('Histoire Nat. Generale,' tom. ii. 1859, pp.
+215-217) on the head of man being covered with long hair; also on
+the upper surfaces of monkeys and of other mammals being more thickly
+clothed than the lower surfaces. This has likewise been observed by
+various authors. Prof. P. Gervais ('Histoire Nat. des Mammif�res,' 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.),
+is opposed to the supposition that man became naked through the action
+of the sun. Mr. Belt believes (89. The 'Naturalist in Nicaragua,'
+1874, p. 209. As some confirmation of Mr. Belt's view, I may quote the
+following passage from Sir W. 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.")
+that within the tropics it is an advantage to man to be destitute of
+hair, as he is thus enabled to free himself of the multitude of ticks
+(acari) and other parasites, with which he is often infested, and which
+sometimes cause ulceration. But whether this evil is of sufficient
+magnitude to have led to the denudation of his body through natural
+selection, may be doubted, since none of the many quadrupeds inhabiting
+the tropics have, as far as I know, acquired any specialised means of
+relief. The view which seems to me the most probable is that man, or
+rather primarily woman, became divested of hair for ornamental purposes,
+as we shall see under Sexual Selection; and, according to this belief,
+it is not 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 disappearance does not relate exclusively
+to man. The tail often differs remarkably in length within the same
+genus: thus in some species of Macacus it 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, whilst in the mandrill there are
+ten very small stunted caudal vertebrae, or, according to Cuvier (90.
+Mr. St. George Mivart, 'Proc. Zoolog. Soc.' 1865, pp. 562, 583. Dr. J.E.
+Gray, 'Cat. Brit. Mus.: 'Skeletons.' Owen, 'Anatomy of Vertebrates,'
+vol. ii. p. 517. Isidore Geoffroy, 'Hist. Nat. Gen.' tom. ii. p. 244.),
+sometimes only five. The tail, whether it be long or short, almost
+always tapers towards the end; and this, I presume, results from the
+atrophy of the terminal muscles, together with their arteries and
+nerves, through disuse, leading to the atrophy of the terminal bones.
+But no explanation can at present be given of the great diversity
+which often occurs in its length. Here, however, we are more specially
+concerned with the complete external disappearance of the tail.
+Professor Broca has recently shewn (91. 'Revue d'Anthropologie,'
+1872; 'La Constitution des vert�bres caudales.') that the tail in all
+quadrupeds consists of two portions, generally separated abruptly
+from each other; the basal portion consists of vertebrae, more or
+less perfectly channelled and furnished with apophyses like ordinary
+vertebrae; whereas those of the terminal portion are not channelled, are
+almost smooth, and scarcely resemble true vertebrae. A tail, though not
+externally visible, is really present in man and the anthropomorphous
+apes, and is constructed on exactly the same pattern in both. In the
+terminal portion the vertebrae, constituting the os coccyx, are quite
+rudimentary, being much reduced in size and number. In the basal
+portion, the vertebrae are likewise few, are united firmly together, and
+are arrested in development; but they have been rendered much broader
+and flatter than the corresponding vertebrae in the tails of other
+animals: they constitute what Broca calls the accessory sacral
+vertebrae. These are of functional importance by supporting certain
+internal parts and in other ways; and their modification is directly
+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 effected, directly or indirectly, through
+natural selection.
+
+But what are we to say about the rudimentary and variable vertebrae of
+the terminal portion of the tail, forming the os coccyx? A notion which
+has often been, and will no doubt again be ridiculed, namely, that
+friction has had something to do with the disappearance of the external
+portion of the tail, is not so ridiculous as it at first appears. Dr.
+Anderson (92. 'Proceedings Zoological Society,' 1872, p. 210.) states
+that the extremely short tail of Macacus 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
+callosities;" 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 attitude; and from the
+circumstance that it does not extend beyond the extremity of the ischial
+tuberosities, it seems as if the tail originally had been bent round by
+the will of the animal, into the interspace between the callosities, to
+escape being pressed between them and the ground, and that in time the
+curvature became permanent, fitting in of itself when the organ happens
+to be sat upon." Under these circumstances it is not surprising that the
+surface of the tail should have been roughened and rendered callous,
+and Dr. Murie (93. 'Proceedings Zoological Society,' 1872, p. 786.), who
+carefully observed this species in the Zoological Gardens, as well as
+three other closely allied forms with slightly longer tails, says that
+when the animal sits down, the tail "is necessarily thrust to one side
+of the buttocks; and whether long or short its root is consequently
+liable to be rubbed or chafed." As we now have evidence that mutilations
+occasionally produce an inherited effect (94. 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 the
+analogous effects of cutting the sympathetic nerve in the neck. I shall
+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 Domestication,' vol. ii. pp. 22-24.), 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 Macacus
+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 position.
+
+I have now endeavoured to shew that some of the most distinctive
+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 which it consumes, or passively to the surrounding conditions,
+cannot have been thus acquired. We must not, however, be too confident
+in deciding what modifications are of service to each being: 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 Geoffroy has shewn in the case of man, many strange
+deviations of structure are tied together. Independently of correlation,
+a change in one part often leads, through the increased or decreased
+use of other parts, to other changes of a quite unexpected nature. It is
+also well to reflect on such facts, as the wonderful growth of galls on
+plants caused by the poison of an insect, and on the remarkable changes
+of colour in the plumage of parrots when fed on certain fishes, or
+inoculated with the poison of toads (95. The 'Variation of Animals and
+Plants under Domestication,' vol. ii. pp. 280, 282.); for we can thus
+see that the fluids of the system, if altered for some special purpose,
+might induce other changes. We should especially bear in mind that
+modifications acquired and continually used during past ages for some
+useful purpose, would probably become firmly fixed, and might be long
+inherited.
+
+Thus a large yet undefined extension may safely be given to the direct
+and indirect results of natural selection; but I now admit, after
+reading the essay by Nageli on plants, and the remarks by various
+authors with respect to animals, more especially those recently made by
+Professor Broca, that in the earlier editions of my 'Origin of Species'
+I perhaps attributed too much to the action of natural selection or
+the survival of the fittest. I have altered the fifth edition of the
+'Origin' so as to confine my remarks to adaptive changes of structure;
+but I am convinced, from the light gained during even the last few
+years, that very many structures which now appear to us useless, will
+hereafter 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 beneficial nor injurious; and this I believe
+to be one of the greatest oversights as yet detected in my work. I may
+be permitted to say, as some excuse, that I had two distinct objects in
+view; firstly, to shew that species had not been separately created,
+and secondly, that natural selection had been the chief agent of change,
+though largely aided by the inherited effects of habit, and slightly
+by the direct action of the surrounding conditions. I was not, however,
+able to annul the influence of my former belief, then almost universal,
+that each species had been purposely created; and this led to my tacit
+assumption that every detail of structure, excepting rudiments, was of
+some special, though unrecognised, service. Any one with this assumption
+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 exaggerated its power,
+which is in itself probable, I have at least, as I hope, done good
+service in aiding to overthrow the dogma of separate creations.
+
+It is, as I can now see, probable that all organic beings, 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 importance. We know not what produces the numberless
+slight differences between the individuals of each species, for
+reversion only carries the problem a few steps backwards, but each
+peculiarity must have had its efficient cause. If these causes, whatever
+they may be, were to act more uniformly and energetically during a
+lengthened period (and against this no reason can be assigned), the
+result would probably be not a mere slight individual difference, but
+a well-marked and constant 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 exciting causes, and likewise
+from the free intercrossing of many individuals. During successive
+periods, the same organism might in this manner acquire successive
+modifications, which would be transmitted in a nearly uniform state
+as long as the exciting causes remained the same and there was free
+intercrossing. With respect to the exciting causes we can only say, as
+when speaking of so-called spontaneous variations, that they relate much
+more closely to the constitution of the varying organism, than to the
+nature of the conditions to which it has been subjected.
+
+CONCLUSION.
+
+In this chapter we have seen that as man at the present day is liable,
+like every other animal, to multiform individual differences or
+slight variations, so no doubt were the early progenitors of man;
+the 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 progenitors of man; and this would inevitably lead
+to a struggle for existence and to natural selection. The latter process
+would be greatly aided by the inherited effects of the increased use of
+parts, and these two processes would incessantly react on each other.
+It appears, also, as we shall hereafter see, that various unimportant
+characters have been acquired by man through sexual selection. An
+unexplained residuum of change must be left to the assumed uniform
+action of those unknown agencies, which occasionally induce strongly
+marked and abrupt deviations of structure in our domestic productions.
+
+Judging from the habits of savages and of the greater number of the
+Quadrumana, primeval men, and even their ape-like progenitors, probably
+lived in society. With strictly social animals, natural selection
+sometimes acts on the individual, through the preservation of variations
+which are beneficial to the community. A community which includes a
+large number of well-endowed individuals increases in number, and is
+victorious over other less favoured 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 apparatus, or the sting of the worker-bee, or the
+great jaws of soldier-ants. With the higher social animals, I am not
+aware that any structure has been modified solely for the good of the
+community, though some are of secondary service to it. For instance, the
+horns of ruminants and the great canine teeth of baboons appear to have
+been acquired by the males as weapons for sexual strife, but they are
+used in defence of the herd or troop. In regard to certain mental powers
+the case, as we shall see in the fifth chapter, is wholly different; for
+these faculties have been chiefly, or even exclusively, gained for the
+benefit of the community, and the individuals thereof have at the same
+time gained an advantage indirectly.
+
+It has often been objected to such views as the foregoing, that man is
+one of the most helpless and defenceless 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 (96.
+'Primeval Man,' 1869, p. 66.) that "the human frame has diverged
+from the structure of brutes, in the direction of greater physical
+helplessness and weakness. That is to say, it is a divergence which of
+all others it is most impossible to ascribe to mere natural selection."
+He adduces the naked and unprotected state of the body, the absence of
+great teeth or claws for defence, 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 defenceless 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 survive.
+
+In regard to bodily size or strength, we do not know whether man is
+descended from some small species, like the chimpanzee, or from one as
+powerful as the gorilla; and, therefore, we cannot say whether man has
+become larger and stronger, or smaller and weaker, than his ancestors.
+We should, however, bear in mind that an animal possessing great size,
+strength, and ferocity, and which, like the gorilla, could defend itself
+from all enemies, would not perhaps have become social: and this would
+most effectually have checked the acquirement of the higher mental
+qualities, such as sympathy and the love of his fellows. Hence it
+might have been an immense advantage to man to have sprung from some
+comparatively weak creature.
+
+The small strength and speed of man, his want of natural 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 dangerous
+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, maintains itself in Southern Africa, as do the dwarfed
+Esquimaux in the Arctic regions. The ancestors of man were, no doubt,
+inferior in intellect, and probably in social disposition, to the lowest
+existing savages; but it is quite conceivable that they might have
+existed, or even flourished, if they had advanced in intellect, whilst
+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 defenceless 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 favourable conditions, have
+sufficed to raise man to his present high position in the organic scale.
+
+
+CHAPTER III.
+
+COMPARISON OF THE MENTAL POWERS OF MAN AND THE LOWER ANIMALS.
+
+The difference in mental power between the highest ape and the
+lowest savage, immense--Certain instincts in common--The
+emotions--Curiosity--Imitation--Attention--Memory--Imagination--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 may
+be urged that, as man differs so greatly in his mental power from all
+other animals, there must be some error in this conclusion. No doubt the
+difference in this respect is enormous, even if we compare the mind of
+one of the lowest savages, who has no words to express any number higher
+than four, and who uses hardly any abstract terms for common objects
+or for the affections (1. See the evidence on those points, as given
+by Lubbock, 'Prehistoric Times,' p. 354, etc.), with that of the most
+highly organised ape. The difference would, no doubt, still remain
+immense, even if one of the higher apes had been improved or civilised
+as much as a dog has been in comparison with its parent-form, the wolf
+or jackal. The Fuegians rank amongst the lowest barbarians; but I was
+continually struck with surprise how closely the three natives on board
+H.M.S. "Beagle," who had lived some years in England, and could talk a
+little English, resembled us in disposition and in most of our mental
+faculties. If no organic being excepting man had possessed any mental
+power, or if his powers had been of a wholly different nature from those
+of the lower animals, then we should never have been able to convince
+ourselves that our high faculties had been gradually developed. But it
+can be shewn 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 navigator Byron, who dashed his
+child on the rocks for dropping a basket of sea-urchins, and a Howard
+or Clarkson; and in intellect, between a savage who uses hardly any
+abstract terms, and a Newton or Shakspeare. Differences of this kind
+between the highest men of the highest races and the lowest savages, are
+connected by the finest gradations. Therefore it is possible that they
+might pass and be developed into each other.
+
+My object in this chapter is to shew that there is no fundamental
+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, shewing that their mental
+powers are much higher than might have been expected. The variability
+of the faculties in the individuals of the same species is an important
+point for us, and some few illustrations will here be given. But it
+would be superfluous to enter into many details on this head, for I have
+found on frequent enquiry, that it is the unanimous opinion of all those
+who have long attended to animals of many kinds, including birds, that
+the individuals differ greatly in every mental characteristic. In what
+manner the mental powers were first developed in the lowest organisms,
+is as hopeless an enquiry as how life itself first originated. These are
+problems for the distant future, if they are ever to be solved by man.
+
+As man possesses the same senses as the lower animals, his fundamental
+intuitions must be the same. Man has also some few instincts in common,
+as that of self-preservation, sexual love, the love of the mother for
+her new-born offspring, the desire possessed by the latter to suck,
+and so forth. But man, perhaps, has somewhat fewer instincts than those
+possessed by the animals which come next to him in the series. The orang
+in the Eastern islands, and the chimpanzee in Africa, build platforms on
+which they sleep; and, as both species follow the same habit, it might
+be argued that this was due to instinct, but we cannot feel sure that it
+is not the result of both animals having similar wants, and possessing
+similar powers of reasoning. These apes, as we may assume, avoid the
+many poisonous fruits of the tropics, and man has no such knowledge:
+but as our domestic animals, when taken to foreign lands, and when
+first turned out in the spring, often eat poisonous herbs, which they
+afterwards avoid, we cannot feel sure that the apes do not learn from
+their own experience or from that of their parents what fruits to
+select. It is, however, certain, as we shall presently see, that apes
+have an instinctive dread of serpents, and probably of other dangerous
+animals.
+
+The fewness and the comparative simplicity of the instincts in the
+higher animals are remarkable in contrast with those of the lower
+animals. Cuvier maintained that instinct and intelligence stand in an
+inverse ratio to each other; and some have thought that the intellectual
+faculties of the higher animals have been gradually developed from their
+instincts. But Pouchet, in an interesting essay (2. 'L'Instinct chez les
+Insectes,' 'Revue des Deux Mondes,' Feb. 1870, p. 690.), has shewn that
+no such inverse ratio really exists. Those insects which possess the
+most wonderful instincts are certainly the most intelligent. In the
+vertebrate series, the least intelligent members, namely fishes and
+amphibians, do not possess complex instincts; and amongst mammals the
+animal most 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. (3. 'The American Beaver and His Works,' 1868.)
+
+Although the first dawnings of intelligence, according to Mr. Herbert
+Spencer (4. 'The Principles of Psychology,' 2nd edit., 1870, pp.
+418-443.), have been developed through the multiplication and
+co-ordination of reflex actions, and although many of the simpler
+instincts graduate into reflex actions, and can hardly be distinguished
+from them, as in the case of young animals sucking, yet the more complex
+instincts seem to have originated independently of intelligence. I am,
+however, very far from wishing to deny that instinctive actions may lose
+their fixed and untaught character, and be replaced by others performed
+by the aid of the free will. On the other hand, some intelligent
+actions, after being performed during several generations, become
+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 organisation, which induce slight variations or individual
+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 marvellous 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 learnt 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 inherited 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 consequence each separate
+part would perhaps tend to be less well fitted to answer to particular
+sensations or associations in a definite and inherited--that is
+instinctive--manner. There seems even to exist some relation between
+a low degree of intelligence and a strong tendency to the formation
+of fixed, though not inherited habits; for as a sagacious physician
+remarked to me, persons who are slightly imbecile tend to act in
+everything by routine or habit; and they are rendered much happier if
+this is encouraged.
+
+I have thought this digression worth giving, because we may easily
+underrate the mental powers of the higher animals, and especially of
+man, when we compare their actions founded on the memory of past events,
+on foresight, reason, and imagination, with exactly similar actions
+instinctively performed by the lower animals; in this latter case the
+capacity of performing such actions has been gained, step by step,
+through the variability of the mental organs and natural selection,
+without any conscious intelligence on the part of the animal during
+each successive generation. No doubt, as Mr. Wallace has argued (5.
+'Contributions to the Theory of Natural Selection,' 1870, p. 212.),
+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 (6.
+For the evidence on this head, see Mr. J. Traherne Moggridge's most
+interesting work, 'Harvesting Ants and Trap-Door Spiders,' 1873, pp.
+126, 128.), the first time it tries as when old and experienced.
+
+To return to our immediate subject: the lower animals, like man,
+manifestly feel pleasure and pain, happiness and misery. Happiness is
+never better exhibited than by young animals, such as puppies, kittens,
+lambs, etc., when playing together, like our own children. Even insects
+play together, as has been described by that excellent observer, P.
+Huber (7. 'Recherches sur les Moeurs des Fourmis,' 1810, p. 173.),
+who saw ants chasing and pretending to bite each other, like so many
+puppies.
+
+The fact that the lower animals are excited by the same emotions as
+ourselves is so well established, that it will not be necessary to weary
+the reader by many details. Terror acts in the same manner on them as
+on us, causing the muscles to tremble, the heart to palpitate, the
+sphincters to be relaxed, and the hair to stand on end. Suspicion, the
+offspring of fear, is eminently characteristic of most wild animals. It
+is, I think, impossible to read the account given by Sir E. Tennent, of
+the behaviour of the female elephants, used as decoys, without admitting
+that they intentionally practise 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
+shew it. Many, and probably true, anecdotes have been published on
+the long-delayed and artful revenge of various animals. The accurate
+Rengger, and Brehm (8. All the following statements, given on
+the authority of these two naturalists, are taken from Rengger's
+'Naturgesch. der S�ugethiere von Paraguay,' 1830, s. 41-57, and from
+Brehm's 'Thierleben,' B. i. s. 10-87.) state that the American and
+African monkeys which they kept tame, certainly revenged themselves. Sir
+Andrew Smith, a zoologist whose scrupulous accuracy was known to
+many persons, told me the following story of which he was himself an
+eye-witness; at the Cape of Good Hope an officer had often plagued a
+certain baboon, and the animal, seeing him approaching one Sunday for
+parade, poured water into a hole and hastily made some thick mud, which
+he skilfully dashed over the officer as he passed by, to the amusement
+of many bystanders. For long afterwards the baboon rejoiced and
+triumphed whenever he saw his victim.
+
+The love of a dog for his master is notorious; as an old writer quaintly
+says (9. Quoted by Dr. Lauder Lindsay, in his 'Physiology of Mind in the
+Lower Animals,' 'Journal of Mental Science,' April 1871, p. 38.), "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 (10. 'Bridgewater Treatise,' p. 263.) has well asked, "who
+that reads the touching instances of maternal affection, related so
+often of the women of all nations, and of the females of all animals,
+can doubt that the principle of action is the same in the two cases?"
+We see maternal affection exhibited in the most trifling details; thus
+Rengger observed an American monkey (a Cebus) carefully driving away the
+flies which plagued her infant; and Duvaucel saw a Hylobates washing the
+faces of her young ones in a stream. So intense is the grief of female
+monkeys for the loss of their young, that it invariably caused the death
+of certain kinds kept under 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 affectionate baboon, who certainly had a fine intellect,
+for she was much astonished at being scratched, and immediately examined
+the kitten's feet, and without more ado bit off the claws. (11. A
+critic, without any grounds ('Quarterly Review,' July 1871, p. 72),
+disputes the possibility of this act as described by Brehm, for the
+sake of discrediting my work. Therefore I tried, and found that I could
+readily seize with my own teeth the sharp little claws of a kitten
+nearly five weeks old.) In the Zoological Gardens, I heard from the
+keeper that an old baboon (C. chacma) had adopted a Rhesus monkey; but
+when a young drill and mandrill were placed in the cage, she seemed to
+perceive that these monkeys, though distinct species, were her nearer
+relatives, for she at once rejected the Rhesus and adopted both of
+them. The young Rhesus, as I saw, was greatly discontented at being thus
+rejected, and it would, like a naughty child, annoy and attack the young
+drill and mandrill whenever it could do so with safety; this conduct
+exciting great indignation in the old baboon. Monkeys 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 fidelity, to which
+I shall recur. Some of Brehm's monkeys took much delight in teasing a
+certain old dog whom they disliked, as well as other animals, in various
+ingenious ways.
+
+Most of the more complex emotions are common to the higher animals
+and ourselves. Every one has seen how jealous a dog is of his master's
+affection, if lavished on any other creature; and I have observed the
+same fact with monkeys. This shews that animals not only love, but
+have desire to be loved. Animals manifestly feel emulation. They love
+approbation or praise; and a dog carrying a basket for his master
+exhibits in a high degree self-complacency or pride. There can, I think,
+be no doubt that a dog feels shame, as distinct from fear, and something
+very like modesty when begging too often for food. A great dog scorns
+the snarling of a little dog, and this may be called magnanimity.
+Several observers have stated that monkeys certainly dislike being
+laughed at; and they sometimes invent imaginary offences. In the
+Zoological Gardens I saw a baboon who always got into a furious rage
+when his keeper took out a letter or book and read it aloud to him; and
+his rage was so violent that, as I witnessed on one occasion, he bit
+his own leg till the blood flowed. Dogs shew what may be fairly called a
+sense of humour, as distinct from mere play; if a bit of stick or other
+such object be thrown to one, he will often carry it away for a short
+distance; and then squatting down with it on the ground close before
+him, will wait until his master comes quite close to take it away. The
+dog will then seize it and rush away in triumph, repeating the same
+manoeuvre, and evidently enjoying the practical joke.
+
+We will now turn to the more intellectual emotions and faculties, which
+are very important, as forming the basis for the development of the
+higher mental powers. Animals manifestly enjoy excitement, and suffer
+from ennui, as may be seen with dogs, and, according to Rengger, with
+monkeys. All animals feel WONDER, and many exhibit CURIOSITY. They
+sometimes suffer from this latter quality, as when the hunter plays
+antics and thus attracts them; I have witnessed this with deer, and so
+it is with the wary chamois, and with some kinds of wild-ducks. Brehm
+gives a curious account of the instinctive dread, which his monkeys
+exhibited, for snakes; but their curiosity was so great that they could
+not desist from occasionally satiating their horror in a most human
+fashion, by lifting up the lid of the box in which the snakes were
+kept. I was so much surprised at his account, that I took a stuffed and
+coiled-up snake into the monkey-house at the Zoological Gardens, and the
+excitement thus caused was one of the most curious spectacles which I
+ever beheld. Three species of Cercopithecus were the most alarmed; they
+dashed about their cages, and uttered sharp signal cries of danger,
+which were understood by the other monkeys. A few young monkeys and one
+old Anubis baboon alone took no notice of the snake. I then placed the
+stuffed specimen on the ground in one of the larger compartments. After
+a time all the monkeys collected round it in a large circle, and staring
+intently, presented a most ludicrous appearance. They became extremely
+nervous; so that when a wooden ball, with which they were familiar as
+a plaything, was accidentally moved in the straw, under which it was
+partly hidden, they all instantly started away. These monkeys behaved
+very differently when a dead fish, a mouse (12. I have given a short
+account of their behaviour on this occasion in my 'Expression of the
+Emotions in Man and Animals,' p. 43.), a living turtle, and other new
+objects were placed in their cages; for though at first frightened, they
+soon approached, handled and examined them. I then placed a live snake
+in a paper bag, with the mouth loosely closed, in one of the larger
+compartments. One of the monkeys 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 exhibited a strange,
+though mistaken, instinctive dread of innocent lizards and frogs. An
+orang, also, has been known to be much alarmed at the first sight of
+a turtle. (13. W.C.L. Martin, 'Natural History of Mammalia,' 1841, p.
+405.)
+
+The principle of IMITATION is strong in man, and especially, as I have
+myself observed, with savages. In certain morbid states of the brain
+this tendency is exaggerated to an extraordinary degree: some hemiplegic
+patients and others, at the commencement of inflammatory softening of
+the brain, unconsciously imitate every word which is uttered, whether in
+their own or in a foreign language, and every gesture or action which
+is performed near them. (14. Dr. Bateman, 'On Aphasia,' 1870, p. 110.)
+Desor (15. Quoted by Vogt, 'M�moire sur les Microcephales,' 1867,
+p. 168.) has remarked that no animal voluntarily imitates an action
+performed by man, until in the ascending scale we come to monkeys, which
+are well known to be ridiculous mockers. Animals, however, sometimes
+imitate each other's actions: thus two species of wolves, which had been
+reared by dogs, learned to bark, as does sometimes the jackal (16. The
+'Variation of Animals and Plants under Domestication,' vol. i. p. 27.),
+but whether 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 (17. 'Annales des Sciences Nat.'
+(1st Series), tom. xxii. p. 397.) of a dog reared by a cat, who learnt
+to imitate the well-known action of a cat licking her paws, and thus
+washing her ears and face; this was also witnessed by the celebrated
+naturalist Audouin. I have received several confirmatory accounts; in
+one of these, a dog had not been suckled by a cat, but had been brought
+up with one, together with kittens, and had thus acquired the above
+habit, which he ever afterwards practised during his life of thirteen
+years. Dureau de la Malle's dog likewise learnt 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 practised it ever afterwards,
+whenever there was an opportunity.
+
+The parents of many animals, trusting to the principle of imitation
+in their young, and more especially to their 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
+account (in the paper above quoted) of his observations on hawks which
+taught their young dexterity, as well as judgment of distances, by
+first dropping through the air dead mice and sparrows, which the young
+generally failed to catch, and then bringing them live birds and letting
+them loose.
+
+Hardly any faculty is more important for the intellectual progress of
+man than ATTENTION. Animals clearly manifest this power, as when a
+cat watches by a hole and prepares to spring on its prey. Wild animals
+sometimes become so absorbed when thus engaged, that they may be easily
+approached. Mr. Bartlett has given me a curious proof how variable this
+faculty is in monkeys. A man who trains monkeys to act in plays, used to
+purchase common kinds from the Zoological Society at the price of five
+pounds for each; but he offered to give double the price, if he might
+keep three or four of them for a few days, in order to select one. When
+asked how he could possibly learn so soon, whether a particular monkey
+would turn out a good actor, he answered that it all depended on their
+power of attention. If when he was talking and explaining anything to a
+monkey, its attention was easily distracted, as by a fly on the wall or
+other trifling object, the case was hopeless. If he tried by punishment
+to make an inattentive monkey act, it turned sulky. On the other hand, a
+monkey which carefully attended to him could always be trained.
+
+It is almost superfluous to state that animals have excellent MEMORIES
+for persons and places. A baboon at the Cape of Good Hope, as I have
+been informed by Sir Andrew Smith, recognised him with joy after an
+absence of nine months. I had a dog who was savage and averse to all
+strangers, and I purposely tried his memory after an absence of five
+years and two days. I went near the stable where he lived, and shouted
+to him in my old manner; he shewed 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 (18. 'Les Moeurs des Fourmis,' 1810, p. 150.) has clearly shewn,
+recognised their fellow-ants belonging to the same community after a
+separation of four months. Animals can certainly by some means judge of
+the intervals of time between recurrent events.
+
+The IMAGINATION is one of the highest prerogatives of man. By this
+faculty he unites former images and ideas, independently of the will,
+and thus creates brilliant and novel results. A poet, as Jean Paul
+Richter remarks (19. Quoted in Dr. Maudsley's 'Physiology and Pathology
+of Mind,' 1868, pp. 19, 220.), "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 (20. Dr. Jerdon,
+'Birds of India,' vol. i. 1862, p. xxi. Houzeau says that his parokeets
+and canary-birds dreamt: 'Etudes sur les Facultes Mentales des Animaux,'
+tom. ii. p. 136.) have vivid dreams, and this is shewn 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 (21. ibid. 1872, tom. ii. p. 181.), 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 presume, be admitted
+that REASON stands at the summit. Only a few persons now dispute that
+animals possess some power of reasoning. Animals may constantly be seen
+to pause, deliberate, and resolve. It is a significant fact, that the
+more the habits of any particular animal are studied by a naturalist,
+the more he attributes to reason and the less to unlearnt instincts.
+(22. Mr. L.H. Morgan's work on 'The American Beaver,' 1868, offers a
+good illustration of this remark. I cannot help thinking, however,
+that he goes too far in underrating the power of instinct.) In future
+chapters we shall see that some animals extremely low in the scale
+apparently display a certain amount of reason. No doubt it is often
+difficult to distinguish between the power of reason and that of
+instinct. 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 travellers received that the ice
+was becoming thin and dangerous. Now, did the dogs act thus from the
+experience of each individual, or from the example of the older and
+wiser dogs, or from an inherited habit, that is from instinct? This
+instinct, may possibly have arisen since the time, long ago, when dogs
+were first employed by the natives in drawing their sledges; or the
+Arctic wolves, the parent-stock of the Esquimaux dog, may have acquired
+an instinct impelling them not to attack their prey in a close pack,
+when on thin ice.
+
+We can only judge by the circumstances under which actions are
+performed, whether they are due to instinct, or to reason, or to the
+mere association of ideas: this latter principle, however, is intimately
+connected with reason. A curious case has been given by Prof. Mobius
+(23. 'Die Bewegungen der Thiere,' etc., 1873, p. 11.), 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 learnt
+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 afterwards introduced; so strongly was the idea
+of a violent shock associated in his feeble mind with the attempt on his
+former neighbours. 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 afterwards associate a shock with a window-frame; but very
+differently from the pike, he would probably reflect on the nature of
+the impediment, and be cautious under analogous 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 attribute this difference
+between the monkey and the pike solely to the association of ideas being
+so much stronger and more persistent in the one than the other, though
+the pike often received much the more severe injury, can we maintain in
+the case of man that a similar difference implies the possession of a
+fundamentally different mind?
+
+Houzeau relates (24. '�tudes sur les Facult�s Mentales des Animaux,'
+1872, tom. ii. p. 265.) that, whilst crossing a wide and arid plain
+in Texas, his two dogs suffered greatly from thirst, and that between
+thirty and forty times they rushed down the hollows to search for water.
+These hollows were not valleys, and there were no trees in them, or
+any other difference in the vegetation, and as they were absolutely dry
+there could have been no smell of damp earth. The dogs behaved as if
+they knew that a dip in the ground offered them the best chance of
+finding water, and Houzeau has often witnessed the same behaviour in
+other animals.
+
+I have seen, as I daresay have others, that when a small object is
+thrown on the ground beyond the reach of one of the elephants in the
+Zoological Gardens, he blows through his trunk on the ground beyond the
+object, so that the current reflected on all sides may drive the object
+within his reach. Again a well-known ethnologist, Mr. Westropp, informs
+me that he observed in Vienna a bear deliberately making with his paw a
+current in some water, which was close to the bars of his cage, so as
+to draw a piece of floating bread within his reach. These actions of
+the elephant and bear can hardly be attributed to instinct or inherited
+habit, as they would be of little use to an animal in a state of nature.
+Now, what is the difference between such actions, when performed by an
+uncultivated man, and by one of the higher animals?
+
+The savage and the dog have often found water at a low level, and the
+coincidence under such circumstances has become associated in their
+minds. A cultivated man would perhaps make some general proposition
+on the subject; but from all that we know of savages it is extremely
+doubtful whether they would do so, and a dog certainly would not. But
+a savage, as well as a dog, would search in the same way, though
+frequently 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 before the mind. (25. Prof. Huxley has analysed with
+admirable clearness the mental steps by which a man, as well as a dog,
+arrives at a conclusion in a case analogous to that given in my text.
+See his article, 'Mr. Darwin's Critics,' in the 'Contemporary Review,'
+Nov. 1871, p. 462, and in his 'Critiques and Essays,' 1873, p. 279.) 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 would 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 animals differ in exactly the same way in this
+power of association 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 shewn
+by the following actions of American monkeys, which stand low in their
+order. Rengger, a most careful observer, states that when he first gave
+eggs to his monkeys in Paraguay, they smashed them, and thus lost much
+of their contents; afterwards they gently hit one end against some hard
+body, and picked off the bits of shell with their fingers. After cutting
+themselves only ONCE with any sharp tool, they would not touch it again,
+or would handle it with the greatest caution. Lumps of sugar were often
+given them wrapped up in paper; and Rengger sometimes put a live wasp
+in the paper, so that in hastily unfolding it they got stung; after this
+had ONCE happened, they always first held the packet to their ears to
+detect any movement within. (26. Mr. Belt, in his most interesting
+work, 'The Naturalist in Nicaragua,' 1874, (p. 119), likewise describes
+various actions of a tamed Cebus, which, I think, clearly shew that this
+animal possessed some reasoning power.)
+
+The following cases relate to dogs. Mr. Colquhoun (27. 'The Moor and the
+Loch,' p. 45. Col. Hutchinson on 'Dog Breaking,' 1850, p. 46.) winged
+two wild-ducks, which fell on the further side of a stream; his
+retriever tried to bring over both at once, but could not succeed; she
+then, though never before known to ruffle a feather, deliberately
+killed one, brought over the other, and returned for the dead bird.
+Col. Hutchinson relates that two partridges were shot at once, one being
+killed, the other wounded; the latter ran away, and was caught by the
+retriever, who on her return came across the dead bird; "she stopped,
+evidently greatly puzzled, and after one or two trials, finding she
+could not take it up without permitting the escape of the winged bird,
+she considered a moment, then deliberately murdered it by giving it a
+severe crunch, and afterwards brought away both together. This was the
+only known instance of her ever having wilfully injured any game." Here
+we have reason though not quite perfect, for the retriever might have
+brought the wounded bird first and then returned for the dead one, as
+in the case of the two wild-ducks. 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 shew how strong their reasoning faculty must have been to overcome
+a fixed habit.
+
+I will conclude by quoting a remark by the illustrious Humboldt. (28.
+'Personal Narrative,' Eng. translat., vol. iii. p. 106.) "The muleteers
+in S. America say, 'I will not give you the mule whose step is easiest,
+but la mas racional,--the one that reasons best'"; and; as, he adds,
+"this popular expression, dictated by long experience, combats the
+system of animated machines, better perhaps than all the arguments of
+speculative philosophy." Nevertheless some writers even yet deny that
+the higher animals possess a trace of reason; and they endeavour to
+explain away, by what appears to be mere verbiage, (29. 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, which have been drawn, seem
+to us to rest upon no better foundation than a great many other
+metaphysical distinctions; that is, the assumption that because you
+can give two things different names, they must therefore have different
+natures. It is difficult to understand how anybody who has ever kept a
+dog, or seen an elephant, can have any doubt as to an animal's power
+of performing the essential processes of reasoning.") all such facts as
+those above given.
+
+It has, I think, now been shewn that man and the higher animals,
+especially the Primates, have some few instincts in common. All have the
+same senses, intuitions, and sensations,--similar passions, affections,
+and emotions, even the more complex ones, such as jealousy, suspicion,
+emulation, gratitude, and magnanimity; they practise deceit and are
+revengeful; they are sometimes susceptible to ridicule, and even have a
+sense of humour; they feel wonder and curiosity; they possess the
+same faculties of imitation, attention, deliberation, choice, memory,
+imagination, the association of ideas, and reason, though in very
+different 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.
+(30. See 'Madness in Animals,' by Dr. W. Lauder Lindsay, in 'Journal of
+Mental Science,' July 1871.) 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 worthless, as their wide
+difference and number prove the difficulty, if not the impossibility,
+of the attempt. It has been asserted that man alone is capable of
+progressive improvement; that he alone makes use of tools or fire,
+domesticates other animals, or possesses property; that no animal
+has the power of abstraction, or of forming general 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 few remarks on the more important and
+interesting of these points.
+
+Archbishop Sumner formerly maintained (31. Quoted by Sir C. Lyell,
+'Antiquity of Man,' p. 497.) that man alone is capable of progressive
+improvement. That he is capable of incomparably greater and more rapid
+improvement than is any other animal, admits of no dispute; and this
+is mainly due to his power of speaking and handing down his acquired
+knowledge. With animals, looking first to the individual, every one who
+has had any experience in setting traps, knows that young animals can be
+caught much more easily than old ones; and they can be much more
+easily approached by an enemy. Even with respect to old animals, it is
+impossible to catch many in the same place and in the same kind of trap,
+or to destroy them by the same kind of poison; yet it is improbable that
+all should have partaken of the poison, and impossible that all should
+have been caught in a trap. They must learn caution by seeing their
+brethren caught or poisoned. In North America, where the fur-bearing
+animals have long been pursued, they exhibit, according to the unanimous
+testimony of all observers, an almost incredible amount of sagacity,
+caution and cunning; but trapping has been there so long carried on,
+that inheritance may possibly have come into play. I have received
+several accounts that when telegraphs are first set up in any district,
+many birds kill themselves by flying against the wires, but that in the
+course of a very few years they learn to avoid this danger, by seeing,
+as it would appear, their comrades killed. (32. For additional evidence,
+with details, see M. Houzeau, '�tudes sur les Facult�s Mentales des
+Animaux,' tom. ii. 1872, p. 147.)
+
+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 (33. See, with respect to birds
+on oceanic islands, my 'Journal of Researches during the Voyage of the
+"Beagle,"' 1845, p. 398. 'Origin of Species,' 5th ed. p. 260.); and this
+caution is certainly in chief part an inherited habit or instinct, but
+in part the result of individual experience. A good observer, Leroy (34.
+'Lettres Phil. sur l'Intelligence des Animaux,' nouvelle edit., 1802, p.
+86.), 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 (35. See the
+evidence on this head in chap. i. vol. i., 'On the Variation of Animals
+and Plants under Domestication.'), and though they may not have gained
+in cunning, and may have lost in wariness and suspicion, yet they
+have progressed in certain moral qualities, such as in affection,
+trust-worthiness, temper, and probably in general intelligence. The
+common rat has conquered and beaten several other species throughout
+Europe, in parts of North America, New Zealand, and recently in Formosa,
+as well as on the mainland of China. Mr. Swinhoe (36. 'Proceedings
+Zoological Society,' 1864, p. 186.), who describes these two latter
+cases, attributes the victory of the common rat over the large Mus
+coninga to its superior cunning; and this latter quality may probably
+be attributed to the habitual exercise of all its faculties in avoiding
+extirpation by man, as well as to nearly all the less cunning or
+weak-minded rats having been continuously destroyed by him. It is,
+however, possible that the success of the common rat may be due to its
+having 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
+evolution of species. We have seen that, according to Lartet, existing
+mammals belonging to several orders have larger brains than their
+ancient tertiary prototypes.
+
+It has often been said that no animal uses any tool; but the chimpanzee
+in a state of nature cracks a native fruit, somewhat like a walnut, with
+a stone. (37. Savage and Wyman in 'Boston Journal of Natural History,'
+vol. iv. 1843-44, p. 383.) Rengger (38. 'S�ugethiere von Paraguay,'
+1830, s. 51-56.) easily taught an American monkey thus to break open
+hard palm-nuts; and afterwards of its own accord, it used stones to open
+other kinds of nuts, as well as boxes. It thus also removed the soft
+rind of fruit that had a disagreeable flavour. Another monkey was taught
+to open the lid of a large box with a stick, and afterwards it used the
+stick as a lever to move heavy bodies; and I have myself seen a young
+orang put a stick into a crevice, slip his hand to the other end, and
+use it in the proper manner as a lever. The tamed 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 nature. (39. The Indian Field, March 4, 1871.) I have seen a young
+orang, when she thought she was going to be whipped, cover and protect
+herself with a blanket or straw. In these several cases stones and
+sticks were employed as implements; but they are likewise used as
+weapons. Brehm (40. 'Thierleben,' B. i. s. 79, 82.) states, on the
+authority of the well-known traveller Schimper, that in Abyssinia when
+the baboons belonging to one species (C. gelada) descend in troops from
+the mountains to plunder the fields, they sometimes encounter troops
+of another species (C. hamadryas), and then a fight ensues. The Geladas
+roll down great stones, which the Hamadryas try to avoid, and then
+both species, making a great uproar, rush furiously against each other.
+Brehm, when accompanying the Duke of Coburg-Gotha, aided in an attack
+with fire-arms on a troop of baboons in the pass of Mensa in Abyssinia.
+The baboons in return rolled so many stones down the mountain, some as
+large as a man's head, that the attackers had to beat a hasty retreat;
+and the pass was actually closed for a time against the caravan. It
+deserves notice that these baboons thus acted in concert. Mr. Wallace
+(41. 'The Malay Archipelago,' vol. i. 1869, p. 87.) 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 (42. 'Primeval Man,' 1869, pp. 145, 147.) 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 important
+distinction; but there appears to me much truth in Sir J. Lubbock's
+suggestion (43. 'Prehistoric Times,' 1865, p. 473, etc.), that when
+primeval man first used flint-stones for any purpose, he would have
+accidentally splintered them, and would then have used the sharp
+fragments. From this step it would be a small one to break the flints
+on purpose, and not a very wide step to fashion them rudely. This latter
+advance, however, may have taken long ages, if we may judge by the
+immense interval of time which elapsed before the men of the neolithic
+period took to grinding and polishing their stone tools. In breaking
+the flints, as Sir J. Lubbock likewise remarks, sparks would have been
+emitted, and in grinding them heat would have been evolved: thus the
+two usual methods of "obtaining fire may have originated." The nature
+of fire would have been known in the many volcanic regions where lava
+occasionally flows through forests. The anthropomorphous apes, guided
+probably by instinct, build for themselves temporary platforms; but as
+many instincts are largely controlled by reason, the simpler ones, such
+as this of building a platform, might readily pass into a voluntary
+and conscious act. The orang is known to cover itself at night with the
+leaves of the Pandanus; and Brehm states that one of his baboons used to
+protect itself from the heat of the sun by throwing a straw-mat over its
+head. In these several habits, we probably see the first steps towards
+some of the simpler arts, such as rude architecture and dress, as they
+arose amongst the early progenitors of man.
+
+ABSTRACTION, GENERAL CONCEPTIONS, SELF-CONSCIOUSNESS, MENTAL
+INDIVIDUALITY.
+
+It would be very difficult for any one with even much more knowledge
+than I possess, to determine 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 differ to a great extent in the meaning which they
+attribute to the above terms, causes a further difficulty. If one
+may judge from various articles which have been published lately, the
+greatest stress seems to be laid on the supposed entire absence in
+animals of the power of abstraction, or of forming general concepts.
+But when a dog sees another dog at a distance, it is often clear that he
+perceives that it is a dog in the abstract; for when he gets nearer his
+whole manner suddenly changes, if the other dog be a friend. A recent
+writer remarks, that in all such cases it is a pure assumption 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. (44. Mr. Hookham, in a letter to
+Prof. Max Muller, in the 'Birmingham News,' May 1873.) 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 neighbouring tree for a squirrel. Now do not these
+actions clearly shew that she had in her mind a general idea or concept
+that some animal is to be discovered and hunted?
+
+It may be freely admitted that no animal is self-conscious, if by this
+term it is implied, that he 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 shewn 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 Buchner (45. 'Conf�rences sur
+la Th�orie Darwinienne,' French translat. 1869, p. 132.) has remarked,
+how little can the hard-worked wife of a degraded Australian savage,
+who uses very few abstract words, and cannot count above four, exert her
+self-consciousness, or reflect on the nature of her own existence. It is
+generally admitted, that the higher animals possess memory, attention,
+association, and even some imagination and reason. If these powers,
+which differ much in different animals, are capable of improvement,
+there seems no great improbability in more complex faculties, such as
+the higher forms of abstraction, and self-consciousness, 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? We see at least that such powers are developed in
+children by imperceptible degrees.
+
+That animals retain their mental individuality is unquestionable.
+When my voice awakened a train of old associations in the mind of the
+before-mentioned dog, he must have retained his mental individuality,
+although every atom of his brain had 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." (46. The Rev. Dr. J. M'Cann, 'Anti-Darwinism,' 1869, p. 13.)
+
+LANGUAGE.
+
+This faculty has justly been considered as one of the chief distinctions
+between man and the lower animals. But man, as a highly competent judge,
+Archbishop Whately remarks, "is not the only animal that can make use
+of language to express what is passing in his mind, and can understand,
+more or less, what is so expressed by another." (47. Quoted in
+'Anthropological Review,' 1864, p. 158.) In Paraguay the Cebus azarae
+when excited utters at least six distinct sounds, which excite in other
+monkeys similar emotions. (48. Rengger, ibid. s. 45.) The movements
+of the features and gestures of monkeys are understood by us, and they
+partly understand ours, as Rengger and others declare. It is a more
+remarkable fact that the dog, since being domesticated, has learnt to
+bark (49. See my 'Variation of Animals and Plants under Domestication,'
+vol. i. p. 27.) 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 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. (50. 'Facult�s Mentales des
+Animaux,' tom. ii. 1872, p. 346-349.)
+
+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. (51. See a discussion on this subject in Mr. E.B. Tylor's
+very interesting work, 'Researches into the Early History of Mankind,'
+1865, chaps. ii. to iv.) This especially holds good with the more simple
+and vivid feelings, which are but little connected with our higher
+intelligence. Our cries of pain, fear, surprise, anger, together with
+their appropriate actions, and the murmur of a mother to her beloved
+child are more expressive than any words. That which distinguishes man
+from the lower animals is not the understanding of articulate sounds,
+for, as every one knows, dogs understand many words and sentences.
+In this respect they are at the same stage of development 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
+articulation 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 persons with events. (52. 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 reversed 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 polly")
+which had got out of its cage, and was eating apples on the kitchen
+table. See also, to the same effect, Houzeau on parrots, 'Facult�s
+Mentales,' tom. ii. p. 309. Dr. A. Moschkau informs me that he knew a
+starling which never made a mistake in saying in German "good morning"
+to persons arriving, and "good bye, old fellow," to those departing. I
+could add several other such cases.) The lower animals differ from man
+solely in his almost infinitely larger power of associating together
+the most diversified sounds and ideas; and this obviously depends on the
+high development of his mental powers.
+
+As Horne 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 learnt. It differs, however, widely from all
+ordinary arts, for man has an instinctive tendency to speak, as we see
+in the babble of our young children; whilst no child has an instinctive
+tendency to brew, bake, or write. Moreover, no philologist now supposes
+that any language has been deliberately invented; it has been slowly
+and unconsciously developed by many steps. (53. See some good remarks
+on this head by Prof. Whitney, in his 'Oriental and Linguistic Studies,'
+1873, p. 354. He observes that the desire of communication between man
+is the living force, which, in the development of language, "works both
+consciously and unconsciously; consciously as regards the immediate end
+to be attained; unconsciously as regards the further consequences of the
+act.") The sounds uttered by birds offer in several respects the nearest
+analogy to language, for all the members of the same species utter the
+same instinctive cries expressive of their emotions; and all the kinds
+which sing, exert their power instinctively; but the actual song, and
+even the call-notes, are learnt from their parents or foster-parents.
+These sounds, as Daines Barrington (54. Hon. Daines Barrington in
+'Philosoph. Transactions,' 1773, p. 262. See also Dureau de la Malle, in
+'Ann. des. Sc. Nat.' 3rd series, Zoolog., tom. x. p. 119.) has proved,
+"are no more innate than language is in man." The first attempts to sing
+"may be compared to the imperfect endeavour in a child to babble."
+The young males continue practising, or as the bird-catchers say,
+"recording," for ten or eleven months. Their first essays shew hardly a
+rudiment of the future song; but as they grow older we can perceive
+what they are aiming at; and at last they are said "to sing their song
+round." Nestlings which have learnt the song of a distinct species, as
+with the canary-birds educated in the Tyrol, teach and transmit their
+new song to their offspring. The slight natural differences of song
+in the same species inhabiting different districts may be appositely
+compared, as Barrington remarks, "to provincial dialects"; and the songs
+of allied, though distinct species may be compared with the languages of
+distinct races of man. I have given the foregoing details to shew 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 (55. 'On the Origin of Language,'
+by H. Wedgwood, 1866. 'Chapters on Language,' by 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 English, under the title of 'Darwinism tested by the Science of
+Language,' 1869.), and the celebrated lectures of Prof. Max Muller 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
+challenge to rivals. It is, therefore, probable that the imitation
+of musical cries by articulate sounds may have given rise to words
+expressive of various complex emotions. The strong tendency in our
+nearest allies, the monkeys, in microcephalous idiots (56. Vogt,
+'M�moire sur les Microcephales,' 1867, p. 169. With respect to savages,
+I have given some facts in my 'Journal of Researches,' etc., 1845, p.
+206.), and in the barbarous races of mankind, to imitate whatever they
+hear deserves notice, as bearing on the subject of imitation. Since
+monkeys certainly understand much that is said to them by man, and
+when wild, utter signal-cries of danger to their fellows (57. See clear
+evidence on this head in the two works so often quoted, by Brehm and
+Rengger.); and since fowls give distinct warnings for danger on
+the ground, or in the sky from hawks (both, as well as a third cry,
+intelligible to dogs) (58. Houzeau gives a very curious account of his
+observations on this subject in his 'Facult�s Mentales des Animaux,'
+tom. ii. p. 348.), may not some unusually wise ape-like animal have
+imitated the growl of a beast of prey, and thus told his fellow-monkeys
+the nature of the expected danger? This would have been a first step in
+the formation of a language.
+
+As the voice was used more and more, the vocal organs would have been
+strengthened and perfected through the principle of the inherited
+effects of use; and this would have reacted on the power of speech. But
+the relation between the continued use of language and the development
+of the brain, has no doubt been far more important. The mental powers in
+some early progenitor of man must have been more highly developed than
+in any existing ape, before even the most imperfect form of speech could
+have come into use; but we may confidently believe that the 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 whilst dreaming. (59. See remarks on this
+head by Dr. Maudsley, 'The Physiology and Pathology of Mind,' 2nd ed.,
+1868, p. 199.) 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 shewn by those curious cases of brain-disease in which speech is
+specially affected, as when the power to remember substantives is lost,
+whilst other words can be correctly used, or where substantives of a
+certain class, or all except the initial letters of substantives and
+proper names are forgotten. (60. Many curious cases have been recorded.
+See, for instance, Dr. Bateman 'On Aphasia,' 1870, pp. 27, 31, 53,
+100, etc. Also, 'Inquiries Concerning the Intellectual Powers,' by
+Dr. Abercrombie, 1838, p. 150.) There is no more improbability in
+the continued use of the mental and vocal organs leading to inherited
+changes in their structure and functions, than in the case of
+hand-writing, which depends partly on the form of the hand and partly
+on the disposition of the mind; and handwriting is certainly inherited.
+(61. 'The Variation of Animals and Plants under Domestication,' vol. ii.
+p. 6.')
+
+Several writers, more especially Prof. Max Muller (62. Lectures on 'Mr.
+Darwin's Philosophy of Language,' 1873.), have lately insisted that the
+use of language implies the power of forming general concepts; and that
+as no animals are supposed to possess this power, an impassable barrier
+is formed between them and man. (63. The judgment of a distinguished
+philologist, such as Prof. Whitney, will have far more weight on this
+point than anything that I can say. He remarks ('Oriental and Linguistic
+Studies,' 1873, p. 297), in speaking of Bleek's views: "Because on
+the grand scale language is the 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 Max Muller's worst paradoxes, that an infant (in fans,
+not speaking) is not a human being, and that deaf-mutes do not become
+possessed of reason until they learn to twist their fingers into
+imitation of spoken words." Max Muller gives in italics ('Lectures
+on Mr. Darwin's Philosophy of Language,' 1873, third lecture) this
+aphorism: "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!) With respect to animals, I have already endeavoured
+to shew that they have this power, at least in a rude and incipient
+degree. As far as concerns infants of from ten to eleven months old,
+and deaf-mutes, it seems to me incredible, that they should be able to
+connect certain sounds with certain general ideas as quickly as they do,
+unless such ideas were already formed in their minds. The same remark
+may be extended to the more intelligent animals; as Mr. Leslie Stephen
+observes (64. 'Essays on Free Thinking,' etc., 1873, p. 82.), "A 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 intelligence, though in an inferior degree, as the
+capacity to speak."
+
+Why the organs now used for speech should have been originally perfected
+for this purpose, rather than any other organs, it is not difficult to
+see. Ants have considerable powers of intercommunication by means of
+their antennae, as shewn by Huber, who devotes a whole chapter to their
+language. We might have used our fingers as efficient instruments, for
+a person 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, whilst
+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 obviously
+probable that these same organs would be still further developed if the
+power of communication had to be improved; and this has been effected by
+the aid of adjoining and well adapted parts, namely the tongue and
+lips. (65. See some good remarks to this effect by Dr. Maudsley, 'The
+Physiology and Pathology of Mind,' 1868, p. 199.) The fact of the higher
+apes not using their vocal organs for speech, no doubt depends on their
+intelligence not having been sufficiently advanced. The possession by
+them of organs, which with long-continued practice might have been used
+for speech, although not thus used, is paralleled by the case of many
+birds which possess organs fitted for singing, though they never sing.
+Thus, the nightingale and crow have vocal organs similarly constructed,
+these being used by the former for diversified song, and by the latter
+only for croaking. (66. Macgillivray, 'Hist. of British Birds,' vol.
+ii. 1839, p. 29. An excellent observer, Mr. Blackwall, remarks that the
+magpie learns to pronounce single words, and even short sentences, more
+readily than almost any other British bird; yet, as he adds, after long
+and closely investigating its habits, he has never known it, in a state
+of nature, display any unusual capacity for imitation. 'Researches in
+Zoology,' 1834, p. 158.) 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 any
+thing more definite, considering our ignorance with respect to the
+successive stages of development through which each creature has passed.
+
+The formation of different languages and of distinct species, and the
+proofs that both have been developed through a gradual process, are
+curiously parallel. (67. See the very interesting parallelism between
+the development of species and languages, given by Sir C. Lyell in 'The
+Geological Evidences of the Antiquity of Man,' 1863, chap. xxiii.)
+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 descent, and analogies due to a similar process of
+formation. The manner in which certain letters or sounds change when
+others change is very like correlated growth. We have in both cases the
+reduplication of parts, the effects of long-continued use, and so forth.
+The frequent presence of rudiments, both in languages and in species, is
+still more remarkable. The letter m in the word am, means I; so that
+in the expression I am, a superfluous and useless rudiment has been
+retained. In the spelling also of words, letters often remain as the
+rudiments of ancient forms of pronunciation. Languages, like organic
+beings, can be classed in groups under groups; and they can be classed
+either naturally according to descent, or artificially by other
+characters. Dominant languages and dialects spread widely, and lead to
+the gradual extinction of other tongues. A language, like a species,
+when once extinct, never, as Sir C. Lyell remarks, reappears. The same
+language never has two birth-places. Distinct languages may be crossed
+or blended together. (68. See remarks to this effect by the Rev. F.W.
+Farrar, in an interesting article, entitled 'Philology and Darwinism,'
+in 'Nature,' March 24th, 1870, p. 528.) We see variability in every
+tongue, and new words are continually cropping up; but as there is a
+limit to the powers of the memory, single words, like whole languages,
+gradually become extinct. As Max Muller (69. 'Nature,' January 6th,
+1870, p. 257.) has well remarked:--"A struggle for life is constantly
+going on amongst 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 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
+favoured words in the struggle for existence is natural selection.
+
+The perfectly regular and wonderfully complex construction of the
+languages of many barbarous nations has often been advanced as a proof,
+either of the divine origin of these languages, or of the high art and
+former civilisation of their founders. Thus F. von Schlegel writes: "In
+those languages which appear to be at the lowest grade of intellectual
+culture, we frequently 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." (70.
+Quoted by C.S. Wake, 'Chapters on Man,' 1868, p. 101.) 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. Philologists
+now admit that conjugations, declensions, etc., originally existed as
+distinct words, since joined together; and as such words express the
+most obvious relations between objects and persons, it is not surprising
+that they should have been used by the men of most races during the
+earliest ages. With respect to perfection, the following illustration
+will best shew how easily we may err: a Crinoid sometimes consists of no
+less than 150,000 pieces of shell (71. Buckland, 'Bridgewater Treatise,'
+p. 411.), 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 differentiation and specialisation of organs as the test
+of perfection. So with languages: the most symmetrical and complex
+ought not to be ranked above irregular, abbreviated, and bastardised
+languages, which have borrowed expressive words and useful forms of
+construction from various conquering, conquered, or immigrant races.
+
+From these few and imperfect remarks I conclude that the extremely
+complex and regular construction of many barbarous languages, is no
+proof that they owe their origin to a special act of creation. (72. See
+some good remarks on the simplification of languages, by Sir J. Lubbock,
+'Origin of Civilisation,' 1870, p. 278.) Nor, as we have seen, does the
+faculty of articulate speech in itself offer any insuperable objection
+to the belief that man has been developed from some lower form.
+
+SENSE OF BEAUTY.
+
+This sense has been declared to be peculiar to man. I refer here only to
+the pleasure given by certain colours, 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 colours before the female, whilst other
+birds, not thus decorated, make no such display, it is impossible
+to doubt that she admires the beauty of her male partner. As women
+everywhere deck themselves with these plumes, the beauty of such
+ornaments cannot be disputed. As we shall see later, the nests of
+humming-birds, and the playing passages of bower-birds are tastefully
+ornamented with gaily-coloured objects; and this shews that they must
+receive some kind of pleasure 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 beautiful colours, the ornaments, and voices of their
+male partners, all the labour and anxiety exhibited by the latter in
+displaying their charms before the females would have been thrown away;
+and this it is impossible to admit. Why certain bright colours should
+excite pleasure cannot, I presume, be explained, any more than why
+certain flavours 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 recurring at irregular intervals are
+highly disagreeable, as every one will admit who has listened at night
+to the irregular flapping of a rope on board ship. The same principle
+seems to come into play with vision, as the eye prefers symmetry or
+figures with some regular recurrence. Patterns of this kind are 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 colours, 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 developed
+as in certain animals, for instance, as in birds. Obviously no animal
+would be capable of admiring such scenes as the heavens at night, a
+beautiful 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 (73. 'The Spectator,' Dec.
+4th, 1869, p. 1430.) has oddly fixed on Caprice "as one of the most
+remarkable and typical differences between 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 existence of an Omnipotent God. On the contrary
+there is ample evidence, derived not from hasty travellers, but from men
+who have long resided with savages, that numerous races have existed,
+and still exist, who have no idea of one or more gods, and who have no
+words in their languages to express such an idea. (74. See an excellent
+article on this subject by the Rev. F.W. Farrar, in the 'Anthropological
+Review,' Aug. 1864, p. ccxvii. For further facts see Sir J. Lubbock,
+'Prehistoric Times,' 2nd edit., 1869, p. 564; and especially the
+chapters on Religion in his 'Origin of Civilisation,' 1870.) The
+question is of course wholly distinct from that higher one, whether
+there exists a Creator and Ruler of the universe; and this has been
+answered in the affirmative by some of the highest intellects that have
+ever existed.
+
+If, however, we include under the term "religion" the belief in unseen
+or spiritual agencies, the case is wholly different; for this belief
+seems to be universal with the less civilised races. Nor is it difficult
+to comprehend how it arose. As soon as the important faculties of
+the imagination, wonder, and curiosity, together with some power of
+reasoning, had become partially developed, man would naturally crave
+to understand what was passing around him, and would have vaguely
+speculated on his own existence. As Mr. M'Lennan (75. 'The Worship of
+Animals and Plants,' in the 'Fortnightly Review,' Oct. 1, 1869, p. 422.)
+has remarked, "Some explanation of the phenomena of life, a man must
+feign for himself, and to judge from the universality of it, the
+simplest hypothesis, and the first to occur to men, seems to have
+been that natural phenomena are ascribable to the 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 shewn, that dreams may have first given
+rise to the notion of spirits; for savages do not readily distinguish
+between subjective and objective impressions. When a savage dreams,
+the figures which appear before him are believed to have come from a
+distance, and to stand over him; or "the soul of the dreamer goes out
+on its travels, and comes home with a remembrance of what it has seen."
+(76. Tylor, 'Early History of Mankind,' 1865, p. 6. See also the three
+striking chapters on the 'Development of Religion,' in Lubbock's 'Origin
+of Civilisation,' 1870. In a like manner Mr. Herbert Spencer, in his
+ingenious essay in the 'Fortnightly Review' (May 1st, 1870, p. 535),
+accounts for the earliest forms of religious belief throughout the
+world, by man being led through dreams, shadows, and other causes, to
+look at himself as a double essence, corporeal and spiritual. As the
+spiritual being is supposed to exist after death and to be powerful, it
+is propitiated by various gifts and ceremonies, and its aid invoked.
+He then further shews that names or nicknames given from some animal
+or other object, to the early progenitors or founders of a tribe, are
+supposed after a long interval to represent the real progenitor of the
+tribe; and such animal or object is then naturally believed still to
+exist as a spirit, is held sacred, and worshipped as a god. Nevertheless
+I cannot but suspect that there is a still earlier and ruder stage, when
+anything which manifests power or movement is thought to be endowed with
+some form of life, and with mental faculties analogous to our own.) But
+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 distance a slight breeze occasionally moved an open parasol,
+which would have been wholly disregarded by the dog, had any one stood
+near it. As it was, every time that the parasol slightly moved, the dog
+growled fiercely and barked. He must, I think, have reasoned to himself
+in a rapid and unconscious manner, that movement without any apparent
+cause indicated the presence of some strange living agent, and that no
+stranger had a right to be on his territory.
+
+The belief in spiritual agencies would easily pass into the belief in
+the existence of one or more gods. For savages would naturally attribute
+to spirits the same passions, the same love of vengeance or simplest
+form of justice, and the same affections which they themselves feel. The
+Fuegians appear to be in this respect in an intermediate condition,
+for when the surgeon on board the "Beagle" shot some young ducklings
+as specimens, York Minster declared in the most solemn manner, "Oh,
+Mr. Bynoe, much rain, much snow, blow much"; and this was evidently a
+retributive punishment for wasting human food. So again he related how,
+when his brother killed a "wild man," storms long raged, much rain and
+snow fell. Yet we could never discover that the Fuegians believed in
+what we should call a God, or practised any religious rites; and Jemmy
+Button, with justifiable pride, stoutly maintained that there was no
+devil in his land. This latter assertion is the more remarkable, as with
+savages the belief in bad spirits is far more common than 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 (77. See an able article on the 'Physical
+Elements of Religion,' by Mr. L. Owen Pike, in 'Anthropological Review,'
+April 1870, p. lxiii.), fear, reverence, gratitude, hope for the future,
+and perhaps other elements. No being could experience so complex an
+emotion until advanced in his intellectual and moral faculties to
+at least a moderately high level. Nevertheless, we see some distant
+approach to this state of mind in the deep love of a dog for his master,
+associated with complete submission, some fear, and perhaps other
+feelings. The behaviour of a dog when returning to his master after an
+absence, and, as I may add, of a monkey to his beloved keeper, is
+widely different from that towards their fellows. In the latter case the
+transports of joy appear to be somewhat less, and the sense of equality
+is shewn in every action. Professor Braubach goes so far as to maintain
+that a dog looks on his master as on a god. (78. '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.)
+
+The same high mental faculties which first led man to believe in unseen
+spiritual agencies, then in fetishism, 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 innocent persons by the
+ordeal of poison or fire; witchcraft, etc.--yet it is well occasionally
+to reflect on these superstitions, for they shew us what an infinite
+debt of gratitude we owe to the improvement of our reason, to science,
+and to our accumulated knowledge. As Sir J. Lubbock (79. 'Prehistoric
+Times,' 2nd edit., p. 571. In this work (p. 571) there will be found
+an excellent account of the many strange and capricious customs of
+savages.) has well observed, "it is not too much to say that the
+horrible dread of unknown evil hangs like a thick cloud over savage
+life, and embitters every pleasure." These miserable and indirect
+consequences of our highest faculties may be compared with the
+incidental and occasional mistakes of the instincts of the lower
+animals.
+
+
+CHAPTER IV.
+
+COMPARISON OF THE MENTAL POWERS OF MAN AND THE LOWER ANIMALS--continued.
+
+The moral sense--Fundamental proposition--The qualities of social
+animals--Origin of sociability--Struggle between opposed instincts--Man
+a social animal--The more enduring social instincts conquer other less
+persistent instincts--The social virtues alone regarded by savages--The
+self-regarding virtues acquired at a later stage of development--The
+importance of the judgment of the members of the same community on
+conduct--Transmission of moral tendencies--Summary.
+
+I fully subscribe to the judgment of those writers (1. See, for
+instance, on this subject, Quatrefages, 'Unit� de l'Esp�ce Humaine,'
+1861, p. 21, etc.) 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 (2. 'Dissertation on Ethical
+Philosophy,' 1837, p. 231, etc.) remarks, "has a rightful supremacy over
+every other principle of human action"; it is summed up in that short
+but imperious word "ought," so full of high significance. It is the
+most noble of all the attributes of man, leading him without a moment's
+hesitation to risk his life for that of a fellow-creature; or after due
+deliberation, impelled simply by the deep feeling of right or duty,
+to sacrifice it in some great cause. Immanuel Kant exclaims, "Duty!
+Wondrous thought, that workest neither by fond insinuation, flattery,
+nor by any threat, but merely by holding up thy naked law in the soul,
+and so extorting for thyself always reverence, if not always obedience;
+before whom all appetites are dumb, however secretly they rebel; whence
+thy original?" (3. 'Metaphysics of Ethics,' translated by J.W. Semple,
+Edinburgh, 1836, p. 136.)
+
+This great question has been discussed by many writers (4. Mr. Bain
+gives a list ('Mental and Moral Science,' 1868, pp. 543-725) of
+twenty-six British authors who have written on this subject, and whose
+names are familiar to every reader; to these, Mr. Bain's own name, and
+those of Mr. Lecky, Mr. Shadworth Hodgson, Sir J. Lubbock, and others,
+might be added.) 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
+history. 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 faculties of man.
+
+The following proposition seems to me in a high degree probable--namely,
+that any animal whatever, endowed with well-marked social instincts
+(5. Sir B. Brodie, after observing that man is a social animal
+('Psychological Enquiries,' 1854, p. 192), asks the pregnant question,
+"ought not this to settle the disputed question as to the existence of
+a moral sense?" Similar ideas have probably occurred to many persons,
+as they did long ago to Marcus Aurelius. Mr. J.S. Mill speaks, in his
+celebrated work, 'Utilitarianism,' (1864, pp. 45, 46), of the social
+feelings as a "powerful natural sentiment," and as "the natural basis
+of 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 out-growth from it; capable, like them, in
+a certain small degree of springing up spontaneously." But in opposition
+to all this, he also remarks, "if, as in 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 most serious blemish in the works of Mr. Mill.), the
+parental and filial affections 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, the social instincts lead an animal to take pleasure in the
+society of its fellows, to feel a certain amount of sympathy with them,
+and to perform various services for them. The services may be of a
+definite and evidently instinctive nature; or there may be only a wish
+and readiness, as with most of the higher social animals, to aid their
+fellows in certain general ways. But these feelings and services are by
+no means extended to all the individuals of the same species, only to
+those of the same association. SECONDLY, as soon as the mental faculties
+had become highly developed, images of all past actions and motives
+would be incessantly passing through the brain of each individual:
+and that feeling of dissatisfaction, or even misery, which invariably
+results, as we 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 community
+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 the conduct of each member; for the
+social instinct, together with sympathy, is, like any other instinct,
+greatly strengthened by habit, and so consequently would be obedience
+to the wishes and judgment of the community. These several subordinate
+propositions must now be discussed, and some of them at considerable
+length.
+
+It may be well first to premise that I do not wish to maintain that any
+strictly social animal, if its intellectual faculties were to become as
+active and as highly developed as in man, 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. (6. Mr. H. Sidgwick remarks, in an able discussion on this
+subject (the 'Academy,' June 15, 1872, p. 231), "a superior bee, we
+may feel sure, would aspire to a milder solution of the population
+question." Judging, however, from the habits of many or most savages,
+man solves the problem by female infanticide, polyandry and promiscuous
+intercourse; therefore it may well be doubted whether it would be by
+a milder method. Miss Cobbe, in commenting ('Darwinism in Morals,'
+'Theological Review,' April 1872, 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 fulfilment of a social duty would tend to
+the injury of individuals; but she overlooks the fact, which she would
+doubtless admit, that the instincts of the bee have been acquired for
+the good of the community. She goes so far as to say that if the theory
+of ethics advocated in this chapter were ever generally accepted, "I
+cannot but believe that in the hour of their triumph would be sounded
+the knell of the virtue of mankind!" It is to be hoped that the belief
+in the permanence of virtue on this earth is not held by many persons
+on so weak a tenure.) Nevertheless, 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 stronger or more enduring instincts,
+and others less strong or enduring; so that there would often be a
+struggle as to which impulse should be followed; and satisfaction,
+dissatisfaction, or even misery would be felt, as past impressions were
+compared during their incessant passage through the mind. In this case
+an inward monitor would tell the animal that it would have been better
+to have followed the one impulse rather than the other. The one course
+ought to have been followed, and the other ought not; the one would have
+been right and the other wrong; but to these terms I shall recur.
+
+
+SOCIABILITY.
+
+Animals of many kinds are social; we find even distinct species living
+together; for example, some American monkeys; and united flocks of
+rooks, jackdaws, and starlings. Man shews 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
+from their companions, and what strong mutual affection the two former
+kinds, at least, shew 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 attention 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 (7. 'Die
+Darwin'sche Theorie,' s. 101.), 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. Rabbits stamp loudly on the ground with
+their hind-feet as a signal: sheep and chamois do the same with their
+forefeet, uttering likewise a whistle. Many birds, and some mammals,
+post sentinels, which in the case of seals are said (8. Mr. R. Brown
+in 'Proc. Zoolog. Soc.' 1868, p. 409.) generally to be the females.
+The leader of a troop of monkeys acts as the sentinel, and utters cries
+expressive both of danger and of safety. (9. Brehm, 'Thierleben,' B. i.
+1864, s. 52, 79. For the 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 trustworthy. For the cases of the old male baboons
+attacking the dogs, see s. 79; and with respect to the eagle, s. 56.)
+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 Cercopithecus griseo-viridis has rushed through a thorny
+brake, each monkey stretches itself on a branch, and another monkey
+sitting by, "conscientiously" examines its fur, and extracts every thorn
+or burr.
+
+Animals also render more important services to one another: thus wolves
+and some other beasts of prey hunt in packs, and aid one another in
+attacking their victims. Pelicans fish in 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 share the
+booty. Social animals mutually defend each other. Bull bisons in N.
+America, when there is danger, drive the cows and calves into the middle
+of the herd, whilst they defend the outside. I shall also in a future
+chapter give an account of two young wild bulls at Chillingham 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 the opposite mountain, and some were still in
+the valley; the latter were attacked by the dogs, but the old males
+immediately hurried down from the rocks, and with mouths widely opened,
+roared so fearfully, that the dogs 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 for aid, climbed on a block of rock, and was
+surrounded. Now one of the largest males, a true hero, came down
+again from the mountain, slowly went to the young one, coaxed him, and
+triumphantly led him away--the dogs being too much astonished to make an
+attack. I cannot resist giving another scene which was witnessed by
+this same naturalist; an eagle seized a young Cercopithecus, which, by
+clinging to a branch, was not at once carried off; it cried loudly for
+assistance, upon which the other members of the troop, with much uproar,
+rushed to the rescue, surrounded the eagle, and pulled out so many
+feathers, that he no longer thought of his prey, but only how to escape.
+This eagle, as Brehm remarks, assuredly would never again attack
+a single monkey of a troop. (10. 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 believes, 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.)
+
+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 sympathise in the pains and pleasures of others,
+is more doubtful, especially with respect to pleasures. Mr. Buxton,
+however, who had excellent means of observation (11. 'Annals and
+Magazine of Natural History,' November 1868, p. 382.), states that his
+macaws, which lived free in Norfolk, took "an extravagant interest" in a
+pair with a nest; and whenever the female left it, she was surrounded
+by a troop "screaming horrible acclamations in her honour." 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, however, as
+Houzeau remarks, they feel no pity. That animals sometimes are far
+from feeling any sympathy is too certain; for they will expel a wounded
+animal from the herd, or gore or worry it to death. This is almost the
+blackest fact in natural history, unless, indeed, the explanation which
+has been suggested is true, that their instinct or reason leads them to
+expel an injured companion, lest beasts of prey, including man, should
+be tempted to follow the troop. In this case their conduct is not much
+worse than that of the North American Indians, who leave their feeble
+comrades to perish on the plains; or the Fijians, who, when their
+parents get old, or fall ill, bury them alive. (12. Sir J. Lubbock,
+'Prehistoric Times,' 2nd ed., p. 446.)
+
+Many animals, however, certainly sympathise with each other's distress
+or danger. This is the case even with birds. Captain Stansbury (13. As
+quoted by Mr. L.H. Morgan, 'The American Beaver,' 1868, p. 272. Capt.
+Stansbury also gives an interesting account of the manner in which a
+very young pelican, carried away by a strong stream, was guided and
+encouraged in its attempts to reach the shore by half a dozen old
+birds.) 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. (14. As Mr. Bain states, "effective
+aid to a sufferer springs from sympathy proper:" 'Mental and Moral
+Science,' 1868, p. 245.) I have myself seen a dog, who never passed a
+cat who lay sick in a basket, and was a great friend of his, without
+giving her a few licks with his tongue, the surest sign of kind feeling
+in a dog.
+
+It must be called sympathy that leads a courageous dog to fly at any one
+who strikes his master, as he certainly will. I saw a person pretending
+to beat a lady, who had a very timid little dog on her lap, and the
+trial had never been made before; the little creature instantly jumped
+away, but after the pretended beating was over, it was really pathetic
+to see how perseveringly he tried to lick his mistress's face, and
+comfort her. Brehm (15. 'Thierleben,' B. i. s. 85.) 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 shewed me some deep and
+scarcely healed wounds on the nape of his own neck, inflicted on him,
+whilst kneeling on the floor, by a fierce baboon. The little American
+monkey, who was a warm friend of this keeper, lived in the same
+large compartment, and was 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 life.
+
+Besides love and sympathy, animals exhibit other qualities connected
+with the social instincts, which in us would be called moral; and I
+agree with Agassiz (16. 'De l'Esp�ce et de la Classe,' 1869, p. 97.)
+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 (17. 'Die Darwin'sche Art-Lehre,'
+1869, s. 54.) 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 likewise very faithful
+to his driver or keeper, and probably considers him as the leader of
+the herd. Dr. Hooker informs me that an elephant, which he was riding
+in India, became so deeply bogged that he remained stuck fast until
+the next day, when he was extricated by men with ropes. Under such
+circumstances elephants will seize with their trunks any object, dead
+or alive, to place under their knees, to prevent their sinking deeper
+in the mud; and the driver was dreadfully afraid lest the animal should
+have seized Dr. Hooker and crushed him to death. But the driver himself,
+as Dr. Hooker was assured, ran no risk. This forbearance under an
+emergency so dreadful for a heavy animal, is a wonderful proof of noble
+fidelity. (18. See also Hooker's 'Himalayan Journals,' vol. ii. 1854, p.
+333.)
+
+All animals living in a body, which defend themselves or attack their
+enemies in concert, must indeed be in some degree faithful to one
+another; and those that follow a leader must be in some degree obedient.
+When the baboons in Abyssinia (19. Brehm, 'Thierleben,' B. i. s. 76.)
+plunder a garden, they silently follow their leader; and if an imprudent
+young animal makes a noise, he receives a slap from the others to
+teach him silence and obedience. Mr. Galton, who has had excellent
+opportunities for observing the half-wild cattle in S. Africa, says (20.
+See his extremely interesting paper on 'Gregariousness in Cattle, and
+in Man,' 'Macmillan's Magazine,' Feb. 1871, p. 353.), that they cannot
+endure even a momentary separation from the herd. They are essentially
+slavish, and accept the common determination, seeking no better lot
+than to be led by any one ox who has enough self-reliance to accept
+the position. The men who break in these animals for harness, watch
+assiduously for those who, by grazing apart, shew a self-reliant
+disposition, and these they train as fore-oxen. Mr. Galton adds that
+such animals are rare and valuable; and if many were born they would
+soon be eliminated, as lions are always on the look-out for the
+individuals 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 experience in performing other instinctive actions; or by
+the same sense of dissatisfaction as when other instinctive actions are
+checked. We see this in innumerable instances, and it is illustrated in
+a striking manner by the acquired instincts of our domesticated animals;
+thus a young shepherd-dog delights in driving and running round a
+flock of sheep, but not in worrying them; a young fox-hound delights
+in hunting a fox, whilst some other kinds of dogs, as I have witnessed,
+utterly disregard foxes. What a strong feeling of inward satisfaction
+must impel a bird, so full of activity, to brood day after day over her
+eggs. Migratory birds are quite miserable if stopped from migrating;
+perhaps they enjoy starting on their long flight; but it is hard to
+believe that the poor pinioned goose, described by Audubon, which
+started on foot at the proper time for its journey of probably more than
+a thousand miles, could have felt any joy in doing so. Some instincts
+are determined solely by painful feelings, as by fear, which leads
+to self-preservation, and is in some cases directed towards special
+enemies. No one, I presume, can analyse 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 comfortable whilst together; but it is a more
+probable view that these sensations were first developed, in order that
+those animals which would profit by living in society, should be induced
+to live together, in the same manner as the sense of hunger and the
+pleasure of eating were, no doubt, first acquired in order to induce
+animals to eat. The feeling of pleasure from society is probably
+an extension of the parental or filial affections, since the social
+instinct seems to be developed by the young remaining for a long time
+with their parents; and this extension may be attributed in part to
+habit, but chiefly to natural selection. With those animals which were
+benefited by living in close association, the individuals which took the
+greatest pleasure in society would best escape various dangers, whilst
+those that cared least for their comrades, and lived solitary, would
+perish in greater numbers. With respect to the origin of the parental
+and filial affections, which apparently lie at the base of the social
+instincts, we know not the steps by which they have been gained; but we
+may infer that it has been to a large extent through natural selection.
+So it has almost certainly been with the unusual and opposite feeling of
+hatred between the nearest relations, as with the worker-bees which
+kill their brother drones, and with the queen-bees which kill their
+daughter-queens; the desire to destroy their nearest relations having
+been in this case of service to the community. Parental affection, or
+some feeling which replaces it, has been developed in certain animals
+extremely low in the scale, for example, in star-fishes and spiders. It
+is also occasionally present in a few members alone in a whole group of
+animals, as in the genus Forficula, or earwigs.
+
+The all-important emotion of sympathy is distinct from that of love. A
+mother may passionately love her sleeping and passive infant, but she
+can hardly at such times be said to feel sympathy for it. The love of a
+man for his dog is distinct from sympathy, and so is that of a dog for
+his master. Adam Smith formerly argued, as has Mr. Bain recently, that
+the basis of sympathy lies in our strong retentiveness of former states
+of pain or pleasure. Hence, "the sight of another person enduring
+hunger, cold, fatigue, revives in us some recollection of these states,
+which are painful even in idea." We are thus impelled to relieve the
+sufferings of another, in order that our own painful feelings may be at
+the same time relieved. In like manner we are led to participate in the
+pleasures of others. (21. See the first and striking chapter in Adam
+Smith'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, indirectly, a source of pleasure to the sympathiser"; and he
+accounts for this through reciprocity. He remarks that "the person
+benefited, or others in his stead, may make up, by sympathy and good
+offices returned, for all the sacrifice." But if, as appears to be the
+case, sympathy is strictly an instinct, its exercise would give direct
+pleasure, in the same manner as the exercise, as before remarked, of
+almost every other instinct.) But I cannot see how this view explains
+the fact that sympathy is excited, in an immeasurably stronger
+degree, by a beloved, than by an indifferent person. The mere sight of
+suffering, independently of love, would suffice to call up in us vivid
+recollections and associations. The explanation may lie in the fact
+that, with all animals, sympathy is directed solely towards the members
+of the same community, and therefore towards known, and more or less
+beloved members, but not to all the individuals of the same species.
+This fact is not more 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 animal. With
+mankind, selfishness, experience, and imitation, probably add, as Mr.
+Bain has shewn, to the power of sympathy; for we are led by the hope
+of receiving good in return to perform acts of sympathetic kindness to
+others; and sympathy is much strengthened by habit. In however complex a
+manner this feeling may have originated, as it is one of high importance
+to all those animals which aid and defend one another, it will have
+been increased through natural selection; for those communities, which
+included the greatest number of the most sympathetic members, would
+flourish best, and rear the greatest number of offspring.
+
+It is, however, impossible to decide in many cases whether 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 tendency to imitation; or again, whether they
+are simply the result of long-continued habit. So remarkable an instinct
+as the placing sentinels to warn the community of danger, can hardly
+have been the indirect result of any of these faculties; it must,
+therefore, have been directly acquired. On the other hand, the habit
+followed by the males of some social animals of defending the community,
+and of attacking their enemies or their prey in concert, may perhaps
+have originated from mutual sympathy; but courage, and in most cases
+strength, must have been previously acquired, probably through natural
+selection.
+
+Of the various instincts and habits, some are much stronger than others;
+that is, some either give more pleasure in their performance, and more
+distress in their prevention, than others; or, which is probably quite
+as important, they are, through inheritance, more persistently followed,
+without exciting any special feeling of pleasure or pain. We are
+ourselves conscious that some habits are much more difficult to cure or
+change than others. Hence a struggle may often be observed in animals
+between different instincts, or between an instinct and some habitual
+disposition; as when a dog rushes after a hare, is rebuked, pauses,
+hesitates, pursues again, or returns ashamed to his master; or as
+between the love of a female dog for her 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, the migratory instinct is
+so powerful, that late in the autumn swallows, house-martins, and swifts
+frequently desert their tender young, leaving them to perish miserably
+in their nests. (22. This fact, the Rev. L. Jenyns states (see his
+edition of 'White's Nat. Hist. of Selborne,' 1853, p. 204) was first
+recorded by the illustrious Jenner, in 'Phil. Transact.' 1824, and has
+since been confirmed by several observers, especially by Mr. Blackwall.
+This latter careful observer examined, late in the autumn, during two
+years, thirty-six nests; he found that twelve contained young dead
+birds, five contained eggs on the point of being hatched, and three,
+eggs not nearly hatched. Many birds, not yet old enough for a
+prolonged flight, are likewise deserted and left behind. See Blackwall,
+'Researches in Zoology,' 1834, pp. 108, 118. For some additional
+evidence, although this is not wanted, see Leroy, 'Lettres Phil.'
+1802, p. 217. For Swifts, Gould's 'Introduction to the Birds of Great
+Britain,' 1823, p. 5. Similar cases have been observed in Canada by Mr.
+Adams; 'Pop. Science Review,' July 1873, p. 283.)
+
+We can perceive that an instinctive impulse, if it be in any way more
+beneficial to a species than some other or opposed instinct, would be
+rendered the more potent of the two through natural selection; for the
+individuals which had it most strongly developed would survive in larger
+numbers. Whether this is the case with the migratory in comparison with
+the maternal instinct, may be doubted. The great persistence, or steady
+action of the former at certain seasons of the year during the whole
+day, may give it for a time paramount force.
+
+MAN A SOCIAL ANIMAL.
+
+Every one will admit that man is a social being. We see this in his
+dislike of solitude, and in his wish for society beyond that of his own
+family. Solitary 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 only
+two or three together, roam the solitudes of some savage lands, they
+always, as far as I can discover, hold friendly relations with other
+families inhabiting the same district. Such families occasionally
+meet in council, and unite for their common defence. 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 conscious that we
+do possess such sympathetic feelings (23. Hume remarks ('An Enquiry
+Concerning the Principles of Morals,' edit. of 1751, p. 132), "There
+seems a necessity for confessing that the happiness and misery of others
+are not spectacles altogether indifferent to us, but that the view of
+the former...communicates a secret joy; the appearance of the latter...
+throws a melancholy damp over the imagination."); but our consciousness
+does not tell us whether they are instinctive, having originated long
+ago in the same manner as with the lower animals, or whether they have
+been acquired by each of us during our early years. As man is a social
+animal, it is 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 would from an inherited
+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 scale are guided
+almost exclusively, and those which stand higher in the scale are
+largely guided, by special instincts in the aid which they give to the
+members of the same community; but they are likewise in part impelled 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 shewn (24. 'Mental and Moral Science,' 1868, p. 254.), the love
+of praise and the strong feeling of glory, and the still stronger horror
+of scorn and infamy, "are due to the workings of sympathy." 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
+uncultivated man could thus think--I am the supreme judge of my own
+conduct, and in the words of Kant, I will not in my own person violate
+the dignity of humanity.
+
+THE MORE ENDURING SOCIAL INSTINCTS CONQUER THE LESS PERSISTENT
+INSTINCTS.
+
+We have not, however, as yet considered the main point, on which, from
+our present point of view, the whole question of the moral sense turns.
+Why should a man feel that he ought to obey one instinctive desire
+rather than another? 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
+indifferent about a stranger: a young and timid mother urged by the
+maternal instinct will, without a moment's hesitation, run the
+greatest danger for her own infant, but not for a mere fellow-creature.
+Nevertheless many a civilised 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 rather
+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 might be so strong, that he would be unable to force
+himself to run any such risk, perhaps not even for his own child.
+
+I am aware that some persons maintain that actions performed
+impulsively, as in the above cases, do not come under the 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. (25. I refer here
+to the distinction between what has been called MATERIAL and FORMAL
+morality. I am glad to find that Professor Huxley ('Critiques and
+Addresses,' 1873, p. 287) takes the same view on this subject as I do.
+Mr. Leslie Stephen remarks ('Essays on Freethinking and Plain Speaking,'
+1873, p. 83), "the metaphysical distinction, between material and
+formal morality is as irrelevant as other such distinctions.") As far
+as exalted motives are concerned, many instances have been recorded
+of savages, destitute of any feeling of general benevolence towards
+mankind, and not guided by any religious motive, who have deliberately
+sacrificed their lives as prisoners(26. I have given one such case,
+namely of three Patagonian Indians who preferred being shot, one after
+the other, to betraying the plans of their companions in war ('Journal
+of Researches,' 1845, p. 103).), 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
+done for the good of others, are not called moral. Moreover, anything
+performed very often by us, will at last be done without deliberation or
+hesitation, and can then hardly be distinguished from an instinct; yet
+surely no one will pretend that such an action ceases to be moral. On
+the contrary, we all feel that an act cannot be considered as perfect,
+or as performed in the most noble manner, unless it be done impulsively,
+without deliberation or effort, in the same manner as by a man in whom
+the requisite qualities are innate. He who is forced to overcome his
+fear or want of sympathy before he acts, deserves, however, in one way
+higher credit than the man whose innate disposition leads him to a good
+act without effort. As we cannot distinguish between motives, we rank
+all actions of a certain class as moral, if 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 performed deliberately, after a
+struggle with opposing motives, or impulsively through instinct, or from
+the effects of slowly-gained habit.
+
+But to return to our more immediate subject. Although some instincts are
+more powerful than others, and thus lead to corresponding actions, yet
+it is untenable, that in man the social instincts (including the love
+of praise and fear of blame) possess greater strength, or have,
+through long habit, acquired greater strength than the instincts of
+self-preservation, hunger, lust, vengeance, 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, see
+with some degree of clearness the reason of this difference.
+
+Man, from the activity of his mental faculties, cannot avoid reflection:
+past impressions and images are incessantly and clearly passing through
+his mind. Now with those animals which live permanently in a body,
+the social instincts are ever present and persistent. Such animals are
+always ready to utter the danger-signal, to defend the community, and to
+give aid to their fellows in accordance with their habits; they feel at
+all times, without the stimulus of any special passion or desire, some
+degree of love and sympathy for them; they are unhappy if long separated
+from them, and always happy to be again in their company. So it is with
+ourselves. Even when we are quite alone, how often do we think with
+pleasure or pain of what others think of us,--of their imagined
+approbation or disapprobation; 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 satisfied. Nor is
+it easy, perhaps hardly possible, to call up with complete vividness
+the feeling, for instance, of hunger; nor indeed, as has often been
+remarked, of any suffering. The 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 a
+habitual one, after success has wondered why he stole some article. (27.
+Enmity or hatred seems also to be a highly persistent feeling, perhaps
+more so than any other that can be named. Envy is defined as hatred of
+another for some excellence or success; and Bacon insists (Essay ix.),
+"Of all other 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 in any one to transfer such feelings to any member of
+the same tribe if he had done him an injury and had become his enemy.
+Nor is it probable that the primitive conscience would reproach a man
+for injuring his enemy; rather it would reproach him, if he had not
+revenged himself. To do good in return for evil, to love your enemy,
+is a height of morality to which it may be doubted whether the social
+instincts would, by themselves, have ever led us. It is necessary
+that these instincts, together with sympathy, should have been highly
+cultivated and extended by the aid of reason, instruction, and the love
+or fear of God, before any such golden rule would ever be thought of and
+obeyed.)
+
+A man cannot prevent past impressions often repassing through his mind;
+he will thus be driven to make a comparison between the impressions of
+past hunger, vengeance satisfied, or danger shunned at other men's cost,
+with the almost ever-present instinct of sympathy, and with his early
+knowledge of what others consider as praiseworthy or blameable. This
+knowledge cannot be banished from his mind, and from instinctive
+sympathy is esteemed of great moment. He will then feel as if he had
+been baulked in following a present instinct or habit, and this with all
+animals causes dissatisfaction, or even misery.
+
+The above case of the swallow affords an illustration, though of a
+reversed nature, of a temporary though for the time strongly persistent
+instinct conquering another instinct, which is usually dominant over
+all others. At the proper season these birds seem all day long to be
+impressed with the desire to migrate; their habits change; they become
+restless, are noisy and congregate in flocks. Whilst the mother-bird
+is feeding, or brooding over her nestlings, the maternal instinct is
+probably stronger than the migratory; 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 activity, she could not prevent the image
+constantly passing through her mind, of her young ones perishing in the
+bleak north from cold and hunger.
+
+At the moment of action, man will no doubt be apt to follow the stronger
+impulse; and though this may occasionally prompt him to the noblest
+deeds, it will more commonly lead him to gratify his own desires at the
+expense of other men. But after their gratification when past and weaker
+impressions are judged by the ever-enduring social instinct, and by his
+deep regard for the good opinion of his fellows, retribution will surely
+come. He will then feel remorse, repentance, regret, or shame; this
+latter feeling, however, relates almost exclusively to the judgment
+of others. He will consequently resolve more or less firmly to act
+differently for the future; and this is conscience; for conscience looks
+backwards, and serves as a guide for the future.
+
+The nature and strength of the feelings which we call regret, shame,
+repentance or remorse, depend apparently not only on the strength of
+the violated instinct, but partly on the strength of the temptation, and
+often still more on the judgment of our fellows. How far each man values
+the appreciation of others, depends on the strength of his innate or
+acquired feeling of sympathy; and on his own capacity for reasoning out
+the 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 though some slight regret 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 I can find no definition implying more than
+an overwhelming sense of repentance. Remorse seems to bear the same
+relation to repentance, as rage does to anger, or agony to pain. It is
+far from strange that an instinct so strong and so generally admired, as
+maternal love, should, if disobeyed, lead to the deepest misery, as soon
+as the impression of the past cause of disobedience is weakened. Even
+when an action is opposed to no special instinct, merely to know that
+our friends and equals despise us for it is enough to cause great
+misery. Who can doubt that the refusal to fight a duel through fear has
+caused many men an agony of shame? Many a Hindoo, it is said, has been
+stirred to the bottom of his soul by having partaken of unclean food.
+Here is another case of what must, I think, be called remorse. Dr.
+Landor acted as a magistrate in West Australia, and relates (28.
+'Insanity in Relation to Law,' Ontario, United States, 1871, p. 1.),
+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, give rise to the deepest feelings,--and this quite apart from
+the social instincts, excepting in so far as the rule is grounded on the
+judgment of the community. How so many strange superstitions have arisen
+throughout the world we know not; nor can we tell how some real and
+great crimes, such as incest, have come to be held in an abhorrence
+(which is not however quite universal) by the lowest savages. It is even
+doubtful whether in some tribes incest would be looked on with greater
+horror, than would the marriage of a man with a woman bearing the same
+name, though not a relation. "To violate this law is a crime which the
+Australians hold in the greatest abhorrence, in this agreeing exactly
+with certain tribes of North America. When the question is put in either
+district, is it worse to kill a girl of a foreign tribe, or to marry
+a girl of one's own, an answer just opposite to ours would be given
+without hesitation." (29. E.B. Tylor, in 'Contemporary Review,' April
+1873, p. 707.) We may, therefore, reject the belief, lately insisted on
+by some writers, that the abhorrence 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 of
+wreaking his vengeance. It is possible, or as we shall hereafter see,
+even probable, that the habit of self-command may, like other habits, be
+inherited. Thus at last man comes to feel, through acquired and perhaps
+inherited habit, that it is best for him to obey his more persistent
+impulses. The imperious word "ought" seems merely to imply the
+consciousness of the existence of a rule of conduct, however it may have
+originated. Formerly it must have been often vehemently urged that an
+insulted gentleman OUGHT to fight a duel. We even say that a pointer
+OUGHT to point, and a retriever to retrieve game. If they fail to do so,
+they fail in their duty and act wrongly.
+
+If any desire or instinct leading to an action opposed to the good of
+others still appears, when recalled to mind, as strong as, or stronger
+than, the social instinct, a man will feel no keen regret at having
+followed it; but he will be conscious that if his conduct were known
+to his fellows, it would meet with their disapprobation; and few are so
+destitute of sympathy as not to feel discomfort when this is realised.
+If he has no such sympathy, and if his desires leading to bad actions
+are at the time strong, and when recalled are not over-mastered by the
+persistent social instincts, and the judgment of others, then he is
+essentially a bad man (30. Dr. Prosper Despine, in his Psychologie
+Naturelle, 1868 (tom. i. p. 243; tom. ii. p. 169) gives many curious
+cases of the worst criminals, who apparently have been entirely
+destitute of conscience.); and the sole restraining motive left is the
+fear of punishment, and the conviction that in the long run it would be
+best for his own selfish interests to regard the good of others rather
+than his own.
+
+It is obvious that every one may with an easy conscience gratify his
+own desires, if they do not interfere with his social instincts, that
+is with the good of others; but in order to be quite free from
+self-reproach, or at least of anxiety, it is almost necessary for him to
+avoid the disapprobation, whether reasonable or not, of his fellow-men.
+Nor must he break through the fixed habits of his life, especially if
+these are supported by reason; for if he does, he will assuredly feel
+dissatisfaction. He must likewise avoid the reprobation of the one God
+or gods in whom, according to his knowledge or superstition, he may
+believe; but in this case the 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, which tells
+us what we ought to do, and of the conscience which reproves us if we
+disobey it, accords well with what we see of the early and undeveloped
+condition of this faculty in mankind. The virtues which must be
+practised, at least generally, by rude men, so that they may associate
+in a body, are those which are still recognised as the most important.
+But they are practised almost exclusively in relation to the men of the
+same tribe; and their opposites are not regarded as crimes in relation
+to the men of other tribes. No tribe could hold together if murder,
+robbery, treachery, etc., were common; consequently such crimes within
+the limits of the same tribe "are branded with everlasting infamy" (31.
+See an able article in the 'North British Review,' 1867, p. 395. See
+also Mr. W. Bagehot's articles on the Importance of Obedience and
+Coherence to Primitive Man, in the 'Fortnightly Review,' 1867, p. 529,
+and 1868, p. 457, etc.); but excite no such sentiment beyond these
+limits. A North-American Indian is well pleased with himself, and is
+honoured by others, when he scalps a man of another tribe; and a Dyak
+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 (32. The fullest account which I have met with is by Dr. Gerland,
+in his 'Ueber den Aussterben der Naturv�lker,' 1868; but I shall have to
+recur to the subject of infanticide in a future chapter.), and has
+met with no reproach; but infanticide, especially of females, has been
+thought to be good for the tribe, or at least not injurious. Suicide
+during former times was not generally considered as a crime (33. See the
+very interesting discussion on suicide in Lecky's 'History of European
+Morals,' vol. i. 1869, p. 223. With respect to savages, Mr. Winwood
+Reade informs me that the negroes of West Africa often commit suicide.
+It is well known how common it was amongst the miserable aborigines
+of South America after the Spanish conquest. For New Zealand, see the
+voyage of the Novara, and for the Aleutian Islands, M�ller, as quoted by
+Houzeau, 'Les Facult�s Mentales,' etc., tom. ii. p. 136.), but rather,
+from the courage displayed, as an honourable act; and it is still
+practised by some semi-civilised and savage nations without reproach,
+for it does not obviously concern others of the tribe. It has been
+recorded that an Indian Thug conscientiously regretted that he had not
+robbed and strangled as many travellers as did his father before him.
+In a rude state of civilisation the robbery of strangers is, indeed,
+generally considered as honourable.
+
+
+Slavery, although in some ways beneficial during ancient times (34. See
+Mr. Bagehot, 'Physics and Politics,' 1872, p. 72.), is a great crime;
+yet it was not so regarded until quite recently, even by the most
+civilised 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 opinion of their women, wives are commonly
+treated like slaves. Most savages are utterly indifferent to the
+sufferings of strangers, or even delight in witnessing them. It is well
+known that the women and children of the North-American Indians aided in
+torturing their enemies. Some savages take a horrid pleasure in cruelty
+to animals (35. See, for instance, Mr. Hamilton's account of the
+Kaffirs, 'Anthropological Review,' 1870, p. xv.), and humanity is an
+unknown virtue. Nevertheless, besides the family affections, kindness
+is common, especially during sickness, between the members of the same
+tribe, and is sometimes extended beyond these limits. Mungo Park's
+touching account of the kindness of the negro women of the interior to
+him is well known. Many instances could be given of the noble fidelity
+of savages towards each other, but not to strangers; common experience
+justifies the maxim of the Spaniard, "Never, never trust an Indian."
+There cannot be fidelity without truth; and this fundamental virtue is
+not rare between the members of the same tribe: thus Mungo Park heard
+the negro women teaching their young children to love the truth. This,
+again, is one of the virtues which becomes so deeply rooted in the mind,
+that it is sometimes practised by savages, even at a high cost, towards
+strangers; but to lie to your enemy has rarely been thought a sin, as
+the history of modern diplomacy too plainly shews. As soon as a tribe
+has a recognised leader, disobedience becomes a crime, and even abject
+submission is looked at as a sacred virtue.
+
+As during rude times no man can be useful or faithful to his tribe
+without courage, this quality has universally been placed in the highest
+rank; and although in civilised countries a good yet timid man may
+be far more useful to the community than a brave one, we cannot help
+instinctively honouring the latter above a coward, however benevolent.
+Prudence, on the other hand, which does not concern the welfare of
+others, though a very useful virtue, has never been highly esteemed. As
+no man can practise the virtues necessary for the welfare of his tribe
+without self-sacrifice, self-command, and the power of endurance, these
+qualities have been at all times highly and most justly valued. The
+American savage voluntarily submits to the most horrid tortures without
+a groan, to prove and strengthen his fortitude and courage; and we
+cannot help admiring him, or even an 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, have never been
+esteemed by savages, though now highly appreciated by civilised
+nations. The greatest intemperance is no reproach with savages. Utter
+licentiousness, and unnatural crimes, prevail to an astounding extent.
+(36. Mr. M'Lennan has given ('Primitive Marriage,' 1865, p. 176) a
+good collection of facts on this head.) As soon, however, as marriage,
+whether polygamous, or monogamous, becomes common, jealousy will lead to
+the inculcation of female virtue; and this, being honoured, will tend to
+spread to the unmarried females. How slowly it spreads to the male sex,
+we see at the present day. Chastity eminently requires self-command;
+therefore it has been honoured from a very early period in the moral
+history of civilised man. As a consequence of this, the senseless
+practice of celibacy has been ranked from a remote period as a virtue.
+(38. Lecky, 'History of European Morals,' vol. i. 1869, p. 109.) The
+hatred of indecency, which appears to us so natural as to be thought
+innate, and which is so valuable an aid to chastity, is a modern virtue,
+appertaining exclusively, as Sir G. Staunton remarks (38. 'Embassy
+to China,' vol. ii. p. 348.), to civilised life. This is shewn by the
+ancient religious rites of various nations, by the drawings on the walls
+of Pompeii, and by the practices of many savages.
+
+We have now seen that actions are regarded by savages, and were probably
+so regarded by primeval man, as good or bad, solely as they 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 reasoning insufficient to recognise the bearing of
+many virtues, especially of the self-regarding virtues, on the
+general welfare 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-continued, perhaps inherited, habit,
+instruction and religion.
+
+I have entered into the above details on the immorality of savages (39.
+See on this subject copious evidence in Chap. vii. of Sir J. Lubbock,
+'Origin of Civilisation,' 1870.), because some authors have recently
+taken a high view of their moral nature, or have attributed most of
+their crimes to mistaken benevolence. (40. For instance Lecky, 'History
+of European Morals,' vol. i. p. 124.) 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 philosophers of the derivative (41. This term
+is used in an able article in the 'Westminster Review,' Oct. 1869,
+p. 498. For the "Greatest happiness principle," see J.S. Mill,
+'Utilitarianism,' p. 17.) school of morals that the foundation of
+morality lay in a form of Selfishness; but more recently the "Greatest
+happiness principle" has been brought prominently forward. It is,
+however, more correct to speak of the latter principle as the standard,
+and not as the motive of conduct. Nevertheless, all the authors whose
+works I have consulted, with a few exceptions (42. Mill recognises
+('System of Logic,' vol. ii. p. 422) in the clearest manner, that
+actions may be performed through habit without the anticipation of
+pleasure. Mr. H. Sidgwick also, in his Essay on Pleasure and Desire
+('The Contemporary Review,' April 1872, p. 671), remarks: "To sum up,
+in contravention of the doctrine that our conscious active impulses
+are always directed towards the production of agreeable sensations in
+ourselves, I would maintain that we find everywhere in consciousness
+extra-regarding impulse, directed towards something that is not
+pleasure; that in many cases the impulse is so far incompatible with the
+self-regarding that the two do not easily co-exist in the same moment
+of consciousness." A dim feeling that our impulses do not by any means
+always arise from any contemporaneous or anticipated pleasure, has,
+I cannot but think, been one chief cause of the acceptance of the
+intuitive theory of morality, and of the rejection of the utilitarian
+or "Greatest happiness" theory. With respect to the latter theory the
+standard and the motive of conduct have no doubt often been confused,
+but they are really in some degree blended.), write as if there must
+be a distinct motive for every action, and that this must be associated
+with some pleasure or displeasure. But man seems often to act
+impulsively, that is from instinct or long habit, without any
+consciousness of pleasure, in the same manner as does probably a bee
+or ant, when it blindly follows its instincts. Under circumstances
+of extreme peril, as during a fire, when a man endeavours 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 experience if he did not make the attempt.
+Should he afterwards reflect over his own conduct, he would feel that
+there lies within him an impulsive power widely different from a search
+after pleasure or happiness; and this seems to be the deeply planted
+social instinct.
+
+In the case of the lower animals it seems much more appropriate to speak
+of their social instincts, as having been developed for the general good
+rather than for the general happiness of the species. The term,
+general good, may be defined as the rearing of the greatest number of
+individuals in full vigour and health, with all their faculties
+perfect, under the conditions to which they are subjected. As the social
+instincts both of man and the lower animals have no doubt been developed
+by nearly the same steps, it would be advisable, if found practicable,
+to use the same definition in both cases, and to take as the standard of
+morality, the general good or welfare of the community, rather than
+the general happiness; but this definition would perhaps require some
+limitation on account of political ethics.
+
+When a man risks his life to save that of a fellow-creature, it seems
+also more correct to say that he acts for the general good, rather
+than for the general happiness of mankind. No doubt the welfare and the
+happiness of the individual usually coincide; and a contented, happy
+tribe will flourish better than one that is discontented and unhappy.
+We have seen that even at an early period in the history of man, the
+expressed wishes of the community will have naturally influenced to a
+large extent the conduct of each member; and as all wish for happiness,
+the "greatest happiness principle" will have become a most important
+secondary guide and object; the social instinct, however, together
+with sympathy (which leads to our regarding the approbation and
+disapprobation of others), having served as the primary impulse and
+guide. Thus the reproach is removed of laying the foundation of the
+noblest part of our nature in the base principle of selfishness; unless,
+indeed, the satisfaction which every animal feels, when it follows its
+proper instincts, and the dissatisfaction felt when prevented, be called
+selfish.
+
+The wishes and opinions of the members of the same community, expressed
+at first orally, but later by writing also, either form the sole
+guides of our conduct, or greatly reinforce the social instincts; such
+opinions, however, have sometimes a tendency directly opposed to these
+instincts. This latter fact is well exemplified by the LAW OF HONOUR,
+that is, the law of the opinion of our equals, and not of all our
+countrymen. The breach of this law, even when the breach is known to be
+strictly accordant with true morality, has caused many a man more agony
+than a real crime. We recognise the same influence in the burning sense
+of shame which most of us have felt, even after the interval of years,
+when calling to mind some accidental breach of a trifling, though fixed,
+rule of etiquette. The judgment of the community will generally be
+guided by some rude experience of what is best in the long run for all
+the members; but this judgment will not rarely err from ignorance and
+weak powers of reasoning. Hence the strangest customs and superstitions,
+in complete opposition to the true welfare and happiness of mankind,
+have become all-powerful throughout the world. We see this in the horror
+felt by a Hindoo who breaks his caste, and in many other such cases. It
+would be difficult to distinguish between the remorse felt by a Hindoo
+who has yielded to the temptation of eating unclean food, from that
+felt after 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 mind
+of men; but it is worthy of remark that a belief constantly inculcated
+during the early years of life, whilst the brain is impressible, appears
+to acquire almost the nature of an instinct; and the very essence of an
+instinct is that it is followed independently of reason. Neither can we
+say why certain admirable virtues, such as the love of truth, are much
+more highly appreciated by some savage tribes than by others (43. Good
+instances are given by Mr. Wallace in 'Scientific Opinion,' Sept. 15,
+1869; and more fully in his 'Contributions to the Theory of Natural
+Selection,' 1870, p. 353.); nor, again, why similar differences prevail
+even amongst highly civilised nations. Knowing how firmly fixed many
+strange customs and superstitions have become, we need feel no surprise
+that the self-regarding virtues, supported as they are by reason, should
+now appear to us so natural as to be thought innate, although they were
+not valued by man in his early condition.
+
+Not withstanding many sources of doubt, man can generally and readily
+distinguish between the higher and lower moral rules. The higher are
+founded on the social instincts, and relate to the welfare of others.
+They are supported by the approbation of our fellow-men and by reason.
+The lower rules, though some of them when implying self-sacrifice hardly
+deserve to be called lower, relate chiefly to self, and arise from
+public opinion, matured by experience and cultivation; for they are not
+practised by rude tribes.
+
+As man advances in civilisation, and small tribes are united into larger
+communities, the simplest reason would tell each individual that he
+ought to extend his social instincts and sympathies to all the members
+of the same nation, though personally unknown to him. This point
+being once reached, there is only an artificial barrier to prevent his
+sympathies extending to the men of all nations and races. If, indeed,
+such men are separated from him by great differences in appearance or
+habits, experience unfortunately shews us how long it is, before we look
+at them as our fellow-creatures. Sympathy beyond the confines of man,
+that is, humanity to the lower animals, seems to be one of the latest
+moral acquisitions. It is apparently unfelt by savages, except towards
+their pets. How little the old Romans knew of it is shewn by their
+abhorrent gladiatorial exhibitions. The very idea of humanity, as far
+as I could observe, was new to most of the Gauchos of the Pampas. This
+virtue, one of the noblest with which man is endowed, seems to arise
+incidentally from our sympathies becoming more tender and more widely
+diffused, until they are extended to all sentient beings. As soon
+as this virtue is honoured and practised by some few men, it spreads
+through instruction and example to the young, and eventually becomes
+incorporated in public opinion.
+
+The highest possible stage in moral culture is when we recognise that we
+ought to control our thoughts, and "not even in inmost thought to think
+again the sins that made the past so pleasant to us." (44. Tennyson,
+Idylls of the King, p. 244.) Whatever makes any bad action familiar
+to the mind, renders its performance by so much the easier. As Marcus
+Aurelius long ago said, "Such as are thy habitual thoughts, such
+also will be the character of thy mind; for the soul is dyed by the
+thoughts." (45. 'The Thoughts of the Emperor M. Aurelius Antoninus,'
+English translation, 2nd edit., 1869. p. 112. Marcus Aurelius was born
+A.D. 121.)
+
+Our great philosopher, Herbert Spencer, has recently explained his views
+on the moral sense. He says (46. Letter to Mr. Mill in Bain's 'Mental
+and Moral Science,' 1868, p. 722.), "I believe that the experiences of
+utility organised and consolidated through all past generations of the
+human race, have been producing corresponding modifications, which,
+by continued transmission and accumulation, have become in us certain
+faculties of moral intuition--certain emotions responding to right
+and wrong conduct, which have no apparent basis in the individual
+experiences of utility." There is not the least inherent improbability,
+as it seems to me, in virtuous tendencies being more or less strongly
+inherited; for, not to mention the various dispositions and habits
+transmitted by many of our domestic animals to their offspring, I have
+heard of authentic cases in which a desire to steal and a tendency to
+lie appeared to run in families of the upper ranks; and as stealing is
+a rare crime in the wealthy classes, we can hardly account by accidental
+coincidence for the tendency occurring in two or three members of the
+same family. If bad tendencies are transmitted, it is probable that good
+ones are likewise transmitted. That the state of the body by affecting
+the brain, has great influence on the moral tendencies is known to most
+of those who have suffered from chronic derangements of the digestion or
+liver. The same fact is likewise shewn by the "perversion or destruction
+of the moral sense being often one of the earliest symptoms of mental
+derangement" (47. Maudsley, 'Body and Mind,' 1870, p. 60.); and insanity
+is notoriously often inherited. Except through the principle of the
+transmission of moral tendencies, we cannot understand the differences
+believed to exist in this respect between the various races of mankind.
+
+Even the partial transmission of virtuous tendencies would be an immense
+assistance to the primary impulse derived directly and indirectly from
+the social instincts. Admitting for a moment that virtuous tendencies
+are inherited, it appears probable, at least in such cases as chastity,
+temperance, humanity to animals, etc., that they become first impressed
+on the mental organization through habit, instruction and example,
+continued during several generations in the same family, and in a quite
+subordinate degree, or not at all, by the individuals possessing such
+virtues having succeeded best in the struggle for life. My chief
+source of doubt with respect to any such inheritance, is that senseless
+customs, superstitions, and tastes, such as the horror of a Hindoo for
+unclean food, ought on the same principle to be transmitted. I have not
+met with any evidence in support of the transmission of superstitious
+customs or senseless habits, although in itself it is perhaps not less
+probable than that animals should acquire inherited tastes for certain
+kinds of food or fear of certain foes.
+
+Finally the social instincts, which no doubt were acquired by man as
+by the lower animals for the good of the community, will from the
+first have given to him some wish to aid his fellows, some feeling
+of sympathy, and have compelled him to regard their approbation and
+disapprobation. Such impulses will have served him at a very early
+period as a rude rule of right and wrong. But as man gradually advanced
+in intellectual power, and was enabled to trace the more remote
+consequences of his actions; as he acquired sufficient knowledge to
+reject baneful customs and superstitions; as he regarded more and more,
+not only the welfare, but the happiness of his fellow-men; as from
+habit, following on beneficial experience, instruction and example, his
+sympathies became more tender and widely diffused, extending to men
+of all races, to the imbecile, maimed, and other useless members of
+society, and finally to the lower animals,--so would the standard of his
+morality rise higher and higher. And it is admitted by moralists of
+the derivative school and by some intuitionists, that the standard of
+morality has risen since an early period in the history of man. (48. A
+writer in the 'North British Review' (July 1869, p. 531), well capable
+of forming a sound judgment, expresses himself strongly in favour of
+this conclusion. Mr. Lecky ('History of Morals,' vol. i. p. 143) seems
+to a certain extent to coincide therein.)
+
+As a struggle may sometimes be seen going on between the various
+instincts of the lower animals, it is not surprising that there should
+be a struggle in man between his social instincts, with their derived
+virtues, and his lower, though momentarily stronger impulses or desires.
+This, as Mr. Galton (49. See his remarkable work on 'Hereditary Genius,'
+1869, p. 349. The Duke of Argyll ('Primeval Man,' 1869, p. 188) has some
+good remarks on the contest in man's nature between right and wrong.)
+has remarked, is all the less surprising, as man has emerged from a
+state of barbarism within a comparatively recent period. After having
+yielded to some temptation we feel a sense of dissatisfaction, shame,
+repentance, or remorse, analogous to the feelings caused by other
+powerful instincts or desires, when left unsatisfied or baulked. We
+compare the weakened impression of a past temptation with the ever
+present social instincts, or with habits, gained in early youth and
+strengthened during our whole lives, until they have become almost as
+strong as instincts. If with the temptation still before us we do not
+yield, it is because either the social instinct or some custom is at the
+moment predominant, or because we have learnt that it will appear to us
+hereafter the stronger, when compared with the weakened impression
+of the temptation, and we realise that its violation 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 case the struggle between our higher and lower impulses will be
+less severe, and virtue will be triumphant.
+
+SUMMARY OF THE LAST TWO CHAPTERS.
+
+There can be no doubt that the difference between the mind of the lowest
+man and that of the highest animal is immense. An anthropomorphous ape,
+if he could take a dispassionate view of his own case, would admit that
+though he could form an artful plan to plunder a garden--though he could
+use stones for fighting or for breaking open nuts, 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 mathematical problem, or reflect on God, or admire
+a grand natural scene. Some apes, however, would probably declare that
+they could and did admire the beauty of the coloured skin and fur of
+their partners in marriage. They would admit, that though they could
+make other apes understand by cries some of their perceptions and
+simpler wants, the notion of expressing definite ideas by definite
+sounds had never crossed their minds. They might insist that they were
+ready to aid their fellow-apes of the same troop in many ways, to risk
+their lives for them, and to take charge of their orphans; but they
+would be forced to acknowledge that disinterested love for all living
+creatures, the most noble attribute of man, was quite beyond their
+comprehension.
+
+Nevertheless the difference in mind between man and the higher animals,
+great as it is, certainly is one of degree and not of kind. We have seen
+that the senses and intuitions, the various emotions and faculties, such
+as love, memory, attention, curiosity, imitation, reason, etc., of
+which man boasts, may be found in an incipient, or even sometimes in a
+well-developed condition, in the lower animals. They are also capable of
+some inherited improvement, as we see in the domestic dog compared
+with the wolf or jackal. If it could be proved that certain high mental
+powers, such as the formation of general concepts, self-consciousness,
+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 is not universal with man; and
+the belief in spiritual agencies naturally follows from other mental
+powers. The moral sense perhaps affords the best and highest distinction
+between man and the lower animals; but I need say nothing on this head,
+as I have so lately endeavoured to shew that the social instincts,--the
+prime principle of man's moral constitution (50. 'The Thoughts of Marcus
+Aurelius,' etc., p. 139.)--with the aid of active intellectual powers
+and the effects of habit, naturally lead to the golden rule, "As ye
+would that men should do to you, do ye to them likewise;" and this lies
+at the foundation of morality.
+
+In 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 trace a perfect gradation from the mind of an utter
+idiot, lower than that of an animal low in the scale, to the mind of a
+Newton.
+
+
+CHAPTER V.
+
+ON THE DEVELOPMENT OF THE INTELLECTUAL AND MORAL FACULTIES DURING
+PRIMEVAL AND CIVILISED TIMES.
+
+Advancement of the intellectual powers through natural
+selection--Importance of imitation--Social and moral faculties--Their
+development within the limits of the same tribe--Natural selection as
+affecting civilised nations--Evidence that civilised nations were once
+barbarous.
+
+The subjects to be discussed in this chapter are of the highest
+interest, but are treated by me in an imperfect and fragmentary
+manner. Mr. Wallace, in an admirable paper before referred to (1.
+Anthropological Review, May 1864, p. clviii.), argues that man, after
+he had partially acquired those intellectual and moral faculties which
+distinguish him from the lower animals, would have been but little
+liable to bodily modifications through natural selection or any other
+means. For man is enabled through his mental faculties "to keep with
+an unchanged body in harmony with the changing universe." He has great
+power of adapting his habits to new conditions of life. He 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
+indigestible. He aids his fellow-men in many ways, and anticipates
+future events. Even at a remote period he practised some division of
+labour.
+
+The lower animals, on the other hand, must have their bodily structure
+modified in order to survive under greatly changed conditions. They
+must be rendered stronger, or acquire more effective teeth or claws, for
+defence against new enemies; or they must be reduced in size, so as to
+escape detection and danger. When they migrate into a colder climate,
+they must become clothed with thicker fur, or have their constitutions
+altered. If they fail to be thus modified, they will cease to exist.
+
+The case, however, is widely different, as Mr. Wallace 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 variations tend to be inherited. Therefore, if they were formerly
+of high importance to primeval man and to his ape-like progenitors, they
+would have been perfected or advanced through natural selection. Of the
+high importance of the intellectual faculties there can be no doubt, for
+man mainly owes to them his predominant position in the world. We can
+see, that in the rudest state of society, the individuals who were the
+most sagacious, who invented and used the best weapons or traps, and who
+were best able to defend themselves, would rear the greatest number of
+offspring. The tribes, which included the largest number of men thus
+endowed, would increase in number and supplant other tribes. Numbers
+depend primarily on the means of subsistence, and this depends partly on
+the physical nature of the country, but in a much higher degree on the
+arts which are there practised. As a tribe increases and is victorious,
+it is often still further increased by the absorption of other tribes.
+(2. After a time the members or tribes which are absorbed into another
+tribe assume, as Sir Henry Maine remarks ('Ancient Law,' 1861, p. 131),
+that they are the co-descendants of the same ancestors.) The stature and
+strength of the men of a tribe are likewise of some importance for its
+success, and these depend in part on the nature and amount of the food
+which can be obtained. In Europe the men of the Bronze period
+were supplanted by a race more powerful, and, judging from their
+sword-handles, with larger hands (3. Morlot, 'Soc. Vaud. Sc. Nat.'
+1860, p. 294.); but their success was probably still more due to their
+superiority in the arts.
+
+All that we know about savages, or may infer from their traditions
+and from old monuments, the history of which is quite forgotten by the
+present inhabitants, shew that from the remotest times successful tribes
+have supplanted other tribes. Relics of extinct or forgotten tribes have
+been discovered throughout the civilised regions of the earth, on the
+wild plains of America, and on the isolated islands in the Pacific
+Ocean. At the present day civilised nations are everywhere supplanting
+barbarous nations, excepting where the climate opposes a deadly barrier;
+and they succeed mainly, though not exclusively, through their arts,
+which are the products of the intellect. It is, therefore, highly
+probable that with mankind the intellectual faculties have been mainly
+and gradually perfected through natural selection; and this conclusion
+is sufficient for our purpose. Undoubtedly it would be interesting to
+trace the development of each separate faculty from the state in which
+it exists in the lower animals to that in which it exists in man; but
+neither my ability nor knowledge permits the attempt.
+
+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 experience would have increased, and much
+modified the intellectual powers in a way, of which we see only traces
+in the lower animals. Apes are much given to imitation, as are the
+lowest savages; and the simple fact previously referred to, that after a
+time no animal can be caught in the same place by the same sort of
+trap, shews 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 defence, the
+plainest self-interest, without the assistance of much reasoning power,
+would prompt the other members to imitate him; and all would thus
+profit. The habitual practice of each new art must likewise in some
+slight degree strengthen the intellect. If the new invention were an
+important one, the tribe would increase in number, spread, and supplant
+other tribes. In a tribe thus rendered more numerous there would always
+be a rather 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 decidedly better. Even
+if they left no children, the tribe would still include their
+blood-relations; and it has been ascertained by agriculturists (4. I
+have given instances in my Variation of Animals under Domestication,
+vol. ii. p. 196.) that by preserving and breeding from the family of
+an animal, which when slaughtered was found to be valuable, the desired
+character has been obtained.
+
+Turning now to the social and moral faculties. In order that primeval
+men, or the ape-like progenitors of man, should become social, they must
+have acquired the same instinctive feelings, which impel other animals
+to live in a body; and they no doubt exhibited the same general
+disposition. They would have felt uneasy when separated from their
+comrades, for whom they would have felt some degree of love; they would
+have warned each other of danger, and have given mutual aid in attack
+or defence. All this implies some degree of sympathy, fidelity, and
+courage. Such social qualities, the paramount importance of which to
+the lower animals is disputed by no one, were no doubt acquired by
+the progenitors of man in a similar manner, namely, through natural
+selection, aided by inherited habit. When two tribes of primeval
+man, living in the same country, came into competition, if (other
+circumstances being equal) the one tribe included a great number of
+courageous, sympathetic and faithful members, who were always ready
+to warn each other of danger, to aid and defend each other, this tribe
+would succeed better and conquer the other. Let it be borne in mind how
+all-important in the never-ceasing wars of savages, fidelity and
+courage must be. The advantage which disciplined soldiers have over
+undisciplined hordes follows chiefly from the confidence which each man
+feels in his comrades. Obedience, as Mr. Bagehot has well shewn (5.
+See a remarkable series of articles on 'Physics and Politics,' in the
+'Fortnightly Review,' Nov. 1867; April 1, 1868; July 1, 1869, since
+separately published.), is of the highest value, for any form of
+government is better than none. Selfish and contentious people will not
+cohere, and without coherence nothing can be effected. A tribe rich in
+the above qualities would spread and be victorious over other tribes:
+but in the course of time it would, judging from all past history, be
+in its turn overcome by some other tribe still more highly endowed.
+Thus the social and moral qualities would tend slowly to advance and be
+diffused throughout the world.
+
+But it may be asked, how within the limits of the same tribe did a
+large number of members first become endowed with these social and
+moral qualities, and how was the standard of excellence raised? It is
+extremely doubtful whether the offspring of the more sympathetic and
+benevolent parents, or of those who were the most faithful to their
+comrades, would be reared in greater numbers than the children of
+selfish and treacherous parents belonging to the same tribe. He who
+was ready to sacrifice his life, as many a savage has been, rather than
+betray his comrades, would often leave no offspring to inherit his noble
+nature. The bravest men, who were always willing to come to the front in
+war, and who freely risked their lives for others, would on an average
+perish in larger numbers than other men. Therefore, it hardly seems
+probable, that the number of men gifted with such virtues, or that
+the standard of their excellence, could be increased through natural
+selection, that is, by the survival of the fittest; for we are not here
+speaking of one tribe being victorious over another.
+
+Although the circumstances, leading to an increase in the 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 reasoning powers and foresight of the members became
+improved, each man would soon learn that if he aided his fellow-men,
+he would commonly receive aid in return. From this low motive he might
+acquire the habit of aiding his fellows; and the habit of performing
+benevolent actions certainly strengthens the feeling of sympathy
+which gives the first impulse to benevolent actions. Habits, moreover,
+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, whilst we love the former and dread the latter when applied to
+ourselves; and this instinct no doubt was originally acquired, like all
+the other social instincts, through natural selection. At how early a
+period the progenitors of man in the course of their development, became
+capable of feeling and being impelled by, the praise or blame of their
+fellow-creatures, we cannot of course say. But it appears that even dogs
+appreciate encouragement, praise, and blame. The rudest savages feel the
+sentiment of glory, as they clearly shew by preserving the trophies of
+their prowess, by their habit of excessive boasting, and even by
+the extreme care which they take of their personal appearance and
+decorations; for unless they regarded the opinion of their comrades,
+such habits would be senseless.
+
+They certainly feel shame at the breach of some of their lesser rules,
+and apparently remorse, as shewn by the case of the Australian who grew
+thin and could not rest from having delayed to murder some other woman,
+so as to propitiate his dead wife's spirit. Though I have not met with
+any other recorded case, it is scarcely credible that a savage, who will
+sacrifice his life rather than betray his tribe, or one who will deliver
+himself up as a prisoner rather than break his parole (6. Mr. Wallace
+gives cases in his 'Contributions to the Theory of Natural Selection,'
+1870, p. 354.), 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 offspring with a
+tendency to inherit his own high character.
+
+With increased experience and reason, man perceives the more remote
+consequences of his actions, and the self-regarding virtues, such as
+temperance, chastity, 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 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 instruction and habit.
+
+It must not be forgotten that although a high standard of morality gives
+but a slight or no advantage to each individual man and his children
+over the other men of the same tribe, yet that an increase in the number
+of well-endowed men and an advancement in the standard of morality will
+certainly give an immense advantage to one tribe over another. A tribe
+including many members who, from possessing in a high degree the spirit
+of patriotism, fidelity, obedience, courage, and sympathy, were always
+ready to aid one another, and to sacrifice themselves for the common
+good, would be victorious over most other tribes; and this would
+be natural selection. At all times throughout the world tribes have
+supplanted other tribes; and as morality is one important element in
+their success, the standard of morality and the number of well-endowed
+men will thus everywhere tend to rise and increase.
+
+It is, however, very difficult to form any judgment why one particular
+tribe and not another has been successful and has risen in the scale
+of civilisation. Many savages are in the same condition as when first
+discovered several centuries ago. As Mr. Bagehot has remarked, we are
+apt to look at progress as normal in human society; but history refutes
+this. The ancients did not even entertain the idea, nor do the Oriental
+nations at the present day. According to another high authority, Sir
+Henry Maine (7. 'Ancient Law,' 1861, p. 22. For Mr. Bagehot's remarks,
+'Fortnightly Review,' April 1, 1868, p. 452.), "the greatest part of
+mankind has never shewn a particle of desire that its civil institutions
+should be improved." Progress seems to depend on many concurrent
+favourable conditions, far too complex to be followed out. But it has
+often been remarked, that a cool climate, from leading to industry and
+to the various arts, has been highly favourable thereto. The Esquimaux,
+pressed by hard necessity, have succeeded in many ingenious inventions,
+but their climate has been too severe for continued progress. Nomadic
+habits, whether over wide plains, or through the dense forests of the
+tropics, or along the shores of the sea, have in every case been highly
+detrimental. Whilst observing the barbarous inhabitants of Tierra del
+Fuego, it struck me that the possession of some property, a fixed abode,
+and the union of many families under a chief, were the indispensable
+requisites for civilisation. Such habits almost necessitate the
+cultivation of the ground; and the first steps in cultivation would
+probably result, as I have elsewhere shewn (8. 'The Variation of Animals
+and Plants under Domestication,' vol. i. p. 309.), from some such
+accident as the seeds of a fruit-tree falling on a heap of refuse, and
+producing an unusually fine variety. The problem, however, of the first
+advance of savages towards civilisation is at present much too difficult
+to be solved.
+
+NATURAL SELECTION AS AFFECTING CIVILISED NATIONS.
+
+I 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 civilised nations may be worth adding.
+This subject has been ably discussed by Mr. W.R. Greg (9. 'Fraser's
+Magazine,' Sept. 1868, p. 353. This article seems to have struck many
+persons, and has given rise to two remarkable essays and a rejoinder in
+the 'Spectator,' Oct. 3rd and 17th, 1868. It has also been discussed in
+the 'Quarterly Journal of Science,' 1869, p. 152, and by Mr. Lawson Tait
+in the 'Dublin Quarterly Journal of Medical Science,' Feb. 1869, and
+by Mr. E. Ray Lankester in his 'Comparative Longevity,' 1870, p. 128.
+Similar views appeared previously in the 'Australasian,' July 13, 1867.
+I have borrowed ideas from several of these writers.), and previously by
+Mr. Wallace and Mr. Galton. (10. For Mr. Wallace, see 'Anthropological
+Review,' as before cited. Mr. Galton in 'Macmillan's Magazine,' Aug.
+1865, p. 318; also his great work, 'Hereditary Genius,' 1870.) Most of
+my remarks are taken from these three authors. With savages, the weak
+in body or mind are soon eliminated; and those that survive commonly
+exhibit a vigorous state of health. We civilised men, on the other hand,
+do our utmost to check the process of elimination; we build asylums for
+the imbecile, the maimed, and the sick; we institute poor-laws; and our
+medical men exert their utmost skill to save the life of every one
+to the last moment. There is reason to believe that vaccination has
+preserved thousands, who from a weak constitution would formerly have
+succumbed to small-pox. Thus the weak members of civilised societies
+propagate their kind. No one who has attended to the breeding of
+domestic animals will doubt that this must be highly injurious to the
+race of man. It is surprising how soon a want of care, or care wrongly
+directed, leads to the degeneration of a domestic race; but excepting in
+the case of man himself, hardly any one is so ignorant as to allow his
+worst animals to breed.
+
+The aid which we feel impelled to give to the helpless is mainly an
+incidental result of the instinct of sympathy, which was originally
+acquired as part of the social instincts, but subsequently rendered, in
+the manner previously indicated, more tender and more widely diffused.
+Nor could we check our sympathy, even at the urging of hard reason,
+without deterioration in the noblest part of our nature. The surgeon may
+harden himself whilst performing an operation, for he knows that he
+is acting for the good of his patient; but if we were intentionally
+to neglect the weak and helpless, it could only be for a contingent
+benefit, with an overwhelming present evil. We must therefore bear the
+undoubtedly bad effects of the weak surviving and propagating their
+kind; but there appears to be at least one check in steady action,
+namely that the weaker and inferior members of society do not marry so
+freely as the sound; and this check might be indefinitely 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. (11. Prof. H. Fick ('Einfluss der Naturwissenschaft auf das
+Recht,' June 1872) has some good remarks on this head, and on other such
+points.)
+
+Man accumulates property and bequeaths it to his children, so that the
+children of the rich have an advantage over the poor in the race for
+success, independently of bodily or mental superiority. On the other
+hand, the children of parents who are short-lived, and are therefore
+on an average deficient in health and vigour, come into their property
+sooner than other children, and will be likely to marry earlier,
+and leave a larger number of offspring to inherit their inferior
+constitutions. But the 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 civilised races
+have extended, and are now everywhere extending their range, so as to
+take the place of the lower races. Nor does the moderate accumulation of
+wealth interfere with the process of selection. When a poor man becomes
+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 have not to labour
+for their daily bread, is important to a degree which cannot be
+over-estimated; as all high intellectual work is carried on by them,
+and on such work, material progress of all kinds mainly depends, not
+to mention other and higher advantages. No doubt wealth when very great
+tends to convert men into useless drones, but their number is never
+large; and some degree of elimination here occurs, for we daily see
+rich men, who happen to be fools or profligate, squandering away their
+wealth.
+
+Primogeniture with entailed estates is a more direct evil, though it
+may formerly have been a great advantage by the creation of a dominant
+class, and any government is better than none. Most eldest sons, though
+they may be weak in body or mind, marry, whilst the younger sons,
+however superior in these respects, do not so generally marry. Nor can
+worthless eldest sons with entailed estates squander their wealth. But
+here, as elsewhere, the relations of civilised life are so complex
+that some compensatory checks intervene. The men who are rich through
+primogeniture are able to select generation after generation the more
+beautiful and charming women; and these must generally be healthy in
+body and active in mind. The evil consequences, such as they may be,
+of the continued preservation of the same line of descent, without any
+selection, are checked by men of rank always wishing to increase their
+wealth and power; and this they effect by marrying heiresses. But the
+daughters of parents who have produced single children, are themselves,
+as Mr. Galton (12. 'Hereditary Genius,' 1870, pp. 132-140.) has shewn,
+apt to be sterile; and thus noble families are continually cut off in
+the direct line, and their wealth flows into some side channel; but
+unfortunately this channel is not determined by superiority of any kind.
+
+Although civilisation thus checks in many ways the action of natural
+selection, it apparently favours the better development of the body, by
+means of good food and the freedom from occasional hardships. This may
+be inferred from civilised men having been found, wherever compared, to
+be physically stronger than savages. (13. Quatrefages, 'Revue des Cours
+Scientifiques,' 1867-68, p. 659.) They appear also to have equal powers
+of endurance, as has been proved in many adventurous expeditions. Even
+the great luxury of the rich can be but little detrimental; for the
+expectation of life of our aristocracy, at all ages and of both sexes,
+is very little inferior to that of healthy English lives in the lower
+classes. (14. See the fifth and sixth columns, compiled from good
+authorities, in the table given in Mr. E.R. Lankester's 'Comparative
+Longevity,' 1870, p. 115.)
+
+We will now look to the intellectual faculties. If in each grade
+of society the members were divided into two equal bodies, the one
+including the intellectually superior and the other the inferior,
+there can be little doubt that the former would succeed best in all
+occupations, and rear a greater number of children. Even in the lowest
+walks of life, skill and ability must be of some advantage; though in
+many occupations, owing to the great division of labour, a very small
+one. Hence in civilised nations there will be some tendency to an
+increase both in the number and in the standard of the intellectually
+able. But I do not wish to assert that this tendency may not be more
+than counterbalanced in other ways, as by the multiplication of the
+reckless and improvident; but even to such as these, ability must be
+some advantage.
+
+It has often been objected to views like the foregoing, that the most
+eminent men who have ever lived have left no offspring to inherit their
+great intellect. Mr. Galton says, "I regret I am unable to solve the
+simple question whether, and how far, men and women who are prodigies of
+genius are infertile. I have, however, shewn that men of eminence are by
+no means so." (15. 'Hereditary Genius,' 1870, p. 330.) Great lawgivers,
+the founders of beneficent religions, great philosophers and discoverers
+in science, aid the progress of mankind in a far higher degree by their
+works than by leaving a numerous progeny. In the case of corporeal
+structures, it is the selection of the slightly better-endowed and the
+elimination of the slightly less well-endowed individuals, and not the
+preservation of strongly-marked and rare anomalies, that leads to the
+advancement of a species. (16. 'Origin of Species' (fifth edition,
+1869), p. 104.) So it will be with the intellectual faculties, since the
+somewhat abler men in each grade of society succeed rather better than
+the less able, and consequently increase in number, if not otherwise
+prevented. When in any nation the standard of intellect and the number
+of intellectual men have increased, we may expect from the law of the
+deviation from an average, that prodigies of genius will, as shewn 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 civilised nations.
+Malefactors are executed, or imprisoned for long periods, so that they
+cannot freely transmit their bad qualities. Melancholic and insane
+persons are confined, or commit suicide. Violent and quarrelsome men
+often come to a bloody end. The restless who will not follow any steady
+occupation--and this relic of barbarism is a great check to civilisation
+(17. 'Hereditary Genius,' 1870, p. 347.)--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; whilst for the rural
+labourers of England at the same age it is 40.59 years. (18. E. Ray
+Lankester, 'Comparative Longevity,' 1870, p. 115. The table of
+the intemperate is from Neison's 'Vital Statistics.' In regard to
+profligacy, see Dr. Farr, 'Influence of Marriage on Mortality,' 'Nat.
+Assoc. for the Promotion of Social Science,' 1858.) Profligate women
+bear few children, and profligate men rarely marry; both suffer from
+disease. In the breeding of domestic animals, the elimination of those
+individuals, though few in number, which are in any marked manner
+inferior, is by no means an unimportant element towards success. This
+especially holds good with injurious characters which tend to reappear
+through reversion, such as blackness in sheep; and with mankind some of
+the worst dispositions, which occasionally without any assignable cause
+make their appearance in families, may perhaps be reversions to a savage
+state, from which we are not removed by very many generations. This view
+seems indeed recognised in the common expression that such men are the
+black sheep of the family.
+
+With civilised nations, as far as an advanced 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, whilst
+treating of the lower races, on the causes which lead to the advance of
+morality, namely, the approbation of our fellow-men--the strengthening
+of our sympathies by habit--example and imitation--reason--experience,
+and even self-interest--instruction during youth, and religious
+feelings.
+
+A most important obstacle in civilised countries to an increase in the
+number of men of a superior class has been strongly insisted on by
+Mr. Greg and Mr. Galton (19. 'Fraser's Magazine,' Sept. 1868, p.
+353. 'Macmillan's Magazine,' Aug. 1865, p. 318. The Rev. F.W. Farrar
+('Fraser's Magazine,' Aug. 1870, p. 264) takes a different view.),
+namely, the fact that the very poor and reckless, who are often degraded
+by vice, almost invariably marry early, whilst the careful and frugal,
+who are generally otherwise virtuous, marry late in life, so that they
+may be able to support themselves and their children in comfort. Those
+who marry early produce within a given period not only a greater number
+of generations, but, as shewn by Dr. Duncan (20. 'On the Laws of the
+Fertility of Women,' in 'Transactions of the Royal Society,' Edinburgh,
+vol. xxiv. p. 287; now published separately under the title of
+'Fecundity, Fertility, and Sterility,' 1871. See, also, Mr. Galton,
+'Hereditary Genius,' pp. 352-357, for observations to the above
+effect.), they produce many more children. The children, moreover, that
+are borne by mothers during the prime of life are heavier and larger,
+and therefore probably more vigorous, than those born at other periods.
+Thus the reckless, degraded, and often vicious members of society, tend
+to increase at a quicker rate than the provident and generally
+virtuous members. Or as Mr. Greg puts the case: "The careless, squalid,
+unaspiring Irishman multiplies like rabbits: the frugal, foreseeing,
+self-respecting, ambitious Scot, stern in his morality, spiritual in his
+faith, sagacious and disciplined in his intelligence, passes his best
+years in struggle and in celibacy, marries late, and leaves few behind
+him. Given a land originally peopled by a thousand Saxons and a thousand
+Celts--and in a dozen generations five-sixths of the population would be
+Celts, but five-sixths of the property, of the power, of the intellect,
+would belong to the one-sixth of Saxons that remained. In the eternal
+'struggle for existence,' it would be the inferior and LESS favoured
+race that had prevailed--and prevailed by virtue not of its good
+qualities but of its faults."
+
+There are, however, some checks to this downward tendency. We have
+seen that the intemperate suffer 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 (21. 'Tenth Annual Report of Births, Deaths, etc., in
+Scotland,' 1867, p. xxix.), that at all ages the death-rate is higher in
+towns than in rural districts, "and during the first five years of
+life the town death-rate is almost exactly double that of the rural
+districts." As these 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" (22. These quotations are taken from our highest
+authority on such questions, namely, Dr. Farr, in his paper 'On the
+Influence of Marriage on the Mortality of the French People,' read
+before the Nat. Assoc. for the Promotion of Social Science, 1858.), but
+what the cause of this may be, seems doubtful. Lastly, if the men who
+prudently delay marrying until they can bring up their families in
+comfort, were to select, as they often do, women in the prime of
+life, the rate of increase in the better class would be only slightly
+lessened.
+
+It was established from an enormous body of statistics, taken during
+1853, that the unmarried men throughout France, between the ages of
+twenty and eighty, die in a much larger proportion than the married: for
+instance, out of every 1000 unmarried men, between the ages of twenty
+and thirty, 11.3 annually died, whilst of the married, only 6.5 died.
+(23. Dr. Farr, ibid. The quotations given below are extracted from the
+same striking paper.) A similar law was proved to hold good, during the
+years 1863 and 1864, with the entire population above the age of twenty
+in Scotland: for instance, out of every 1000 unmarried men, between the
+ages of twenty and thirty, 14.97 annually died, whilst of the married
+only 7.24 died, that is less than half. (24. 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 considers very carefully written.) Dr. Stark remarks on this,
+"Bachelorhood is more destructive to life than the most unwholesome
+trades, or than residence in an unwholesome house or district where
+there has never been the most distant attempt at sanitary improvement."
+He considers that the lessened mortality is the direct result of
+"marriage, and the more regular domestic habits which attend that
+state." He admits, however, that the intemperate, 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 constitution, ill
+health, or any great infirmity in body or mind, will often not wish
+to marry, or will be rejected. Dr. Stark seems to have come to the
+conclusion that marriage in itself is a main cause of prolonged life,
+from finding that aged married men still have a considerable advantage
+in this respect over the unmarried of the same advanced age; but every
+one must have known instances of men, who with weak health during youth
+did not marry, and yet have survived to old age, though remaining weak,
+and therefore always with a lessened chance of life or of marrying.
+There is another remarkable circumstance which seems to support Dr.
+Stark's conclusion, namely, that widows and widowers in France suffer in
+comparison with the married a very heavy rate of mortality; but Dr.
+Farr attributes this to the 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 unmarried
+men, which seems to be a general law, "is mainly due to the constant
+elimination of imperfect types, and to the skilful selection of the
+finest individuals out of each successive generation;" the selection
+relating only to the marriage state, and acting on all corporeal,
+intellectual, and moral qualities. (25. 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 unfortunate.")
+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 specified in the two last paragraphs, and perhaps
+others as yet unknown, do not prevent the reckless, the vicious and
+otherwise inferior members of society from increasing at a quicker rate
+than the better class of men, the nation will retrograde, as has too
+often occurred in the history of the world. We must remember that
+progress is no invariable rule. It is very difficult to say why one
+civilised 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 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 vigour of body leads to vigour of mind.
+
+It has been urged by several writers that as high intellectual powers
+are advantageous to a nation, the old Greeks, who stood some grades
+higher in intellect than any race that has ever existed (26. See
+the ingenious and original argument on this subject by Mr. Galton,
+'Hereditary Genius,' pp. 340-342.), ought, if the power of natural
+selection were real, to have risen still higher in the scale, increased
+in number, and stocked the whole of Europe. Here we have the tacit
+assumption, so often made with respect to corporeal structures, that
+there is some innate tendency towards continued development in mind and
+body. But development of all kinds depends on many concurrent favourable
+circumstances. Natural selection acts only tentatively. Individuals and
+races may have acquired certain indisputable advantages, and yet
+have perished from failing in other characters. The Greeks may have
+retrograded from a want of coherence between the many small states, from
+the small size of their whole country, from the practice of slavery,
+or from extreme sensuality; for they did not succumb until "they were
+enervated and corrupt to the very core." (27. Mr. Greg, 'Fraser's
+Magazine,' Sept. 1868, p. 357.) The western nations of Europe, who now
+so immeasurably surpass their former savage progenitors, and stand at
+the summit of civilisation, owe little or none of their superiority
+to direct inheritance from the old Greeks, though they owe much to the
+written works of that wonderful people.
+
+Who can positively say why the Spanish nation, so dominant at one time,
+has been distanced in the race. The awakening of the nations of Europe
+from the dark ages is a still more perplexing problem. At that early
+period, as Mr. Galton has remarked, 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 (28. 'Hereditary
+Genius,' 1870, pp. 357-359. The Rev. F.W. Farrar ('Fraser's Magazine,'
+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.); 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, compared 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 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. (29. Mr. Galton, 'Macmillan's
+Magazine,' August 1865, p. 325. See also, 'Nature,' 'On Darwinism and
+National Life,' Dec. 1869, p. 184.) Looking to the distant future, I
+do not think that the Rev. Mr. Zincke takes an exaggerated view when he
+says (30. 'Last Winter in the United States,' 1868, p. 29.): "All other
+series of events--as that which resulted in the culture of mind in
+Greece, and that which resulted in the empire of Rome--only appear to
+have purpose and value when viewed in connection with, or rather as
+subsidiary to...the great stream of Anglo-Saxon emigration to the west."
+Obscure as is the problem of the advance of civilisation, we can at
+least see that a nation which produced during a lengthened period the
+greatest number of highly intellectual, energetic, brave, patriotic, and
+benevolent men, would generally prevail over less favoured 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 civilised nations to abject poverty, celibacy, and
+to the late marriages of the prudent. But as man suffers from the
+same physical evils as the lower animals, he has no right to expect an
+immunity from the evils consequent on the struggle for existence. Had he
+not been subjected during primeval times to natural selection, assuredly
+he would never have attained to his present rank. Since we see in many
+parts of the world enormous areas of the most fertile land capable of
+supporting numerous happy homes, but peopled only by a few wandering
+savages, it might be argued that the struggle for existence had not
+been sufficiently severe to force man upwards to his highest standard.
+Judging from all that we know of man and the lower animals, there has
+always been sufficient variability in their intellectual and moral
+faculties, for a steady advance through natural selection. No doubt such
+advance demands many favourable concurrent circumstances; but it may
+well be doubted whether the most favourable would have sufficed, had
+not the rate of increase been rapid, and the consequent struggle for
+existence extremely severe. It even appears from what we see, for
+instance, in parts of S. America, that a people which may be called
+civilised, such as the Spanish settlers, is liable to become indolent
+and to retrograde, when the conditions of life are very easy. With
+highly civilised 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 whilst the brain is
+impressible, and of a high standard of excellence, inculcated by the
+ablest and best men, embodied in the laws, customs and traditions of the
+nation, and enforced by public opinion. It should, however, be borne in
+mind, that the enforcement of public opinion depends on our appreciation
+of the approbation and disapprobation of others; and this appreciation
+is founded on our sympathy, which it can hardly be doubted was
+originally developed through natural selection as one of the most
+important elements of the social instincts. (31. I am much indebted
+to Mr. John Morley for some good criticisms on this subject: see, also
+Broca, 'Les Selections,' 'Revue d'Anthropologie,' 1872.)
+
+ON THE EVIDENCE THAT ALL CIVILISED NATIONS WERE ONCE BARBAROUS.
+
+The present subject has been treated in so full and admirable a manner
+by Sir J. Lubbock (32. 'On the Origin of Civilisation,' 'Proceedings of
+the Ethnological Society,' Nov. 26, 1867.), 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 (33.
+'Primeval Man,' 1869.) and formerly by Archbishop Whately, in favour of
+the belief that man came into the world as a civilised being, and
+that all savages have since undergone degradation, seem to me weak
+in comparison with those advanced on the other side. Many nations, no
+doubt, have fallen away in civilisation, and some may have lapsed into
+utter barbarism, though on this latter head I have met with no evidence.
+The Fuegians were probably compelled by other conquering hordes to
+settle in their inhospitable country, and they may have become in
+consequence somewhat more degraded; but it would be difficult to prove
+that they have fallen much below the Botocudos, who inhabit the finest
+parts of Brazil.
+
+The evidence that all civilised nations are the descendants of
+barbarians, consists, on the one side, of clear traces of their former
+low condition in still-existing customs, beliefs, language, etc.; and on
+the other side, of proofs that savages are independently able to raise
+themselves a few steps in the scale of civilisation, and have actually
+thus risen. The evidence on the first head is extremely curious, but
+cannot be here given: I refer to such cases as that of the art of
+enumeration, which, as Mr. Tylor clearly shews by reference to the words
+still used in some places, originated in counting the fingers, first of
+one hand and then of the other, and lastly of the toes. We have traces
+of this in our own decimal system, and in the Roman numerals, where,
+after the V, which is supposed to be an abbreviated picture of a human
+hand, we pass on to VI, etc., when the other hand no doubt was used.
+So again, "when we speak of three-score and ten, we are counting by the
+vigesimal system, each score thus ideally made, standing for 20--for
+'one man' as a Mexican or Carib would put it." (34. 'Royal Institution
+of Great Britain,' March 15, 1867. Also, 'Researches into the Early
+History of Mankind,' 1865.) According to a large and increasing school
+of philologists, every language bears the marks of its slow and gradual
+evolution. So it is with the art of writing, for letters are rudiments
+of pictorial representations. It is hardly possible to read Mr.
+M'Lennan's work (35. 'Primitive Marriage,' 1865. 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. Feb. 1868. Prof. Schaaffhausen
+('Anthropolog. Review,' Oct. 1869, p. 373) remarks on "the vestiges of
+human sacrifices found both in Homer and the Old Testament.") and not
+admit that almost all civilised nations still retain traces of such rude
+habits as the forcible capture of wives. What ancient nation, as the
+same author asks, can be named that was originally monogamous? The
+primitive idea of justice, as shewn by the law of battle and other
+customs of which vestiges still remain, was likewise most rude. Many
+existing superstitions are the remnants of former false religious
+beliefs. The highest form of religion--the grand idea of God hating sin
+and loving righteousness--was unknown during primeval times.
+
+Turning to the other kind of evidence: Sir J. Lubbock has shewn 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 amongst savages in various parts of the world,
+it cannot be doubted that these have nearly all been independent
+discoveries, excepting perhaps the art of making fire. (36. Sir J.
+Lubbock, 'Prehistoric Times,' 2nd edit. 1869, chaps. xv. and xvi. et
+passim. See also the excellent 9th Chapter in Tylor's 'Early History of
+Mankind,' 2nd edit., 1870.) The Australian boomerang is a good instance
+of one such independent discovery. The Tahitians when first visited had
+advanced in many respects beyond the inhabitants of most of the other
+Polynesian islands. There are no just grounds for the belief that the
+high culture of the native Peruvians and Mexicans was derived from
+abroad (37. Dr. F. M�ller has made some good remarks to this effect
+in the 'Reise der Novara: Anthropolog. Theil,' Abtheil. iii. 1868,
+s. 127.); 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-civilised land, if washed to the shores of America, would not
+have produced any marked effect on the natives, unless they had already
+become somewhat advanced. Looking to a very remote period in the history
+of the world, we find, to use Sir J. Lubbock's well-known terms, a
+paleolithic and neolithic period; and no one will pretend that the
+art of grinding rough flint tools was a borrowed one. In all parts of
+Europe, as far east as Greece, in Palestine, India, Japan, New Zealand,
+and Africa, including Egypt, flint tools have been discovered in
+abundance; and of their use the 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 countries, which include nearly the whole civilised
+world, were once in a barbarous condition. To believe that man was
+aboriginally civilised and then suffered utter degradation in so
+many regions, is to take a pitiably low view of human nature. It is
+apparently a truer and more cheerful view that progress has been much
+more general than retrogression; that man has risen, though by slow and
+interrupted steps, from a lowly condition to the highest standard as yet
+attained by him in knowledge, morals and religion.
+
+
+CHAPTER VI.
+
+ON THE AFFINITIES AND GENEALOGY OF MAN.
+
+Position of man in the animal series--The natural system
+genealogical--Adaptive characters of slight value--Various small points
+of resemblance between man and the Quadrumana--Rank of man in the
+natural system--Birthplace and antiquity of man--Absence of fossil
+connecting links--Lower stages in the genealogy of man, as inferred,
+firstly from his affinities and secondly from his structure--Early
+androgynous condition of the Vertebrata--Conclusion.
+
+Even if it be granted that the difference between man and his nearest
+allies is as great in corporeal structure as some naturalists maintain,
+and although we must grant that the difference between them is immense
+in mental power, yet the facts given in the earlier chapters appear to
+declare, in the plainest manner, that man is descended from some lower
+form, notwithstanding that connecting-links have not hitherto been
+discovered.
+
+Man is liable to numerous, slight, and diversified variations, which
+are induced by the same general causes, are governed and transmitted in
+accordance with the same general laws, as in the lower animals. Man has
+multiplied so rapidly, that he has necessarily been exposed to struggle
+for existence, and 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 re-appearance 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 a large extent, if man is the
+co-descendant with other mammals of some unknown and lower form.
+
+Some naturalists, from being deeply impressed with the mental and
+spiritual powers of man, have divided the whole organic world into three
+kingdoms, the Human, the Animal, and the Vegetable, thus giving to man
+a separate kingdom. (1. Isidore Geoffroy St.-Hilaire gives a detailed
+account of the position assigned to man by various naturalists in
+their classifications: 'Hist. Nat. Gen.' tom. ii. 1859, pp. 170-189.)
+Spiritual powers cannot be compared or classed by the naturalist: but he
+may endeavour to shew, as I have done, that the mental faculties of
+man and the lower animals do not differ in kind, although immensely in
+degree. A difference in degree, however great, does not justify us in
+placing man in a distinct kingdom, as will perhaps be best illustrated
+by comparing the mental powers of two insects, namely, a coccus or
+scale-insect and an ant, which undoubtedly belong to the same class.
+The difference is here greater than, though of a somewhat different kind
+from, that between man and the highest mammal. The female coccus, whilst
+young, attaches itself by its proboscis to a plant; sucks the sap, but
+never moves again; is fertilised 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 Huber has shewn, a large volume;
+I may, however, briefly specify a few points. Ants certainly communicate
+information to each other, and several unite for the same work, or for
+games of play. They recognise 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 afterwards build it up again. They store up seeds, of which
+they prevent the germination, and which, if damp, are brought up to the
+surface to dry. They keep aphides and other insects as milch-cows. They
+go out to battle in regular bands, and freely sacrifice their lives for
+the common weal. They emigrate according to a preconcerted plan. They
+capture slaves. They move the eggs of their aphides, as well as their
+own eggs and cocoons, into warm parts of the nest, in order that they
+may be quickly hatched; and endless similar facts could be given. (2.
+Some of the most interesting facts ever published on the habits of ants
+are given by Mr. Belt, in his 'Naturalist in Nicaragua,' 1874. See also
+Mr. Moggridge's admirable work, 'Harvesting Ants,' etc., 1873, also
+'L'Instinct chez les Insectes,' by M. George Pouchet, 'Revue des Deux
+Mondes,' Feb. 1870, p. 682.) 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 extinct.
+
+Professor Owen, relying chiefly on the structure of the brain, has
+divided the mammalian series into four sub-classes. One of these
+he devotes to man; in another he places both the marsupials and the
+Monotremata; so that he makes man as distinct from all other mammals as
+are these two latter groups conjoined. This view has not been
+accepted, as far as I am aware, by any naturalist capable of forming an
+independent judgment, and therefore need not here be further considered.
+
+We can understand why a classification founded on any single character
+or organ--even an organ so wonderfully complex and important as the
+brain--or on the high development of the mental faculties, is almost
+sure to prove unsatisfactory. This principle has indeed been tried
+with hymenopterous insects; but when thus classed by their habits or
+instincts, the arrangement proved thoroughly artificial. (3.
+Westwood, 'Modern Classification of Insects,' vol. ii. 1840, p. 87.)
+Classifications may, of course, be based on any character whatever, as
+on size, colour, or the element inhabited; but naturalists have long
+felt a profound conviction that there is a natural system. This system,
+it is now generally admitted, must be, as far as possible, genealogical
+in arrangement,--that is, the co-descendants of the same form must be
+kept together in one group, apart from the co-descendants of any other
+form; but if the parent-forms are related, so will be their descendants,
+and the two groups together will form a larger group. The amount
+of difference between the several groups--that is the amount of
+modification which each has undergone--is expressed by such terms as
+genera, families, orders, and classes. As we have no record of the lines
+of descent, the pedigree can be discovered only by observing the degrees
+of resemblance between the beings which are to be classed. For this
+object numerous points of resemblance are of much more importance
+than the amount of similarity or dissimilarity in a few points. If two
+languages were found to resemble each other in a multitude of words and
+points of construction, they would be universally recognised as having
+sprung from a common source, notwithstanding that they differed greatly
+in some few words or points of construction. But with organic beings the
+points of resemblance must not consist of adaptations to similar habits
+of life: two animals may, for instance, have had their whole frames
+modified for living in the water, and yet they will not be brought any
+nearer to each other in the natural system. Hence we can see how it
+is that resemblances in several unimportant structures, in useless
+and rudimentary organs, or not now functionally active, or in
+an embryological condition, are by far the most serviceable for
+classification; for they can hardly be due to adaptations within a
+late period; and thus they reveal the old lines of descent or of true
+affinity.
+
+We can further see why a great amount of modification in some one
+character ought not to lead us to separate widely any two organisms. A
+part which already differs much from the same part in other allied
+forms has already, according to the theory of evolution, varied much;
+consequently it would (as long as the organism remained exposed to the
+same exciting conditions) be liable to further variations of the
+same kind; and these, if beneficial, would be preserved, and thus be
+continually augmented. In many cases the continued development of a
+part, for instance, of the beak of a bird, or of the teeth of a mammal,
+would not aid the species in gaining its food, or for any other object;
+but with man we can see no definite limit to the 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
+outweigh a multitude of resemblances in other less important or quite
+unimportant points.
+
+The greater number of naturalists who have taken into consideration the
+whole structure of man, including his mental faculties, have followed
+Blumenbach and Cuvier, and have placed man in a separate Order, under
+the title of the Bimana, and therefore on an equality with the orders
+of the Quadrumana, Carnivora, etc. Recently many of our best naturalists
+have recurred to the view first propounded by Linnaeus, so remarkable
+for his sagacity, and have placed man in the same Order with the
+Quadrumana, under the title of the Primates. The justice of this
+conclusion will be admitted: for in the first place, we must bear in
+mind the comparative insignificance for classification of the
+great development of the brain in man, and that the strongly-marked
+differences between the skulls of man and the Quadrumana (lately
+insisted upon by Bischoff, Aeby, and others) apparently follow from
+their differently developed brains. In the second place, we must
+remember that nearly all the other and more important differences
+between man and the Quadrumana are manifestly adaptive in their nature,
+and relate chiefly to the erect position of man; such as the structure
+of his hand, foot, and pelvis, the curvature of his spine, and the
+position of his head. The family of Seals offers a good illustration of
+the small importance of adaptive characters for classification. These
+animals differ from all other Carnivora in the form of their bodies and
+in the structure of their limbs, far more than does man from the higher
+apes; yet in most systems, from that of Cuvier to the most recent one by
+Mr. Flower (4. 'Proceedings Zoological Society,' 1863, p. 4.), seals are
+ranked as a mere family in the Order of the Carnivora. If man had not
+been his own classifier, he would never have thought of founding a
+separate order for his own reception.
+
+It would be beyond my limits, and quite beyond my knowledge, even to
+name the innumerable points of structure in which man agrees with the
+other Primates. Our great anatomist and philosopher, Prof. Huxley, has
+fully discussed this subject (5. 'Evidence as to Man's Place in Nature,'
+1863, p. 70, et passim.), 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. Consequently there "is no justification
+for placing man in a distinct order."
+
+In an early part of this work I brought forward various facts, shewing
+how closely man agrees in constitution with the higher mammals; and this
+agreement must depend on our close similarity in minute structure and
+chemical composition. I gave, as instances, our liability to the same
+diseases, and to the attacks of allied parasites; our tastes in common
+for the same stimulants, and the similar effects produced by them, as
+well as by various drugs, and other such facts.
+
+As small unimportant points of resemblance between man and the
+Quadrumana are not commonly noticed in systematic works, and as, when
+numerous, they clearly reveal our relationship, I will specify a few
+such points. The relative position of our features is manifestly the
+same; and the various emotions are displayed by nearly similar movements
+of the muscles and skin, chiefly above the eyebrows and round the mouth.
+Some few expressions are, indeed, almost the same, as in the weeping
+of certain kinds of monkeys and in the laughing noise made by others,
+during which the corners of the mouth are drawn backwards, and the lower
+eyelids wrinkled. The external ears are curiously alike. In man the
+nose is much more prominent than in most monkeys; but we may trace the
+commencement of an aquiline curvature in the nose of the Hoolock Gibbon;
+and this in the Semnopithecus nasica is carried to a ridiculous extreme.
+
+The faces of many monkeys are ornamented with beards, whiskers, or
+moustaches. The hair on the head grows to a great length in some species
+of Semnopithecus (6. Isidore Geoffroy St.-Hilaire, 'Hist. Nat. Gen.'
+tom. ii. 1859, p. 217.); and in the Bonnet monkey (Macacus radiatus) it
+radiates from a point on the crown, with a parting down the middle.
+It is commonly said that the forehead gives to man his noble and
+intellectual appearance; but the thick hair on the head of the Bonnet
+monkey terminates downwards abruptly, and is succeeded by hair so short
+and fine that at a little distance the forehead, with the exception of
+the eyebrows, appears quite naked. It has been erroneously asserted that
+eyebrows are not present in any monkey. In the species just named the
+degree of nakedness of the forehead differs in different individuals;
+and Eschricht states (7. '�ber die Richtung der Haare,' etc., M�ller's
+'Archiv fur Anat. und Phys.' 1837, s. 51.) that in our children the
+limit between the hairy scalp and the naked forehead is sometimes not
+well defined; so that here we seem to have a trifling case of reversion
+to a progenitor, in whom the forehead had not as yet become quite naked.
+
+It is well known that the hair on our arms tends to converge from above
+and below to a point at the elbow. This curious arrangement, so unlike
+that in most of the lower mammals, is common to the gorilla, chimpanzee,
+orang, some species of Hylobates, and even to some few American monkeys.
+But in Hylobates agilis the hair on the fore-arm is directed downwards
+or towards the wrist in the ordinary manner; and in H. lar it is nearly
+erect, with only a very slight forward inclination; so that in this
+latter species it is in a transitional state. It can hardly be doubted
+that with most mammals the thickness of the hair on the back and its
+direction, is adapted to throw off the rain; even the transverse hairs
+on the fore-legs of a dog may serve for this end when he is coiled up
+asleep. Mr. Wallace, who has carefully studied the habits of the orang,
+remarks that the convergence of the hair towards the elbow on the arms
+of the orang may be explained as serving to throw off the rain, for this
+animal during rainy weather sits with its arms bent, and with the hands
+clasped round a branch or over its head. According to Livingstone, the
+gorilla also "sits in pelting rain with his hands over his head." (8.
+Quoted by Reade, 'The African Sketch Book,' vol i. 1873, p. 152.) 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 points 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. (9. On the hair in Hylobates,
+see 'Natural History of Mammals,' by C.L. Martin, 1841, p. 415. Also,
+Isidore Geoffroy on the American monkeys and other kinds, 'Hist. Nat.
+Gen.' vol. ii. 1859, pp. 216, 243. Eschricht, ibid. s. 46, 55, 61. Owen,
+'Anatomy of Vertebrates,' vol. iii. p. 619. Wallace, 'Contributions to
+the Theory of Natural Selection,' 1870, p. 344.)
+
+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 of 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 elsewhere attempted to
+shew (10. 'Origin of Species,' 5th edit. 1869, p.194. 'The Variation of
+Animals and Plants under Domestication,' vol. ii. 1868, p. 348.), 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 fore-arms of man and certain
+monkeys, as this character is common to almost all the anthropomorphous
+apes, it may probably be attributed to inheritance; but this is not
+certain, as some very distinct American monkeys are thus characterised.
+
+Although, as we have now seen, man has no just right to form a separate
+Order for his own reception, he may perhaps claim a distinct Sub-order
+or Family. Prof. Huxley, in his last work (11. 'An Introduction to the
+Classification of Animals,' 1869, p. 99.), divides the primates into
+three Sub-orders; namely, the Anthropidae with man alone, the Simiadae
+including monkeys of all kinds, and the Lemuridae with the diversified
+genera of lemurs. As far as differences in certain important points of
+structure are concerned, man may no doubt rightly claim the rank of a
+Sub-order; and this rank is too low, if we look chiefly to his mental
+faculties. Nevertheless, from a genealogical point of view it appears
+that this rank is too high, and that man ought to form merely a Family,
+or possibly even only a Sub-family. If we imagine three lines of descent
+proceeding from a common stock, it is quite conceivable that two of them
+might after the lapse of ages be so slightly changed as still to remain
+as species of the same genus, whilst the third line might become so
+greatly 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 would still retain through inheritance numerous small points of
+resemblance with the other two. Here, then, would occur the difficulty,
+at present insoluble, how much weight we ought to assign in our
+classifications to strongly-marked differences in some few points,--that
+is, to the amount of modification undergone; and how much to close
+resemblance 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 perhaps 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 Simiadae. This family is divided by almost
+all naturalists into the Catarrhine group, or Old World monkeys, all
+of which are characterised (as their name expresses) by the peculiar
+structure of their nostrils, and by having four premolars in each jaw;
+and into the Platyrrhine group or New World monkeys (including two very
+distinct sub-groups), all of which are characterised by differently
+constructed nostrils, and by having six premolars in each jaw. Some
+other small differences might be mentioned. Now man unquestionably
+belongs in his dentition, in the structure of his nostrils, and some
+other respects, to the Catarrhine or Old World division; nor does he
+resemble the Platyrrhines more closely than the Catarrhines in any
+characters, excepting 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 characters proper to the Old World
+division; losing at the same time all its own distinctive characters.
+There can, consequently, hardly be a doubt that man is an off-shoot from
+the Old World Simian stem; and that under a genealogical point of view
+he must be classed with the Catarrhine division. (12. This is nearly
+the same classification as that provisionally adopted by Mr. St. George
+Mivart, ('Transactions, Philosophical Society," 1867, p. 300), who,
+after separating the Lemuridae, divides the remainder of the Primates
+into the Hominidae, the Simiadae which answer to the Catarrhines, the
+Cebidae, and the Hapalidae,--these two latter groups answering to the
+Platyrrhines. Mr. Mivart still abides by the same view; see 'Nature,'
+1871, p. 481.)
+
+The anthropomorphous apes, namely the gorilla, chimpanzee, orang, and
+hylobates, are by most naturalists separated from the other Old World
+monkeys, as a distinct sub-group. I am aware that Gratiolet, relying
+on the structure of the brain, does not admit the existence of this
+sub-group, and no doubt it is a broken one. Thus the orang, as Mr. St.
+G. Mivart remarks, "is one of the most peculiar and aberrant forms to be
+found in the Order." (13. 'Transactions, Zoolog. Soc.' vol. vi. 1867,
+p. 214.) The remaining non-anthropomorphous Old World monkeys, are again
+divided by some naturalists into two or three smaller sub-groups; the
+genus Semnopithecus, with its peculiar sacculated stomach, being
+the type of one sub-group. But it appears from M. Gaudry's wonderful
+discoveries in Attica, that during the Miocene period a form existed
+there, which connected Semnopithecus and Macacus; and this probably
+illustrates the manner in which the other and higher groups were once
+blended together.
+
+If the anthropomorphous apes be admitted to form a natural sub-group,
+then as man agrees with them, not only in all those characters which
+he possesses in common with the whole Catarrhine group, but in other
+peculiar characters, such as the absence of a tail and of callosities,
+and in general appearance, we may infer that some ancient member of the
+anthropomorphous sub-group gave birth to man. It is not probable that,
+through the law of analogous variation, a member of one of the other
+lower sub-groups should have given rise to a man-like creature,
+resembling the higher anthropomorphous apes in so many respects. No
+doubt man, in comparison with most of his allies, has undergone an
+extraordinary amount of modification, chiefly in consequence of 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." (14. Mr. St. G. Mivart, 'Transactions of the Philosophical
+Society,' 1867, p. 410.)
+
+Every naturalist, who believes in the principle of evolution, will grant
+that the two main divisions of the Simiadae, namely the Catarrhine and
+Platyrrhine monkeys, with their sub-groups, have all proceeded from
+some one extremely ancient progenitor. The early descendants of this
+progenitor, before they had diverged to any considerable extent from
+each other, would still have formed a single natural group; but some of
+the species or incipient genera would have already begun 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 Lemuridae, which differ greatly from each
+other in the form of their muzzles (15. Messrs. Murie and Mivart on the
+Lemuroidea, 'Transactions, Zoological Society,' vol. vii, 1869, p. 5.),
+and to an extraordinary degree in their dentition.
+
+The Catarrhine and Platyrrhine monkeys agree in a multitude of
+characters, as is shewn by their unquestionably belonging to one and the
+same Order. The many characters which they possess in common can hardly
+have been independently acquired by so many distinct species; so that
+these characters must have been inherited. But a naturalist would
+undoubtedly have ranked as an ape or a monkey, an ancient form which
+possessed many 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 group. And as man from
+a genealogical point of view belongs to the Catarrhine or Old World
+stock, we must conclude, however much the conclusion may revolt
+our pride, that our early progenitors would have been properly thus
+designated. (16. Haeckel has come to this same conclusion. See '�ber
+die Entstehung des Menschengeschlechts,' in Virchow's 'Sammlung.
+gemein. wissen. Vortr�ge,' 1868, s. 61. Also his 'Nat�rliche
+Sch�pfungsgeschichte,' 1868, in which he gives in detail his views on
+the genealogy of man.) But we must not fall into the error of supposing
+that the early progenitor of the whole Simian stock, including man, was
+identical with, or even closely resembled, any existing ape or monkey.
+
+ON THE BIRTHPLACE AND ANTIQUITY OF MAN.
+
+We are naturally led to enquire, where was the birthplace of man at
+that stage of descent when our progenitors diverged from the Catarrhine
+stock? The fact that they belonged to this stock clearly shews that they
+inhabited the Old World; but not Australia nor any oceanic island, as
+we may infer from the laws of 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 that Africa
+was formerly inhabited by extinct apes closely allied to the gorilla and
+chimpanzee; and as these two species are now man's nearest allies, it is
+somewhat more probable that our early progenitors lived on the African
+continent than elsewhere. But it is useless to speculate on this
+subject; for two or three anthropomorphous apes, one the Dryopithecus
+(17. Dr. C. Forsyth Major, 'Sur les Singes fossiles trouv�s en Italie:'
+'Soc. Ital. des Sc. Nat.' tom. xv. 1872.) of Lartet, nearly as large
+as a man, and closely allied to Hylobates, existed in Europe during
+the Miocene age; and since so remote a period the earth has certainly
+undergone many great revolutions, and there has been ample time for
+migration on the largest scale.
+
+At the period and place, whenever and wherever it was, when man
+first lost his hairy covering, he probably inhabited a hot country; a
+circumstance favourable 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
+shewn by the existence of the Dryopithecus. We are also quite ignorant
+at how rapid a rate organisms, whether high or low in the scale, may
+be modified under favourable circumstances; 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 extinct or living species, has often
+been advanced as a grave objection to the belief that man is descended
+from some lower form; but this objection will not appear of much weight
+to those who, from general reasons, believe in the general principle
+of evolution. Breaks often occur in all parts of the series, some being
+wide, sharp and defined, others less so in various degrees; as between
+the orang and its nearest allies--between the Tarsius and the other
+Lemuridae--between the elephant, and in a more striking manner between
+the Ornithorhynchus or Echidna, and all other mammals. But these breaks
+depend merely on the number of related forms which have become extinct.
+At some future period, not very distant as measured by centuries, the
+civilised races of man will almost certainly exterminate, and
+replace, the savage races throughout the world. At the same time the
+anthropomorphous apes, as Professor Schaaffhausen has remarked (18.
+'Anthropological Review,' April 1867, p. 236.), will no doubt be
+exterminated. The break between man and his nearest allies will then be
+wider, for it will intervene between man in a more civilised state, as
+we may hope, even than the Caucasian, and some ape as low as a baboon,
+instead of as now between the negro or Australian and the gorilla.
+
+With respect to the absence of fossil remains, serving to connect man
+with his ape-like progenitors, no one will lay much stress on this fact
+who reads Sir C. Lyell's discussion (19. 'Elements of Geology,' 1865,
+pp. 583-585. 'Antiquity of Man,' 1863, p. 145.), where he shews that in
+all the vertebrate classes the discovery of fossil remains has been a
+very slow and fortuitous process. Nor should it be forgotten that those
+regions which are the most likely to afford remains connecting man
+with some extinct ape-like creature, have not as yet been searched by
+geologists.
+
+LOWER STAGES IN THE GENEALOGY OF MAN.
+
+We have seen that man appears to have diverged from the Catarrhine or
+Old World division of the Simiadae, after these had diverged from the
+New World division. We will now endeavour to follow the remote traces of
+his genealogy, trusting principally to the mutual affinities between the
+various classes and orders, with some slight reference to the periods,
+as far as ascertained, of their successive appearance on the earth. The
+Lemuridae stand below and near to the Simiadae, and constitute a very
+distinct family of the primates, or, according to Haeckel and others, a
+distinct Order. This group is diversified and broken to an extraordinary
+degree, and includes many aberrant forms. It has, therefore, probably
+suffered much extinction. Most of the remnants survive on islands, such
+as Madagascar and the Malayan archipelago, where they have not
+been exposed to so severe a competition as they would have been on
+well-stocked continents. This group likewise presents many gradations,
+leading, as Huxley remarks (20. 'Man's Place in Nature,' p. 105.),
+"insensibly from the crown and summit of the animal creation down to
+creatures from which there is but a step, as it seems, to the lowest,
+smallest, and least intelligent of the placental mammalia." From these
+various considerations it is probable that the Simiadae were originally
+developed from the progenitors of the existing Lemuridae; and these in
+their turn from forms standing very low in the mammalian series.
+
+The Marsupials stand in many important characters below the placental
+mammals. They appeared at an earlier geological period, and their range
+was formerly much more extensive than at present. Hence the Placentata
+are generally supposed to have been derived from the Implacentata or
+Marsupials; not, however, from forms closely resembling the existing
+Marsupials, but from their early progenitors. The Monotremata are
+plainly allied to the Marsupials, forming a third and still lower
+division in the great mammalian series. They are represented at the
+present day solely by the Ornithorhynchus and Echidna; and these
+two forms may be safely considered as relics of a much larger group,
+representatives of which have been preserved in Australia through some
+favourable concurrence of circumstances. The Monotremata are eminently
+interesting, as leading in several important points of structure towards
+the class of reptiles.
+
+In attempting to trace the genealogy of the Mammalia, and therefore of
+man, lower down in the series, we become involved in greater and greater
+obscurity; but as a most capable judge, Mr. Parker, has remarked, we
+have good reason to believe, that no true bird or reptile intervenes
+in the direct line of descent. He who wishes to see what ingenuity and
+knowledge can effect, may consult Prof. Haeckel's works. (21. Elaborate
+tables are given in his 'Generelle Morphologie' (B. ii. s. cliii. and
+s. 425); and with more especial reference to man in his 'Nat�rliche
+Sch�pfungsgeschichte,' 1868. Prof. Huxley, in reviewing this latter work
+('The Academy,' 1869, p. 42) says, that he considers the phylum or
+lines of descent of the Vertebrata to be admirably discussed by Haeckel,
+although he differs on some points. He expresses, also, his high
+estimate of the general tenor and spirit of the whole work.) I will
+content myself with a few general remarks. Every evolutionist will
+admit that the five great vertebrate classes, namely, mammals, birds,
+reptiles, amphibians, and fishes, are descended from some one prototype;
+for they have much in common, especially during their embryonic state.
+As the class of fishes is the most lowly organised, and appeared before
+the others, we may conclude that all the members of the vertebrate
+kingdom are derived from some fishlike 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 towards reptiles; and Prof. Huxley has discovered, and is
+confirmed by Mr. Cope and others, that the Dinosaurians are in many
+important characters intermediate between certain reptiles and certain
+birds--the birds referred to being the ostrich-tribe (itself evidently
+a widely-diffused remnant of a larger group) and the Archeopteryx, that
+strange Secondary bird, with a long lizard-like tail. Again,
+according to Prof. Owen (22. 'Palaeontology' 1860, p. 199.), 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 generalised type, that is, they presented diversified affinities with
+other groups of organisms. The Lepidosiren is also so closely allied to
+amphibians and fishes, that naturalists long disputed in which of these
+two classes to rank it; it, and also some few Ganoid fishes, have been
+preserved from utter extinction by inhabiting rivers, which are harbours
+of refuge, and are related to the great waters of the ocean in the same
+way that islands are to continents.
+
+Lastly, one single member of the immense and diversified class of
+fishes, namely, the lancelet or amphioxus, is so different from all
+other fishes, that Haeckel 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
+amongst the worms. Many years ago Prof. Goodsir perceived that the
+lancelet presented some affinities with the Ascidians, which are
+invertebrate, hermaphrodite, marine creatures permanently attached to
+a support. They hardly 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 kingdom of the
+Mollusca; but they have recently been placed by some naturalists amongst
+the Vermes or worms. Their larvae somewhat resemble tadpoles in shape
+(23. At the Falkland Islands I had the satisfaction of seeing, in
+April, 1833, and therefore some years before any other naturalist, the
+locomotive 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
+filament. 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 development
+the tail was closely coiled round the head of the larva.), and have the
+power of swimming freely about. Mr. Kovalevsky (24. 'Memoires de l'Acad.
+des Sciences de St. Petersbourg,' tom. x. No. 15, 1866.) has lately
+observed that the larvae of Ascidians are related to the Vertebrata,
+in their manner of development, in the relative position of the nervous
+system, and in possessing a structure closely like the chorda dorsalis
+of vertebrate animals; and in this he has been since confirmed by Prof.
+Kupffer. M. Kovalevsky writes to me from Naples, that he has now
+carried these observations yet further, and should his results be well
+established, the whole will form a discovery of the very greatest
+value. Thus, if we may rely on embryology, ever the safest guide in
+classification, it seems that we have at last gained a clue to the
+source whence the Vertebrata were derived. (25. But I am bound to add
+that some competent judges dispute this conclusion; for instance,
+M. Giard, in a series of papers in the 'Archives de Zoologie
+Experimentale,' for 1872. Nevertheless, this naturalist remarks, p. 281,
+"L'organisation de la larve ascidienne en dehors de toute hypoth�se
+et de toute th�orie, nous montre comment la nature peut produire la
+disposition fondamentale du type vert�br� (l'existence d'une
+corde dorsale) chez un invert�br� par la seule condition vitale de
+l'adaptation, et cette simple possibilit� du passage supprime l'ab�me
+entre les deux sous-r�gnes, encore bien qu'en ignore par o� le passage
+s'est fait en realit�.") We should then be justified in believing that
+at an extremely remote period a group of animals existed, resembling in
+many respects the larvae of our present Ascidians, which diverged into
+two great branches--the one retrograding in development and producing
+the present class of Ascidians, the other rising to the crown and summit
+of the animal kingdom by giving birth to the Vertebrata.
+
+We have thus far endeavoured rudely to trace the genealogy of the
+Vertebrata by the aid of their mutual affinities. We will now look to
+man as he exists; and we shall, I think, be able partially to restore
+the structure of our early progenitors, during successive periods, but
+not in due order of time. This can be effected by means of the rudiments
+which man still retains, by the characters which occasionally make their
+appearance in him through reversion, and by the aid of the principles
+of morphology and embryology. The various facts, to which I shall here
+allude, have been given in the previous chapters.
+
+The early progenitors of man must have been once covered with hair, both
+sexes having beards; their ears were probably pointed, and capable of
+movement; and their bodies were provided with a tail, having the proper
+muscles. Their limbs and bodies were also acted on by many muscles
+which now only occasionally reappear, but are normally present in the
+Quadrumana. At this or some earlier period, the great artery and nerve
+of the humerus ran through a supra-condyloid foramen. The intestine gave
+forth a much larger diverticulum or caecum than that now existing. The
+foot was then prehensile, judging from the condition of the great toe
+in the foetus; and our progenitors, no doubt, were arboreal in their
+habits, and frequented some warm, forest-clad land. The males had great
+canine teeth, which served them as formidable weapons. At a much earlier
+period the uterus was double; the excreta were voided through a cloaca;
+and the eye was protected by a third eyelid or nictitating membrane. At
+a still earlier period the progenitors of man must have been aquatic in
+their habits; for morphology plainly tells us that our lungs consist of
+a modified swim-bladder, which once served as a float. The clefts on the
+neck in the embryo of man shew 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 birthplace, a shore washed by the
+tides. At about this same early period the true kidneys were replaced by
+the corpora wolffiana. The heart existed as a simple pulsating vessel;
+and the chorda dorsalis took the place of a vertebral column. These
+early ancestors of man, thus seen in the dim recesses of time, must have
+been as simply, or even still more simply organised than the lancelet or
+amphioxus.
+
+There is one other point deserving a fuller notice. It has long been
+known that in the vertebrate kingdom one sex bears rudiments of various
+accessory parts, appertaining to the reproductive system, which properly
+belong to the opposite sex; and it has now been ascertained that at
+a very early embryonic period both sexes possess true male and female
+glands. Hence some remote progenitor of the whole vertebrate kingdom
+appears to have been hermaphrodite or androgynous. (26. This is the
+conclusion of Prof. Gegenbaur, one of the highest authorities in
+comparative anatomy: see 'Grundz�ge der vergleich. Anat.' 1870, s. 876.
+The result has been arrived at chiefly from the study of the Amphibia;
+but it appears from the researches of Waldeyer (as quoted in 'Journal
+of Anat. and Phys.' 1869, p. 161), that the sexual organs of even "the
+higher vertebrata are, in their early condition, hermaphrodite." Similar
+views have long been held by some authors, though until recently without
+a firm basis.) But here we encounter a singular difficulty. In the
+mammalian class the males possess rudiments of a uterus with the
+adjacent passage, in their vesiculae prostaticae; they bear also
+rudiments of mammae, and some male Marsupials have traces of a marsupial
+sack. (27. The male Thylacinus offers the best instance. Owen, 'Anatomy
+of Vertebrates,' vol. iii. p. 771.) Other analogous facts could be
+added. Are we, then, to suppose that some extremely ancient mammal
+continued androgynous, after it had acquired the chief distinctions of
+its class, and therefore after it had diverged from the lower classes of
+the vertebrate kingdom? This seems very improbable, for we have to look
+to fishes, the lowest of all the classes, to find any still existent
+androgynous forms. (28. Hermaphroditism has been observed in several
+species of Serranus, 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. Gunther 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 shewn ('Accad. delle Scienze,' Bologna,
+Dec. 28, 1871) that eels are androgynous.) 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 colours, 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 imperfect mammary organs
+is, in some respects, especially curious. The Monotremata have the
+proper milk-secreting glands with orifices, but no nipples; and as these
+animals stand at the very base of the mammalian series, it is probable
+that the progenitors of the class also had milk-secreting glands, but no
+nipples. This conclusion is supported by what is known of their manner
+of development; for Professor Turner informs me, on the authority
+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 Marsupials differ from the Monotremata by possessing
+nipples; so that probably these organs were first acquired by the
+Marsupials, after they had diverged from, and risen above, the
+Monotremata, and were then transmitted to the placental mammals. (29.
+Prof. Gegenbaur has shewn ('Jen�ische Zeitschrift,' Bd. vii. p. 212)
+that 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.) No one will suppose that the
+marsupials still remained androgynous, after they had approximately
+acquired their present structure. How then are we to account for male
+mammals possessing mammae? It is possible that they were first developed
+in the females and then transferred to the males, but from what follows
+this is hardly probable.
+
+It may be suggested, as another view, that long after the progenitors
+of the whole mammalian class had ceased to be androgynous, both sexes
+yielded milk, and thus nourished their young; and in the case of the
+Marsupials, that both sexes carried their young in marsupial sacks. This
+will not appear altogether improbable, if we reflect that the males of
+existing syngnathous fishes receive the eggs of the females in their
+abdominal pouches, hatch them, and afterwards, as some believe, nourish
+the young (30. 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 Anatomy and Physiology,' Nov. 1, 1866, p. 78. Dr. Gunther
+has likewise described similar cases.);--that certain other male fishes
+hatch the eggs within their mouths or branchial cavities;--that certain
+male toads take the chaplets of eggs from the females, and wind them
+round their own thighs, keeping them there until the tadpoles are
+born;--that certain male birds undertake the whole duty of incubation,
+and that male pigeons, as well as the females, feed their nestlings with
+a secretion from their crops. But the above suggestion first occurred
+to me from mammary glands of male mammals being so much more perfectly
+developed than the rudiments of the other accessory reproductive parts,
+which are found in the one sex though proper to the other. The mammary
+glands and nipples, as they exist in male mammals, can indeed hardly
+be called rudimentary; they are merely not fully developed, and not
+functionally active. They are sympathetically affected under the
+influence of certain diseases, like the same organs in the female. They
+often secrete a few drops of milk at birth and at puberty: this latter
+fact occurred in the curious case, before referred to, where a young man
+possessed two pairs of 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 (31. Mlle. C. Royer has suggested a similar view
+in her 'Origine de l'homme,' etc., 1870.), and that afterwards from some
+cause (as from the production of a smaller number of young) the males
+ceased to give this aid, disuse of the organs during maturity would
+lead to their becoming inactive; and from two well-known principles of
+inheritance, this state of inactivity would probably be transmitted to
+the males at the corresponding age of maturity. But at an earlier age
+these 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 progress in the organic scale better
+than any one else, as resting on the amount of differentiation and
+specialisation 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 natural
+selection, their parts will have become more and more differentiated
+and specialised for various functions from the advantage gained by the
+division of physiological labour. The same part appears often to have
+been modified first for one purpose, and then long afterwards for some
+other and quite distinct purpose; and thus all the parts are rendered
+more and more complex. But each organism still 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 organisation 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, however, be supposed
+that groups of organic beings are always supplanted, and disappear as
+soon as they have given birth to other and more perfect groups. The
+latter, though victorious over their predecessors, may not have become
+better adapted for all places in the economy of nature. Some old forms
+appear to have survived from inhabiting protected sites, where they have
+not been exposed to very severe competition; and these often aid us in
+constructing our genealogies, by giving us a fair idea of former and
+lost populations. But we must not fall into the error of looking at the
+existing members of any lowly-organised group as 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 (32. The inhabitants of the seashore must be greatly
+affected by the tides; animals living either about the MEAN high-water
+mark, or about the MEAN low-water mark, pass through a complete cycle
+of tidal changes in a fortnight. Consequently, their food supply
+will undergo marked changes week by week. The vital functions of such
+animals, living under these conditions for many generations, can
+hardly fail to run their course in regular weekly periods. Now it is a
+mysterious fact that in the higher and now terrestrial Vertebrata, as
+well as in other classes, many normal and abnormal processes have one or
+more whole weeks as their periods; this would be rendered intelligible
+if the Vertebrata are descended from an animal allied to the existing
+tidal Ascidians. Many instances of such periodic processes might be
+given, as the gestation of mammals, the duration of fevers, etc. The
+hatching of eggs affords also a good example, for, according to Mr.
+Bartlett ('Land and Water,' Jan. 7, 1871), the eggs of the pigeon are
+hatched in two weeks; those of the fowl in three; those of the duck
+in four; those of the goose in five; and those of the ostrich in seven
+weeks. As far as we can judge, a recurrent period, if approximately of
+the right duration for any process or function, would not, when once
+gained, be liable to change; consequently it might be thus transmitted
+through almost any number of generations. But if the function changed,
+the period would have to change, and would be apt to change almost
+abruptly by a whole week. This 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 primordial birthplace of these animals.), resembling the larvae
+of existing Ascidians. These animals probably gave rise to a group of
+fishes, as lowly organised as the lancelet; and from these the Ganoids,
+and other fishes like the Lepidosiren, must have been developed. From
+such fish a very small advance would carry us on to the Amphibians.
+We have seen that birds and reptiles were once intimately connected
+together; and the Monotremata 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,
+proceeded.
+
+Thus we have given to man a pedigree of prodigious length, but not, it
+may be said, of noble quality. The world, it has often been remarked,
+appears as if it had long been preparing for the advent of man: and
+this, in one sense is strictly true, for he owes his birth to a long
+line of progenitors. If any single link in this chain had never existed,
+man would not have been exactly what he now is. Unless we wilfully close
+our eyes, we may, with our present knowledge, approximately recognise
+our parentage; nor need we feel ashamed of it. The most humble organism
+is something much higher than the inorganic dust under our feet; and
+no one with an unbiassed mind can study any living creature, however
+humble, without being struck with enthusiasm at its marvellous structure
+and properties.
+
+
+CHAPTER VII.
+
+ON THE RACES OF MAN.
+
+The nature and value of specific characters--Application to the races of
+man--Arguments in favour of, and opposed to, ranking the so-called
+races of man as distinct species--Sub-species--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 enquire what is the value of the differences
+between them under a classificatory point of view, and how they have
+originated. In determining whether two or more allied forms ought to be
+ranked as species or varieties, naturalists are practically guided by
+the following considerations; namely, the amount of difference between
+them, and whether such differences relate to few or many points of
+structure, and whether they are of physiological importance; but more
+especially whether they are constant. Constancy of character is what is
+chiefly valued and sought for by naturalists. Whenever it can be shewn,
+or rendered probable, that the forms in question have remained distinct
+for a long period, this becomes an argument of much weight in favour of
+treating them as species. Even a slight degree of sterility between
+any two forms when first crossed, or in their offspring, is generally
+considered as a decisive test of their specific distinctness; and their
+continued persistence without blending within the same area, is usually
+accepted as sufficient evidence, either of some degree of mutual
+sterility, or in the case of animals of some 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 variable 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 the other inhabitants are specifically distinct,
+are themselves usually looked at as distinct; but in truth this affords
+no aid in distinguishing geographical races from so-called good or true
+species.
+
+Now let us apply these generally-admitted principles to the races of
+man, viewing him in the same spirit as a naturalist would any other
+animal. In regard to the amount of difference between the races, we must
+make some allowance for our nice powers of discrimination gained by the
+long habit of observing ourselves. In India, as Elphinstone remarks,
+although a newly-arrived European cannot at first distinguish the
+various native races, yet they soon appear to him extremely dissimilar
+(1. 'History of India,' 1841, vol. i. p. 323. Father Ripa makes exactly
+the same remark with respect to the Chinese.); 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 supposed; certain negro tribes must be excepted,
+whilst others, as Dr. Rohlfs writes to me, and as I have myself seen,
+have Caucasian features. This general similarity is well shewn by the
+French photographs in the Collection Anthropologique du Museum de Paris
+of the men belonging to various races, the greater number of which
+might pass for Europeans, as many persons to whom I have shewn 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 colour of the skin and hair, by slight differences
+in the features, and by expression.
+
+There is, however, no doubt that the various races, when carefully
+compared and measured, differ much from each other,--as in the texture
+of the hair, the relative proportions of all parts of the body (2. A
+vast number of measurements of Whites, Blacks, and Indians, are given
+in the 'Investigations in the Military and Anthropolog. Statistics of
+American Soldiers,' by B.A. Gould, 1869, pp. 298-358; 'On the capacity
+of the lungs,' p. 471. See also the numerous and valuable tables, by Dr.
+Weisbach, from the observations of Dr. Scherzer and Dr. Schwarz, in
+the 'Reise der Novara: Anthropolog. Theil,' 1867.), the capacity of the
+lungs, the form and capacity of the skull, and even in the convolutions
+of the brain. (3. See, for instance, Mr. Marshall's account of the brain
+of a Bushwoman, in 'Philosophical Transactions,' 1864, p. 519.) But it
+would be an endless task to specify the numerous points of difference.
+The races differ also in constitution, in acclimatisation and in
+liability to certain diseases. Their mental characteristics are likewise
+very distinct; chiefly as it would appear in their emotional, but partly
+in their intellectual faculties. Every one who has had the opportunity
+of comparison, must have been struck with the contrast between the
+taciturn, even morose, aborigines of S. America and the light-hearted,
+talkative negroes. There is a nearly similar contrast between the Malays
+and the Papuans (4. Wallace, 'The Malay Archipelago,' vol. ii. 1869, p.
+178.), 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 favour of
+classing the races of man as distinct species, and then the arguments
+on the other side. If a naturalist, who had never before seen a Negro,
+Hottentot, Australian, or Mongolian, were to compare them, he would at
+once perceive that they differed in a multitude of characters, some of
+slight and some of considerable importance. On enquiry he would find
+that they were adapted to live under widely different climates, and that
+they differed somewhat in bodily constitution and mental disposition.
+If he were then told that hundreds of similar specimens could be brought
+from the same countries, he would assuredly declare that they were
+as good species as many to which he had been in the habit of affixing
+specific names. This conclusion would be greatly strengthened as soon as
+he had ascertained that these forms had all retained the same character
+for many centuries; and that negroes, apparently identical with existing
+negroes, had lived at least 4000 years ago. (5. With respect to the
+figures in the famous Egyptian caves of Abou-Simbel, M. Pouchet says
+('The Plurality of the Human Races,' Eng. translat., 1864, p. 50), that
+he was far from finding recognisable representations of the dozen or
+more nations which some authors believe that they can recognise. Even
+some of the most strongly-marked races cannot be identified with that
+degree of unanimity which might have been expected from what has
+been written on the subject. Thus Messrs. Nott and Gliddon ('Types of
+Mankind,' p. 148), state that Rameses II., or the Great, has features
+superbly European; whereas Knox, another firm believer in the specific
+distinctness of the races of man ('Races of Man,' 1850, p. 201),
+speaking of young Memnon (the same as Rameses II., as I am informed
+by Mr. Birch), insists in the strongest manner that he is identical in
+character with the Jews of Antwerp. Again, when I looked at the statue
+of Amunoph III., I agreed with two officers of the establishment, both
+competent judges, that he had a strongly-marked negro type of features;
+but Messrs. Nott and Gliddon (ibid. p. 146, fig. 53), describe him as
+a hybrid, but not of "negro intermixture.") He would also hear, on the
+authority of an excellent observer, Dr. Lund (6. As quoted by Nott and
+Gliddon, 'Types of Mankind,' 1854, p. 439. They give also corroborative
+evidence; but C. Vogt thinks that the subject requires further
+investigation.), that the human skulls found in the caves of Brazil,
+entombed with many extinct mammals, belonged to the same type as that
+now prevailing throughout the American Continent.
+
+Our naturalist would then perhaps turn to 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 considerable change of
+climate; and that the species which come nearest to man have never been
+reared to maturity, even under the temperate climate of Europe. He
+would be deeply impressed with the fact, first noticed by Agassiz (7.
+'Diversity of Origin of the Human Races,' in the 'Christian Examiner,'
+July 1850.), 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 shewn, by
+nearly the same line which divides the great Malayan and Australian
+zoological provinces. The Aborigines of America range throughout the
+Continent; and this at first appears opposed to the above rule, for most
+of the productions of the Southern and Northern halves differ widely:
+yet some few living forms, as the opossum, range from the one into the
+other, as did formerly some of the gigantic Edentata. The Esquimaux,
+like other Arctic animals, extend round the whole polar regions. It
+should be observed that the amount of difference between the mammals of
+the several zoological provinces does not correspond with the degree of
+separation between the latter; so that it can hardly be considered as an
+anomaly that the Negro differs more, and the American much less from
+the other races of man, than do the mammals of the African and American
+continents from the 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 should 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 informed by
+Mr. Denny that the most different kinds of dogs, fowls, and pigeons, in
+England, are infested by the same species of Pediculi or lice. Now Mr.
+A. Murray has carefully examined the Pediculi collected in different
+countries from the different races of man (8. 'Transactions of the Royal
+Society of Edinburgh,' vol. xxii, 1861, p. 567.); and he finds that
+they differ, not only in colour, 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 Pediculi were darker
+coloured, and appeared different from those proper to the natives of
+Chiloe in South America, of which he gave me specimens. These, again,
+appeared larger and much softer than European lice. Mr. Murray procured
+four kinds from Africa, namely, from the Negroes of the Eastern and
+Western coasts, from the Hottentots and 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 different districts. With insects slight structural
+differences, if constant, are generally esteemed of specific value: and
+the fact of the races of man being infested by parasites, which appear
+to be specifically distinct, might fairly be urged as an argument that
+the races themselves ought to be classed as distinct species.
+
+Our supposed naturalist having proceeded thus far in his investigation,
+would next enquire whether the races of men, when crossed, were in
+any degree sterile. He might consult the work (9. 'On the Phenomena of
+Hybridity in the Genus Homo,' Eng. translat., 1864.) of Professor Broca,
+a cautious and philosophical observer, and in this he would find good
+evidence that some races were quite fertile together, but evidence of an
+opposite nature in regard to other races. Thus it has been asserted that
+the native women of Australia and Tasmania rarely produce children to
+European men; the evidence, however, on this head has now been shewn to
+be almost valueless. The half-castes are killed by the pure blacks:
+and an account has lately been published of eleven half-caste youths
+murdered and burnt at the same time, whose remains were found by the
+police. (10. See the interesting letter by Mr. T.A. Murray, in the
+'Anthropological Review,' April 1868, p. liii. In this letter Count
+Strzelecki's statement that Australian women who have borne children to
+a white man, are afterwards sterile with their own race, is disproved.
+M. A. de Quatrefages has also collected (Revue des Cours Scientifiques,
+March, 1869, p. 239), much evidence that Australians and Europeans
+are not sterile when crossed.) Again, it has often been said that when
+mulattoes intermarry, they produce few children; on the other hand, Dr.
+Bachman, of Charleston (11. 'An Examination of Prof. Agassiz's Sketch
+of the Nat. Provinces of the Animal World,' Charleston, 1855, p.
+44.), 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. Enquiries formerly made
+by Sir C. Lyell on this subject led him, as he informs me, to the same
+conclusion. (12. Dr. Rohlfs writes to me that he 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 admiring 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.) In the United States the census for the
+year 1854 included, according to Dr. Bachman, 405,751 mulattoes; and
+this number, considering all the circumstances of the case, seems
+small; but it may partly be accounted for by the degraded and anomalous
+position of the class, and by the profligacy of the women. A certain
+amount of absorption of mulattoes into 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 work
+(13. 'Military and Anthropological Statistics of American Soldiers,'
+by B.A. Gould, 1869, p. 319.) as a well-known phenomenon; and this,
+although a different consideration from their lessened fertility, may
+perhaps be advanced as a proof of the specific distinctness of the
+parent races. No doubt both animal and vegetable hybrids, when produced
+from extremely distinct species, are liable to premature death; but
+the parents of mulattoes cannot be put under the category of extremely
+distinct species. The common Mule, so notorious for long life and
+vigour, and yet so sterile, shews how little necessary connection 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 fertility of converse crosses
+between the same two species. With forms which must be ranked as
+undoubted species, a perfect series exists from those which are
+absolutely sterile when crossed, to those which are almost or completely
+fertile. The degrees of sterility do not coincide strictly with the
+degrees of difference between the parents in external structure or
+habits of life. Man in many respects may be compared with those animals
+which have long been domesticated, and a large body of evidence can
+be advanced in favour of the Pallasian doctrine (14. 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 incapacity 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
+shewn by me (ibid. vol. ii. p. 185, and 'Origin of Species,' 5th edit.
+p. 317), that the sterility of crossed species has not been acquired
+through natural selection: we can see that when two forms have already
+been rendered very sterile, it is scarcely possible that their sterility
+should be augmented by the preservation or survival of the more and more
+sterile individuals; for, as the sterility increases, fewer and fewer
+offspring will be produced from which to breed, and at last only single
+individuals will be produced at the rarest intervals. But there is even
+a higher grade of sterility than this. Both Gartner and Kolreuter have
+proved that in genera of plants, including many species, a series can be
+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 shewn 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.), that domestication tends to eliminate the sterility which
+is so general a result of the crossing of species in a state of nature.
+From these several considerations, it may be justly urged that the
+perfect fertility of the intercrossed races of man, if 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 species or varieties; but after
+carefully studying the evidence, 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. (15. 'The Variation of Animals,' etc., vol. ii. p.
+92.) I refer to this point, because Dr. Rohlfs informs me that he has
+frequently seen in Africa the offspring of negroes crossed with members
+of other races, either completely black or completely white, or rarely
+piebald. On the other hand, it is notorious that in America mulattoes
+commonly present an intermediate appearance.
+
+We have now seen that a naturalist might feel himself fully justified in
+ranking the races of man as distinct species; for he has found that they
+are distinguished by many differences in structure and constitution,
+some being of importance. These differences have, also, remained nearly
+constant for very long periods of time. Our naturalist will have been
+in some degree influenced by the enormous range of man, which is a
+great anomaly in the class of mammals, if mankind be viewed as a single
+species. He will have been struck with the distribution of the several
+so-called races, which accords with that of other undoubtedly distinct
+species of mammals. Finally, he might urge that the mutual fertility of
+all the races has not as yet been fully proved, and even if proved would
+not be an absolute proof of their specific identity.
+
+On the other side of the question, if our supposed naturalist were to
+enquire whether the forms of man keep distinct like ordinary species,
+when mingled together in large numbers in the same country, he would
+immediately discover that this was by no means the case. In Brazil he
+would behold an immense mongrel population of Negroes and Portuguese;
+in Chiloe, and other parts of South America, he would behold the whole
+population consisting of Indians and Spaniards blended in various
+degrees. (16. M. de Quatrefages has given ('Anthropological Review,'
+Jan. 1869, p. 22), an interesting account of the success and energy of
+the Paulistas in Brazil, who are a much crossed race of Portuguese and
+Indians, with a mixture of the blood of other races.) In many parts of
+the same continent he would meet with the most complex crosses between
+Negroes, Indians, and Europeans; and judging from the vegetable kingdom,
+such triple crosses afford the severest test of the mutual fertility
+of the parent forms. In one island of the Pacific he would find a small
+population of mingled Polynesian and English blood; and in the Fiji
+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 the races were highly variable.
+This fact strikes every one on first beholding the negro slaves in
+Brazil, who have been imported from all parts of Africa. The same remark
+holds good with the 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.
+Hottentot women offer certain peculiarities, more strongly marked than
+those occurring in any other race, but these are known not to be
+of constant occurrence. In the several American tribes, colour and
+hairiness differ considerably; as does colour to a certain degree, and
+the shape of the features greatly, in the Negroes of Africa. The shape
+of the skull varies much in some races (17. For instance, with the
+aborigines of America and Australia, Prof. Huxley says ('Transact.
+Internat. Congress of Prehist. Arch.' 1868, p. 105), that the skulls of
+many South Germans and Swiss are "as short and as broad as those of
+the Tartars," etc.); and so it is with every other character. Now all
+naturalists have learnt by dearly bought experience, how rash it is to
+attempt to define species by the aid of inconstant characters.
+
+But the most weighty of all the arguments against treating the races
+of man as distinct species, is that they graduate into each other,
+independently in many cases, as far as we can judge, of their having
+intercrossed. Man has been studied more carefully than any other animal,
+and yet there is the greatest possible diversity amongst capable judges
+whether he should be classed as a single species or race, or as two
+(Virey), as three (Jacquinot), as four (Kant), five (Blumenbach), six
+(Buffon), seven (Hunter), eight (Agassiz), eleven (Pickering), fifteen
+(Bory St. Vincent), sixteen (Desmoulins), twenty-two (Morton), sixty
+(Crawfurd), or as sixty-three, according to Burke. (18. See a good
+discussion on this subject in Waitz, 'Introduction 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.) This diversity of judgment does not prove that the
+races ought not to be ranked as species, but it shews that they graduate
+into each other, and that it is hardly possible to discover clear
+distinctive characters between them.
+
+Every naturalist who has had the misfortune to undertake the description
+of a group of highly varying organisms, 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 himself that he
+has no right to give names to objects which he cannot define. Cases
+of this kind occur in the Order which includes man, namely in certain
+genera of monkeys; whilst in other genera, as in Cercopithecus, most
+of the species can be determined with certainty. In the American genus
+Cebus, the various forms are ranked by some naturalists as species, by
+others as mere geographical races. Now if numerous specimens of Cebus
+were collected from all parts of South America, and those forms which at
+present appear to be specifically distinct, were found to graduate
+into each other by close steps, they would usually be ranked as
+mere varieties or races; and this course has been followed by most
+naturalists with respect to the races of man. Nevertheless, it must be
+confessed that there are forms, at least in the vegetable kingdom (19.
+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 Compositae of
+N. America.), 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 characteristics of true
+species, but which hardly deserve so high a rank. Now if we reflect on
+the weighty arguments above given, for raising the races of man to the
+dignity of species, and the insuperable difficulties on the other side
+in defining them, 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
+distinguished only with much difficulty, whilst the smaller genera
+within the same family include forms that are perfectly distinct; yet
+all must be ranked equally as species. So again, species within the same
+large genus by no means resemble each other to the same degree: on the
+contrary, some of them can generally be arranged in little groups round
+other species, like satellites round planets. (20. 'Origin of Species,'
+5th edit. p. 68.)
+
+The question whether mankind consists of one or several species has of
+late years been much discussed by anthropologists, who are divided into
+the two schools of monogenists and polygenists. Those who do not admit
+the principle of evolution, must look at species as separate creations,
+or 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 endeavour to decide this point, until some definition of
+the term "species" is generally accepted; and the definition must not
+include an indeterminate element such as an act of creation. We might as
+well attempt without any definition to decide whether a certain number
+of houses should be called a village, town, or city. We have a practical
+illustration of the difficulty in the never-ending doubts whether many
+closely-allied mammals, birds, insects, and plants, which represent
+each other respectively in North America and Europe, should be ranked
+as species or geographical races; and the like holds true of the
+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 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. (21. See Prof. Huxley to this effect in the 'Fortnightly
+Review,' 1865, p. 275.) With our domestic animals the question whether
+the various races have arisen from one or more species is somewhat
+different. Although it may be admitted that all the races, as well as
+all the natural species within the same genus, have sprung from the same
+primitive stock, yet it is a fit subject for discussion, whether all
+the 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 constant 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 Vogt (22. 'Lectures on Man,' Eng.
+translat., 1864, p. 468.), 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 shewn by von Nathusius
+(23. 'Die Rassen des Schweines,' 1860, s. 46. 'Vorstudien f�r
+Geschichte,' etc., Schweinessch�del, 1864, s. 104. With respect to
+cattle, see M. de Quatrefages, 'Unit� de l'Esp�ce Humaine,' 1861, p.
+119.), with the 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 developed gibbon or semnopithecus, the chimpanzee a
+highly developed macacus, and the gorilla a highly developed mandrill.
+If this conclusion, which rests almost exclusively on brain-characters,
+be admitted, we should have a case of convergence at least in external
+characters, for the anthropomorphous apes are certainly more like
+each other in many points, than they are to other apes. All analogical
+resemblances, as of a whale to a fish, may indeed be said to be cases
+of convergence; but this term has never been applied to superficial and
+adaptive resemblances. It would, however, be extremely rash to attribute
+to convergence close similarity of character in many points of structure
+amongst the modified descendants of widely distinct beings. The form of
+a crystal is determined solely by the molecular forces, and it is not
+surprising that dissimilar substances should sometimes assume the same
+form; but with organic beings we should bear in mind that the form of
+each depends on an infinity of complex relations, namely on variations,
+due to causes far too intricate to be followed,--on the nature of the
+variations preserved, these depending on the physical conditions, and
+still more on the surrounding organisms which compete with each,--and
+lastly, on inheritance (in itself a fluctuating element) from
+innumerable progenitors, all of which have had their forms determined
+through equally complex relations. It appears incredible that the
+modified descendants of two organisms, if these differed from each other
+in a marked manner, should ever afterwards converge so closely as to
+lead to a near approach to identity throughout their whole organisation.
+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 supposed by some naturalists, from
+two or more species, which differed from each other as much, or nearly
+as much, as does the orang from the gorilla, it can hardly be doubted
+that marked differences in the structure of certain bones would still be
+discoverable in man as he now exists.
+
+Although the existing races of man differ in many respects, as in
+colour, hair, shape of skull, proportions of the body, etc., yet if
+their whole structure be taken into consideration they are found to
+resemble each other closely in a multitude of points. Many of these
+are of so unimportant or of so singular a nature, that it is extremely
+improbable that they should have been independently acquired by
+aboriginally distinct species or races. The same remark holds good with
+equal or greater force with respect to the numerous points of mental
+similarity between the most distinct races of man. The American
+aborigines, Negroes and Europeans are as different from each other in
+mind as any three races that can be named; yet I was incessantly struck,
+whilst living with the Fuegians on board the "Beagle," with the many
+little traits of character, shewing how similar their minds were to
+ours; and so it was with a full-blooded negro with whom I happened once
+to be intimate.
+
+He who will read Mr. Tylor's and Sir J. Lubbock's interesting works
+(24. Tylor's 'Early History of Mankind,' 1865: with respect to
+gesture-language, see p. 54. Lubbock's 'Prehistoric Times,' 2nd edit.
+1869.) can hardly fail to be deeply impressed with the close similarity
+between the men of all races in tastes, dispositions and habits. This
+is shewn by the pleasure which they all take in dancing, rude music,
+acting, painting, tattooing, and otherwise decorating themselves; in
+their mutual comprehension of gesture-language, 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 (25.
+'On Analogous Forms of Implements,' in 'Memoirs of Anthropological
+Society' by H.M. Westropp. 'The Primitive Inhabitants of Scandinavia,'
+Eng. translat., edited by Sir J. Lubbock, 1868, p. 104.), 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 has been made
+by archaeologists (26. Westropp 'On Cromlechs,' etc., 'Journal of
+Ethnological Soc.' as given in 'Scientific Opinion,' June 2nd, 1869,
+p. 3.) 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 (27. 'Journal of Researches: Voyage of the
+"Beagle,"' p. 46.), that there, as in so many other parts of the world,
+men have generally chosen the summits of lofty hills, to throw up piles
+of stones, either as a record of some remarkable event, or for burying
+their dead.
+
+Now when naturalists observe a close agreement in numerous small details
+of habits, tastes, and dispositions between two or more domestic
+races, or between nearly-allied natural forms, they use this fact as an
+argument that they are descended from a common progenitor who was thus
+endowed; and consequently that all should be classed under the same
+species. The same argument may be applied with much force to the races
+of man.
+
+As it is improbable that the numerous and unimportant points of
+resemblance between the several races of man in bodily 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 practised 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 learnt they
+would never have been forgotten. (28. 'Prehistoric Times,' 1869, p.
+574.) He thus shews that "the spear, which is but a development of the
+knife-point, and the club, which is but a long hammer, are the only
+things left." He admits, however, that the art of making fire probably
+had been already discovered, for it is common to all the races now
+existing, and was known to the ancient cave-inhabitants of Europe.
+Perhaps the art of making rude canoes or rafts was likewise known; but
+as man existed at a remote epoch, when the land in many places stood
+at a very different level to what it does now, he would have been able,
+without the aid of canoes, to have spread widely. Sir J. Lubbock further
+remarks how improbable it is that our earliest ancestors could have
+"counted as high as ten, considering that so many races now in existence
+cannot get beyond four." Nevertheless, at this early period, the
+intellectual and social faculties of man could hardly have been inferior
+in any extreme degree to those possessed at present by the lowest
+savages; otherwise primeval man could not have been so eminently
+successful in the struggle for life, as proved by his early and wide
+diffusion.
+
+From the fundamental differences between certain languages, some
+philologists have inferred that when man first became widely diffused,
+he was not a speaking animal; but it may be suspected that languages,
+far less perfect than any now spoken, aided by gestures, might have
+been used, and yet have left no traces on subsequent and more
+highly-developed tongues. Without the use of some language, however
+imperfect, it appears doubtful whether man's intellect could have risen
+to the standard implied by his dominant position at an early period.
+
+Whether primeval man, when he possessed but few arts, and those of the
+rudest kind, and when his power of language was extremely imperfect,
+would have deserved to be called man, must depend on the definition
+which we employ. In a series of forms graduating insensibly from some
+ape-like creature to man as he now exists, it would be impossible to fix
+on any definite point where the term "man" ought to be used. But this is
+a matter of very little importance. So again, it is almost a matter of
+indifference whether the so-called races of man are thus designated, or
+are ranked as species or sub-species; but the latter term appears the
+more appropriate. Finally, we may conclude that when the principle of
+evolution is generally accepted, as it surely will be before long, the
+dispute between the monogenists and the polygenists will die a silent
+and unobserved death.
+
+One other question ought not to be passed over without notice, namely,
+whether, as is sometimes assumed, each sub-species or race of man has
+sprung from a single pair of progenitors. With our domestic animals
+a new race can readily be formed by carefully matching the varying
+offspring from a single pair, or even from a single individual
+possessing some new character; but most of our races have been formed,
+not intentionally from a selected pair, but unconsciously by the
+preservation of many 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, without any one pair having been
+separated and bred from, in either country. Many races have been thus
+formed, and their manner of formation is closely analogous to that of
+natural species. We know, also, that the horses taken to the Falkland
+Islands have, during successive generations, become smaller and weaker,
+whilst those which have run wild on the Pampas have acquired larger and
+coarser heads; and such changes are manifestly due, not to any one pair,
+but to all the individuals having been subjected to the same conditions,
+aided, perhaps, by the principle of reversion. The new sub-breeds
+in such cases are not descended from any single pair, but from many
+individuals which have varied in different degrees, but in the same
+general manner; and we may conclude that the races of man have been
+similarly produced, the modifications being either the direct result of
+exposure to different conditions, or the indirect result of some form of
+selection. But to this latter subject we shall presently return.
+
+ON THE 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 Shaaffhausen (29. Translation in 'Anthropological Review,' Oct. 1868,
+p. 431.), "lower in the scale than the rudest living savages"; they must
+therefore have differed, to a certain extent, from any existing race.
+The remains described by Professor Broca from Les Eyzies, though they
+unfortunately appear to have belonged to a single family, indicate a
+race with a most singular combination of low or simious, and of high
+characteristics. This race is "entirely different from any other,
+ancient or modern, that we have heard of." (30. 'Transactions,
+International Congress of Prehistoric Archaeology' 1868, pp. 172-175.
+See also Broca (tr.) in 'Anthropological Review,' Oct. 1868, p. 410.) It
+differed, therefore, from the quaternary race of the caverns of Belgium.
+
+Man can long resist conditions which appear extremely unfavourable for
+his existence. (31. Dr. Gerland, 'Ueber das Aussterben der Naturv�lker,'
+1868, s. 82.) 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 pestilential
+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, sickness, 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 powerful than the other, the contest is soon settled by war,
+slaughter, cannibalism, slavery, and absorption. Even when a weaker
+tribe is not thus abruptly swept away, if it once begins to decrease,
+it generally goes on decreasing until it becomes extinct. (32. Gerland
+(ibid. s. 12) gives facts in support of this statement.)
+
+When civilised nations come into contact with barbarians 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 civilised nations, some
+are plain and simple, others complex and obscure. We can see that the
+cultivation of the land will be fatal in many ways to savages, for they
+cannot, or will not, change their habits. New diseases and vices have in
+some cases proved highly destructive; and it appears that a new disease
+often causes much death, until those who are most susceptible to its
+destructive influence are gradually weeded out (33. See remarks to this
+effect in Sir H. Holland's 'Medical Notes and Reflections,' 1839, p.
+390.); and so it may be with the evil effects from spirituous liquors,
+as well as with the unconquerably strong taste for them shewn by so many
+savages. It further appears, mysterious as is the fact, that the first
+meeting of distinct and separated people generates disease. (34. I 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 civilisation as poisonous to savages.")
+Mr. Sproat, who in Vancouver Island closely attended to the subject
+of extinction, believed that changed habits of life, consequent on
+the advent of Europeans, induces much ill health. He lays, also,
+great stress on the apparently trifling cause that the natives become
+"bewildered and dull by the new life around them; they lose the motives
+for exertion, and get no new ones in their place." (35. Sproat, 'Scenes
+and Studies of Savage Life,' 1868, p. 284.)
+
+The grade of their civilisation seems to be a most important element in
+the success of competing nations. A few centuries ago Europe feared the
+inroads of Eastern barbarians; now any such fear 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 civilised nations; had they done so, the old moralists
+would have mused over the event; but there is no lament in any writer
+of that period over the perishing barbarians. (36. Bagehot, 'Physics and
+Politics,' 'Fortnightly Review,' April 1, 1868, p. 455.) The most potent
+of all the causes of extinction, appears in many cases to be lessened
+fertility and ill-health, especially amongst the children, arising from
+changed conditions of life, notwithstanding that the 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
+information respecting it. I have collected the following cases.
+
+When Tasmania was first colonised the natives were roughly estimated
+by some at 7000 and by others at 20,000. Their number was soon greatly
+reduced, chiefly by fighting with the English and with each other.
+After the famous hunt by all the colonists, when the remaining natives
+delivered themselves up to the government, they consisted only of 120
+individuals (37. All the statements here given are taken from 'The Last
+of the Tasmanians,' by J. Bonwick, 1870.), who were in 1832 transported
+to Flinders Island. This island, situated between Tasmania and
+Australia, is forty miles long, and from twelve to eighteen miles broad:
+it seems healthy, and the natives were well treated. Nevertheless, they
+suffered greatly in health. In 1834 they consisted (Bonwick, p. 250)
+of forty-seven adult males, forty-eight adult females, and sixteen
+children, or in all of 111 souls. In 1835 only one hundred were left. As
+they continued rapidly to decrease, and as they themselves thought that
+they should not perish so quickly elsewhere, they were removed in 1847
+to Oyster Cove in the southern part of Tasmania. They then consisted
+(Dec. 20th, 1847) of fourteen men, twenty-two women and ten children.
+(38. This is the statement of the Governor of Tasmania, Sir W. Denison,
+'Varieties of Vice-Regal Life,' 1870, vol. i. p. 67.) But the change of
+site did no good. Disease and death still pursued them, and in 1864
+one man (who died in 1869), and three elderly women alone survived.
+The infertility of the 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 civilise 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." 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 reproduction 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 months. (39. For these
+cases, see Bonwick's 'Daily Life of the Tasmanians,' 1870, p. 90: and
+the 'Last of the Tasmanians,' 1870, p. 386.)
+
+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. (40. 'Observations
+on the Aboriginal Inhabitants of New Zealand,' published by the
+Government, 1859.) 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 residents 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
+subsistence 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, shewing a decrease of 32.29 per cent! (41. 'New
+Zealand,' by Alex. Kennedy, 1873, p. 47.) Mr. Fenton, after shewing
+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 unproductiveness of the women,
+and on the extraordinary mortality of the young children (pp. 31, 34).
+In proof of this he shews (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 introduction 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 shews (p. 40)
+that about 1830, the art of manufacturing putrid corn (maize), by long
+steeping in water, was discovered and largely practised; and this proves
+that a change of habits was beginning amongst the natives, even when New
+Zealand was only thinly inhabited by Europeans. When I visited the Bay
+of 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 (42.
+'Life of J.C. Patteson,' by C.M. Younge, 1874; see more especially vol.
+i. p. 530.), that the Melanesians of the New Hebrides and neighbouring
+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 population amounted to about 300,000. According to a loose census in
+1823, the numbers then were 142,050. In 1832, and at several subsequent
+periods, an accurate census was officially taken, but I have been able
+to obtain only the following returns:                Native Population          Annual rate of decrease
+                                           per cent., assuming it to
+              (Except during 1832 and      have been uniform between
+              1836, when the few           the successive censuses;
+              foreigners in the islands    these censuses being taken
+  Year        were included.)              at irregular intervals.
+
+  1832              130,313
+                                                   4.46
+  1836              108,579
+                                                   2.47
+  1853               71,019
+                                                   0.81
+  1860               67,084
+                                                   2.18
+  1866               58,765
+                                                   2.17
+  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 labour imposed on conquered tribes
+and to newly introduced diseases, which have been on several 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. Ruschenberger of the
+U.S. Navy, who visited these islands between 1835 and 1837, in one
+district of Hawaii, only twenty-five men out of 1134, and in another
+district only ten out of 637, had a family with as many as three
+children. Of eighty married women, only thirty-nine had ever borne
+children; and "the official report gives an average of half a child to
+each married couple in the whole island." This is almost exactly
+the same average as with the Tasmanians at Oyster Cove. Jarves, who
+published his History in 1843, says that "families who have three
+children are freed from all taxes; those having more, are rewarded by
+gifts of land and other encouragements." This unparalleled enactment by
+the government well shews how infertile the race had become. The Rev.
+A. Bishop stated in the Hawaiian 'Spectator' in 1839, that a large
+proportion of the children die at early ages, and Bishop Staley informs
+me that this is still the case, just as in New Zealand. This has been
+attributed to the neglect of the children by the women, but it is
+probably in large part due to innate weakness of constitution in the
+children, in relation to the lessened fertility of their parents. There
+is, moreover, a further resemblance to the case of New Zealand, in the
+fact that there is a large excess of male over female births: the census
+of 1872 gives 31,650 males to 25,247 females of all ages, that is 125.36
+males for every 100 females; whereas in all civilised countries the
+females exceed the males. No doubt the profligacy of the women may in
+part account for their small fertility; but their changed habits of life
+is a much more probable cause, and which will at the same time account
+for the increased mortality, especially of the children. The islands
+were visited by Cook in 1779, Vancouver in 1794, and often subsequently
+by whalers. In 1819 missionaries arrived, and found that idolatry had
+been already abolished, and other changes effected by the king. After
+this period there was a rapid change in almost all the habits of life
+of the natives, and they soon became "the most civilised of the Pacific
+Islanders." One of my informants, Mr. Coan, who was born on the islands,
+remarks that the natives have undergone a greater change in their habits
+of life in the course of fifty years than Englishmen during a thousand
+years. From information received from 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.
+(43. 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. 277. Ruschenberger
+is quoted by Bonwick, 'Last of the Tasmanians,' 1870, p. 378. Bishop
+is quoted by Sir E. Belcher, 'Voyage Round the World,' 1843, vol. i. p.
+272. I owe the census of the several years to the kindness of Mr. Coan,
+at the request of Dr. Youmans of New York; and in most 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 numbers given.)
+
+Lastly, Mr. Macnamara states (44. 'The Indian Medical Gazette,' Nov.
+1, 1871, p. 240.) that the low and degraded 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, suffer from dysentery and
+fever when on the plains; and they die if they attempt to pass the whole
+year there.
+
+We thus see that many of the wilder races of man are apt to suffer much
+in health when subjected to changed conditions or habits of life,
+and not exclusively from being transported to a new climate. Mere
+alterations in habits, which do not appear injurious in themselves,
+seem to have this same effect; and in several cases the children are
+particularly liable to suffer. It has often been said, as Mr. Macnamara
+remarks, that man can resist with impunity the greatest diversities of
+climate and other changes; but this is true only of the civilised
+races. Man in his wild condition seems to be in this respect almost as
+susceptible as his nearest allies, the anthropoid apes, which have never
+yet survived long, when removed from their native country.
+
+Lessened fertility from changed conditions, as in the case of the
+Tasmanians, Maories, Sandwich Islanders, and apparently the Australians,
+is still more interesting than their liability to ill-health and death;
+for even a slight degree of infertility, combined with those other
+causes which tend to check the increase of every population, would
+sooner or later lead to extinction. The diminution of fertility may be
+explained in some cases by the profligacy of the women (as until lately
+with the Tahitians), but Mr. Fenton has shewn that this explanation
+by no means suffices with the New Zealanders, nor does it with the
+Tasmanians.
+
+In the paper above quoted, Mr. Macnamara gives reasons for believing
+that the inhabitants of districts subject to malaria are apt to be
+sterile; but this cannot apply in several of the above cases. Some
+writers have suggested that the aborigines of 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 sensitive to the evil effects of
+inter-breeding, especially in areas so large as New Zealand, and the
+Sandwich archipelago with its diversified stations. On the contrary, it
+is known that the present inhabitants of Norfolk Island are nearly
+all cousins or near relations, as are the Todas in India, and the
+inhabitants of some of the Western Islands of Scotland; and yet they
+seem not to have suffered in fertility. (45. On the close relationship
+of the Norfolk Islanders, 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.)
+
+A much more probable view is suggested by the analogy of the lower
+animals. The reproductive system can be shewn 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. xviii. of vol. ii. of my 'Variation of Animals and Plants under
+Domestication.' I can here give only the briefest abstract; and every
+one interested in the subject may consult the above work. Very slight
+changes increase the health, vigour, and fertility of most or all
+organic beings, whilst other changes are known to render a large number
+of animals sterile. One of the most familiar cases, is that of tamed
+elephants not breeding in India; though they often breed in Ava, where
+the females are allowed to roam about the forests to some extent, and
+are thus placed under more natural conditions. The case of various
+American monkeys, both sexes of which have been kept for many 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 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. (46. For the evidence on this head, see
+'Variation of Animals,' etc., vol. ii. p. 111.) Certain groups of
+animals are much more liable than others to be affected by captivity;
+and generally all the species of the same group are affected in the same
+manner. But sometimes a single species in a group is rendered sterile,
+whilst the others are not so; on the other hand, a single species may
+retain its fertility whilst most of the others fail to breed. The males
+and females of some species when confined, or when allowed to live
+almost, but not quite free, in their native country, never unite; others
+thus circumstanced frequently unite but never produce offspring; others
+again 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 age.
+
+Seeing how general is this law of the susceptibility of the reproductive
+system to changed conditions of life, and that it holds good with our
+nearest allies, the Quadrumana, I can hardly doubt that it applies to
+man in his primeval state. Hence if savages of any race are induced
+suddenly to change their habits of life, they become more or less
+sterile, and their young 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 conditions.
+
+We can see why it is that aborigines, who have long inhabited islands,
+and who must have been long exposed to nearly uniform conditions, should
+be specially affected by any change in their habits, as seems to be
+the case. Civilised 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 instances have been recorded. (47. 'Variation of Animals,'
+etc., vol. ii. p. 16.) The immunity of civilised 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 civilised 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 sixteen of
+them returned to Pitcairn Island in 1859, they numbered in January 1868,
+300 souls; the males and females being in exactly equal numbers. What a
+contrast does this case present with that of the Tasmanians; the Norfolk
+Islanders INCREASED in only twelve and a half years from 194 to 300;
+whereas the Tasmanians DECREASED during fifteen years from 120 to 46, of
+which latter number only ten were children. (48. 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.)
+
+So again in the interval between the census of 1866 and 1872 the natives
+of full blood in the Sandwich Islands decreased by 8081, whilst the
+half-castes, who are believed to be healthier, 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 generation.
+
+The cases which I have here given all relate to aborigines, who have
+been subjected to new conditions as the result of the immigration of
+civilised men. But sterility and ill-health would probably follow, if
+savages were compelled by any cause, such as the inroad of a conquering
+tribe, to desert their homes and to change their habits. It is an
+interesting circumstance that the chief check to wild animals becoming
+domesticated, which implies the power of their breeding freely when
+first captured, and one chief check to wild men, when brought into
+contact with civilisation, surviving to form a civilised 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 afterwards 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 European rat. Though the
+difficulty is great to our imagination, 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 extinction; the end, in most cases, being promptly
+determined by the inroads of conquering tribes.
+
+ON THE FORMATION OF THE RACES OF MAN.
+
+In some cases the crossing of distinct races has led to the formation of
+a new race. The singular fact that the Europeans and Hindoos, who belong
+to the same Aryan stock, and speak a language fundamentally the same,
+differ widely in appearance, whilst Europeans differ but little from
+Jews, who belong to the Semitic stock, and speak quite another language,
+has been accounted for by Broca (49. 'On Anthropology,' translation,
+'Anthropological Review,' Jan. 1868, p. 38.), through certain Aryan
+branches having been largely crossed by indigenous tribes during their
+wide diffusion. When two races in close contact cross, the first result
+is a heterogeneous mixture: thus Mr. Hunter, in describing the Santali
+or hill-tribes of India, says that hundreds of imperceptible gradations
+may be traced "from the black, squat tribes of the mountains to the tall
+olive-coloured Brahman, with his intellectual brow, calm eyes, and high
+but narrow head"; so that it is necessary in courts of justice to ask
+the witnesses whether they are Santalis or Hindoos. (50. 'The Annals of
+Rural Bengal,' 1868, p. 134.) 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 evidence. But as with
+our domesticated animals, a cross-breed can certainly be fixed and made
+uniform by careful selection (51. 'The Variation of Animals and
+Plants under Domestication,' vol. ii. p. 95.) 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 colour 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 shewed that this is not
+tenable, and he has since been followed by almost all anthropologists.
+(52. Pallas, 'Act. Acad. St. Petersburg,' 1780, part ii. p. 69. He was
+followed by Rudolphi, in his 'Beytrage zur Anthropologie,' 1812. An
+excellent summary of the evidence is given by Godron, 'De l'Esp�ce,'
+1859, vol. ii. p. 246, etc.) This view has been rejected chiefly because
+the distribution of the variously coloured races, most of whom must have
+long inhabited their present homes, does not coincide with corresponding
+differences of climate. Some little weight may be given to such cases as
+that of the Dutch families, who, as we hear on excellent authority (53.
+Sir Andrew Smith, as quoted by Knox, 'Races of Man,' 1850, p. 473.),
+have not undergone the least change of colour after residing for three
+centuries in South Africa. An argument on the same side may likewise
+be drawn from the uniform appearance in various parts of the world of
+gipsies and Jews, though the uniformity of the latter has been somewhat
+exaggerated. (54. See De Quatrefages on this head, 'Revue des Cours
+Scientifiques,' Oct. 17, 1868, p. 731.) A very damp or a very dry
+atmosphere has been supposed to be more influential in modifying the
+colour of the skin than mere heat; but as D'Orbigny in South America,
+and Livingstone in Africa, arrived at diametrically opposite conclusions
+with respect to dampness and dryness, any conclusion on this head
+must be considered as very doubtful. (55. Livingstone's 'Travels and
+Researches in S. Africa,' 1857, pp. 338, 339. D'Orbigny, as quoted by
+Godron, 'De l'Espece,' vol. ii. p. 266.)
+
+Various facts, which I have given elsewhere, prove that the colour 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 afterwards found that this same idea had long ago occurred to
+Dr. Wells. (56. See a paper read before the Royal Soc. in 1813, and
+published in his Essays in 1818. I have given an account of Dr. Wells'
+views in the Historical Sketch (p. xvi.) to my 'Origin of Species.'
+Various cases of colour correlated with constitutional peculiarities are
+given in my 'Variation of Animals and Plants under Domestication,'
+vol. ii. pp. 227, 335.) It has long been known that negroes, and even
+mulattoes, are almost completely exempt from the yellow-fever, so
+destructive in tropical America. (57. See, for instance, Nott and
+Gliddon, 'Types of Mankind,' p. 68.) They likewise escape to a large
+extent the fatal intermittent fevers, that prevail along at least 2600
+miles of the shores of Africa, and which annually cause one-fifth of the
+white settlers to die, and another fifth to return home invalided. (58.
+Major Tulloch, in a paper read before the Statistical Society, April 20,
+1840, and given in the 'Athenaeum,' 1840, p. 353.) This immunity in the
+negro seems to be partly inherent, depending on some unknown peculiarity
+of constitution, and partly the result of acclimatisation. Pouchet (59.
+'The Plurality of the Human Race' (translat.), 1864, p. 60.) states that
+the negro regiments recruited near the Soudan, and borrowed from the
+Viceroy of Egypt for the Mexican war, escaped the yellow-fever almost
+equally with the negroes originally brought from various parts of Africa
+and accustomed to the climate of the West Indies. That acclimatisation
+plays a part, is shewn by the many cases in which negroes have become
+somewhat liable to tropical fevers, after having resided for some time
+in a colder climate. (60. Quatrefages, 'Unit� de l'Esp�ce Humaine,'
+1861, p. 205. Waitz, 'Introduction to Anthropology,' translat., vol. i.
+1863, p. 124. Livingstone gives analogous cases in his 'Travels.') 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 acclimatisation, implies exposure during a prodigious
+length of time; for the aborigines of tropical America who have resided
+there from time immemorial, are not exempt from yellow fever; and the
+Rev. H.B. Tristram states, that there are districts in Northern Africa
+which the native inhabitants are compelled annually to leave, though the
+negroes can remain with safety.
+
+That the immunity of the negro is in any degree correlated with the
+colour of his skin is a mere conjecture: it may be correlated with some
+difference in his blood, nervous system, or other tissues. Nevertheless,
+from the facts above alluded to, and from some connection apparently
+existing between complexion and a tendency to consumption, the
+conjecture seemed to me not improbable. Consequently I endeavoured, with
+but little success (61. In the spring of 1862 I obtained permission from
+the Director-General of the Medical department of the Army, to transmit
+to the surgeons of the various regiments on foreign service a blank
+table, with the following appended remarks, but I have received no
+returns. "As several well-marked cases have been recorded with our
+domestic animals of a relation between the colour of the dermal
+appendages and the constitution; and it being notorious that there is
+some limited degree of relation between the colour of the races of man
+and the climate inhabited by them; the following investigation seems
+worth consideration. Namely, whether there is any relation in Europeans
+between the colour of their hair, and their liability to the diseases
+of tropical countries. If the surgeons of the several regiments, when
+stationed in unhealthy tropical districts, would be so good as first to
+count, as a standard of comparison, how many men, in the force whence
+the sick are drawn, have dark and light-coloured hair, and hair of
+intermediate or doubtful tints; and if a similar account were kept by
+the same medical gentlemen, of all the men who suffered from malarious
+and yellow fevers, or from dysentery, it would soon be apparent,
+after some thousand cases had been tabulated, whether there exists any
+relation between the colour of the hair and constitutional 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 climate, might have become dark-coloured by
+the better preservation of dark-haired or dark-complexioned individuals
+during a long succession of generations."), to ascertain how far it
+holds good. The late Dr. Daniell, who had long lived on the West Coast
+of Africa, told me that he did not believe in any such relation. He was
+himself unusually fair, and had withstood the climate in a wonderful
+manner. When he first arrived as a boy on the coast, an old and
+experienced negro chief predicted from his appearance that this would
+prove the case. Dr. Nicholson, of Antigua, after having attended to this
+subject, writes to me that dark-coloured Europeans escape the yellow
+fever more than those that are light-coloured. Mr. J.M. Harris
+altogether denies that Europeans with dark hair withstand a hot climate
+better than other men: on the contrary, experience has taught him in
+making a selection of men for service on the coast of Africa, to choose
+those with red hair. (62. 'Anthropological Review,' Jan. 1866, p. xxi.
+Dr. Sharpe also says, with respect to India ('Man a Special Creation,'
+1873, p. 118), "that it has been noticed by some medical officers
+that Europeans with light hair and florid complexions suffer less from
+diseases of tropical countries than persons with dark hair and sallow
+complexions; and, so far as I know, there appear to be good grounds for
+this remark." On the other hand, Mr. Heddle, of Sierra Leone, "who has
+had more clerks killed under him than any other man," by the climate
+of the West African Coast (W. Reade, 'African Sketch Book,' vol. ii.
+p. 522), holds a directly opposite view, as does Capt. Burton.) 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 (63. 'Man a Special Creation,' 1873, p. 119.), that
+a tropical sun, which burns and blisters a white skin, does not injure
+a black one at all; and, as he adds, this is not due to habit in the
+individual, for children only six or eight months old are often carried
+about naked, and are not affected. I have been assured by a medical man,
+that 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,
+whilst the white parts of his skin have on several occasions been
+much inflamed and blistered. With the lower animals there is, also, a
+constitutional difference in liability to the action of the sun between
+those parts of the skin clothed with white hair and other parts. (64.
+'Variation of Animals and Plants under Domestication,' vol. ii. pp.
+336, 337.) Whether the saving of the skin from being thus burnt is of
+sufficient importance to account for a dark tint having been gradually
+acquired by man through natural selection, I am unable to judge. If it
+be so, we should have to assume that the natives of tropical America
+have lived there for a much shorter time than the Negroes in Africa, or
+the Papuans in the southern parts of the Malay archipelago, just as the
+lighter-coloured 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 colour 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. (65. See, for instance, Quatrefages
+('Revue des Cours Scientifiques,' Oct. 10, 1868, p. 724) on the effects
+of residence in Abyssinia and Arabia, and other analogous cases. Dr.
+Rolle ('Der Mensch, seine 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 colour, according to the position of the valleys
+inhabited by them.)
+
+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
+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
+shewing that in the Southern States the house-slaves of the
+third generation present a markedly different appearance from the
+field-slaves. (66. Harlan, 'Medical Researches,' p. 532. Quatrefages
+('Unit� de l'Esp�ce Humaine,' 1861, p. 128) has collected much evidence
+on this head.)
+
+If, however, we look to the races of man as distributed over the world,
+we must infer that their characteristic differences cannot be accounted
+for by the direct action of different conditions of life, even after
+exposure to them for an enormous period of time. The Esquimaux live
+exclusively on animal food; they are clothed in thick fur, and are
+exposed to intense cold and to prolonged darkness; yet they do not
+differ in any extreme degree from the inhabitants of Southern China, who
+live entirely on vegetable food, and are exposed almost naked to a hot,
+glaring climate. The unclothed Fuegians live on the marine productions
+of their inhospitable shores; the Botocudos of Brazil wander about the
+hot forests of the interior and live chiefly on vegetable productions;
+yet these tribes resemble each other so closely that the Fuegians on
+board the "Beagle" were mistaken by some Brazilians for Botocudos. The
+Botocudos again, as well as the other inhabitants of tropical America,
+are wholly different from the Negroes who inhabit the opposite shores of
+the Atlantic, are exposed to a nearly similar climate, and follow nearly
+the same habits of life.
+
+Nor can the differences between the races of man be accounted for 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 civilised nations, the reduced size of the jaws from lessened
+use--the habitual play of different muscles serving to express different
+emotions--and the increased size of the brain from greater intellectual
+activity, have together produced a considerable effect on their general
+appearance when compared with savages. (67. See Prof. Schaaffhausen,
+translat., in 'Anthropological Review,' Oct. 1868, p. 429.) Increased
+bodily stature, without any corresponding increase in the size of the
+brain, may (judging from the previously adduced case of rabbits), have
+given to some races an elongated skull of the dolichocephalic type.
+
+Lastly, the little-understood principle of correlated development has
+sometimes come into action, as in the case of great muscular development
+and strongly projecting supra-orbital ridges. The colour of the skin
+and hair are plainly correlated, as is the texture of the hair with
+its colour in the Mandans of North America. (68. Mr. Catlin states ('N.
+American Indians,' 3rd ed., 1842, vol. i. p. 49) that in the whole tribe
+of the Mandans, about one in ten or twelve of the members, of all ages
+and both sexes, have bright silvery grey hair, which is hereditary. Now
+this hair is as coarse and harsh as that of a horse's mane, whilst the
+hair of other colours is fine and soft.) The colour also of the skin,
+and the odour 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 excretory pores are related. (69. On the odour of the skin,
+Godron, 'Sur l'Esp�ce,' tom. ii. p. 217. On the pores in the skin, Dr.
+Wilckens, 'Die Aufgaben der Landwirth. Zootechnik,' 1869, s. 7.) 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 differences 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
+therefore led to enquire whether slight individual differences, to
+which man is eminently liable, may not have been preserved and augmented
+during a long series of generations through natural selection. But here
+we are at once met by the objection that beneficial variations alone
+can be thus preserved; and as far as we are enabled to judge, although
+always liable to err on this head, none of the differences between
+the races of man are of any direct or special service to him. The
+intellectual and moral or social faculties must of course be excepted
+from this remark. The great variability of all the external differences
+between the races of man, likewise indicates that they cannot be of much
+importance; for if important, they would long ago have been either fixed
+and preserved, or 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 Selection, which appears to have acted powerfully
+on man, as on many other animals. I do not intend to assert that sexual
+selection will account for all the differences between the races.
+An unexplained residuum is left, about which we can only say, in our
+ignorance, that as 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 intercrossing. Such variations come
+under the provisional class, alluded to in our second chapter, which
+for 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 shewn that it would be an inexplicable fact if
+man had not been modified by this agency, which appears to have acted
+powerfully on innumerable animals. It can further be shewn that the
+differences between the races of man, as in colour, 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 the Second Part of
+this work. At the close I shall return to man, and, after attempting to
+shew how far he has been modified through sexual selection, will give a
+brief summary of the chapters in this First Part.
+
+
+NOTE ON THE RESEMBLANCES AND DIFFERENCES IN THE STRUCTURE AND THE
+DEVELOPMENT OF THE BRAIN IN MAN AND APES BY PROFESSOR HUXLEY, F.R.S.
+
+The controversy respecting the nature and the extent of the differences
+in the structure of the brain in man and the apes, which arose some
+fifteen years ago, has not yet come to an end, though the subject
+matter of the dispute is, at present, totally different from what it
+was formerly. It was originally asserted and re-asserted, with singular
+pertinacity, that the brain of all the apes, even the highest, differs
+from that of man, in the absence of such conspicuous structures as the
+posterior lobes of the cerebral hemispheres, with the posterior cornu
+of the lateral ventricle and the hippocampus minor, contained in those
+lobes, which are so obvious in man.
+
+But the truth that the three structures in question are as well
+developed in apes' as in human brains, or even better; and that it is
+characteristic of all the Primates (if we exclude the Lemurs) to have
+these parts well developed, stands at present on as secure a basis as
+any proposition in comparative anatomy. Moreover, it is admitted by
+every one of the long series of anatomists who, of late years, have paid
+special attention to the arrangement of the complicated sulci and gyri
+which appear upon the surface of the cerebral hemispheres in man and the
+higher apes, that they are disposed after the very same pattern in him,
+as in them. Every principal gyrus and sulcus of a chimpanzee's brain
+is clearly 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, Professor Bischoff published a
+memoir (70. 'Die Grosshirn-Windungen des Menschen;' 'Abhandlungen der K.
+Bayerischen Akademie,' B. x. 1868.) on the cerebral convolutions of man
+and apes; and as the purpose of my learned colleague was certainly not
+to diminish the value of the differences between apes and men in this
+respect, I am glad to make a citation from him.
+
+"That the apes, and especially the orang, chimpanzee and gorilla, come
+very close to man in their organisation, much nearer than to any other
+animal, is a well known fact, disputed by nobody. Looking at the matter
+from the point of view of organisation alone, no one probably would ever
+have disputed the view of Linnaeus, that man should be placed, merely as
+a peculiar species, at the head of the mammalia and of those apes. Both
+shew, 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" (loc. cit. p. 101).
+
+There remains, then, no dispute as to the resemblance in fundamental
+characters, between the ape's brain and man's: nor any as to the
+wonderfully close similarity between the chimpanzee, orang and man,
+in even the details of the arrangement of the gyri and sulci of the
+cerebral hemispheres. Nor, turning to the differences between the brains
+of the highest apes and that of man, is there any serious question as
+to the nature and extent of these differences. It is admitted that the
+man's cerebral hemispheres are absolutely and relatively larger than
+those of the orang and chimpanzee; that his frontal lobes are less
+excavated by the upward protrusion of the roof of the orbits; that his
+gyri and sulci are, as a rule, less symmetrically disposed, and present
+a greater number of secondary plications. And it is admitted that, as a
+rule, in man, the temporo-occipital or "external perpendicular" fissure,
+which is usually so strongly marked a feature of the ape's brain is but
+faintly marked. But it is also clear, that none of these differences
+constitutes a sharp demarcation between the man's and the ape's brain.
+In respect to the external perpendicular fissure of Gratiolet, in the
+human brain for instance, Professor Turner remarks: (71. 'Convolutions
+of the Human Cerebrum Topographically Considered,' 1866, p. 12.)
+
+"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 outwards. I saw it in the right hemisphere of a female
+brain pass more than two inches outwards; and on another specimen, also
+the right hemisphere, it proceeded for four-tenths of an inch outwards,
+and then extended downwards, as far as the lower margin of the outer
+surface of the hemisphere. The imperfect definition 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 bridging gyri lies to
+the longitudinal fissure, the shorter is the external parieto-occipital
+fissure" (loc. cit. 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 extensive
+obliteration of the external perpendicular sulcus by "bridging
+convolutions," on one side or the other, has been noted over and over
+again by Prof. Rolleston, Mr. Marshall, M. Broca and Professor Turner.
+At the conclusion of a special paper on this subject the latter writes:
+(72. Notes more especially on the bridging convolutions in the Brain
+of the Chimpanzee, 'Proceedings of the Royal Society of Edinburgh,'
+1865-6.)
+
+"The three specimens of the brain of a chimpanzee, just described,
+prove, that the generalisation 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 animal which
+have, up to this time, been figured or described. The superficial
+position of the second bridging convolution is evidently less frequent,
+and has as yet, I believe, only been seen in the brain (A) recorded in
+this communication. The asymmetrical arrangement in the convolutions of
+the two hemispheres, which previous observers have referred to in their
+descriptions, is also well illustrated in these specimens" (pp. 8, 9).
+
+Even were the presence of the temporo-occipital, or external
+perpendicular, sulcus, a mark of distinction between the higher apes and
+man, the value of such a distinctive character would be rendered very
+doubtful by the structure of the brain in the Platyrrhine apes. In fact,
+while the temporo-occipital is one of the most constant 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 (73. Flower, 'On the Anatomy of Pithecia Monachus,'
+'Proceedings of the Zoological Society,' 1862.); 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
+convolution of the two sides in the human brain is subject to much
+individual variation; and that, in those individuals of the Bushman race
+who have been examined, the gyri and sulci of the two hemispheres are
+considerably less complicated and more symmetrical than in the European
+brain, while, in some individuals of the chimpanzee, their complexity
+and asymmetry become notable. This is particularly the case in the brain
+of a young male chimpanzee figured by M. Broca. ('L'ordre des Primates,'
+p. 165, fig. 11.)
+
+Again, as respects the question of absolute size, it is 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
+chimpanzee's brains resemble man's, but in which they differ from the
+lower apes, and that is the presence of two corpora candicantia--the
+Cynomorpha having but one.
+
+In view of these facts I do not hesitate in this year 1874, to repeat
+and insist upon the proposition which I enunciated in 1863: (74. 'Man's
+Place in Nature,' p. 102.)
+
+"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, Professor Bischoff does not deny
+the second part of this statement, but he first makes the irrelevant
+remark that it is not wonderful if the brains of an orang and a 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, Semnopithecus, Cynocephalus, Cercopithecus,
+Macacus, Cebus, Callithrix, Lemur, Stenops, Hapale, we shall not meet
+with a greater, or even as great a, break in the degree of development
+of the convolutions, as we find between the brain of a man and that of
+an orang or chimpanzee."
+
+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
+Professor 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 Professor Bischoff most unaccountably does,
+we write the series of animals he has chosen to mention as follows:
+Homo, Pithecus, Troglodytes, Hylobates, 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. Professor Bischoff ignores
+the fact that long before he wrote, Gratiolet had suggested the
+separation of the Lemurs from the other Primates on the very ground of
+the difference in their cerebral characters; and that Professor Flower
+had made the following observations in the course of his description
+of the brain of the Javan Loris: (75. 'Transactions of the Zoological
+Society,' vol. v. 1862.)
+
+"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 said, that,
+admitting the similarity between the adult brains of man and apes, they
+are nevertheless, in reality, widely different, because they exhibit
+fundamental differences in the mode of their development. No one would
+be more ready than I to admit the force of this argument, if such
+fundamental 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 apes.
+
+Gratiolet originated the statement that there is a fundamental
+difference 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
+hemispheres, while, in the human foetus, the sulci first become visible
+on the frontal lobes. (76. Chez tous les singes, les plis post�rieurs se
+developpent les premiers; les plis ant�rieurs se developpent plus tard,
+aussi la vert�bre occipitale et la parietale sont-elles relativement
+tres-grandes chez le foetus. L'Homme pr�sente une exception remarquable
+quant a l'�poque de l'apparition des plis frontaux, qui sont les
+premiers indiqu�s; mais le d�veloppement general du lobe frontal,
+envisag� seulement par rapport a son volume, suit les m�mes lois que
+dans les singes: Gratiolet, 'M�moire sur les plis c�r�bres de l'Homme et
+des Primateaux,' p. 39, Tab. iv, fig. 3.)
+
+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"
+(77. Gratiolet's words are (loc. cit. p. 39): "Dans le foetus dont il
+s'agit les plis c�r�braux posterieurs sont bien developp�s, tandis que
+les plis du lobe frontal sont a peine indiqu�s." The figure, however
+(Pl. iv, fig. 3), shews the fissure of Rolando, and one of the frontal
+sulci plainly enough. Nevertheless, M. Alix, in his 'Notice sur
+les travaux anthropologiques de Gratiolet' ('Mem. de la Societ�
+d'Anthropologie de Paris,' 1868, page 32), writes thus: "Gratiolet a
+eu entre les mains le cerveau d'un foetus de Gibbon, singe eminemment
+sup�rieur, et tellement rapproch� de l'orang, que des naturalistes
+tres-comp�tents l'ont rang� 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�J� DEVELOPP�ES LORSQU'IL N'EXISTENT PAS ENCORE DE
+PLIS SUR LE LOBE FRONTAL. Il etait donc bien autoris� a dire que, chez
+l'homme les circonvolutions apparaissent d'a en w, tandis que chez les
+singes elles se developpent d'w en a."), and the other of a human foetus
+at the 22nd or 23rd week of uterogestation, in which Gratiolet notes
+that the insula was uncovered, but that nevertheless "des incisures
+sement de lobe anterieur, une scissure peu profonde indique la
+separation du lobe occipital, tres-reduit, d'ailleurs d�s cette �poque.
+Le reste de la surface c�r�brale est encore absolument lisse."
+
+Three views of this brain are given in Plate II, figs. 1, 2, 3, of
+the work cited, shewing 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
+hemisphere is more marked than any of those vaguely indicated in
+the anterior half. If the figure is correct, it in no way justifies
+Gratiolet's conclusion: "Il y a donc entre ces cerveaux [those of a
+Callithrix and of a Gibbon] et celui du foetus humain une diff�rence
+fondamental. Chez celui-ci, longtemps avant que les plis temporaux
+apparaissent, les plis frontaux, ESSAYENT d'exister."
+
+Since Gratiolet's time, however, the development of the gyri and sulci
+of the brain has been made the subject of renewed investigation by
+Schmidt, Bischoff, Pansch (78. 'Ueber die typische Anordnung der Furchen
+und Windungen auf den Grosshirn-Hemisph�ren des Menschen und der Affen,'
+'Archiv f�r Anthropologie,' iii. 1868.), and more particularly by
+Ecker (79. 'Zur Entwicklungs Geschichte der Furchen und Windungen
+der Grosshirn-Hemisph�ren im Foetus des Menschen,' 'Archiv f�r
+Anthropologie,' iii. 1868.), 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 backwards far beyond the
+cerebellum.
+
+2. The sulci, properly so called, begin to appear in the interval
+between the end of the fourth and the beginning of the sixth month of
+foetal life, but Ecker is careful to point out that, not only the time,
+but the order, of their appearance is subject to 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
+hemisphere (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 (loc. cit. pp. 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 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 tadpole has all
+the characters of a fish, and if it went no further, would have to be
+grouped among fishes. But it is equally true that a tadpole is very
+different from any known fish.
+
+In like manner, the brain of a human foetus, at the fifth month, may
+correctly be said to be, not only the brain of an ape, but that of an
+Arctopithecine or marmoset-like ape; for its hemispheres, with their
+great posterior lobster, and with no sulci but the sylvian and the
+calcarine, present the characteristics found only in the group of the
+Arctopithecine Primates. But it is equally true, as Gratiolet remarks,
+that, in its widely open sylvian fissure, it differs from the brain of
+any actual marmoset. No doubt it would be much more similar to the brain
+of an advanced foetus of a marmoset. But we know nothing whatever of the
+development of the brain in the marmosets. In the 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 parallele 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 favour 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 Catarrhini. We have no
+information whatever respecting the development of the brain in the
+Cynomorpha; and, as regards the Anthropomorpha, nothing but the account
+of the brain of the Gibbon, near birth, already referred to. At the
+present moment there is not a shadow of evidence to shew 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: "Il est dangereux dans
+les sciences de conclure trop vite." I fear he must have forgotten 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 contributions 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 favour of obscurantism. (80. For
+example, M. l'Abbe Lecomte in his terrible pamphlet, 'Le Darwinisme et
+l'origine de l'Homme,' 1873.)
+
+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 modification of the
+same form as that from which the other Primates have sprung.
+
+
+
+PART II. SEXUAL SELECTION.
+
+
+CHAPTER VIII.
+
+PRINCIPLES OF SEXUAL SELECTION.
+
+Secondary sexual characters--Sexual selection--Manner of action--Excess
+of males--Polygamy--The male alone generally modified through sexual
+selection--Eagerness of the male--Variability of the
+male--Choice exerted by the female--Sexual compared with natural
+selection--Inheritance, at corresponding periods of life, at
+corresponding seasons of the year, and as limited by sex--Relations
+between the several forms of inheritance--Causes why one sex and the
+young are not modified through sexual selection--Supplement on the
+proportional numbers of the two sexes throughout the animal kingdom--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 appendages at the apex of the abdomen in male
+insects. Unless indeed we confine the term "primary" to the reproductive
+glands, it is scarcely possible to decide 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 the receptacles for the ova in certain male fishes, and those
+temporarily developed in certain male frogs. The females of most bees
+are provided with a special apparatus for collecting and carrying
+pollen, and their ovipositor is modified into a sting for the defence
+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
+offence or means of defence against rivals, his gaudy colouring and
+various ornaments, his power of song, and other such characters.
+
+Besides the primary and secondary sexual differences, such as the
+foregoing, the males and females of some animals differ in structures
+related to different habits of life, and not at all, or only indirectly,
+to the reproductive functions. Thus the females of certain flies
+(Culicidae and Tabanidae) are blood-suckers, whilst the males, living
+on flowers, have mouths destitute of mandibles. (1. Westwood, 'Modern
+Classification of Insects,' vol. ii. 1840, p. 541. For the statement
+about Tanais, mentioned below, I am indebted to Fritz Muller.) The males
+of certain moths and of some crustaceans (e.g. Tanais) have imperfect,
+closed mouths, and cannot feed. The complemental males of certain
+Cirripedes live like epiphytic plants either on the female or the
+hermaphrodite form, and are destitute of a mouth and of prehensile
+limbs. In these cases it is the male which has been modified, and has
+lost certain important organs, which the females possess. In other cases
+it is the female which has lost such parts; for instance, the female
+glow-worm is destitute of wings, as also are many female moths, some of
+which never leave their cocoons. Many female parasitic crustaceans have
+lost their natatory legs. In some weevil-beetles (Curculionidae) there
+is a great difference between the male and female in the length of the
+rostrum or snout (2. Kirby and Spence, 'Introduction to Entomology,'
+vol. iii. 1826, p. 309.); 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 (3. 'Birds
+of New Zealand,' 1872, p. 66.) that the male uses his strong beak in
+chiselling the larvae of insects out of decayed wood, whilst 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
+useless.
+
+We are, however, here concerned only with sexual selection. This depends
+on the advantage which certain individuals have over others of the same
+sex and species solely in respect of 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, ceteris paribus, the greatest number to inherit their
+superiority; whilst those which generated or nourished their offspring
+badly, would leave but few to inherit their weaker powers. As the male
+has to find the female, he requires organs of sense and locomotion,
+but if these organs are necessary for the other purposes of life, as
+is generally the case, they will have been developed through natural
+selection. When the male has found the female, he sometimes absolutely
+requires prehensile organs to hold her; thus Dr. Wallace informs me that
+the males of certain moths cannot unite with the females if their tarsi
+or feet are broken. The males of many oceanic crustaceans, when adult,
+have their legs and 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
+development has been the result of ordinary or natural selection. Some
+animals extremely low in the scale have been modified for this same
+purpose; thus the males of certain parasitic worms, when fully grown,
+have the lower surface of the terminal part of their bodies roughened
+like a rasp, and with this they coil round and permanently hold the
+females. (4. M. Perrier advances this case ('Revue Scientifique,' Feb.
+1, 1873, p. 865) as one fatal to the belief in sexual election, inasmuch
+as he supposes that I attribute all the differences between the sexes to
+sexual selection. This distinguished naturalist, therefore, like so many
+other Frenchmen, has not taken the trouble to understand even the first
+principles of sexual selection. An English naturalist insists that the
+claspers of certain male animals could not have been developed 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 maintain that the choice of the female had anything
+to do with the development of the prehensile organs in the male.)
+
+When the two sexes follow exactly the same habits of life, and the male
+has the sensory 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 would succeed in pairing
+with the females; and judging from the structure of the female, they
+would be in all other respects equally well adapted for their ordinary
+habits of life. Since in such cases the males have acquired their
+present structure, not from being better fitted to survive in the
+struggle for existence, but from having gained an advantage over
+other males, and from having transmitted this advantage to their male
+offspring alone, sexual selection must here have come into action. It
+was the importance of this distinction which led me to 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 offence and
+the means of defence 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 odours, 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
+chapters, as being in many respects interesting, but especially as
+depending on the will, choice, and rivalry of the individuals of either
+sex. When we behold two males fighting for the possession of the female,
+or several male birds displaying their gorgeous plumage, and performing
+strange antics before an assembled body of females, we cannot doubt
+that, though led by instinct, they know what they are about, and
+consciously exert their mental and bodily powers.
+
+Just as man can improve the breeds of his game-cocks by the selection of
+those birds which are victorious in the cockpit, so it appears that
+the strongest and most vigorous males, or those provided with the best
+weapons, have prevailed under nature, and have led to the improvement of
+the natural breed or species. A slight degree of variability leading
+to some advantage, however slight, in reiterated deadly contests
+would suffice for the work of sexual selection; and it is certain that
+secondary sexual characters are eminently variable. Just as man can give
+beauty, according to his standard of taste, to his male poultry, or
+more strictly can modify the beauty originally acquired by the parent
+species, can give to the Sebright bantam a new and elegant plumage, an
+erect and peculiar carriage--so it appears that 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. No doubt this implies
+powers of discrimination and taste on the part of the female which will
+at first appear extremely improbable; but by the facts to be adduced
+hereafter, I hope to be able to shew 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 object.
+
+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 sexual
+selection has played an important part in the history of the organic
+world. It is certain that amongst almost all animals there is a struggle
+between the males for the possession of the female. This fact is so
+notorious that it would be superfluous to give instances. Hence the
+females have the opportunity of selecting one out of several males, on
+the supposition 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 statement.
+
+Mr. Swaysland of Brighton has been in the habit, during the last forty
+years, of catching our migratory birds on their first arrival, and he
+has never known the females of any species to arrive before their males.
+During one spring he shot thirty-nine males of Ray's wagtail (Budytes
+Raii) before he saw a single female. Mr. Gould has ascertained by the
+dissection of those snipes which arrive the first in this country, that
+the males come before the females. And the like holds good with most
+of the migratory birds of the United States. (5. J.A. Allen, on the
+'Mammals and Winter Birds of Florida,' Bulletin of Comparative Zoology,
+Harvard College, p. 268.) 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. (6. Even with those plants in which the sexes are separate, the
+male flowers are generally mature before the female. As first shewn 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-fertilised. 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.) The cause of this difference between
+the males and females in their periods of arrival and maturity is
+sufficiently obvious. Those males which annually first migrated into any
+country, or which in the spring were first ready to breed, or were the
+most eager, would leave the largest number of offspring; and these would
+tend to inherit similar instincts and constitutions. It must be borne
+in mind that it would have been impossible to change very materially
+the time of sexual maturity in the females, without at the same time
+interfering with the period of the production of the young--a period
+which must be determined by the seasons of the year. On the whole there
+can be no doubt that with almost all animals, in which the sexes are
+separate, there is a constantly recurrent struggle between the males for
+the possession of the females.
+
+Our difficulty in regard to sexual selection lies in understanding how
+it is that the males which conquer other males, or those which prove the
+most attractive to the females, leave a greater number of offspring to
+inherit their superiority than 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 perfected 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 characters are well developed, the males
+considerably exceeded the females in number; but this is not by any
+means always true. If the males were to the females as two to one, or as
+three to two, or even in a somewhat lower ratio, the whole affair would
+be simple; for the better-armed or more attractive males would leave
+the largest number of offspring. But after investigating, as far as
+possible, the numerical proportion of the sexes, I do not believe that
+any great inequality in number commonly exists. In most cases sexual
+selection appears to have been effective in the following manner.
+
+Let us take any species, a bird for instance, and divide the females
+inhabiting a district into two equal bodies, the one consisting of the
+more vigorous and better-nourished individuals, and the other of the
+less vigorous and healthy. The former, there can be little doubt, would
+be ready to breed in the spring before the others; and this is the
+opinion of Mr. Jenner Weir, who has 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. (7. Here is
+excellent evidence on the character of the offspring from an experienced
+ornithologist. Mr. J.A. Allen, in speaking ('Mammals 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-coloured than those hatched earlier in the season. In cases where
+several broods are reared each year, as a general rule the birds of the
+earlier broods seem in all respects the most perfect and vigorous.") The
+males, as we have seen, are generally ready to breed before the females;
+the strongest, and with some species the best armed of the males, drive
+away the weaker; and the former would then unite with the more vigorous
+and better-nourished females, because they are the first to breed. (8.
+Hermann M�ller 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 der Darwin'schen Lehre auf Bienen,'
+'Verh. d. V. Jahrg.' xxix. p. 45.) 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 weapons.
+
+But in very many cases the males which conquer their rivals, do not
+obtain possession of the females, independently of the choice of the
+latter. The courtship of animals is by no means so simple and short an
+affair as might be thought. The females are most excited by, or prefer
+pairing with, the more ornamented males, or those which are the best
+songsters, or play the best antics; but it is obviously probable that
+they would at the same time prefer the more vigorous and lively males,
+and this has in some cases been confirmed by actual observation. (9.
+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.) 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
+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 selecting particular
+females, it is plain that those which were the most vigorous and had
+conquered others, would have the freest choice; and it is almost certain
+that they would select vigorous as well as attractive females. Such
+pairs would have an advantage in rearing offspring, more especially if
+the male had the power to defend the female during the pairing-season
+as occurs with some of the higher animals, or aided 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 vigorous
+individuals.
+
+NUMERICAL PROPORTION OF THE TWO SEXES.
+
+I have remarked that sexual selection would be a simple affair if the
+males were considerably more numerous than the females. Hence I was led
+to investigate, as far as I could, the proportions between the two sexes
+of as many animals as possible; but the materials are scanty. I will
+here give only a brief abstract of the results, retaining the details
+for a supplementary 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 6878 births during twelve years, the male births were to the female
+as 110.1 to 100. It is, however, in some degree doubtful whether it
+is safe to infer that the 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 Russia as 108.9, and with
+the Jews of Livonia as 120, to 100 female births. But I shall recur to
+this curious point of the excess of male births in the supplement
+to this chapter. At the Cape of Good Hope, however, male children
+of European extraction have been born during several years in the
+proportion of between 90 and 99 to 100 female children.
+
+For our present purpose we are concerned with the proportions 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 two
+years of infancy, is considerably larger than that of females. So
+it almost certainly is with male lambs, and probably with some other
+animals. The males of some species kill one another by fighting; or they
+drive one another about until they become greatly emaciated. They must
+also be often exposed to various dangers, whilst wandering about in
+eager search for the females. In many kinds of fish the males are much
+smaller than the females, and they are believed often to be devoured by
+the latter, or by other fishes. The females of some birds appear to die
+earlier than the males; they are also liable to be destroyed on their
+nests, or whilst in charge of their young. With insects the female
+larvae are often larger than those of the males, and would consequently
+be more likely to be devoured. In some cases the mature females are less
+active and less rapid in their movements 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 proportions of
+the sexes at maturity; and this is but little trustworthy, 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 females.
+
+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
+throughout 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 shewn in the supplement, the
+proportions seem to fluctuate either during different seasons or in
+different localities in a sufficient degree to lead to such selection.
+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 evidence of this habit. The
+intellectual powers of such animals are, perhaps, not sufficient to lead
+them to collect and guard a harem of females. That some relation exists
+between 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 favourable to the action
+of sexual selection. Nevertheless many animals, which are strictly
+monogamous, especially birds, display strongly-marked secondary sexual
+characters; whilst some few animals, which are polygamous, do not have
+such characters.
+
+We will first briefly run through the mammals, and then turn to birds.
+The gorilla seems to be polygamous, and the male 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 caraya presents well-marked sexual differences, in colour,
+beard, and vocal organs; and the male generally lives with two or three
+wives: the male of the Cebus capucinus differs somewhat from the female,
+and appears to be polygamous. (10. On the Gorilla, Savage and Wyman,
+'Boston Journal of Natural History,' vol. v. 1845-47, p. 423. On
+Cynocephalus, Brehm, 'Thierleben,' B. i. 1864, s. 77. On Mycetes,
+Rengger, 'Naturgeschichte der S�ugethiere von Paraguay,' 1830, ss. 14,
+20. On Cebus, Brehm, ibid. s. 108.) Little is known on this head with
+respect to most other monkeys, but some species are strictly monogamous.
+The ruminants are eminently polygamous, and they 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 South Africa, says that in herds of about a dozen there was
+rarely more than one mature male. The Asiatic Antilope saiga appears to
+be the most inordinate polygamist in the world; for Pallas (11.
+Pallas, 'Spicilegia Zoolog., Fasc.' xii. 1777, p. 29. Sir Andrew Smith,
+'Illustrations of the Zoology of S. Africa,' 1849, pl. 29, on the Kobus.
+Owen, in his 'Anatomy of Vertebrates' (vol. iii. 1868, p. 633) gives a
+table shewing incidentally which species of antelopes are gregarious.)
+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
+N. America is polygamous, but, except in his greater size and in the
+proportions of his body, differs but little from the mare. The wild
+boar presents well-marked sexual characters, in his great tusks and some
+other points. In Europe and in India he leads a solitary life, except
+during the breeding-season; but as is believed by Sir W. Elliot, who has
+had many opportunities in India of observing this animal, he consorts at
+this season with several females. Whether this holds good in Europe is
+doubtful, but 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 one-fifth more than the females. (12. Dr. Campbell, in 'Proc. Zoolog.
+Soc.' 1869, p. 138. See also an interesting paper by Lieut. Johnstone,
+in 'Proceedings, Asiatic Society of Bengal,' May 1868.) 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 Rodents
+being polygamous, excepting that amongst the Rodents, the common rat,
+according to some rat-catchers, lives with several females. Nevertheless
+the two sexes of some sloths (Edentata) differ in the character and
+colour of certain patches of hair on their shoulders. (13. Dr. Gray, in
+'Annals and Magazine of Natural History,' 1871, p. 302.) 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 colour. (14. See Dr. Dobson's excellent paper in
+'Proceedings of the Zoological Society,' 1873, p. 241.) In the great
+order of Rodents, as far as I can learn, the sexes rarely differ, and
+when they do so, it is but slightly in the tint of the fur.
+
+As I hear from Sir Andrew Smith, the lion in South Africa sometimes
+lives with a single female, but generally with more, and, in one case,
+was found with as many as five females; so that he is polygamous. As far
+as I can discover, he is the only polygamist amongst all the terrestrial
+Carnivora, and he alone presents well-marked sexual characters. If,
+however, we turn to the marine Carnivora, as we shall hereafter see, the
+case is widely different; for many species of seals offer extraordinary
+sexual differences, and they are eminently polygamous. Thus, 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 (15. 'The Eared Seals,' American
+Naturalist, vol. iv. Jan. 1871.), that in the monogamous species, "or
+those living in small communities, there is little difference in size
+between the males and females; in the social species, or rather those
+of which the males have harems, the males are vastly larger than the
+females."
+
+Amongst birds, many species, the sexes of which differ greatly from each
+other, are certainly monogamous. In Great Britain we see well-marked
+sexual differences, for instance, in the wild-duck which pairs with a
+single female, the common blackbird, and the bullfinch which is said to
+pair for life. I am informed by Mr. Wallace that the like is true of the
+Chatterers or 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 humming-birds are polygamous. The male
+widow-bird, remarkable for his caudal plumes, certainly seems to be
+a polygamist. (16. 'The Ibis,' vol. iii. 1861, p. 133, on the Progne
+Widow-bird. See also on the Vidua axillaris, ibid. vol. ii. 1860, p.
+211. On the polygamy of the Capercailzie and Great Bustard, see L.
+Lloyd, 'Game Birds of Sweden,' 1867, pp. 19, and 182. Montagu and
+Selby speak of the Black Grouse as polygamous and of the Red Grouse as
+monogamous.) 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 Gallinaceae 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 presented between the sexes of the polygamous peacock or
+pheasant, and the monogamous guinea-fowl or partridge! Many similar
+cases could be given, as in the grouse tribe, in which the males of the
+polygamous capercailzie and black-cock differ greatly from the females;
+whilst the sexes of the monogamous red grouse and ptarmigan differ very
+little. In the Cursores, except amongst the bustards, few species offer
+strongly-marked sexual differences, and the great bustard (Otis tarda)
+is said to be polygamous. With the Grallatores, extremely few species
+differ sexually, but the ruff (Machetes pugnax) affords a marked
+exception, and this species is believed by Montagu to be a polygamist.
+Hence it appears that amongst birds there often exists a close
+relation between polygamy and the development of strongly-marked sexual
+differences. I asked Mr. Bartlett, of the Zoological Gardens, who has
+had very large experience with birds, whether the male tragopan (one of
+the Gallinaceae) was polygamous, and I was struck by his answering, "I
+do not know, but should think so from his splendid colours."
+
+It deserves notice that the instinct of pairing with a single female is
+easily lost under domestication. The wild-duck is strictly monogamous,
+the domestic-duck highly polygamous. The Rev. W.D. Fox informs me that
+out of some half-tamed wild-ducks, on a large pond in his neighbourhood,
+so many mallards were shot by the gamekeeper that only one was left for
+every seven or eight females; yet unusually large broods were reared.
+The guinea-fowl is strictly monogamous; but Mr. Fox finds that his birds
+succeed best when he keeps one cock to 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 temporarily 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 polygamist (17. Noel Humphreys, 'River
+Gardens,' 1857.); and the male during the breeding-season differs
+conspicuously from the female.
+
+To sum up on the means through which, as far as we can judge, sexual
+selection has led to the development of secondary sexual characters.
+It has been shewn that the largest number of vigorous offspring will
+be reared from the pairing of the strongest and best-armed males,
+victorious in contests over other males, with the most vigorous and
+best-nourished females, which are the first to breed in the spring. If
+such females select the more attractive, and at the same time vigorous
+males, they will rear a larger number of offspring than the retarded
+females, which must pair with the less vigorous and less attractive
+males. So it will be if the more vigorous males select the more
+attractive and at the same time healthy and vigorous females; and this
+will especially hold good if the male defends the female, and aids in
+providing food for the young. The advantage thus gained by the more
+vigorous pairs in rearing a larger number of offspring has apparently
+sufficed to render sexual selection efficient. But a large numerical
+preponderance of males over females will be still more efficient;
+whether the preponderance is only occasional and local, or permanent;
+whether it occurs at birth, or afterwards from the greater destruction
+of the females; or whether it indirectly 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
+fight together and sedulously display their charms before the females;
+and the victors transmit their superiority to their male offspring. Why
+both sexes do not thus acquire the characters of their fathers, will be
+considered hereafter. That the males of all mammals eagerly pursue the
+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." (18. Kirby and Spence, 'Introduction
+to Entomology,' vol. iii. 1826, p. 342.) Two good authorities, Mr.
+Blackwall and Mr. C. Spence Bate, tell me that the males of spiders and
+crustaceans 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 can discover, almost invariably the male
+which retains such organs, or has them most developed; and this shews
+that the male is the more active member in the courtship of the sexes.
+(19. One parasitic Hymenopterous insect (Westwood, 'Modern Class. of
+Insects,' vol. ii. p. 160) forms an exception to the rule, as the male
+has rudimentary wings, and never quits the cell in which it is born,
+whilst the female has well-developed wings. Audouin believes that the
+females of this species are impregnated by the males which are born in
+the same cells with them; but it is much more probable that the females
+visit other cells, so that close inter-breeding 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.)
+
+The female, on the other hand, with the rarest exceptions, is less eager
+than the male. As the illustrious Hunter (20. 'Essays and Observations,'
+edited by Owen, vol. i. 1861, p. 194.) long ago observed, she generally
+"requires to be courted;" she is coy, and may often be seen endeavouring
+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
+shewn by various facts, given hereafter, and by the results fairly
+attributable to sexual selection, that the female, though comparatively
+passive, generally exerts some choice and accepts one male in preference
+to others. Or she may accept, as appearances would sometimes lead us to
+believe, not the male which is the most attractive to her, but the one
+which is the least distasteful. The exertion of some choice on the part
+of the female seems a law almost as general as the eagerness of the
+male.
+
+We are naturally led to enquire 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 fertilisation 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-organised aquatic animals, permanently affixed
+to the same spot and having their sexes separate, the male element is
+invariably brought to the female; and of this we can see the reason, for
+even if the ova were detached before fertilisation, and did not require
+subsequent nourishment or protection, there would yet be greater
+difficulty in transporting them than the male element, because, being
+larger than the latter, they are produced in far smaller numbers. So
+that many of the lower animals are, in this respect, analogous with
+plants. (21. Prof. Sachs ('Lehrbuch der Botanik,' 1870, S. 633) in
+speaking of the male and female reproductive cells, remarks, "verh�lt
+sich die eine bei der Vereinigung activ,...die andere erscheint bei der
+Vereinigung passiv.") The males of affixed and aquatic animals having
+been led to emit their fertilising element in this way, it is natural
+that any of their descendants, which rose in the scale and became
+locomotive, should retain the same habit; and they would approach the
+female as closely as possible, in order not to risk the loss of the
+fertilising element in a long passage of it through the water. With some
+few of the lower animals, the females alone are fixed, and the males
+of these must be the seekers. But it is difficult to 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 Nathusius, who
+has had very wide experience, is strongly of the same opinion. (22.
+'Vortr�ge uber Viehzucht,' 1872, p. 63.) Good evidence also in favour
+of this conclusion can be produced by a comparison of the two sexes
+in mankind. During the Novara Expedition (23. '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 Domestication,' vol. ii. 1868, p.
+75.) a vast 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 (24. 'Proceedings
+of the Royal Society,' vol. xvi. July 1868, pp. 519 and 524.), 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
+greater frequency of deficiency in females before described." Professor
+Macalister likewise remarks (25. 'Proc. Royal Irish Academy,' vol. x.
+1868, p. 123.) that variations in the muscles "are probably more common
+in males than females." Certain muscles which are not normally present
+in mankind are also more frequently developed in the male than in the
+female sex, although exceptions to this rule are said to occur. Dr. Burt
+Wilder (26. 'Massachusetts Medical Society,' vol. ii. No. 3, 1868,
+p. 9.) has tabulated the cases of 152 individuals with supernumerary
+digits, of which 86 were males, and 39, or less than half, females, the
+remaining 27 being of unknown sex. It should not, however, be overlooked
+that women would more frequently endeavour to conceal a deformity of
+this kind than men. Again, Dr. L. Meyer asserts that the ears of man
+are more variable in form than those of a woman. (27. 'Archiv fur Path.
+Anat. und Phys.' 1871, p. 488.) Lastly the temperature is more variable
+in man than in woman. (28. The conclusions recently arrived at by Dr. J.
+Stockton Hough, on the temperature of man, are given in the 'Pop. Sci.
+Review,' Jan. 1st, 1874, p. 97.)
+
+The cause of the greater general variability in the male sex, than in
+the female is unknown, except in so far as secondary sexual characters
+are extraordinarily variable, and are usually confined to the males;
+and, as we shall presently see, this fact is, to a certain extent,
+intelligible. Through the action of sexual and natural selection male
+animals have been rendered in very many instances widely different
+from their females; but independently of selection the two sexes, from
+differing constitutionally, tend to vary in 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 exerting his
+voice, pouring out odoriferous secretions, etc.: and this expenditure
+is generally concentrated within a short period. The great vigour of
+the male during the season of love seems often to intensify his colours,
+independently of any marked difference from the female. (29. Prof.
+Mantegazza is inclined to believe ('Lettera a Carlo Darwin,' 'Archivio
+per l'Anthropologia,' 1871, p. 306) that the bright colours, 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 coloured in the
+autumn of their first year.) In mankind, and even as low down in the
+organic scale as in the Lepidoptera, the temperature of the body is
+higher in the male than in the female, accompanied in the case of man
+by a slower pulse. (30. For mankind, see Dr. J. Stockton Hough, whose
+conclusions are given in the 'Popular Science Review,' 1874, p. 97. See
+Girard's observations on the Lepidoptera, as given in the 'Zoological
+Record,' 1869, p. 347.) 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 become 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, differences of character. For instance, Mr.
+Allen shews that with a large number of birds inhabiting the
+northern and southern United States, the specimens from the south are
+darker-coloured 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 two sexes of the same species
+appear to have been differently affected; in the Agelaeus phoeniceus the
+males have had their colours greatly intensified in the south; whereas
+with Cardinalis virginianus it is the females which have been thus
+affected; with Quiscalus major the females have been rendered extremely
+variable in tint, whilst the males remain nearly uniform. (31. 'Mammals
+and Birds of E. Florida,' pp. 234, 280, 295.)
+
+A few exceptional cases occur in various classes of animals, in which
+the females instead of the males have acquired well pronounced secondary
+sexual characters, such as brighter colours, greater size, strength, or
+pugnacity. With birds there has sometimes been a complete transposition
+of the ordinary characters proper to each sex; the females having become
+the more eager in courtship, the males remaining comparatively passive,
+but apparently selecting the more attractive females, as we may infer
+from the results. Certain hen birds have thus been rendered more
+highly coloured 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 attractive males. This process,
+however, though it might lead to the modification of both sexes, would
+not make the one sex different from the other, unless indeed their
+tastes for the beautiful differed; but this is a supposition too
+improbable to be worth considering in the case of any animal, excepting
+man. There are, however, many animals in which the sexes resemble each
+other, both being furnished with the same ornaments, which analogy would
+lead us to attribute to the agency of sexual selection. In such cases it
+may be suggested with more plausibility, that there has been a double
+or mutual process of sexual selection; the more vigorous and precocious
+females 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 transmitted to the offspring of both sexes. If, indeed,
+during a lengthened period the males of any species were greatly to
+exceed the females in number, and then during another lengthened period,
+but under different conditions, the reverse were to occur, a double, but
+not simultaneous, process of sexual selection might easily be carried
+on, by which the two sexes might be rendered widely different.
+
+We shall hereafter see that many animals exist, of which neither sex
+is brilliantly coloured or provided with special ornaments, and yet
+the members of both sexes or of one alone have probably acquired simple
+colours, 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 colours, appears to
+have been sometimes checked from the danger thus incurred. But in other
+cases the males during long ages may have struggled together for the
+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 shewn, 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 individuals. 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 polygamous, 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. This 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 wonderful extreme; and in some
+cases to an extreme which, as far as the general conditions of life are
+concerned, must be slightly injurious to the male. From this fact we
+learn that the advantages which favoured males derive from conquering
+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 conditions of life. We 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 animals
+of many classes, and in the course of ages has produced a conspicuous
+result, it is necessary to bear in mind the laws of inheritance, as far
+as they are known. Two distinct elements are included under the term
+"inheritance"--the transmission, and the development of characters; but
+as these generally go together, the distinction is often overlooked. We
+see this 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 offspring of either sex. The same fact is likewise
+manifest, when characters proper to the male are occasionally developed
+in the female when she grows old or becomes diseased, as, for instance,
+when the common hen assumes the flowing tail-feathers, hackles, comb,
+spurs, voice, and even pugnacity of the cock. Conversely, the same
+thing is evident, more or less plainly, with castrated males. Again,
+independently of old age or disease, characters are occasionally
+transferred from the male to the female, as when, in certain breeds of
+the fowl, spurs regularly appear in the young and healthy females. But
+in truth they are simply developed in the female; for in every breed
+each detail in the structure of the spur is transmitted through the
+female to her male offspring. 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 transference 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 gathering
+pollen for the larvae, yet in most of the species it is partially
+developed in the males to whom it is quite useless, and it is perfectly
+developed in the males of Bombus or the humble-bee. (32. H. Muller,
+'Anwendung der Darwin'schen Lehre,' etc., Verh. d. n. V. Jahrg., xxix.
+p. 42.) 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 reversion, characters are
+transmitted through two, three, or many more generations, and are then
+developed under certain unknown favourable conditions. This important
+distinction between transmission and development will be best kept
+in mind by the aid of the hypothesis of pangenesis. According to this
+hypothesis, every unit or cell of the body throws off gemmules or
+undeveloped atoms, which are transmitted to the offspring of both sexes,
+and are multiplied by self-division. They may remain undeveloped during
+the early years of life or during successive generations; and their
+development into units or cells, like those from which they were
+derived, depends on their affinity for, and union with other units or
+cells previously developed in the due order of growth.
+
+INHERITANCE AT CORRESPONDING PERIODS OF LIFE.
+
+This tendency is well established. A new character, appearing in a young
+animal, 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 offspring at the same
+advanced age. When deviations from this rule occur, the transmitted
+characters much oftener appear before, than after the corresponding age.
+As I have dwelt on this subject sufficiently in another work (33. The
+'Variation of Animals and Plants under Domestication,' vol. ii. 1868,
+p. 75. In the last chapter but one, the provisional hypothesis of
+pangenesis, above alluded to, is fully explained.), 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 bankiva; and these characters are faithfully
+transmitted by each breed to their offspring at the corresponding
+periods of life. For instance, the chickens of spangled Hamburgs, whilst
+covered with down, have a few dark spots on the head and rump, but are
+not striped longitudinally, as in many other breeds; in their first
+true plumage, "they are beautifully pencilled," that is each feather is
+transversely marked by numerous dark bars; but in their second plumage
+the feathers all become spangled or tipped with a dark round spot. (34.
+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.) 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 aboriginal
+parent species does not undergo any change of plumage with advancing
+age, excepting that at maturity the breast becomes more iridescent; yet
+there are breeds which do not acquire their characteristic colours until
+they have moulted two, three, or four times; and these modifications of
+plumage are regularly transmitted.
+
+INHERITANCE AT CORRESPONDING SEASONS OF THE YEAR.
+
+With animals in a state of nature, innumerable instances occur of
+characters appearing periodically at different seasons. We see this in
+the horns of the stag, and in the fur of Arctic animals which becomes
+thick and white during the winter. Many birds acquire bright colours and
+other decorations during the breeding-season alone. Pallas states
+(35. 'Novae species Quadrupedum e Glirium ordine,' 1778, p. 7. On the
+transmission of colour by the horse, see 'Variation of Animals and
+Plants under Domestication,' vol. i. p. 51. Also vol. ii. p. 71, for a
+general discussion on 'Inheritance as limited by Sex.'), that in Siberia
+domestic cattle and horses become lighter-coloured during the winter;
+and I have myself observed, and heard of similar strongly marked changes
+of colour, that is, from brownish cream-colour or reddish-brown to a
+perfect white, in several ponies in England. Although I do not know that
+this tendency to change the colour of the coat during different seasons
+is transmitted, yet it probably is so, as all shades of colour are
+strongly inherited by the horse. Nor is this form of inheritance, as
+limited by the seasons, more remarkable than its limitation by age or
+sex.
+
+INHERITANCE AS LIMITED BY SEX.
+
+The equal transmission of characters to both sexes is the commonest
+form of inheritance, at least with those animals which do not present
+strongly-marked sexual differences, and indeed with many of these. But
+characters are somewhat commonly transferred exclusively to that sex, in
+which they first appear. Ample evidence on this head has been advanced
+in my work on 'Variation under Domestication,' but a few instances may
+here be given. There are breeds of the sheep and goat, in which the
+horns of the male differ greatly in shape from those of the female;
+and these differences, acquired under domestication, are regularly
+transmitted to the same sex. As a rule, it is the females alone in cats
+which are tortoise-shell, the corresponding colour 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 variations in certain breeds are
+transmitted equally to both sexes. There are also certain sub-breeds
+of the fowl in which the males can hardly be distinguished from one
+another, whilst the females differ considerably in colour. The sexes
+of the pigeon in the parent-species do not differ in any external
+character; nevertheless, in certain domesticated breeds the male is
+coloured differently from the female. (36. Dr. Chapuis, 'Le Pigeon
+Voyageur Belge,' 1865, p. 87. Boitard et Corbie, 'Les Pigeons de
+Voli�re,' etc., 1824, p. 173. See, also, on similar differences in
+certain breeds at Modena, 'Le variazioni dei Colombi domestici,' del
+Paolo Bonizzi, 1873.) 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 differences between the
+sexes are wholly due to the form of inheritance which has prevailed; for
+they have arisen, not from, but rather in opposition to, the wish of the
+breeder.
+
+
+Most of our domestic races have been formed by the 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
+dissimilarity 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 say, one sex may lose characters proper to it, and
+may thus come somewhat to resemble the opposite sex; for instance, the
+males of some breeds of the fowl have lost their masculine tail-plumes
+and hackles. On the other hand, the differences between the sexes may be
+increased under domestication, as with merino sheep, in which the ewes
+have lost their horns. Again, characters proper to one sex may suddenly
+appear in the other sex; as in those sub-breeds of the fowl in which the
+hens acquire spurs whilst young; or, as in certain Polish sub-breeds, in
+which the females, as there is reason to believe, originally acquired a
+crest, and subsequently 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
+which the characters are usually transferred in an equal degree to both
+sexes) varied into pale blue, could he by long-continued selection make
+a breed, in which the males alone should be of this tint, whilst the
+females remained unchanged? I will here only say, that this, though
+perhaps not impossible, would be extremely difficult; for the natural
+result of breeding from the pale-blue males would be to change the whole
+stock of both sexes to this tint. If, however, variations of the 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 colour, as indeed has been effected
+with a Belgian breed, in which the males alone are streaked with black.
+In a similar manner, if any variation appeared in a female pigeon, which
+was from the first sexually limited in its development to the
+females, it would be easy to make a breed with the females alone thus
+characterised; but if the variation was not thus originally limited, the
+process would be extremely difficult, perhaps impossible. (37. Since
+the publication of the first edition of this work, it has been highly
+satisfactory to me to find the following remarks (the 'Field,' Sept.
+1872) from so experienced a breeder as Mr. Tegetmeier. After describing
+some curious cases in pigeons, of the transmission of colour 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 colours of birds by a course of
+artificial selection. When he did so, he was in ignorance of these facts
+that I have related; but it is remarkable how very closely he suggested
+the right method of procedure.")
+
+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 certain sub-breeds of the pigeon, black striae,
+though transmitted through the female, should be developed in the male
+alone, whilst every other character is equally transferred to both
+sexes. Why, again, with cats, the tortoise-shell colour should, with
+rare exceptions, be developed in the female alone. The very same
+character, such as deficient or supernumerary digits, colour-blindness,
+etc., may with mankind be inherited by the males alone of one family,
+and in another family by the females alone, though in both cases
+transmitted through the opposite as well as through the same sex.
+(38. References are given in my 'Variation of Animals and Plants under
+Domestication,' vol. ii. p. 72.) Although we are thus ignorant, the two
+following rules seem often to hold good--that variations which first
+appear in either sex at a late period of life, tend to be developed in
+the same sex alone; whilst variations which first appear early in life
+in either sex tend to be developed in both sexes. I am, however, far
+from supposing that this is the sole determining cause. As I have not
+elsewhere discussed this subject, and it has an important bearing on
+sexual selection, I must here enter into lengthy and somewhat intricate
+details.
+
+It is in itself probable that any character appearing at an early age
+would tend to be inherited equally by both sexes, for the sexes do not
+differ much in 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 somewhat late period of life; otherwise the
+young males would have been similarly characterised; 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 adult female; and in most of these
+cases the variations through which the young and old acquired their
+present characters, probably occurred, according to our rule, 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 whilst
+young. There are, moreover, many animals, in which the two sexes closely
+resemble each other, and yet both differ from their young: and here
+the characters of the adults must have been acquired late in life;
+nevertheless, these characters, in apparent contradiction to our
+rule, are transferred to both sexes. We must not however, overlook the
+possibility or even probability of successive variations of the same
+nature occurring, under exposure to similar conditions, simultaneously
+in both sexes at a rather late period of life; and in this case the
+variations would be transferred to the offspring of both sexes at a
+corresponding late age; and there would then be no real contradiction
+to the rule that variations occurring late in life are transferred
+exclusively to the sex in which they first appeared. This latter rule
+seems to hold true more generally than the second one, namely,
+that variations which occur in either sex early in life tend to be
+transferred to both sexes. As it was 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. (39. I am much obliged to Mr. Cupples for
+having made enquiries for me in regard to the Roebuck and Red Deer
+of Scotland from Mr. Robertson, the experienced head-forester to the
+Marquis of Breadalbane. In regard to Fallow-deer, I have to thank Mr.
+Eyton and others for information. For the Cervus alces of N. America,
+see 'Land and Water,' 1868, pp. 221 and 254; and for the C. Virginianus
+and strongyloceros of the same continent, see J.D. Caton, in 'Ottawa
+Acad. of Nat. Sc.' 1868, p. 13. For Cervus Eldi of Pegu, see Lieut.
+Beaven, 'Proccedings of the Zoological Society,' 1867, p. 762.) But with
+the reindeer the case is widely different; for, as I hear from Prof.
+Nilsson, who kindly made special enquiries for me in Lapland, the horns
+appear in the young animals within four or five weeks after birth,
+and at the same time in both sexes. So that here we have a structure,
+developed at a most unusually early age in one species of the family,
+and likewise common to both sexes in this one species alone.
+
+In several kinds of antelopes, only the males are provided with horns,
+whilst in the greater number both sexes bear horns. With respect to the
+period of development, Mr. Blyth informs me that there was at one time
+in the Zoological Gardens a young koodoo (Ant. strepsiceros), of which
+the males alone are horned, and also the young of a closely-allied
+species, the eland (Ant. oreas), in which both sexes are horned. Now it
+is in strict conformity with our rule, that in the young male koodoo,
+although ten months old, the horns were remarkably small, considering
+the size ultimately attained by them; whilst in the young male eland,
+although only three months old, the horns were already very much
+larger than in the koodoo. It is also a noticeable fact that in the
+prong-horned antelope (40. Antilocapra Americana. I have to thank Dr.
+Canfield for information with respect to the horns of the female: see
+also his paper in 'Proceedings of the Zoological Society,' 1866, p. 109.
+Also Owen, 'Anatomy of Vertebrates,' vol. iii. p. 627), only a few
+of the females, about one in five, have horns, and these are in a
+rudimentary state, though sometimes above four inches long: so that as
+far as concerns the possession of horns by the males alone, this species
+is in an intermediate condition, and the horns do not appear until about
+five or six months after birth. Therefore in comparison with what little
+we know of the 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 afterwards. (41. 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.) 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 enquiry (42. I am greatly indebted to Prof. Victor Carus
+for having made enquiries for me, from the highest authorities, with
+respect to the merino sheep of Saxony. On the Guinea coast of Africa
+there is, however, a breed of sheep in which, as with merinos, the rams
+alone bear horns; and Mr. Winwood Reade informs me that in one case
+observed by him, a young ram, born on Feb. 10th, first shewed horns
+on March 6th, so that in this instance, in conformity with rule, the
+development of the horns occurred at a later period of life than in
+Welsh sheep, in which both sexes are horned.), that the horns are
+developed later in life in this breed than in ordinary sheep in which
+both sexes are horned. But with domesticated sheep the presence
+or absence of horns is not a firmly fixed character; for a certain
+proportion of the merino ewes bear small horns, and some of the rams are
+hornless; and in most breeds hornless ewes are occasionally produced.
+
+Dr. W. Marshall has lately made a special study of the protuberances so
+common on the heads of birds (43. '�ber die knochernen Sch�delh�cker der
+V�gel,' in the 'Niederland. Archiv fur Zoologie,' B.i. Heft 2, 1872.),
+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 life. The eared pheasant
+(Crossoptilon auritum), however, offers a remarkable exception, for
+both sexes possess the fine caudal plumes, the large ear-tufts and the
+crimson velvet about the head; 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. (44. In the common
+peacock (Pavo cristatus) the male alone possesses spurs, whilst both
+sexes of the Java Peacock (P. muticus) offer the unusual case of being
+furnished with spurs. Hence I fully expected that in the latter species
+they would have been developed earlier 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, compared on April 23rd, 1869, there
+was no difference in the development of the spurs. The spurs, however,
+were as yet represented merely by slight knobs or elevations. I presume
+that I should have been informed if any difference in the rate of
+development had been observed subsequently.) The male and female Peacock
+differ conspicuously from each other in almost every part of their
+plumage, except in the elegant head-crest, which is common to both
+sexes; and this is developed very early in life, long before the other
+ornaments, which are confined to the male. The wild-duck offers an
+analogous case, for the beautiful green speculum on the wings is common
+to both sexes, though duller and somewhat smaller in the female, and it
+is developed early in life, whilst the curled tail-feathers and other
+ornaments of the male are developed later. (45. In some other species
+of the Duck family the speculum differs in a greater degree in the two
+sexes; but I have not been able to discover whether its full development
+occurs later in life in the males of such species, than in the male of
+the common duck, as ought to be the case according to our rule. With the
+allied Mergus cucullatus we have, however, a case of this kind: the two
+sexes differ conspicuously in general plumage, and to a considerable
+degree in the speculum, which is pure white in the male and
+greyish-white in the female. Now the young males at first entirely
+resemble the females, and have a greyish-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,
+'Ornithological Biography,' vol. iii. 1835, pp. 249-250.) Between such
+extreme cases of close sexual resemblance and wide dissimilarity, as
+those of the Crossoptilon and peacock, many intermediate ones could be
+given, in which the characters follow 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 coloured scales, for instance, in two species of
+butterflies, in one of which the sexes differ in colour, whilst in the
+other they are alike, are developed at the same relative age in the
+cocoon. Nor do we know whether all the scales are simultaneously
+developed on the wings of the same species of butterfly, in which
+certain coloured marks are confined to one sex, whilst others are common
+to both sexes. A difference of this kind in the period of development
+is not so improbable as it may at first appear; for with the Orthoptera,
+which assume their adult state, not by a single metamorphosis, but by a
+succession of moults, the young males of some species at first resemble
+the females, and acquire their distinctive masculine characters only at
+a later moult. Strictly analogous cases occur at the successive moults
+of certain male crustaceans.
+
+We have as yet considered the transference of characters, 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 congenital, as is probably
+colour-blindness--yet these peculiarities, and other similar ones, are
+often limited in their transmission to one sex; so that the rule that
+characters, developed at an early period, tend to be transmitted to both
+sexes, here wholly fails. But this rule, as before remarked, does
+not appear to be nearly so general as the converse one, namely,
+that characters which appear late in life in one sex are transmitted
+exclusively to the same sex. From the fact of the above abnormal
+peculiarities becoming attached to one sex, long before the sexual
+functions are active, we may infer that there must be some difference
+between the sexes at an extremely early age. With respect to
+sexually-limited diseases, we know too little of the period at which
+they originate, to draw any safe conclusion. Gout, however, seems to
+fall under our rule, for it is generally caused by intemperance during
+manhood, and is transmitted from the father to his sons in a much more
+marked manner than to his daughters.
+
+In the various domestic breeds of sheep, goats, and cattle, the males
+differ from their respective females in the shape or development of
+their horns, forehead, mane, dewlap, tail, and hump on the shoulders;
+and these peculiarities, in accordance with our rule, are not fully
+developed until 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 alone. On
+the other hand, the tortoise-shell colour, 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 development of the wattle and the crop occurs
+rather late in life, and conformably with the rule, these characters are
+transmitted in full perfection to the males alone. The following cases
+perhaps come within the class previously alluded to, in which both sexes
+have varied in the same manner at a rather late period of life, and
+have consequently transferred their new characters to both sexes at a
+corresponding late period; and if so, these cases are not opposed to
+our rule:--there exist sub-breeds of the pigeon, described by Neumeister
+(46. 'Das Ganze der Taubenzucht,' 1837, ss. 21, 24. For the case of the
+streaked pigeons, see Dr. Chapuis, 'Le pigeon voyageur Belge,' 1865, p.
+87.), in which both sexes change their colour 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 by the period at which such
+characters are developed. Thus in all the many breeds in which the adult
+male differs greatly in colour from the female, 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 coloured in nearly the same manner
+as their parents, and this renders it probable that their colours first
+appeared early in life. We have instances of this fact in all black and
+white breeds, in which the young and old of both sexes are alike; nor
+can it be maintained that there is something peculiar in a black or
+white plumage, 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 coloured. With the so-called Cuckoo sub-breeds
+of the fowl, in which the feathers are transversely pencilled with dark
+stripes, both sexes and the chickens are coloured in nearly the same
+manner. The laced plumage of the Sebright bantam is the same in both
+sexes, and in the young chickens the wing-feathers are distinctly,
+though imperfectly laced. Spangled Hamburgs, however, offer a partial
+exception; for the two sexes, though not quite alike, resemble each
+other more closely than do the sexes of the aboriginal parent-species;
+yet they acquire their characteristic plumage late in life, for the
+chickens are distinctly pencilled. With respect to other characters
+besides colour, 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 (47. For
+full particulars and references on all these points respecting the
+several breeds of the Fowl, see 'Variation of Animals and Plants under
+Domestication,' vol. i. pp. 250, 256. In regard to the higher animals,
+the sexual differences which have arisen under domestication are
+described in the same work under the head of each species.); and in
+this breed the adults of both sexes are characterised by a great bony
+protuberance and an immense crest.
+
+Finally, from what we have now seen of the relation which exists in
+many natural species and domesticated races, between the period of
+the development of their characters and the manner of their
+transmission--for example, the striking fact of the early 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 efficient cause of characters being inherited by both sexes, is
+their development at an early age, whilst the sexes differ but little
+in constitution. It appears, however, that some difference must exist
+between the sexes even during a very early embryonic period, for
+characters developed at this age not rarely become attached to one sex.
+
+SUMMARY AND CONCLUDING REMARKS.
+
+From the foregoing discussion on the various laws of inheritance, we
+learn that the characters of the parents often, or even generally, tend
+to become developed in the offspring of the same sex, at the same age,
+and periodically at the same season of the year, in which they first
+appeared in the parents. But these rules, owing to unknown causes, are
+far from being fixed. Hence during the modification of a species, the
+successive changes may readily be transmitted in different ways; some to
+one sex, and some to both; some to the offspring at one age, and some
+to the offspring at all ages. Not only are the laws of inheritance
+extremely complex, but so are the causes which induce and govern
+variability. The variations thus induced are preserved and accumulated
+by sexual selection, which is in itself an extremely complex affair,
+depending, as it does, on the ardour in love, the courage, and the
+rivalry of the males, as well as on the powers of perception, the taste,
+and will of the female. Sexual selection will also be largely dominated
+by natural selection tending towards the general welfare of the 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
+the species are similarly modified. In the following chapters it will be
+seen that all these cases frequently occur in nature.
+
+Sexual selection can never act on any animal before the age for
+reproduction arrives. From the great eagerness of the male it has
+generally acted on this sex and not on the females. The males have thus
+become provided with weapons for fighting with their rivals, with organs
+for discovering and securely holding the female, and for exciting or
+charming her. 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 early age,
+but would have been actually injurious--as by acquiring bright colours,
+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 charming the opposite sex, would,
+if they happened to arise in the female, be of no service to her, they
+would not be preserved in her through sexual selection. We have also
+good evidence with domesticated animals, that variations of all kinds
+are, if not carefully selected, soon lost through intercrossing and
+accidental deaths. Consequently in a state of nature, if variations
+of the above kind chanced to arise 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, and the two sexes would in consequence be modified in
+the same manner, although such characters were of no use to the
+females: but I shall hereafter have to recur to these more intricate
+contingencies. Lastly, the females may acquire, and apparently have
+often acquired by transference, characters from the male sex.
+
+As variations occurring later 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 prey or of escaping from danger. Differences of
+this kind between the two sexes do occasionally occur, especially in
+the lower classes. But this implies that the two sexes follow different
+habits in their struggles for existence, which is a rare circumstance
+with the higher animals. The case, however, is widely different with the
+reproductive functions, in which respect the sexes necessarily 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 secondary
+sexual characters.
+
+In the following chapters, I shall treat of the secondary sexual
+characters in animals of all classes, and shall endeavour in each case
+to apply the principles explained in the present chapter. The lowest
+classes will detain us for a very short time, but the higher animals,
+especially birds, must be treated at considerable length. It should be
+borne in mind that for reasons already assigned, I intend to give only
+a few illustrative instances of the innumerable structures by the aid of
+which the male finds the female, or, when found, holds her. On the other
+hand, all structures and instincts by the aid of which the male conquers
+other males, and by which he allures or excites the female, will be
+fully discussed, as these are in many ways the most interesting.
+
+SUPPLEMENT ON THE PROPORTIONAL NUMBERS OF THE TWO SEXES IN ANIMALS
+BELONGING TO VARIOUS CLASSES.
+
+As no one, as far as I can discover, has paid attention to the relative
+numbers of the two sexes throughout the animal kingdom, I will here
+give such materials as I have been able to collect, although they are
+extremely imperfect. They consist in only a few instances of actual
+enumeration, and the numbers are not very large. As the proportions
+are known with certainty only in mankind, I will first give them as a
+standard of comparison.
+
+MAN.
+
+In England during ten years (from 1857 to 1866) the average number of
+children born alive yearly was 707,120, in the proportion of 104.5 males
+to 100 females. But in 1857 the male births throughout England were as
+105.2, and in 1865 as 104.0 to 100. Looking to separate districts, in
+Buckinghamshire (where about 5000 children are annually born) the MEAN
+proportion of male to female births, during the whole period of the
+above ten years, was as 102.8 to 100; whilst in N. Wales (where the
+average annual births are 12,873) it was as high as 106.2 to 100. Taking
+a still smaller district, viz., Rutlandshire (where the annual births
+average only 739), in 1864 the male births were as 114.6, and in 1862
+as only 97.0 to 100; but even in this small district the average of the
+7385 births during the whole ten years, was as 104.5 to 100: that is in
+the same ratio as throughout England. (48. 'Twenty-ninth Annual Report
+of the Registrar-General for 1866.' In this report (p. xii.) a special
+decennial table is given.) The proportions are sometimes slightly
+disturbed by unknown causes; thus Prof. Faye states "that in some
+districts of Norway there has been during a decennial period a steady
+deficiency of boys, whilst in others the opposite condition has
+existed." In France during forty-four years the male to the female
+births have been as 106.2 to 100; but during this period it has occurred
+five times in one department, and six times in another, that the female
+births have exceeded the males. In Russia the average proportion is as
+high as 108.9, and in Philadelphia in the United States as 110.5 to 100.
+(49. For Norway and Russia, see abstract of Prof. Faye's researches, in
+'British and Foreign Medico-Chirurg. Review,' April 1867, pp. 343, 345.
+For France, the 'Annuaire pour l'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. Zouteveen, in the Dutch Translation
+of this work (vol. i. p. 417), where much information is given on the
+proportion of the sexes.) The average for Europe, deduced by Bickes from
+about seventy million 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 successive years between 90
+and 99 males for every 100 females. It is a singular fact that with Jews
+the proportion of male births is decidedly larger than with 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 countries being the
+same as usual, for instance, in Livonia as 104 to 100. (50. In regard to
+the Jews, see M. Thury, 'La Loi de Production des Sexes,' 1863, p. 25.)
+
+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
+unfavourable." (51. 'British and Foreign Medico-Chirurg. Review,' April
+1867, p. 343. Dr. Stark also remarks ('Tenth Annual Report of Births,
+Deaths, etc., in Scotland,' 1867, p. xxviii.) that "These examples
+may suffice to show that, at almost every stage of life, the males in
+Scotland have a greater liability to death and a higher death-rate than
+the females. The fact, however, of this peculiarity being most strongly
+developed at that infantile period of life when the dress, food, and
+general treatment of both sexes are alike, seems to prove that the
+higher male death-rate is an impressed, natural, and constitutional
+peculiarity due to sex alone.") Dr. Stockton Hough accounts for these
+facts in part by the more frequent defective development of males than
+of females. We have before seen that the male sex is more variable in
+structure than 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 (52. 'West Riding Lunatic Asylum
+Reports,' vol. i. 1871, p. 8. Sir J. Simpson has proved that the head
+of the male infant exceeds that of the female by 3/8ths of an inch in
+circumference, and by 1/8th in transverse diameter. Quetelet has
+shewn that woman is born smaller than man; see Dr. Duncan, 'Fecundity,
+Fertility, and Sterility,' 1871, p. 382.), 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
+countries, where statistical records have been kept, are found to
+preponderate considerably over the males. (53. With the savage Guaranys
+of Paraguay, according to the accurate Azara ('Voyages dans l'Amerique
+merid.' tom. ii. 1809, pp. 60, 179), the women are to the men in the
+proportion of 14 to 13.)
+
+It seems at first sight a mysterious fact that in different nations,
+under 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.
+(54. Babbage, 'Edinburgh Journal of Science,' 1829, vol. i. p. 88; also
+p. 90, on still-born children. On illegitimate children in England, see
+'Report of Registrar-General for 1866,' p. xv.) 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 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 labours, from various causes, such as attempts at concealment by
+tight lacing, hard work, distress of mind, etc., their male infants
+would proportionably suffer. And this probably is the most efficient of
+all the causes of the proportion of males to females born alive being
+less amongst illegitimate children than amongst the legitimate. With
+most animals the greater size of the adult male than of the female, is
+due to the stronger males having conquered the weaker in their struggles
+for the possession of the females, and no doubt it is owing to this fact
+that the two sexes of at least some animals differ in size at birth.
+Thus we have the curious fact that we may attribute the more frequent
+deaths of male than female infants, especially amongst the illegitimate,
+at least in part to sexual selection.
+
+It has often been supposed that the relative age of the two parents
+determine the sex of the offspring; and Prof. Leuckart (55. Leuckart,
+in Wagner 'Handw�rterbuch der Phys.' B. iv. 1853, s. 774.) has advanced
+what he considers sufficient evidence, 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 discountenance this belief. According to
+Dr. Stockton Hough (56. 'Social Science Association of Philadelphia,'
+1874.), the season of the year, the poverty or wealth of the parents,
+residence in the country or in cities, the crossing of foreign
+immigrants, etc., all influence the proportion of the sexes. With
+mankind, polygamy has also been supposed to lead to the birth of
+a greater proportion of female infants; but Dr. J. Campbell (57.
+'Anthropological Review,' April 1870, p. cviii.) carefully attended to
+this subject in the harems of Siam, and concludes that the proportion of
+male to female births is the same as from monogamous unions. Hardly any
+animal has been rendered so highly polygamous as the English race-horse,
+and we shall immediately see that his male and female offspring are
+almost exactly equal in number. I will now give the facts which I have
+collected with respect to the proportional numbers of the sexes of
+various animals; and will then briefly discuss how far selection has
+come into play in determining the result.
+
+HORSES.
+
+Mr. Tegetmeier has been so kind as to tabulate for me from the 'Racing
+Calendar' the births of race-horses during a period of twenty-one years,
+viz., from 1846 to 1867; 1849 being omitted, as no returns were that
+year published. The total births were 25,560 (58. 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 shewing how
+infertile these highly-nurtured and rather closely-interbred animals
+have become, that not far from one-third of the mares failed to produce
+living foals. Thus during 1866, 809 male colts and 816 female colts were
+born, and 743 mares failed to produce offspring. During 1867, 836 males
+and 902 females were born, and 794 mares failed.), consisting of 12,763
+males and 12,797 females, or in the proportion of 99.7 males to 100
+females. As these numbers are tolerably large, and as they are drawn
+from all parts of England, during several years, we may with much
+confidence conclude that with the domestic horse, or at least with the
+race-horse, the two sexes are produced in almost equal numbers. The
+fluctuations in the proportions during successive years are closely like
+those which occur with mankind, when a small and thinly-populated area
+is considered; thus in 1856 the male horses were as 107.1, and in 1867
+as only 92.6 to 100 females. In the tabulated returns the proportions
+vary in cycles, for the males exceeded the females during six successive
+years; and the females exceeded the males during two periods each of
+four years; this, however, may be accidental; at least I can detect
+nothing of the kind with man in the decennial table in the Registrar's
+Report for 1866.
+
+DOGS.
+
+During a period of twelve years, from 1857 to 1868, the births of a
+large number of greyhounds, throughout England, were sent to the 'Field'
+newspaper; and I am again indebted to Mr. Tegetmeier for carefully
+tabulating the results. The recorded births were 6878, consisting of
+3605 males and 3273 females, that is, in the proportion of 110.1 males
+to 100 females. The greatest fluctuations occurred in 1864, when
+the proportion was as 95.3 males, and in 1867, as 116.3 males to 100
+females. The above average proportion of 110.1 to 100 is probably nearly
+correct in the case of the greyhound, but whether it would hold with
+other domesticated breeds is in some degree doubtful. Mr. Cupples has
+enquired 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 mind.
+
+SHEEP.
+
+The sexes of sheep are not ascertained by agriculturists until several
+months after birth, at the period when the males are castrated; so that
+the following returns do not give the proportions at birth. Moreover,
+I find that several great breeders in Scotland, who annually raise some
+thousand sheep, are firmly convinced that a larger proportion of
+males than of females die during the first year or two. Therefore the
+proportion of males would be somewhat larger at birth than at the age of
+castration. This is a remarkable coincidence with what, as we have seen,
+occurs with mankind, and both cases probably depend on the same cause.
+I have received returns from four gentlemen in England who have bred
+Lowland sheep, chiefly Leicesters, during the last ten to sixteen years;
+they amount altogether to 8965 births, consisting of 4407 males and 4558
+females; that is in the proportion of 96.7 males to 100 females. With
+respect to Cheviot and black-faced sheep bred in Scotland, I have
+received returns from six breeders, two of them on a large scale,
+chiefly for the years 1867-1869, but some of the returns extend back to
+1862. The total number recorded amounts to 50,685, consisting of 25,071
+males and 25,614 females or in the proportion of 97.9 males to 100
+females. If we take the English and Scotch returns together, the total
+number amounts to 59,650, consisting of 29,478 males and 30,172 females,
+or as 97.7 to 100. So that with sheep at the age of castration the
+females are certainly in excess of the males, but probably this would
+not hold good at birth. (59. 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 returns as to
+sheep.)
+
+Of CATTLE I have received returns from nine gentlemen of 982 births,
+too few to be trusted; these consisted of 477 bull-calves and 505
+cow-calves; i.e., in the proportion of 94.4 males to 100 females. The
+Rev. W.D. 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 enquired from
+several breeders of PIGS, and most of them estimate the male to the
+female births as about 7 to 6. This same gentleman has bred RABBITS
+for many years, and has noticed that a far greater number of bucks are
+produced than does. But estimations are of little value.
+
+Of mammalia in a state of nature I have been able to learn very little.
+In regard to the common rat, I have received conflicting statements. Mr.
+R. Elliot, of Laighwood, informs me that a rat-catcher assured him that
+he had always found the males in great 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" (60. Bell,
+'History of British Quadrupeds,' p. 100.): 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 (61. 'Illustrations
+of the Zoology of S. Africa,' 1849, pl. 29.) (Kobus ellipsiprymnus),
+remarks, that in the herds of this and other species, the males are few
+in number compared with the females: the natives believe that they
+are born in this proportion; others believe that the younger males
+are expelled from the herds, and Sir A. Smith says, that though he has
+himself never seen herds consisting of young males alone, others affirm
+that this does occur. It appears probable that the young when expelled
+from the herd, would often fall a prey to the many beasts of prey of the
+country.
+
+BIRDS.
+
+With respect to the FOWL, I have received only one account, namely, that
+out of 1001 chickens of a highly-bred stock of Cochins, reared during
+eight years by Mr. Stretch, 487 proved males and 514 females; i.e., as
+94.7 to 100. In regard to domestic pigeons there is good evidence either
+that the males are produced in excess, or that they live longer; for
+these birds invariably pair, and single males, as Mr. Tegetmeier informs
+me, can always be purchased cheaper than females. Usually the two birds
+reared from the two eggs laid in the same nest are a male and a female;
+but Mr. Harrison Weir, who has been so large a breeder, says that he has
+often bred two cocks from the same nest, and seldom two hens; moreover,
+the hen is generally the weaker of the two, and more liable to perish.
+
+With respect to birds in a state of nature, Mr. Gould and others (62.
+Brehm ('Thierleben,' B. iv. s. 990) comes to the same conclusion.) are
+convinced that the males are generally the more numerous; and as the
+young males of many species resemble the females, the latter would
+naturally appear to be the more numerous. Large numbers of pheasants are
+reared by Mr. Baker of Leadenhall from eggs laid by wild birds, and
+he informs Mr. Jenner Weir that four or five males to one female
+are generally produced. An experienced observer remarks (63. On the
+authority of L. Lloyd, 'Game Birds of Sweden,' 1867, pp. 12, 132.), that
+in Scandinavia the broods of the capercailzie and black-cock contain
+more males than females; and that with the Dal-ripa (a kind of
+ptarmigan) more males than females attend the leks or places of
+courtship; but this latter circumstance is accounted for by some
+observers by a greater number of hen birds being killed by vermin. From
+various facts given by White of Selborne (64. 'Nat. Hist. of Selborne,'
+letter xxix. edit. of 1825, vol. i. p. 139.), it seems clear that the
+males of the partridge must be in considerable excess in the south of
+England; and I have been assured that this is the case in Scotland. Mr.
+Weir on enquiring from the dealers, who receive at certain seasons large
+numbers of ruffs (Machetes pugnax), was told that the males are much the
+more numerous. This same naturalist has also enquired for me from the
+birdcatchers, who annually catch an astonishing number of various small
+species alive for the London market, and he was unhesitatingly answered
+by an old and trustworthy man, that with the chaffinch the males are in
+large excess: he thought as high as 2 males to 1 female, or at least as
+high as 5 to 3. (65. Mr. Jenner Weir received similar information, on
+making enquiries during the following year. To shew the number of living
+chaffinches caught, I may mention that in 1869 there was a match between
+two experts, and one man caught in a day 62, and another 40, male
+chaffinches. The greatest number ever caught by one man in a single day
+was 70.) The males of the blackbird, he likewise maintained, were by far
+the more numerous, whether caught by traps or by netting at night. These
+statements may apparently be trusted, because this same man said that
+the sexes are about equal with the lark, the twite (Linaria montana),
+and goldfinch. On the other hand, he is certain that with the common
+linnet, the females preponderate greatly, but unequally during different
+years; during some years he has found the females to the males as four
+to one. It should, however, be borne in mind, that the chief season for
+catching birds does not begin till September, so that with some species
+partial migrations may have begun, and the flocks at this period often
+consist of hens alone. Mr. Salvin paid particular attention to the sexes
+of the humming-birds in Central America, and is convinced that with most
+of the species the males are in excess; thus one year he procured 204
+specimens belonging to ten species, and these consisted of 166 males and
+of 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 the males of Campylopterus
+hemileucurus were to the females as 5 to 2, and on another occasion (66.
+'Ibis,' vol. ii. p. 260, as quoted in Gould's 'Trochilidae,' 1861, p.
+52. For the foregoing proportions, I am indebted to Mr. Salvin for a
+table of his results.) in exactly the reversed ratio. As bearing on this
+latter point, I may add, that Mr. Powys found in Corfu and Epirus the
+sexes of the chaffinch keeping apart, and "the females by far the most
+numerous"; whilst in Palestine Mr. Tristram found "the male flocks
+appearing greatly to exceed the female in number." (67. 'Ibis,' 1860, p.
+137; and 1867, p. 369.) So again with the Quiscalus major, Mr. G. Taylor
+says, that in Florida there were "very few females in proportion to the
+males," (68. 'Ibis,' 1862, p. 187.) whilst in Honduras the proportion
+was the other way, the species there having the character of a
+polygamist.
+
+FISH.
+
+With fish the proportional numbers of the sexes can be ascertained only
+by catching them in the adult or nearly adult state; and there are many
+difficulties in arriving at any just conclusion. (69. Leuckart quotes
+Bloch (Wagner, 'Handw�rterbuch der Phys.' B. iv. 1853, s. 775), that
+with fish there are twice as many males as females.) Infertile females
+might readily be mistaken for males, as Dr. Gunther has remarked to me
+in regard to trout. With some species the males are believed to die
+soon after fertilising the ova. With many species the males are of much
+smaller size than the females, so that a large number of males would
+escape from the same net by which the females were caught. M. Carbonnier
+(70. Quoted in the 'Farmer,' March 18, 1869, p. 369.), who has
+especially attended to the natural history of the pike (Esox lucius),
+states that many males, owing to their small size, are devoured by the
+larger females; and he believes that the males of almost all fish
+are exposed from this same cause to greater danger than the females.
+Nevertheless, in the few cases in which the proportional numbers have
+been actually observed, the males appear to be largely in excess. Thus
+Mr. R. Buist, the superintendent of the Stormontfield experiments, says
+that in 1865, out of 70 salmon first landed for the purpose of obtaining
+the ova, upwards of 60 were males. In 1867 he again "calls attention to
+the vast disproportion of the males to the females. We had at the outset
+at least ten males to one female." Afterwards females sufficient for
+obtaining ova were procured. He adds, "from the great proportion of
+the males, they are constantly fighting and tearing each other on the
+spawning-beds." (71. 'The Stormontfield Piscicultural Experiments,'
+1866, p. 23. The 'Field' newspaper, June 29, 1867.) This disproportion,
+no doubt, can be accounted for in part, but whether wholly is doubtful,
+by the males ascending the rivers before the females. Mr. F. Buckland
+remarks in regard to trout, that "it is a curious fact that the males
+preponderate very largely in number over the females. It INVARIABLY
+happens that when the first rush of fish is made to the net, there will
+be at least seven or eight males to one female found captive. I cannot
+quite account for this; either the males are more numerous than the
+females, or the latter seek safety by concealment rather than flight."
+He then adds, that by carefully searching the banks sufficient females
+for obtaining ova can be found. (72. 'Land and Water,' 1868, p. 41.) Mr.
+H. Lee informs me that out of 212 trout, taken for this purpose in Lord
+Portsmouth's park, 150 were males and 62 females.
+
+The males of the Cyprinidae likewise seem to be in excess; but several
+members of this Family, viz., the carp, tench, bream and minnow,
+appear regularly to follow the practice, rare in the animal kingdom,
+of polyandry; for the female whilst spawning is always attended by two
+males, one on each side, and in the case of the bream by three or four
+males. This fact is so well known, that it is always recommended to
+stock a pond with two male tenches to one female, or at least with three
+males to two females. With the minnow, an excellent observer states,
+that on the spawning-beds the males are ten times as numerous as the
+females; when a female comes amongst the males, "she is immediately
+pressed closely by a male on each side; and when they have been in that
+situation for a time, are superseded by other two males." (73. Yarrell,
+'Hist. British Fishes,' vol. i. 1826, p. 307; on the Cyprinus carpio, p.
+331; on the Tinca vulgaris, p. 331; on the Abramis brama, p. 336. See,
+for the minnow (Leuciscus phoxinus), 'Loudon's Magazine of Natural
+History,' vol. v. 1832, p. 682.)
+
+INSECTS.
+
+In this great Class, the Lepidoptera almost alone afford means for
+judging of the proportional numbers of the sexes; for they have been
+collected with special care by many good observers, and have been
+largely bred from the egg or caterpillar state. I had hoped that some
+breeders of silk-moths might have kept an exact record, but after
+writing to France and Italy, and consulting various treatises, I cannot
+find that this has ever been done. The general opinion appears to be
+that the sexes are nearly equal, but in Italy, as I hear from Professor
+Canestrini, many breeders are convinced that the females are produced
+in excess. This same naturalist, however, informs me, that in the two
+yearly broods of the Ailanthus silk-moth (Bombyx cynthia), the males
+greatly preponderate in the first, whilst in the second the two sexes
+are nearly equal, or the females rather in excess.
+
+In regard to Butterflies in a state of nature, several observers have
+been much struck by the apparently enormous preponderance of the males.
+(74. Leuckart quotes Meinecke (Wagner, 'Handw�rterbuch der Phys.' B. iv.
+1853, s. 775) that the males of Butterflies are three or four times as
+numerous as the females.) Thus Mr. Bates (75. 'The Naturalist on the
+Amazons,' vol. ii. 1863, pp. 228, 347.), in speaking of several species,
+about a hundred in number, which inhabit the upper Amazons, says
+that the males are much more numerous than the females, even in the
+proportion of a hundred to one. In North America, Edwards, who had great
+experience, estimates in the genus Papilio the males to the females as
+four to one; and Mr. Walsh, who informed me of this statement, says
+that with P. turnus this is certainly the case. In South Africa, Mr. R.
+Trimen found the males in excess in 19 species (76. Four of these cases
+are given by Mr. Trimen in his 'Rhopalocera Africae Australis.'); and
+in one of these, which swarms in open places, he estimated the number of
+males as fifty to one female. With another species, in which the males
+are numerous in certain localities, he collected only five females
+during seven years. In the island of Bourbon, M. Maillard states that
+the males of one species of Papilio are twenty times as numerous as the
+females. (77. Quoted by Trimen, 'Transactions of the Ent. Society,' vol.
+v. part iv. 1866, p. 330.) Mr. Trimen informs me that as far as he has
+himself seen, or heard from others, it is rare for the females of any
+butterfly to exceed the males in number; but three South African species
+perhaps offer an exception. Mr. Wallace (78. 'Transactions, Linnean
+Society,' vol. xxv. p. 37.) states that the females of Ornithoptera
+croesus, in the Malay archipelago, are more common and more easily
+caught than the males; but this is a rare butterfly. I may here add,
+that in Hyperythra, a genus of moths, Guenee says, that from four to
+five females are sent in collections from India for one male.
+
+When this subject of the proportional numbers of the sexes of insects
+was brought before the Entomological Society (79. 'Proceedings,
+Entomological Society,' Feb. 17, 1868.), it was generally admitted that
+the males of most Lepidoptera, in the adult or imago state, are caught
+in greater numbers than the females: but this fact was attributed by
+various observers to the more retiring habits of the females, and to the
+males emerging earlier from the cocoon. This latter circumstance is well
+known to occur with most Lepidoptera, as well as with other insects.
+So that, as M. Personnat remarks, the males of the domesticated Bombyx
+Yamamai, are useless at the beginning of the season, and the females
+at the end, from the want of mates. (80. Quoted by Dr. Wallace in
+'Proceedings, Entomological Society,' 3rd series, vol. v. 1867, p. 487.)
+I cannot, however, persuade myself that these causes suffice 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 very close attention during many years to the smaller moths,
+informs me that when he collected them in the imago state, he thought
+that the males were ten times as numerous as the females, but that since
+he has reared them on a large scale from the caterpillar state, he is
+convinced that the females are the more numerous. Several entomologists
+concur in this view. Mr. Doubleday, however, and some others, take an
+opposite view, and are convinced that they have reared from the eggs and
+caterpillars a larger proportion of males than of females.
+
+Besides the more active habits of the males, their earlier emergence
+from the cocoon, and in some cases their frequenting more open stations,
+other causes may be assigned for an apparent or real difference in the
+proportional numbers of the sexes of Lepidoptera, when captured in the
+imago state, and when reared from the egg or caterpillar state. I hear
+from Professor Canestrini, that it is believed by many breeders in
+Italy, that the female caterpillar of the silk-moth suffers more from
+the recent disease than the male; and Dr. Staudinger informs me that in
+rearing Lepidoptera more females die in the cocoon than males. With many
+species the female caterpillar is larger than the male, and a collector
+would naturally choose the finest specimens, and thus unintentionally
+collect a larger number of females. Three collectors have told me that
+this was their practice; but Dr. Wallace is sure that most collectors
+take all the specimens which they can find of the rarer kinds, which
+alone are worth the trouble of rearing. Birds when surrounded by
+caterpillars would probably devour the largest; and Professor Canestrini
+informs me that in Italy some breeders believe, though on insufficient
+evidence, that in the first 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 consume 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 Elachista 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 endeavoured to
+gain admittance. In Australia, Mr. 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. (81. Blanchard,
+'Metamorphoses, Moeurs des Insectes,' 1868, pp. 225-226.)
+
+Mr. Doubleday has called my attention to M. Staudinger's (82.
+'Lepidopteren-Doubletten Liste,' Berlin, No. x. 1866.) list of
+Lepidoptera, which gives the prices of the males and females of 300
+species or well-marked varieties of butterflies (Rhopalocera). The
+prices for both sexes of the very common species are of course the same;
+but in 114 of the rarer species they differ; the males being in all
+cases, excepting one, the cheaper. On an average of the prices of the
+113 species, the price of the male to that of the female is as 100 to
+149; and this apparently indicates that inversely the males exceed the
+females in the same proportion. About 2000 species or varieties of moths
+(Heterocera) are catalogued, those with wingless females being here
+excluded on account of the difference in habits between the two sexes:
+of these 2000 species, 141 differ in price according to sex, the
+males of 130 being cheaper, and those of only 11 being dearer than the
+females. The average price of the males of the 130 species, to that of
+the females, is as 100 to 143. With respect to the butterflies in this
+priced list, Mr. Doubleday thinks (and no man in England has had more
+experience), that there is nothing in the habits of the species which
+can account for the difference in the prices of the two sexes, and that
+it can be accounted for only by an excess in the 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 emergence of the males will account for his
+collectors securing a larger number of males than of females, and
+consequently for the lower prices of the former. With respect to
+specimens reared from the caterpillar-state, Dr. Staudinger believes,
+as previously stated, that a greater number of females than of males die
+whilst confined to 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 cases: (See
+following table.)
+
+So that in these eight lots of cocoons and eggs, males were produced
+in excess. Taken together the proportion of males is as 122.7 to 100
+females. But the numbers are hardly large enough to be trustworthy.
+
+On the whole, from these various sources of evidence, all pointing in
+the same direction, I infer that with most species of Lepidoptera,
+the mature males generally exceed the females in number, whatever the
+proportions may be at their first emergence from the egg.
+
+                                                    Males   Females
+  The Rev. J. Hellins* of Exeter reared, during
+    1868, imagos of 73 species, which
+    consisted of                                     153       137
+
+  Mr. Albert Jones of Eltham reared, during
+    1868, imagos of 9 species, which
+    consisted of                                     159       126
+
+  During 1869 he reared imagos from 4 species
+    consisting of                                    114       112
+
+  Mr. Buckler of Emsworth, Hants, during 1869,
+    reared imagos from 74 species,
+    consisting of                                    180       169
+
+  Dr. Wallace of Colchester reared from one
+    brood of Bombyx cynthia                           52        48
+
+  Dr. Wallace raised, from cocoons of Bombyx
+    Pernyi sent from China, during 1869              224       123
+
+  Dr. Wallace raised, during 1868 and 1869, from
+    two lots of cocoons of Bombyx yamamai             52        46
+
+                                           Total     934       761
+
+(*83. This naturalist has been so kind as to send me some results from
+former years, in which the females seemed to preponderate; but so many
+of the figures were estimates, that I found it impossible to tabulate
+them.)
+
+With reference to the other Orders of insects, I have been able to
+collect very little reliable information. With the stag-beetle (Lucanus
+cervus) "the males appear to be much more numerous than the females";
+but when, as Cornelius remarked during 1867, an unusual number of these
+beetles appeared in one part of Germany, the females appeared to exceed
+the males as six to one. With one of the Elateridae, the males are said
+to be much more numerous than the females, and "two or three are often
+found united with one female (84. Gunther's 'Record of Zoological
+Literature,' 1867, p. 260. On the excess of female Lucanus, ibid,
+p. 250. On the males of Lucanus in England, Westwood,' 'Modern
+Classification of Insects,' vol. i. p. 187. On the Siagonium, ibid.
+p. 172.); so that here polyandry seems to prevail." With Siagonium
+(Staphylinidae), in which the males are furnished with horns, "the
+females are far more numerous than the opposite sex." Mr. Janson stated
+at the Entomological Society that the females of the bark feeding
+Tomicus villosus are so common as to be a plague, whilst the males are
+so rare as to be hardly known.
+
+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. (85. Walsh in 'The American Entomologist,' vol. i.
+1869, p. 103. F. Smith, 'Record of Zoological Lit.' 1867, p. 328.) 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 Cecidomyiidae (Diptera). With some common species
+of Saw-flies (Tenthredinae) Mr. F. Smith has reared hundreds of
+specimens from larvae of all sizes, but has never reared a single male;
+on the other hand, Curtis says (86. 'Farm Insects,' pp. 45-46.), that
+with certain species (Athalia), bred by him, the males were to the
+females as six to one; whilst exactly the reverse occurred with the
+mature insects of the same species caught in the fields. In the family
+of bees, Hermann M�ller (87. 'Anwendung der Darwin'schen Lehre,' Verh.
+d. n. Jahrg., xxiv.), 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
+number; in others the reverse occurred; and in others the two sexes were
+nearly equal. But as in most cases the males emerge from the cocoons
+before the females, they are at the commencement of the breeding-season
+practically in excess. M�ller also observed that the relative number of
+the two sexes in some species differed much in different localities. But
+as H. M�ller has himself remarked to me, these remarks must be received
+with some caution, as one sex might more easily escape observation than
+the other. Thus his brother Fritz M�ller has noticed in Brazil that the
+two sexes of the same species of bee sometimes frequent different kinds
+of flowers. With respect to the Orthoptera, I know hardly anything
+about the relative number of the sexes: Korte (88. 'Die Strich, Zug oder
+Wanderheuschrecke,' 1828, p. 20.), however, says that out of 500 locusts
+which he examined, the males were to the females as five to six. With
+the Neuroptera, Mr. Walsh states that in many, but by no means in all
+the species of the Odonatous group, there is a great overplus of males:
+in the genus Hetaerina, also, the males are generally at least four
+times as numerous as the females. In certain species in the genus
+Gomphus the males are equally in excess, whilst in two other species,
+the females are twice or thrice as numerous as the males. In some
+European species of Psocus thousands of females may be collected without
+a single male, whilst with other species of the same genus both sexes
+are common. (89. 'Observations on N. American Neuroptera,' by H. Hagen
+and B.D. Walsh, 'Proceedings, Ent. Soc. Philadelphia,' Oct. 1863, pp.
+168, 223, 239.) In England, Mr. MacLachlan has captured hundreds of the
+female Apatania muliebris, but has never seen the male; and of Boreus
+hyemalis only four or five males have been seen here. (90. 'Proceedings,
+Ent. Soc. London,' Feb. 17, 1868.) With most of these species (excepting
+the Tenthredinae) there is at present no evidence that the females are
+subject to parthenogenesis; and thus we see how ignorant we are of the
+causes of the apparent discrepancy in the proportion of the two sexes.
+
+In the other classes of the Articulata I have been able to collect
+still less information. With spiders, Mr. Blackwall, who has carefully
+attended to this class during many years, writes to me that the males
+from their more erratic habits are more commonly seen, and therefore
+appear more numerous. This is actually the case with a few species; but
+he mentions several species in six genera, in which the females appear
+to be much more numerous than the males. (91. Another great authority
+with respect to this class, Prof. Thorell of Upsala ('On European
+Spiders,' 1869-70, part i. p. 205), speaks as if female spiders were
+generally commoner than the males.) 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. (92. See, on
+this subject, Mr. O.P. Cambridge, as quoted in 'Quarterly Journal of
+Science,' 1868, page 429.)
+
+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 (93. 'Beitr�ge zur Parthenogenesis,' p. 174.) carefully examined
+no less than 13,000 specimens of Apus from twenty-one localities, and
+amongst these he found only 319 males. With some other forms (as Tanais
+and Cypris), as Fritz M�ller informs me, there is reason to believe
+that the males are much shorter-lived than the females; and this would
+explain their scarcity, supposing the two sexes to be at first equal in
+number. On the other hand, M�ller has invariably taken far more males
+than females of the Diastylidae and of Cypridina on the shores of
+Brazil: thus with a species in the latter genus, 63 specimens caught the
+same day included 57 males; but he suggests that this preponderance may
+be due to some unknown difference in the habits of the two sexes. With
+one of the higher Brazilian crabs, namely a Gelasimus, Fritz M�ller
+found the males to be more numerous than the females. According to the
+large experience of Mr. C. Spence Bate, the reverse seems to be the case
+with six common British crabs, the names of which he has given me.
+
+THE PROPORTION OF THE SEXES IN RELATION TO NATURAL SELECTION.
+
+There is reason to suspect that in some cases man has 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. Wright 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 other peculiarity, for instance, that of
+producing twins; and concerning the above tendency a good authority, Mr.
+J. Downing, has communicated to me facts which seem to prove that this
+does occur in certain families of short-horn cattle. Col. Marshall
+(94. 'The Todas,' 1873, pp. 100, 111, 194, 196.) 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 polyandrous in their marriages,
+during former times invariably practised female infanticide; but this
+practice has now been discontinued for a considerable period. Of the
+children born within late years, the males are more numerous than the
+females, in the proportion of 124 to 100. Colonel Marshall accounts for
+this fact in the following 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, whilst the third mother has
+three sons and three daughters. The first mother, following the tribal
+custom, destroys four daughters and preserves two. The second retains
+her six sons. The third kills two daughters and keeps one, as also her
+three sons. We have then from the three families, nine sons and three
+daughters, with which to continue the breed. But whilst the males belong
+to families in which the tendency to produce sons is great, the females
+are of those of a converse inclination. Thus the bias strengthens with
+each generation, until, as we find, families grow to have habitually
+more sons than daughters."
+
+That this result would follow from the above form of 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 additional evidence, but cannot decide whether what I have
+found is trustworthy; nevertheless the facts are, perhaps, worth giving.
+The Maories of New Zealand have long practised infanticide; and Mr.
+Fenton (95. 'Aboriginal Inhabitants of New Zealand: Government Report,'
+1859, p. 36.) states that he "has met with instances of women who have
+destroyed four, six, and even seven children, mostly females. However,
+the universal testimony of those best qualified to judge, is conclusive
+that this custom has for many years been almost extinct. Probably the
+year 1835 may be named as the period of its ceasing to exist."
+Now amongst the New 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 disproportion of the sexes cannot be demonstratively
+fixed, it is quite clear that this course of decrease was in full
+operation during the years 1830 to 1844, when the non-adult population
+of 1844 was being produced, and has continued with great energy up to
+the present time." The following statements are taken from Mr. Fenton
+(p. 26), but as the numbers are not large, and as the census was not
+accurate, uniform results cannot be expected. It should be borne in
+mind in this and the following cases, that the normal state of every
+population is an excess of women, at least in all civilised countries,
+chiefly owing to the greater mortality of the male sex during youth,
+and partly to accidents of all kinds later in life. In 1858, the native
+population of New Zealand was estimated as consisting of 31,667 males
+and 24,303 females of all ages, that is in the ratio of 130.3 males
+to 100 females. But during this same year, and in certain limited
+districts, the numbers were ascertained with much care, and the males
+of all ages were here 753 and the females 616; that is in the ratio of
+122.2 males to 100 females. It is more important for us that during this
+same year of 1858, the NON-ADULT males within the same district were
+found to be 178, and the NON-ADULT females 142, that is in the ratio
+of 125.3 to 100. It may be added that in 1844, at which period female
+infanticide had only lately ceased, the NON-ADULT males in one district
+were 281, and the NON-ADULT females only 194, that is in the ratio of
+144.8 males to 100 females.
+
+In the Sandwich Islands, the males exceed the females in number.
+Infanticide was formerly practised there to a frightful extent, but was
+by no means confined to female infants, as is shewn by Mr. Ellis (96.
+'Narrative of a Tour through Hawaii,' 1826, p. 298.), and as I have been
+informed by Bishop Staley and the Rev. Mr. Coan. Nevertheless, another
+apparently trustworthy writer, Mr. Jarves (97. 'History of the
+Sandwich Islands,' 1843, p. 93.), whose observations apply to the whole
+archipelago, remarks:--"Numbers of women are to be found, who confess
+to the murder of from three to six or eight children," and he adds,
+"females from being considered less useful than males were more often
+destroyed." From what is known to occur in other parts of the world,
+this statement is probable; but must be received with much caution. The
+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 4723 males and 3776
+females; that is in the ratio of 125.08 to 100. At the same time the
+number of males under fourteen years in Kauai and under eighteen in Oahu
+was 1797, and of females of the same ages 1429; and here we have the
+ratio of 125.75 males to 100 females.
+
+In a census of all the islands in 1850 (98. This is given in the Rev.
+H.T. Cheever's 'Life in the Sandwich Islands,' 1851, p. 277.), the males
+of all ages amount to 36,272, and the females to 33,128, or as 109.49 to
+100. The males under seventeen years amounted to 10,773, and the females
+under the same age to 9593, or as 112.3 to 100. From the census of 1872,
+the proportion of males of all ages (including half-castes) to females,
+is as 125.36 to 100. It must be borne in mind that all these returns
+for the Sandwich Islands give the proportion of living males to living
+females, and not of the births; and judging from all civilised countries
+the proportion of males would have been considerably higher if the
+numbers had referred to births. (99. Dr. Coulter, in describing
+('Journal R. Geograph. Soc.' vol. v. 1835, p. 67) the state of
+California about the year 1830, says that the natives, reclaimed by
+the Spanish missionaries, have nearly all perished, 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 women in number; but he does not
+know whether this is due to a failure of female offspring, or to more
+females dying during early youth. The latter alternative, according to
+all analogy, is very improbable. He adds that "infanticide, properly
+so called, is not common, though very frequent recourse is had to
+abortion." If Dr. Coulter is correct about infanticide, this case
+cannot be advanced in support of Colonel 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 enquiries 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 sometimes take place to a limited extent.
+Therefore I am unable to decide whether we can, on the above principles,
+account for the preponderance of male births in greyhounds. On the other
+hand, we have seen that with horses, cattle, and sheep, which are too
+valuable for the young of either sex to be destroyed, if there is any
+difference, the females are slightly in excess.)
+
+From the several foregoing cases we have some reason to believe that
+infanticide practised in the manner 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 races, which have
+already become somewhat infertile. Besides the several causes previously
+alluded to, the greater facility of parturition amongst savages, and the
+less consequent injury to their male infants, would tend to increase the
+proportion of live-born males to females. There does not, however, seem
+to be any necessary connection between savage life and a marked excess
+of males; that is if we may judge by the character of the scanty
+offspring of the lately existing Tasmanians and of the crossed offspring
+of the Tahitians now inhabiting Norfolk Island.
+
+As the males and females of many animals differ somewhat in habits and
+are exposed in different degrees to danger, it is probable that in many
+cases, more of one sex than of the other are habitually destroyed. But
+as far as I can trace out the 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 paramount importance, we can see that those communities would
+flourish best which contained females having a strong inherited
+tendency to produce more and more females; and in such cases an unequal
+sex-producing tendency would be 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 tendency 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 fertilisation 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 intricate
+that it is safer to leave its solution for the future.
+
+
+CHAPTER IX.
+
+SECONDARY SEXUAL CHARACTERS IN THE LOWER CLASSES OF THE ANIMAL KINGDOM.
+
+These characters absent in the lowest classes--Brilliant
+colours--Mollusca --Annelids--Crustacea, secondary sexual characters
+strongly developed; dimorphism; colour; characters not acquired
+before maturity--Spiders, sexual colours of; stridulation by the
+males--Myriapoda.
+
+With animals belonging to the lower classes, the two sexes are not
+rarely united in the same individual, and therefore secondary sexual
+characters cannot be developed. In many cases where the sexes are
+separate, both are permanently attached to some support, and the one
+cannot search or struggle for the other. Moreover it is almost certain
+that these animals have too imperfect senses and much too low mental
+powers to appreciate each other's beauty or other attractions, or to
+feel rivalry.
+
+Hence in these classes or sub-kingdoms, such as the Protozoa,
+Coelenterata, 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 colour from the females;
+but we have no reason to suppose that such differences have been
+augmented through sexual selection. Contrivances by which the male
+holds the female, and which are indispensable for the propagation 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-anemones
+(Actiniae), some jelly-fish (Medusae, Porpita, etc.), some Planariae,
+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 colours 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 colours have been thus acquired, except where one sex is much more
+brilliantly or conspicuously coloured than the other, and where there
+is no difference in habits between the sexes sufficient to account for
+their different colours. But the evidence is rendered as complete as it
+can ever be, only when the more ornamented individuals, almost always
+the males, voluntarily display their attractions before the other
+sex; for we cannot believe that such display is useless, and if it be
+advantageous, sexual selection will almost inevitably follow. We may,
+however, extend this conclusion to both sexes, when coloured alike, if
+their colours are plainly analogous to those of one sex alone in certain
+other species of the same group.
+
+How, then, are we to account for the beautiful or even gorgeous colours
+of many animals in the lowest classes? It appears doubtful whether such
+colours often serve as a protection; but that we may easily err on this
+head, will be admitted by every one who reads Mr. Wallace's excellent
+essay on this subject. It would not, for instance, at first occur to
+any one that the transparency of the Medusae, or jelly-fish, is of the
+highest service to them as a protection; but when we are reminded
+by Haeckel that not only the Medusae, but many floating Mollusca,
+crustaceans, and even small oceanic fishes partake of this same
+glass-like appearance, often accompanied by prismatic colours, we can
+hardly doubt that they thus escape the notice of pelagic birds and other
+enemies. M. Giard is also convinced (1. 'Archives de Zoolog. Exper.'
+Oct. 1872, p. 563.) that the bright tints of certain sponges and
+ascidians serve as a protection. Conspicuous colours 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
+defence; but this subject will be discussed more conveniently hereafter.
+
+We can, in our ignorance of most of the lowest animals, only say that
+their bright tints result either from the chemical nature or the minute
+structure of their tissues, independently of any benefit thus derived.
+Hardly any colour is finer than that of arterial blood; but there is
+no reason to suppose that the colour of the blood is in itself any
+advantage; and though it adds to the beauty of the maiden's cheek, no
+one will pretend that it has been acquired for this purpose. So again
+with many animals, especially the lower ones, the bile is richly
+coloured; thus, as I am informed by Mr. Hancock, the extreme beauty of
+the Eolidae (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 colours, it would have been a strange fact if substances
+similarly coloured had not often originated, independently of any useful
+end thus gained, in the complex laboratory of living organisms.
+
+THE SUB-KINGDOM OF THE MOLLUSCA.
+
+Throughout this great division of the animal kingdom, as far as I can
+discover, secondary sexual characters, such as we are here considering,
+never occur. Nor could they be expected in the three lowest classes,
+namely, in the Ascidians, Polyzoa, and Brachiopods (constituting the
+Molluscoida of some authors), for most of these animals are permanently
+affixed to a support or have their sexes united in the same individual.
+In the Lamellibranchiata, or bivalve shells, 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 fighting with other males. As I am informed by Mr.
+Gwyn Jeffreys, the sole external difference between the sexes consists
+in the shell sometimes differing a little in form; for instance, the
+shell of the male periwinkle (Littorina littorea) is narrower and has
+a more elongated spire than that of the female. But differences of
+this nature, it may be presumed, are directly connected with the act of
+reproduction, or with the development of the ova.
+
+The Gasteropoda, though capable of locomotion and furnished with
+imperfect eyes, do not appear to be 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
+pulmoniferous gasteropods, or land-snails, the pairing is preceded by
+courtship; for these animals, though hermaphrodites, are compelled
+by their structure to pair together. Agassiz remarks, "Quiconque a eu
+l'occasion d'observer les amours des lima�ons, ne saurait mettre en
+doute la s�duction deploy�e dans les mouvements et les allures
+qui pr�parent et accomplissent le double embrassement de ces
+hermaphrodites." (2. 'De l'Esp�ce et de la Class.' etc., 1869, p.
+106.) 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 pomatia), one of which was weakly,
+into a small and ill-provided garden. After a short time the strong and
+healthy individual disappeared, and was traced by its track of slime
+over a wall into an adjoining well-stocked garden. Mr. Lonsdale
+concluded that it had deserted its sickly mate; but after an absence of
+twenty-four hours it returned, and apparently communicated the result of
+its successful exploration, for both then started along the same track
+and disappeared over the wall.
+
+Even in the highest class of the Mollusca, the Cephalopoda or
+cuttle-fishes, in which the sexes are separate, secondary sexual
+characters of the present kind do not, as far as I can discover,
+occur. This is a surprising circumstance, as these animals possess
+highly-developed sense-organs and have considerable mental powers, as
+will be admitted by every one who has watched their artful endeavours
+to escape from an enemy. (3. See, for instance, the account which I have
+given in my 'Journal of Researches,' 1845, p. 7.) Certain Cephalopoda,
+however, are characterised by one extraordinary sexual character, namely
+that the male element collects within one of the arms or tentacles,
+which is then cast off, and clinging by its sucking-discs to the female,
+lives for a time an independent life. So completely does the cast-off
+arm resemble a separate animal, that it was described by Cuvier as
+a parasitic worm under the name of Hectocotyle. But this marvellous
+structure may be classed as a primary rather than as a secondary sexual
+character.
+
+Although with the Mollusca sexual selection does not seem to have come
+into play; yet many univalve and bivalve shells, such as volutes, cones,
+scallops, etc., are beautifully coloured and shaped. The colours do not
+appear in most cases to be of any use as a protection; they are probably
+the direct result, as in the lowest classes, of the nature of the
+tissues; the patterns and the sculpture of the shell depending on its
+manner of growth. The amount of light seems to be influential to a
+certain extent; for although, as repeatedly stated by Mr. Gwyn Jeffreys,
+the shells of some species living at a profound depth are brightly
+coloured, yet we generally see the lower surfaces, as well as the parts
+covered by the mantle, less highly-coloured than the upper and exposed
+surfaces. (4. I have given ('Geological Observations on Volcanic
+Islands,' 1844, p. 53) a curious instance of the influence of light on
+the colours of a frondescent incrustation, deposited by the surf on
+the coast-rocks of Ascension and formed by the solution of triturated
+sea-shells.) In some cases, as with shells living amongst corals or
+brightly-tinted seaweeds, the bright colours may serve as a protection.
+(5. Dr. Morse has lately discussed this subject in his paper on the
+'Adaptive Coloration of Mollusca,' 'Proc. Boston Soc. of Nat. Hist.'
+vol. xiv. April 1871.) But that many of the nudibranch Mollusca, or
+sea-slugs, are as beautifully coloured as any shells, may be seen in
+Messrs. Alder and Hancock's magnificent work; and from information
+kindly given me by Mr. Hancock, it seems extremely doubtful whether
+these colours 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-coloured, white, or
+otherwise conspicuous species, do not seek concealment; whilst again
+some equally conspicuous species, as well as other dull-coloured kinds
+live under stones and in dark recesses. So that with these nudibranch
+molluscs, colour apparently does not stand in any close relation to the
+nature of the places which they inhabit.
+
+These naked sea-slugs are hermaphrodites, yet they pair together, as
+do land-snails, many of which have extremely pretty shells. It is
+conceivable that two hermaphrodites, attracted by each other's greater
+beauty, might unite and leave offspring which would inherit their
+parents' greater beauty. But with such lowly-organised creatures this
+is extremely improbable. Nor is it at all obvious how the offspring from
+the more beautiful pairs of hermaphrodites would have any advantage over
+the offspring of the less beautiful, so as to increase in number, unless
+indeed vigour 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 colours were beneficial to a hermaphrodite animal in relation
+to its general habits of life, the more brightly-tinted individuals
+would succeed best and would increase in number; but this would be a
+case of natural and not of sexual selection.
+
+SUB-KINGDOM OF THE VERMES: CLASS, ANNELIDA (OR SEA-WORMS).
+
+In this class, although the sexes, when separate, sometimes differ from
+each other in characters of such importance that they have been placed
+under distinct genera or even families, yet the differences do not seem
+of the kind which can be safely attributed to sexual selection. These
+animals are often beautifully coloured, but as the sexes do not differ
+in this respect, we are but little concerned with them. Even the
+Nemertians, though so lowly organised, "vie in beauty and variety of
+colouring with any other group in the invertebrate series"; yet Dr.
+McIntosh (6. See his beautiful monograph on 'British Annelids,' part i.
+1873, p. 3.) cannot discover that these colours are of any service. The
+sedentary annelids become duller-coloured, according to M. Quatrefages
+(7. See M. Perrier: 'L'Origine de l'Homme d'apr�s Darwin,' 'Revue
+Scientifique', Feb. 1873, p. 866.), after the period of reproduction;
+and this I presume 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: CLASS, CRUSTACEA.
+
+In this great class we first meet with undoubted secondary sexual
+characters, often developed in a remarkable manner. Unfortunately the
+habits of crustaceans are very imperfectly known, and we cannot
+explain the uses of many structures peculiar to one sex. With the
+lower parasitic species the males are of small size, and they alone are
+furnished with perfect swimming-legs, antennae and sense-organs;
+the females being destitute of these organs, with their bodies often
+consisting of a mere distorted mass. But these extraordinary differences
+between the two sexes are no doubt related to their widely different
+habits of life, and consequently do not concern us. In various
+crustaceans, belonging to distinct families, the anterior antennae are
+furnished 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 the smelling-threads has probably
+been acquired through sexual selection, by the better provided males
+having been the more successful in finding partners and in producing
+offspring. Fritz M�ller 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 M�ller suggests 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, whilst
+other individuals varied in the shape and size of their chelae; so that
+of the former, those which were best able to find the female, and of the
+latter, those which were best able to hold her, have left the greatest
+number of progeny to inherit their respective advantages. (8. 'Facts and
+Arguments for Darwin,' English translat., 1869, p. 20. See the previous
+discussion on the olfactory threads. Sars has described a somewhat
+analogous case (as quoted in 'Nature,' 1870, p. 455) in a Norwegian
+crustacean, the Pontoporeia affinis.)
+
+[Fig.4. Labidocera Darwinii (from Lubbock). Labelled are: a. Part of
+right anterior antenna of male, forming a prehensile organ. b. Posterior
+pair of thoracic legs of male. c. Ditto of female.]
+
+In some of the lower crustaceans, the right anterior antenna of the male
+differs greatly in structure from the left, the 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
+converted (Fig. 4) into an elegant, and sometimes wonderfully complex,
+prehensile organ. (9. See Sir J. Lubbock in 'Annals and Mag. of Nat.
+Hist.' vol. xi. 1853, pl. i. and x.; and vol. xii. (1853), pl. vii.
+See also Lubbock in 'Transactions, Entomological Society,' vol. iv.
+new series, 1856-1858, p. 8. With respect to the zigzagged antennae
+mentioned below, see Fritz M�ller, 'Facts and Arguments for Darwin,'
+1869, p. 40, foot-note.) It serves, as I hear from Sir J. Lubbock, to
+hold the female, and for this same purpose one of the two posterior legs
+(b) on the same side of the body is converted into a forceps. In another
+family the inferior or posterior antennae are "curiously zigzagged" in
+the males alone.
+
+[Fig. 5. Anterior part of body of Callianassa (from Milne-Edwards),
+showing the unequal and differently-constructed right and left-hand
+chelae of the male. N.B.--The artist by mistake has reversed the
+drawing, and made the left-hand chela the largest.
+
+Fig. 6. Second leg of male Orchestia Tucuratinga (from Fritz M�ller).
+
+Fig. 7. Ditto of female.]
+
+In the higher crustaceans the anterior legs are developed into chelae
+or pincers; and these are generally larger in the male than in the
+female,--so much so that the market value of the male edible crab
+(Cancer pagurus), according to Mr. C. Spence Bate, is five times as
+great as that of the female. In many species the chelae are of unequal
+size on the opposite side of the body, the right-hand one being, as I
+am informed by Mr. Bate, generally, though not invariably, the largest.
+This inequality is also often much greater in the male than in the
+female. The two chelae of the male often differ in structure (Figs. 5,
+6, and 7), the smaller one resembling that of the female. What advantage
+is gained by their inequality in size on the opposite sides of the body,
+and by the inequality being much greater in the male than in the female;
+and why, when they are of equal size, both are often much larger in
+the male than in the female, is not known. As I hear from Mr. Bate, the
+chelae are sometimes of such length and size that they cannot possibly
+be used for carrying food to the mouth. In the males of certain
+fresh-water prawns (Palaemon) the right leg is actually longer than the
+whole body. (10. See a paper by Mr. C. Spence Bate, with figures, in
+'Proceedings, Zoological Society,' 1868, p. 363; and on the nomenclature
+of the genus, ibid. p. 585. I am greatly indebted to Mr. Spence Bate for
+nearly all the above statements with respect to the chelae of the higher
+crustaceans.) The great size of the one leg with its chelae may aid the
+male in fighting with his rivals; but this will not account for
+their inequality in the female on the opposite sides of the body. In
+Gelasimus, according to a statement quoted by Milne Edwards (11. 'Hist.
+Nat. des Crust.' tom. ii. 1837, p. 50.), the male and the female live
+in the same burrow, and this shews that they pair; the male closes
+the mouth of the burrow with one of its chelae, which is enormously
+developed; so that here it indirectly serves as a means of defence.
+Their main use, however, 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 (Pagurus) for weeks together,
+carries about the shell inhabited by the female. (12. Mr. C. Spence
+Bate, 'British Association, Fourth Report on the Fauna of S. Devon.')
+The sexes, however, of the common shore-crab (Carcinus maenas), as Mr.
+Bate informs me, unite directly after the female has moulted her hard
+shell, when she is so soft that she would be injured if seized by the
+strong pincers of the male; but as she is caught and carried about by
+the male before moulting, she could then be seized with impunity.
+
+[Fig.8. Orchestia Darwinii (from Fritz M�ller), showing the
+differently-constructed chelae of the two male forms.]
+
+Fritz M�ller states that certain species of Melita are distinguished
+from all other amphipods by the females having "the coxal lamellae of
+the penultimate pair of feet produced into hook-like processes, of which
+the males lay hold with the hands of the first pair." The development of
+these hook-like processes 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 (see
+Orchestia darwinii, Fig. 8) presents a case of dimorphism, like that of
+Tanais; for there are two male forms, which differ in the structure of
+their chelae. (13. Fritz M�ller, 'Facts and Arguments for Darwin,'
+1869, pp. 25-28.) As either chela would certainly suffice to hold the
+female,--for both are now used for this purpose,--the two male forms
+probably originated by some having varied in one manner and some in
+another; both forms having derived certain special, but nearly equal
+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 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 parasitic genera, however, in which the
+sexes follow different habits of life, and most of the Entomostraca must
+be excepted. The chelae of many crustaceans are weapons well adapted for
+fighting. Thus when a Devil-crab (Portunus puber) was seen by a son of
+Mr. Bate fighting with a Carcinus maenas, the latter was soon thrown on
+its back, and had every limb torn from its body. When several males of
+a Brazilian Gelasimus, a species furnished with immense pincers, were
+placed together in a glass vessel by Fritz M�ller, they mutilated and
+killed one another. Mr. Bate put a large male Carcinus maenas into a pan
+of water, inhabited by a female which was paired with a smaller male;
+but the latter was soon dispossessed. Mr. Bate adds, "if 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),
+Gammarus marinus, from its female, both of whom were imprisoned in the
+same vessel with many individuals of the same species. The female, when
+thus divorced, soon joined the others. After a time the male was put
+again into the same vessel; and he then, after swimming about for a
+time, dashed into the crowd, and without any fighting at once took away
+his wife. This fact shews that in the Amphipoda, an order low in the
+scale, the males and females recognise each other, and are mutually
+attached.
+
+The mental powers of the Crustacea are probably higher than at
+first sight appears probable. Any one who tries to catch one of the
+shore-crabs, so common on tropical coasts, will perceive how wary and
+alert they are. There is a large crab (Birgus latro), found on coral
+islands, which makes a thick bed of the picked fibres of the cocoa-nut,
+at the bottom of a deep burrow. It feeds on the fallen fruit of this
+tree by tearing off the husk, fibre by fibre; and it always begins at
+that end where the three eye-like depressions are situated. It then
+breaks through one of these eyes by hammering with its heavy front
+pincers, and turning round, extracts the albuminous core with its narrow
+posterior pincers. But these actions are probably instinctive, so that
+they would be performed as well by a young animal as by an old one.
+The following case, however, can hardly be so considered: a trustworthy
+naturalist, Mr. Gardner (14. 'Travels in the Interior of Brazil,' 1846,
+p. 111. I have given, in my 'Journal of Researches,' p. 463, an account
+of the habits of the Birgus.), whilst watching a shore-crab (Gelasimus)
+making its burrow, threw some shells towards the hole. One rolled in,
+and three other shells remained within a few inches of the mouth. In
+about five minutes the crab brought out the shell which had fallen in,
+and carried it away to a distance of a foot; it then saw the three other
+shells lying near, and evidently thinking that they might likewise roll
+in, carried them to the spot where it had laid the first. It would, I
+think, be difficult to distinguish this act from one performed by man by
+the aid of reason.
+
+Mr. Bate does not know of any well-marked case of difference of colour
+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 females differ slightly in tint, but Mr. Bate thinks not more than
+may be accounted for by their different habits of life, such as by the
+male wandering more about, and being thus more exposed to the light. Dr.
+Power tried to distinguish by colour the sexes of the several species
+which inhabit the Mauritius, but failed, except with one species of
+Squilla, probably S. stylifera, the male of which is described as being
+"of a beautiful bluish-green," with some of the appendages cherry-red,
+whilst the female is clouded with brown and grey, "with the red about
+her much less vivid than in the male." (15. Mr. Ch. Fraser, in 'Proc.
+Zoolog. Soc.' 1869, p. 3. I am indebted to Mr. Bate for Dr. Power's
+statement.) In this case, we may suspect the agency of sexual selection.
+From M. Bert's observations on Daphnia, when placed in a vessel
+illuminated by a prism, we have reason to believe that even the lowest
+crustaceans can distinguish colours. With Saphirina (an oceanic genus of
+Entomostraca), the males are furnished with minute shields or cell-like
+bodies, which exhibit beautiful changing colours; these are absent
+in the females, and in both sexes of one species. (16. Claus, 'Die
+freilebenden Copepoden,' 1863, s. 35.) It would, however, be extremely
+rash to conclude that these curious organs serve to attract the females.
+I am informed by Fritz M�ller, that in the female of a Brazilian species
+of Gelasimus, the whole body is of a nearly uniform greyish-brown. In
+the male the posterior part of the cephalo-thorax is pure white, with
+the anterior part of a rich green, shading into dark brown; and it is
+remarkable that these colours are liable to change in the course of
+a few minutes--the white becoming dirty grey or even black, the green
+"losing much of its brilliancy." It deserves especial notice that the
+males do not acquire their bright colours until they become mature. They
+appear to be much more numerous than the females; they differ also in
+the larger size of their chelae. In some species of the genus, 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 probable that the male in this species has become gaily
+ornamented in order to attract or excite the female.
+
+It has just been stated that the male Gelasimus does not acquire his
+conspicuous colours until mature and nearly ready to breed. This seems
+a general rule in the whole class in respect to the many remarkable
+structural differences between the sexes. We shall hereafter find the
+same law prevailing throughout the great sub-kingdom of the Vertebrata;
+and in all cases it is eminently distinctive of characters which have
+been acquired through sexual selection. Fritz M�ller (17. 'Facts and
+Arguments,' etc., p. 79.) 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; whilst young, his claspers resemble those of the
+female.
+
+CLASS, ARACHNIDA (SPIDERS).
+
+The sexes do not generally differ much in colour, but the males are
+often darker than the females, as may be seen in Mr. Blackwall's
+magnificent work. (18. 'A History of the Spiders of Great Britain,'
+1861-64. For the following facts, see pp. 77, 88, 102.) In some species,
+however, the difference is conspicuous: thus the female of Sparassus
+smaragdulus is dullish green, whilst the adult male has the abdomen of
+a fine yellow, with three longitudinal stripes of rich red. In certain
+species of Thomisus the sexes closely resemble each other, in others
+they differ much; and analogous cases occur in many other genera. It
+is often difficult to say which of the two sexes departs most from the
+ordinary coloration of the genus to which the species belong; but Mr.
+Blackwall thinks that, as a general rule, it is the male; and Canestrini
+(19. This author has recently published a valuable essay on the
+'Caratteri sessuali secondarii degli Arachnidi,' in the 'Atti della Soc.
+Veneto-Trentina di Sc. Nat. Padova,' vol. i. Fasc. 3, 1873.) remarks
+that in certain genera the males can be specifically distinguished
+with ease, but the females with great difficulty. I am informed by Mr.
+Blackwall that the sexes whilst young usually resemble each other;
+and both often undergo great changes in colour during their successive
+moults, before arriving at maturity. In other cases the male alone
+appears to change colour. Thus the male of the above bright-coloured
+Sparassus at first resembles the female, and acquires his peculiar
+tints only when nearly adult. Spiders are possessed of acute senses, and
+exhibit much intelligence; as is well known, the females often shew 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 colour 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 colour in the male of some species, for instance of
+Theridion lineatum, it would appear that these sexual characters of
+the males have not as yet become well fixed. Canestrini draws the same
+conclusion from the fact that the males of certain species present two
+forms, differing from each other in the size and length of their jaws;
+and this reminds us of the above cases of dimorphic crustaceans.
+
+The male is generally much smaller than the female, sometimes to
+an extraordinary degree (20. Aug. Vinson ('Araneides des Iles de la
+Reunion,' pl. vi. figs. 1 and 2) gives a good instance of the small size
+of the male, in Epeira nigra. In this species, as I may add, the male
+is testaceous and the female black with legs banded with red. Other even
+more striking cases of inequality in size between the sexes have been
+recorded ('Quarterly Journal of Science,' July 1868, p. 429); but I
+have not seen the original accounts.), and he is forced to be extremely
+cautious in making his advances, as the female often carries her coyness
+to a dangerous pitch. De Geer saw a male that "in the midst of his
+preparatory caresses was seized by the object of his attentions,
+enveloped by her in a web and then devoured, a sight which, as he
+adds, filled him with horror and indignation." (21. Kirby and Spence,
+'Introduction to Entomology,' vol. i. 1818, p. 280.) The Rev. O.P.
+Cambridge (22. 'Proceedings, Zoological Society,' 1871, p. 621.)
+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 which the diminutive male escapes from the ferocity of the
+female, by gliding about and playing hide and seek over her body and
+along her gigantic limbs: in such a pursuit it is evident that the
+chances of escape would be in favour 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, probably to the size we now see them, i.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 Theridion (23. Theridion (Asagena, Sund.) serratipes,
+4-punctatum et guttatum; see Westring, in Kroyer, 'Naturhist.
+Tidskrift,' vol. iv. 1842-1843, p. 349; and vol. ii. 1846-1849, p. 342.
+See, also, for other species, 'Araneae Suecicae,' p. 184.) have the
+power of making a stridulating sound, whilst the females are mute.
+The apparatus consists of a serrated ridge at the base of the abdomen,
+against which the hard hinder part of the thorax is rubbed; and of this
+structure not a trace can be detected in the females. It deserves notice
+that several writers, including the well-known arachnologist Walckenaer,
+have declared that spiders are attracted by music. (24. Dr. H.H. van
+Zouteveen, in his Dutch translation of this work (vol. i. p. 444),
+has collected several cases.) From the analogy of the Orthoptera and
+Homoptera, to be described in the next chapter, we may feel almost sure
+that the stridulation serves, as Westring 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. (25. Hilgendorf, however, has lately called attention to an
+analogous structure in some of the higher crustaceans, which seems
+adapted to produce sound; see 'Zoological Record,' 1869, p. 603.)
+
+CLASS, MYRIAPODA.
+
+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 limbata,
+however, and perhaps in some few other species, the males differ
+slightly in colour from the females; but this Glomeris is a highly
+variable species. In the males of the Diplopoda, the legs belonging
+either to one of the anterior or of the posterior segments of the body
+are modified into prehensile hooks which serve to secure the female.
+In some species of Iulus 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. (26. Walckenaer et P.
+Gervais, 'Hist. Nat. des Insectes: Apteres,' tom. iv. 1847, pp. 17, 19,
+68.)
+
+
+CHAPTER X.
+
+SECONDARY SEXUAL CHARACTERS OF INSECTS.
+
+Diversified structures possessed by the males for seizing the
+females--Differences between the sexes, of which the meaning is
+not understood--Difference in size between the
+sexes--Thysanura--Diptera--Hemiptera--Homoptera, musical powers
+possessed by the males alone--Orthoptera, musical instruments of the
+males, much diversified in structure; pugnacity; colours--Neuroptera,
+sexual differences in colour--Hymenoptera, pugnacity and
+odours--Coleoptera, colours; furnished with great horns, apparently
+as an ornament; battles, stridulating organs generally common to both
+sexes.
+
+In the immense class of insects the sexes sometimes differ in their
+locomotive-organs, and often in their sense-organs, as in the pectinated
+and beautifully plumose antennae of the males of many species. In
+Chloeon, one of the Ephemerae, the male has great pillared eyes, of
+which the female is entirely destitute. (1. Sir J. Lubbock, 'Transact.
+Linnean Soc.' vol. xxv, 1866, p. 484. With respect to the Mutillidae see
+Westwood, 'Modern Class. of Insects,' vol. ii. p. 213.) The ocelli are
+absent in the females of certain insects, as in the Mutillidae; 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 contrivances, therefore, by which the male
+is able to seize the female, may be briefly passed over. Besides the
+complex structures at the apex of the abdomen, which ought perhaps to
+be ranked as primary organs (2. These organs in the male often differ
+in closely-allied species, and afford excellent specific characters. But
+their importance, from a functional point of view, as Mr. R. MacLachlan
+has remarked to me, has probably been overrated. It has been suggested,
+that slight differences in these organs would suffice to prevent the
+intercrossing of well-marked varieties or incipient species, and would
+thus aid in their development. That this can hardly be the case, we
+may infer from the many recorded cases (see, for instance, Bronn,
+'Geschichte der Natur,' B. ii. 1843, s. 164; and Westwood, 'Transact.
+Ent. Soc.' vol. iii. 1842, p. 195) of distinct species having been
+observed in union. Mr. MacLachlan informs me (vide 'Stett. Ent.
+Zeitung,' 1867, s. 155) that when several species of Phryganidae, which
+present strongly-pronounced differences of this kind, were confined
+together by Dr. Aug. Meyer, THEY COUPLED, and one pair produced fertile
+ova.), "it is astonishing," as Mr. B.D. Walsh (3. 'The Practical
+Entomologist,' Philadelphia, vol. ii. May 1867, p. 88.) has remarked,
+"how many different organs are worked in by nature for the seemingly
+insignificant object of enabling the male to grasp the female firmly."
+The mandibles or jaws are sometimes used for this purpose; thus the male
+Corydalis cornutus (a neuropterous insect in some degree allied to the
+Dragon flies, 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. (4. Mr. Walsh,
+ibid. p. 107.) One of the stag-beetles of North America (Lucanus
+elaphus) uses his jaws, which are much larger than those of the female,
+for the same purpose, but probably likewise for fighting. In one of the
+sand-wasps (Ammophila) the jaws in the two sexes are closely alike, but
+are used for widely different purposes: the males, as Professor Westwood
+observes, "are exceedingly ardent, seizing their partners round the neck
+with their sickle-shaped jaws" (5. 'Modern Classification of Insects,'
+vol. ii. 1840, pp. 205, 206. Mr. Walsh, who called my attention to
+the double use of the jaws, says that he has repeatedly observed this
+fact.); whilst the females use these organs for burrowing in sand-banks
+and making their nests.
+
+[Fig. 9. Crabro cribrarius. Upper figure, male; lower figure, female.]
+
+The tarsi of the front-legs are dilated in many male beetles, or
+are furnished with broad cushions of hairs; and in many genera of
+water-beetles they are armed with a round flat sucker, so that the male
+may adhere to the slippery body of the female. It is a much more unusual
+circumstance that the females of some water-beetles (Dytiscus) have
+their elytra deeply grooved, and in Acilius sulcatus thickly set with
+hairs, as an aid to the male. The females of some other water-beetles
+(Hydroporus) have their elytra punctured for the same purpose. (6. We
+have here a curious and inexplicable case of dimorphism, for some of the
+females of four European species of Dytiscus, and of certain species
+of Hydroporus, have their elytra smooth; and no intermediate gradations
+between the sulcated or punctured, and the quite 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.) In the male of Crabro cribrarius (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. (7. Westwood, 'Modern Class.' vol. ii. p. 193. The following
+statement about Penthe, and others in inverted commas, are taken from
+Mr. Walsh, 'Practical Entomologist,' Philadelphia, vol. iii. p. 88.) 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, exactly like those on the tarsi of the Carabidae, "and
+obviously for the same end." In male dragon-flies, "the appendages
+at the tip of the tail are modified in an almost infinite variety of
+curious patterns to enable them to embrace the neck of the female."
+Lastly, in the males of many insects, the legs are furnished with
+peculiar spines, knobs or spurs; or the whole leg is bowed or thickened,
+but this is by no means invariably a sexual character; or one pair, or
+all three pairs are elongated, sometimes to an extravagant length. (8.
+Kirby and Spence, 'Introduct.' etc., vol. iii. pp. 332-336.)
+
+[Fig. 10. Taphroderes distortus (much enlarged). Upper figure, male;
+lower figure, female.]
+
+The sexes of many species in all the orders present differences, of
+which the meaning is not understood. One curious case is that of a
+beetle (Fig. 10), the male of which has left mandible much enlarged;
+so that the mouth is greatly distorted. In another Carabidous beetle,
+Eurygnathus (9. 'Insecta Maderensia,' 1854, page 20.), 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 differ in neuration (10. E. Doubleday, 'Annals and Mag. of
+Nat. Hist.' vol. i. 1848, p. 379. I may add that the wings in certain
+Hymenoptera (see Shuckard, 'Fossorial Hymenoptera,' 1837, pp. 39-43)
+differ in neuration according to sex.), and sometimes considerably in
+outline, as in the Aricoris epitus, which was shewn 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 discs of the posterior pair. (11. 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.) In several British
+butterflies, as shewn 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 (12. 'The Naturalist in Nicaragua,' 1874, pp. 316-320.
+On the phosphorescence of the eggs, see 'Annals and Magazine of Natural
+History,' Nov. 1871, p. 372.) 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 recognised as 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
+conspicuous than the male; and why the larvae themselves are likewise
+luminous.
+
+DIFFERENCE IN SIZE BETWEEN THE SEXES.
+
+With insects of all kinds the males are commonly smaller than the
+females; and this difference can often be detected even in the larval
+state. So considerable is the difference between the male and female
+cocoons of the silk-moth (Bombyx mori), that in France they are
+separated by a particular mode of weighing. (13. Robinet, 'Vers a Soie,'
+1848, p. 207.) 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 Bombyx cynthia and yamamai, and especially 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." (14. 'Transact. Ent. Soc.' 3rd series, vol. v. p. 486.)
+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
+impregnated as soon as possible. This end would be gained by the
+males being first matured in large numbers ready for the advent of the
+females; and this again would naturally follow, as Mr. A.R. Wallace
+has remarked (15. 'Journal of Proc. Ent. Soc.' Feb. 4, 1867, p. lxxi.),
+through natural selection; for the smaller males would be first matured,
+and thus would procreate a large number of offspring which would inherit
+the reduced size of their male parents, whilst the larger males from
+being matured later would leave fewer offspring.
+
+There are, however, exceptions to the rule of male insects being smaller
+than the females: and some of 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 (16.
+For this and other statements on the size of the sexes, see Kirby and
+Spence, ibid. vol. iii. p. 300; on the duration of life in insects, see
+p. 344.); 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 colours. But the most curious case,
+shewing 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 amongst the Bees, the males of Apis mellifica,
+Anthidium manicatum, and Anthophora acervorum, and amongst the Fossores,
+the males of the Methoca ichneumonides, are larger than the females.
+The explanation of this anomaly is that a marriage flight is absolutely
+necessary with these species, and the male requires great strength and
+size in order to carry the female through the air. Increased size has
+here been acquired in opposition to the usual relation between size and
+the period of development, for the males, though larger, emerge before
+the smaller females.
+
+We will now review the several Orders, selecting such facts as more
+particularly concern us. The Lepidoptera (Butterflies and Moths) will be
+retained for a separate chapter.
+
+ORDER, THYSANURA.
+
+The members of this lowly organised order are wingless, dull-coloured,
+minute insects, with ugly, almost misshapen heads and bodies. Their
+sexes do not differ, but they are interesting as shewing us that the
+males pay sedulous court to the females even low down in the animal
+scale. Sir J. Lubbock (17. 'Transact. Linnean Soc.' vol. xxvi. 1868,
+p. 296.) says: "it is very amusing to see these little creatures
+(Smynthurus luteus) coquetting together. The male, which is much smaller
+than the female, runs round her, and they butt one another, standing
+face to face and moving backward and forward like two playful lambs.
+Then the female pretends to run away and the male runs after her with
+a queer appearance of anger, gets in front and stands facing her again;
+then she turns coyly round, but he, quicker and more active, scuttles
+round too, and seems to whip her with his antennae; then for a bit they
+stand face to face, play with their antennae, and seem to be all in all
+to one another."
+
+ORDER, DIPTERA (FLIES).
+
+The sexes differ little in colour. 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 (18. 'The Malay Archipelago,' vol.
+ii. 1869, p. 313.) 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 colour,
+edged with black, with a pale central stripe, and as these insects have
+altogether a very elegant appearance, it is perhaps more probable that
+they serve as ornaments. That the males of some Diptera fight together
+is certain; Prof. Westwood (19. 'Modern Classification of Insects,' vol.
+ii. 1840, p. 526.) has several times seen this with the Tipulae. The
+males of other Diptera apparently try to win the females by their music:
+H. M�ller (20. 'Anwendung,' etc., 'Verh. d. n. V. Jahrg.' xxix. p. 80.
+Mayer, in 'American Naturalist,' 1874, p. 236.) 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. (21. See Mr. B.T. Lowne's interesting work, 'On the Anatomy of
+the Blow-fly, Musca vomitoria,' 1870, p. 14. He remarks (p. 33) that,
+"the captured flies utter a peculiar plaintive note, and that this sound
+causes other flies to disappear.")
+
+ORDER, HEMIPTERA (FIELD-BUGS).
+
+Mr. J.W. Douglas, who has particularly attended to the British species,
+has kindly given me an account of their sexual differences. The males of
+some species are furnished with wings, whilst the females are wingless;
+the sexes differ in the form of their bodies, elytra, antennae and
+tarsi; but as the signification of these differences are unknown, they
+may be here passed over. The females are generally larger and more
+robust than the males. With British, and, as far as Mr. Douglas knows,
+with exotic species, the sexes do not commonly differ much in colour;
+but in about six British species the male is considerably darker than
+the female, and in about four other species the female is darker than
+the male. Both sexes of some species are beautifully coloured; and
+as these insects emit an extremely nauseous odour, their conspicuous
+colours may serve as a signal that they are unpalatable to insectivorous
+animals. In some few cases their colours appear to be directly
+protective: thus Prof. Hoffmann informs me that he could hardly
+distinguish a small pink and green species from the buds on the trunks
+of lime-trees, which this insect frequents.
+
+Some species of Reduvidae make a stridulating noise; and, in the case of
+Pirates stridulus, this is said (22. Westwood, 'Modern Classification of
+Insects,' vol. ii. p. 473.) to be effected by the movement of the
+neck within the pro-thoracic cavity. According to Westring, Reduvius
+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.
+
+ORDER: HOMOPTERA.
+
+Every one who has wandered in a tropical forest must have been
+astonished at the din made by the male Cicadae. The females are mute; as
+the Grecian poet Xenarchus says, "Happy the Cicadas live, since they
+all have voiceless wives." The noise thus made could be plainly heard on
+board the "Beagle," when anchored at a quarter of a mile from the shore
+of Brazil; and Captain Hancock says it can be heard at the distance of
+a mile. The Greeks formerly kept, and the Chinese now keep these insects
+in cages for the sake of their song, so that it must be pleasing to
+the ears of some men. (23. These particulars are taken from Westwood's
+'Modern Classification of Insects,' vol. ii. 1840, p. 422. See, also,
+on the Fulgoridae, Kirby and Spence, 'Introduct.' vol. ii. p. 401.) The
+Cicadidae usually sing during the day, whilst the Fulgoridae appear to
+be night-songsters. The sound, according to Landois (24. 'Zeitschrift
+f�r wissenschaft. Zoolog.' B. xvii. 1867, ss. 152-158.), is produced by
+the vibration of the lips of the spiracles, which are set into motion
+by a current of air emitted from the tracheae; but this view has lately
+been disputed. Dr. Powell appears to have proved (25. 'Transactions of
+the New Zealand Institute,' vol. v. 1873, p. 286.) that it is produced
+by the vibration of a membrane, set into action by a special muscle.
+In the living insect, whilst 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, but
+is much less developed than in the male, and is never used for producing
+sound.
+
+With respect to the object of the music, Dr. Hartman, in speaking of the
+Cicada septemdecim of the United States, says (26. I am indebted to Mr.
+Walsh for having sent me this extract from 'A Journal of the Doings of
+Cicada septemdecim,' by Dr. Hartman.), "the drums are now (June 6th and
+7th, 1851) heard in all directions. This I believe to be the marital
+summons from the males. Standing in thick chestnut sprouts about as high
+as my head, where hundreds were around me, I observed the females coming
+around the drumming males." He adds, "this season (Aug. 1868) a dwarf
+pear-tree in my garden produced about fifty larvae of Cic. pruinosa; and
+I several times noticed the females to alight near a male while he was
+uttering his clanging notes." Fritz M�ller 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 distance 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, whilst the females are pale-coloured or obscure.
+
+ORDER, ORTHOPTERA (CRICKETS AND GRASSHOPPERS).
+
+The males in the three saltatorial families in this Order are remarkable
+for their musical powers, namely the Achetidae or crickets, the
+Locustidae for which there is no equivalent English name, and the
+Acridiidae or grasshoppers. The stridulation produced by some of the
+Locustidae is so loud that it can be heard during the night at the
+distance of a mile (27. L. Guilding, 'Transactions of the Linnean
+Society,' vol. xv. p. 154.); and that made by certain species is not
+unmusical even to the human ear, so that the Indians on the Amazons keep
+them in wicker cages. All observers agree that the sounds serve either
+to call or excite the mute females. With respect to the migratory
+locusts of Russia, Korte has given (28. I state this on the authority of
+Koppen, '�ber die Heuschrecken in S�drussland,' 1866, p. 32, for I have
+in vain endeavoured to procure Korte's work.) an interesting case of
+selection by the female of a male. The males of this species (Pachytylus
+migratorius) whilst coupled with the female stridulate from anger or
+jealousy, if approached by other males. The house-cricket when surprised
+at night uses its voice to warn its fellows. (29. Gilbert White,
+'Natural History of Selborne,' vol. ii. 1825, p. 262.) In North America
+the Katy-did (Platyphyllum concavum, one of the Locustidae) is described
+(30. Harris, 'Insects of New England,' 1842, p. 128.) as mounting on
+the upper branches of a tree, and in the evening beginning "his noisy
+babble, while rival notes issue from the neighbouring trees, and the
+groves resound with the call of Katy-did-she-did the live-long night."
+Mr. Bates, in speaking of the European field-cricket (one of the
+Achetidae), 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,
+whilst the successful musician caresses with his antennae the mate he
+has won." (31. 'The Naturalist on the Amazons,' vol. i. 1863, p. 252.
+Mr. Bates gives a very interesting discussion on the gradations in the
+musical apparatus of the three families. See also Westwood, 'Modern
+Classification of Insects,' vol. ii. pp. 445 and 453.) Dr. Scudder was
+able to excite one of these insects to answer him, by rubbing on a
+file with a quill. (32. 'Proceedings of the Boston Society of Natural
+History,' vol. xi. April 1868.) In both sexes a remarkable auditory
+apparatus has been discovered by Von Siebold, situated in the front
+legs. (33. 'Nouveau Manuel d'Anat. Comp.' (French translat.), tom. 1,
+1850, p. 567.)
+
+[Fig.11. Gryllus campestris (from Landois). 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.
+
+Fig.12. Teeth of Nervure of Gryllus domesticus (from Landois).]
+
+In the three Families the sounds are differently produced. In the males
+of the Achetidae both wing-covers have the same apparatus; and this
+in the field-cricket (see Gryllus campestris, Fig. 11) consists, as
+described by Landois (34. 'Zeitschrift f�r wissenschaft. Zoolog.' B.
+xvii. 1867, s. 117.), of 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 opposite wing. First one
+wing is rubbed over the other, and then the movement is reversed.
+Both wings are raised a little at the same time, so as to increase the
+resonance. In some species the wing-covers of the males are furnished at
+the base with a talc-like plate. (35. Westwood, 'Modern Classification
+of Insects,' vol. i. p. 440.) 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 shewn (36. 'Ueber der Tonapparat der Locustiden, ein Beitrag
+zum Darwinismus,' 'Zeitschrift f�r wissenschaft. Zoolog.' B. xxii. 1872,
+p. 100.) 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 shews that their development is in part directly due
+to the stimulus from the friction of one wing over the other.
+
+[Fig.13. Chlorocoelus Tanana (from Bates). a,b. Lobes of opposite
+wing-covers.]
+
+In the Locustidae the opposite wing-covers differ from each other in
+structure (Fig. 13), and the action cannot, as in the last family, be
+reversed. The left wing, which acts as the bow, lies over the right wing
+which serves as the fiddle. One of the 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 viridissima 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, coloured 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 Ephippiger
+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
+the wing-covers, and which has probably the effect of increasing the
+sound." (37. Westwood 'Modern Classification of Insects,' vol. i. p.
+453.)
+
+We thus see that the musical apparatus is more differentiated or
+specialised in the Locustidae (which include, I believe, the most
+powerful performers in the Order), than in the Achetidae, in which both
+wing-covers have the same structure and the same function. (38. Landois,
+'Zeitschrift f�r wissenschaft. Zoolog.' B. xvii. 1867, ss. 121, 122.)
+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-covers had serrated
+nervures on the under surface, and could be indifferently used as the
+bow; but that in the Locustidae the two wing-covers gradually became
+differentiated and perfected, on the principle of the division of
+labour, the one to act exclusively as the bow, and the other as the
+fiddle. Dr. Gruber takes the same view, and has shewn that rudimentary
+teeth are commonly found on the inferior surface of the right wing. By
+what steps the more simple apparatus in the Achetidae originated, we do
+not know, but it is probable that the basal portions of the wing-covers
+originally overlapped each other as they do at present; and that the
+friction of the nervures produced a grating sound, as is now the case
+with the wing-covers of the females. (39. Mr. Walsh also informs me
+that he has noticed that the female of the Platyphyllum concavum, "when
+captured makes a feeble grating noise by shuffling her wing-covers
+together.") A grating sound thus occasionally and accidentally made
+by the males, if it served them ever so little as a love-call to the
+females, might readily have been intensified through sexual selection,
+by variations in the roughness of the nervures having been continually
+preserved.
+
+[Fig.14. Hind-leg of Stenobothrus pratorum: r, the stridulating
+ridge; lower figure, the teeth forming the ridge, much magnified (from
+Landois).
+
+Fig.15. Pneumora (from specimens in the British Museum). Upper figure,
+male; lower figure, female.]
+
+In the last and third family, namely the Acridiidae or grasshoppers, the
+stridulation is produced in a very different manner, and according to
+Dr. Scudder, is not so shrill as in the preceding Families. The inner
+surface of the femur (Fig. 14, r) is furnished with a longitudinal
+row of minute, elegant, lancet-shaped, elastic teeth, from 85 to 93 in
+number (40. Landois, ibid. s. 113.); and these are scraped across the
+sharp, projecting nervures on the wing-covers, which are thus made to
+vibrate and resound. Harris (41. 'Insects of New England,' 1842, p.
+133.) says that when one of the males begins to play, he first "bends
+the shank of the hind-leg beneath the thigh, where it is lodged in a
+furrow designed to receive it, and then draws the leg briskly up and
+down. He does not play both fiddles together, but alternately, first
+upon one and then on the other." In many species, the base of the
+abdomen is hollowed out into a great cavity which is believed to act as
+a resounding board. In Pneumora (Fig. 15), a S. African genus belonging
+to the same family, we meet with a new and remarkable modification; in
+the males a small notched ridge projects obliquely from each side of
+the abdomen, against which the hind femora are rubbed. (42. Westwood,
+'Modern Classification,' vol i. p. 462.) As the male is furnished with
+wings (the female being wingless), it is remarkable that the thighs are
+not rubbed in the usual manner against the wing-covers; but this may
+perhaps be accounted for by the unusually small size of the hind-legs.
+I have not been able to examine the inner surface of the thighs, which,
+judging from analogy, would be finely serrated. The species of Pneumora
+have been more profoundly modified for the sake of stridulation than
+any other orthopterous insect; for in the male the whole body has been
+converted into a musical instrument, being distended with air, like
+a great pellucid bladder, so as to increase the resonance. Mr. Trimen
+informs me that at the Cape of Good Hope these insects make a wonderful
+noise during the night.
+
+In the three foregoing families, the females are almost always destitute
+of an efficient musical apparatus. But there are a few exceptions to
+this rule, for Dr. Gruber has shewn that both sexes of Ephippiger vitium
+are thus provided; though the organs differ in the male and female to a
+certain extent. Hence we cannot suppose that they have been transferred
+from the male to the female, as appears to have been the case with the
+secondary sexual characters of many other animals. They must have been
+independently developed in the two sexes, which no doubt mutually call
+to each other during the season of love. In most other Locustidae (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 transferred. Landois also found such rudiments on the
+under surface of the wing-covers of the female Achetidae, 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 other hand, they
+become further developed, and acquire their perfect structure at the
+last moult, when the insect is mature and ready to breed.
+
+From the facts now given, we see that the means by which the males of
+the Orthoptera produce their sounds are extremely diversified, and are
+altogether different from those employed by the Homoptera. (43. Landois
+has recently found in certain Orthoptera rudimentary structures closely
+similar to the sound-producing organs in the Homoptera; and this is a
+surprising fact. See 'Zeitschrift f�r wissenschaft, Zoolog.' B. xxii.
+Heft 3, 1871, p. 348.) But throughout the animal kingdom we often find
+the same object gained by the most diversified means; this seems due
+to the whole organisation having undergone multifarious changes in the
+course of ages, and as part after part varied different variations were
+taken advantage of for the same general purpose. The diversity of means
+for producing sound in the three families of the Orthoptera and in
+the Homoptera, impresses the mind with the high importance of these
+structures to the males, for the sake of calling or alluring the
+females. We need feel no surprise at the amount of modification which
+the Orthoptera have undergone in this respect, as we now know, from
+Dr. Scudder's remarkable discovery (44. 'Transactions, Entomological
+Society,' 3rd series, vol. ii. ('Journal of Proceedings,' p. 117).),
+that there has been more than ample time. This naturalist has lately
+found a fossil insect in the Devonian formation of New Brunswick, which
+is furnished with "the well-known tympanum or stridulating apparatus of
+the male Locustidae." The insect, though in most respects related to the
+Neuroptera, appears, as is so often the case with very ancient forms, to
+connect the two related Orders of the Neuroptera and 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 manoeuvring with their sword-like
+front-limbs, like hussars with their sabres. The Chinese keep these
+insects in little bamboo cages, and match them like game-cocks. (45.
+Westwood, 'Modern Classification of Insects,' vol. i. p. 427; for
+crickets, p. 445.) With respect to colour, 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
+colour, it is not probable that they owe their bright tints to sexual
+selection. Conspicuous colours may be of use to these insects, by giving
+notice that they are unpalatable. Thus it has been observed (46. Mr. Ch.
+Horne, in 'Proceedings of the Entomological Society,' May 3, 1869, p.
+xii.) that a bright-coloured Indian locust was invariably rejected when
+offered to birds and lizards. Some cases, however, are known of sexual
+differences in colour in this Order. The male of an American cricket
+(47. The Oecanthus nivalis, Harris, 'Insects of New England,' 1842, p.
+124. The two sexes of OE. pellucidus of Europe differ, as I hear from
+Victor Carus, in nearly the same manner.) is described as being as white
+as ivory, whilst the female varies from almost white to greenish-yellow
+or dusky. Mr. Walsh informs me that the adult male of Spectrum femoratum
+(one of the Phasmidae) "is of a shining brownish-yellow colour; the
+adult female being of a dull, opaque, cinereous brown; the young of both
+sexes being green." Lastly, I may mention that the male of one curious
+kind of cricket (48. Platyblemnus: Westwood, 'Modern Classification,'
+vol. i. p. 447.) is furnished with "a long membranous appendage, which
+falls over the face like a veil;" but what its use may be, is not known.
+
+ORDER, NEUROPTERA.
+
+Little need here be said, except as to colour. In the Ephemeridae the
+sexes often differ slightly in their obscure tints (49. B.D. Walsh, the
+'Pseudo-neuroptera of Illinois,' in 'Proceedings of the Entomological
+Society of Philadelphia,' 1862, p. 361.); 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 (50. 'Modern Classification,' vol. ii. p. 37.), the
+males of some of the Agrionidae, "are of a rich blue with black wings,
+whilst the females are fine green with colourless wings." But in Agrion
+Ramburii these colours are exactly reversed in the two sexes. (51.
+Walsh, ibid. p. 381. I am indebted to this naturalist for the following
+facts on Hetaerina, Anax, and Gomphus.) In the extensive N. American
+genus of Hetaerina, the males alone have a beautiful carmine spot at the
+base of each wing. In Anax junius the basal part of the abdomen in the
+male is a vivid ultramarine blue, and in the female grass-green. In the
+allied genus Gomphus, on the other hand, and in some other genera, the
+sexes differ but little in colour. In closely-allied 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 difference in colour between the sexes of many
+Libellulidae, 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
+colours 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 colours serve as a sexual attraction. Certain
+dragon-flies apparently are attracted by particular colours: Mr.
+Patterson observed (52. 'Transactions, Ent. Soc.' vol. i. 1836, p.
+lxxxi.) that the Agrionidae, of which the males are blue, settled in
+numbers on the blue float of a fishing line; whilst two other species
+were attracted by shining white colours.
+
+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 coloured exactly like the females; but that their
+bodies in a short time assume a conspicuous milky-blue tint, owing
+to the exudation of a kind of oil, soluble in ether and alcohol. Mr.
+MacLachlan believes that in the male of Libellula depressa this
+change of colour does not occur until nearly a fortnight after the
+metamorphosis, when the sexes are ready to pair.
+
+Certain species of Neurothemis present, according to Brauer (53. See
+abstract in the 'Zoological Record' for 1867, p. 450.), a curious case
+of dimorphism, some of the females having ordinary wings, whilst others
+have them "very richly netted, as in the males of the same species."
+Brauer "explains the phenomenon on Darwinian principles by the
+supposition that the close 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 several
+species of Agrion, in which some individuals are of an orange colour,
+and these are invariably females. This is probably a case of reversion;
+for in the true Libellulae, when the sexes differ in colour, the females
+are orange or yellow; so that supposing Agrion to be descended from some
+primordial form which resembled the typical Libellulae 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. MacLachlan to fight together,
+excepting, as he believes, in some of the smaller species of Agrion. In
+another group in this Order, namely, the Termites or white ants, both
+sexes at the time of swarming may be seen running about, "the male after
+the female, sometimes two chasing one female, and contending with great
+eagerness who shall win the prize." (54. Kirby and Spence, 'Introduction
+to Entomology,' vol. ii. 1818, p. 35.) The Atropos pulsatorius is said
+to make a noise with its jaws, which is answered by other individuals.
+(55. Houzeau, 'Les Facult�s Mentales,' etc. Tom. i. p. 104.)
+
+ORDER, HYMENOPTERA.
+
+That inimitable observer, M. Fabre (56. See an interesting article, 'The
+Writings of Fabre,' in 'Nat. Hist. Review,' April 1862, p. 122.), 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 supremacy, and when the victory is decided, quietly
+flies away in company with the conqueror." Westwood (57. 'Journal of
+Proceedings of Entomological Society,' Sept. 7, 1863, p. 169.) says
+that the males of one of the saw-flies (Tenthredinae) "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 recognising each other after long intervals of time, and are deeply
+attached. For instance, Pierre Huber, whose accuracy no one doubts,
+separated some ants, and when, after an interval of four months, they
+met others which had formerly belonged to the same community, they
+recognised and caressed one another with their antennae. Had they been
+strangers they would have fought together. Again, when two communities
+engage in a battle, the ants on the same side sometimes attack each
+other in the general confusion, but they soon perceive their mistake,
+and the one ant soothes the other. (58. P. Huber, 'Recherches sur les
+Moeurs des Fourmis,' 1810, pp. 150, 165.)
+
+In this Order slight differences in colour, according to sex, are
+common, but conspicuous differences are rare except in the family of
+Bees; yet both sexes of certain groups are so brilliantly coloured--for
+instance in Chrysis, in which vermilion and metallic greens
+prevail--that we are tempted to attribute the result to sexual
+selection. In the Ichneumonidae, according to Mr. Walsh (59.
+'Proceedings of the Entomological Society of Philadelphia,' 1866, pp.
+238, 239.), the males are almost universally lighter-coloured 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 Sirex juvencus is banded with orange, whilst
+the female is dark purple; but it is difficult to say which sex is the
+more ornamented. In Tremex columbae the female is much brighter coloured
+than the male. I am informed by Mr. F. Smith, that the male ants of
+several species are black, the females being testaceous.
+
+In the family of Bees, especially in the solitary species, as I hear
+from the same entomologist, the sexes often differ in colour. The males
+are generally the brighter, and in Bombus as well as in Apathus, much
+more variable in colour than the females. In Anthophora retusa the male
+is of a rich fulvous-brown, whilst the female is quite black: so are the
+females of several species of Xylocopa, the males being bright yellow.
+On the other hand the females of some species, as of Andraena fulva, are
+much brighter coloured than the males. Such differences in colour
+can hardly be accounted for by the males being defenceless and thus
+requiring protection, whilst the females are well defended by their
+stings. H. M�ller (60. 'Anwendung der Darwinschen Lehre auf Bienen,'
+Verh. d. n. V. Jahrg. xxix.), who has particularly attended to the
+habits of bees, attributes these differences in colour in chief part to
+sexual selection. That bees have a keen perception of colour is certain.
+He says that the males search eagerly and fight for the possession of
+the females; and he accounts through such contests for the mandibles of
+the males being in certain species larger than those of the females.
+In some cases the males are far more numerous than the females, either
+early in the season, or at all times and places, or locally; whereas
+the females in other cases are apparently in excess. In some species the
+more beautiful males appear to have been selected by the females; and in
+others the more beautiful females by the males. Consequently in certain
+genera (M�ller, p. 42), the males of the several species differ much in
+appearance, whilst the females are almost indistinguishable; in other
+genera the reverse occurs. H. M�ller believes (p. 82) that the colours
+gained by one sex through sexual selection have often been transferred
+in a variable degree to the other sex, just as the pollen-collecting
+apparatus of the female has often been transferred to the male, to whom
+it is absolutely useless. (61. M. Perrier in his article 'la Selection
+sexuelle d'apr�s 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 unfertilised ova,
+they could not transmit new characters to their male offspring. This
+is an extraordinary objection. A female bee fertilised 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
+characters of their male grandfathers? To take a case with ordinary
+animals as nearly parallel as possible: if a female of any white
+quadruped or bird were crossed by a male of a black breed, and the male
+and female offspring were paired together, will it be pretended that the
+grandchildren would not inherit a tendency to blackness from their
+male grandfather? The acquirement of new characters by the sterile
+worker-bees is a much more difficult case, but I have endeavoured to
+shew in my 'Origin of Species,' how these sterile beings are subjected
+to the power of natural selection.)
+
+Mutilla Europaea makes a stridulating noise; and according to Goureau
+(62. Quoted by Westwood, 'Modern Classification of Insects,' vol. ii.
+p. 214.) both sexes have this power. He attributes the sound to the
+friction of the third and preceding abdominal segments, and I find that
+these surfaces are marked with very fine concentric ridges; but so is
+the projecting thoracic collar into which the head articulates, and
+this collar, when scratched with the point of a needle, emits the proper
+sound. It is rather surprising that both sexes should have the power
+of stridulating, as the male is winged and the female wingless. It is
+notorious that Bees express certain emotions, as of anger, by the tone
+of their humming; and according to H. M�ller (p. 80), the males of some
+species make a peculiar singing noise whilst pursuing the females.
+
+ORDER, COLEOPTERA (BEETLES).
+
+Many beetles are coloured 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 colours, which are often arranged in stripes, spots, crosses,
+and other elegant patterns. Such colours 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
+colours 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 have been developed in one sex and then transferred
+to the other; and this view is even in some degree probable in those
+groups which possess other well-marked secondary sexual characters.
+Blind beetles, which cannot of course behold each other's beauty, never,
+as I hear from Mr. Waterhouse, jun., exhibit bright colours, 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, offer an exception to the
+rule that the sexes of beetles do not differ in colour. Most of these
+insects are large and splendidly coloured. The males in the genus
+Pyrodes (63. Pyrodes pulcherrimus, in which the sexes differ
+conspicuously, has been described by Mr. Bates in 'Transact. Ent. Soc.'
+1869, p. 50. I will specify the few other cases in which I have heard
+of a difference in colour between the sexes of beetles. Kirby and Spence
+('Introduct. to Entomology,' vol. iii. p. 301) mention a Cantharis,
+Meloe, Rhagium, and the Leptura 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 Longicorns. Messrs.
+R. Trimen and Waterhouse, jun., inform me of two Lamellicorns, viz., a
+Peritrichia and Trichius, the male of the latter being more obscurely
+coloured than the female. In Tillus elongatus the male is black, and
+the female always, as it is believed, of a dark blue colour, with a red
+thorax. The male, also, of Orsodacna atra, as I hear from Mr. Walsh,
+is black, the female (the so-called O. ruficollis) having a rufous
+thorax.), which I saw in Mr. Bates's collection, are generally redder
+but rather duller than the females, the latter being coloured of a more
+or less splendid golden-green. On the other hand, in one species the
+male is golden-green, the female being richly tinted with red and
+purple. In the genus Esmeralda the sexes differ so greatly in colour
+that they have been ranked as distinct species; in one species both
+are of a beautiful shining green, but the male has a red thorax. On the
+whole, as far as I could judge, the females of those Prionidae, in which
+the sexes differ, are coloured more richly than the males, and this
+does not accord with the common rule in regard to colour, when acquired
+through sexual selection.
+
+[Fig.16. Chalcosoma atlas. Upper figure, male (reduced); lower figure,
+female (nat. size).
+
+Fig. 17. Copris isidis.
+
+Fig. 18. Phanaeus faunus.
+
+Fig. 19. Dipelicus cantori.
+
+Fig. 20. Onthophagus rangifer, enlarged. (In Figs. 17 to 20 the
+left-hand figures are males.)]
+
+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 wonderful both from their size and diversified shapes. Instead of
+describing them, I have given figures of the males and females of some
+of the more remarkable forms. (Figs. 16 to 20.) The females generally
+exhibit rudiments of the horns in the form of small knobs or ridges; but
+some are destitute of even the slightest rudiment. On the other hand,
+the horns are nearly as well developed in the female as in the male
+Phanaeus 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 (64. 'Proceedings of the
+Entomological Society of Philadephia,' 1864, p. 228.) found that in
+Phanaeus carnifex the horns were thrice as long in some males as in
+others. Mr. Bates, after examining above a hundred males of Onthophagus
+rangifer (Fig. 20), thought that he had at last discovered a species in
+which the horns did not vary; but further research proved the contrary.
+
+The extraordinary size of the horns, and their widely different
+structure in closely-allied forms, indicate that they have been formed
+for some purpose; but their excessive variability in the males of the
+same species leads to the inference that this purpose cannot be of a
+definite nature. The horns do not shew marks of friction, as if used
+for any ordinary work. Some authors suppose (65. Kirby and Spence,
+'Introduction to Entomology,' vol. iii. p. 300.) that as the males
+wander about much more than the females, they require horns as a defence
+against their enemies; but as the horns are often blunt, they do not
+seem well adapted for defence. 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 evidence, 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 two sexes in above a hundred
+species of the Copridae, did not find any marked difference in this
+respect amongst well-developed individuals. In Lethrus, moreover, a
+beetle belonging to the same great division of the Lamellicorns, the
+males are known to fight, but are not provided with horns, though their
+mandibles are much larger than those of the female.
+
+The conclusion that the horns have been acquired as ornaments is that
+which best agrees with the fact of their having been so immensely, yet
+not fixedly, developed,--as shewn by their extreme variability in the
+same species, and by their extreme diversity in closely-allied species.
+This view will at first appear extremely improbable; but we shall
+hereafter find with many animals 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.
+
+[Fig.21. Onitis furcifer, male viewed from beneath.
+
+Fig.22. Onitis furcifer. Left-hand figure, male, viewed laterally.
+Right-hand figure, female. a. Rudiment of cephalic horn. b. Trace of
+thoracic horn or crest.]
+
+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 exhibit a rudiment
+of a single horn on the head (Fig. 22, a), and of a crest (b) on the
+thorax. That the slight thoracic crest in the female is a rudiment of
+a projection proper to the male, though 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 the
+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 Lamellicorn
+beetles, as in Phanaeus (Fig. 18).
+
+The old belief that rudiments have been created to complete 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. We may
+reasonably suspect that the males originally bore horns and transferred
+them to the females in a rudimentary condition, as in so many other
+Lamellicorns. Why the males subsequently lost their horns, we know not;
+but this may have been caused through the principle of compensation,
+owing to the development of the large horns and projections on the lower
+surface; and as these are confined to the males, the rudiments of the
+upper horns on the females would not have been thus obliterated.
+
+[Fig. 23. Bledius taurus, magnified. Left-hand figure, male; right-hand
+figure, female.]
+
+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 (66. Kirby and Spence,
+'Introduction to Entomology,' vol. iii. p. 329.), 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 sets, differing
+greatly in the size of their bodies and in the development of their
+horns, without intermediate gradations. In a species of Bledius (Fig.
+23), also belonging to the Staphylinidae, Professor Westwood states
+that, "male specimens can be found in the same locality in which the
+central horn of the thorax is very large, but the horns of the head
+quite rudimental; and others, in which the thoracic horn is much
+shorter, whilst the protuberances on the head are long." (67. 'Modern
+Classification of Insects,' vol. i. p. 172: Siagonium, p. 172. In
+the British Museum I noticed one male specimen of Siagonium in an
+intermediate condition, so that the dimorphism is not strict.) Here we
+apparently have a case of compensation, which throws light on that just
+given, of the supposed loss of the upper horns by the males of Onitis.
+
+LAW OF BATTLE.
+
+Some male beetles, which seem ill-fitted for fighting, nevertheless
+engage in conflicts for the possession of the females. Mr. Wallace (68.
+'The Malay Archipelago,' vol. ii. 1869, p. 276. Riley, Sixth 'Report
+on Insects of Missouri,' 1874, p. 115.) saw two males of Leptorhynchus
+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 possessing 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 (69. 'Entomological Magazine,' vol. i. 1833, p. 82. See also
+on the conflicts of this species, Kirby and Spence, ibid. vol. iii. p.
+314; and Westwood, ibid. vol. i. p. 187.) enclosed two males with one
+female in a box, the larger male severely pinched the smaller one, until
+he resigned his pretensions. A friend informs me that when a boy he
+often put the males together to see them fight, and he noticed that
+they were much bolder and fiercer than the females, as with the higher
+animals. The males would seize hold of his finger, if held in front
+of them, but not so the females, although they have stronger jaws.
+The males of many of the Lucanidae, as well as of the above-mentioned
+Leptorhynchus, 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
+away. (70. Quoted from Fischer, in 'Dict. Class. d'Hist. Nat.' tom.
+x. p. 324.) The two sexes of another Lamellicorn beetle, the Ateuchus
+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 believes,
+would remain on the same spot until she died. (71. 'Ann. Soc. Entomolog.
+France,' 1866, as quoted in 'Journal of Travel,' by A. Murray, 1868, p.
+135.)
+
+[Fig. 24. Chiasognathus Grantii, reduced. Upper figure, male; lower
+figure, female.]
+
+The great mandibles of the male Lucanidae 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 Lucanus elaphus of N. 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. Chile--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.
+
+Sexual selection, which implies the possession of considerable
+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 shew mutual affection; many have the power
+of stridulating when excited; many are furnished with the most
+extraordinary horns, apparently for the sake of ornament; and some,
+which are diurnal in their habits, are gorgeously coloured. Lastly,
+several of the largest beetles in the world belong to this family, which
+was placed by Linnaeus and Fabricius as the head of the Order. (72.
+Westwood, 'Modern Classification,' vol. i. p. 184.)
+
+STRIDULATING ORGANS.
+
+Beetles belonging 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 (73. Wollaston, 'On Certain Musical
+Curculionidae,' 'Annals and Mag. of Nat. Hist.' vol. vi. 1860, p. 14.),
+but it is not comparable with that made by the Orthoptera. The rasp
+generally consists of a narrow, slightly-raised surface, crossed by very
+fine, parallel ribs, sometimes so fine as to cause iridescent colours,
+and having a very elegant appearance under the microscope. In some
+cases, as with Typhoeus, minute, bristly or scale-like prominences, with
+which the whole surrounding surface is covered in approximately parallel
+lines, could be traced passing into the ribs of the rasp. The transition
+takes place by their 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 specially modified for the purpose. It is rapidly moved across
+the rasp, or conversely the rasp across the scraper.
+
+[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 abdominal segment, each rasp (74.
+Landois, 'Zeitschrift fur wissenschaft Zoolog.' B. xvii. 1867, s. 127.)
+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 general outline. In many Crioceridae, and in Clythra
+4-punctata (one of the Chrysomelidae), and in some Tenebrionidae, etc.
+(75. I am greatly indebted to Mr. G.R. Crotch for having sent me many
+prepared specimens of various beetles belonging to these three families
+and to others, as well as for valuable information. He believes that the
+power of stridulation in the Clythra has not been previously observed. I
+am also much indebted to Mr. E.W. Janson, for information and specimens.
+I may add that my son, Mr. F. Darwin, finds that Dermestes murinus
+stridulates, but he searched in vain for the apparatus. Scolytus
+has lately been described by Dr. Chapman as a stridulator, in the
+'Entomologist's Monthly Magazine,' vol. vi. p. 130.), 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 femora. (76.
+Schiodte, translated, in 'Annals and Magazine of Natural History,' vol.
+xx. 1867, p. 37.) In certain Curculionidae and Carabidae (77. Westring
+has described (Kroyer, 'Naturhist. Tidskrift,' B. ii. 1848-49, p. 334)
+the stridulating organs in these two, as well as in other families.
+In the Carabidae I have examined Elaphrus uliginosus and Blethisa
+multipunctata, sent to me by Mr. Crotch. In Blethisa the transverse
+ridges on the furrowed border of the abdominal segment do not, as far as
+I could judge, come into play in scraping the rasps on the elytra.), the
+parts are completely reversed in position, for the rasps are seated on
+the inferior surface of the elytra, near their apices, or along their
+outer margins, and the edges of the abdominal segments serve as the
+scrapers. In 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 number of long-horned beetles
+(Longicornia) the organs are situated quite otherwise, the rasp being on
+the meso-thorax, which is rubbed against the pro-thorax; Landois counted
+238 very fine ribs on the rasp of Cerambyx heros.
+
+[Fig.26. Hind-leg of Geotrupes stercorarius (from Landois). r. Rasp. c.
+Coxa. f. Femur. t. Tibia. tr. Tarsi.]
+
+Many Lamellicorns have the power of stridulating, and the organs differ
+greatly in position. Some species stridulate very loudly, so that
+when Mr. F. Smith caught a Trox sabulosus, a gamekeeper, who stood
+by, thought he had caught a mouse; but I failed to discover the proper
+organs in this beetle. In Geotrupes and 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 projecting part
+of one of the abdominal segments. In the nearly allied Copris lunaris,
+an excessively narrow fine rasp runs along the sutural margin of the
+elytra, with another short rasp near the basal outer margin; but in
+some other Coprini the rasp is seated, according to Leconte (78. I am
+indebted to Mr. Walsh, of Illinois, for having sent me extracts from
+Leconte's 'Introduction to Entomology,' pp. 101, 143.), on the dorsal
+surface of the abdomen. In Oryctes it is seated on the pro-pygidium;
+and, according to the same entomologist, in some other Dynastini, on the
+under surface of the elytra. Lastly, Westring states that in Omaloplia
+brunnea the rasp is placed on the pro-sternum, and the scraper on the
+meta-sternum, the parts thus occupying the under surface of the body,
+instead of the upper surface as in the 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
+shuffling or hissing noise by the rubbing together of any hard and rough
+parts of their bodies, which happened to be in contact; and that from
+the noise thus produced being in some way useful, the rough surfaces
+were gradually developed into regular stridulating organs. Some beetles
+as they move, now produce, either intentionally or unintentionally, a
+shuffling noise, without possessing any proper organs for the purpose.
+Mr. Wallace informs me that the Euchirus longimanus (a Lamellicorn,
+with the anterior legs wonderfully elongated in the male) "makes, whilst
+moving, a low hissing sound by the protrusion and contraction of the
+abdomen; and when seized it produces a grating sound by rubbing its
+hind-legs against the edges of the elytra." The hissing sound is clearly
+due to a narrow rasp running along the sutural margin of each elytron;
+and I could likewise make the grating sound by rubbing the shagreened
+surface of the femur against the granulated margin of the corresponding
+elytron; but I could not here detect any proper rasp; nor is it likely
+that I could have overlooked it in so large an insect. After examining
+Cychrus, and reading what Westring has written about this beetle, it
+seems very doubtful whether it possesses any true rasp, though it has
+the power of emitting a sound.
+
+From the analogy of the Orthoptera and Homoptera, I expected to find the
+stridulating organs in the Coleoptera differing according to sex; but
+Landois, who has carefully examined several species, observed no such
+difference; nor did Westring; nor did Mr. G.R. Crotch in preparing the
+many specimens which he had the kindness to send me. Any difference
+in these organs, if slight, would, however, be difficult to detect, on
+account of their great variability. Thus, in the first pair of specimens
+of Necrophorus humator and of Pelobius which I examined, the rasp was
+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 stridulating, my son, Mr. F. Darwin,
+collected fifty-seven living specimens, which he separated into two
+lots, according as they made a greater or lesser noise, when held in the
+same manner. He then examined all 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 (Curculionidae), 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 Coleoptera. Mr. Crotch discovered that the males alone of
+two species of Heliopathes (Tenebrionidae) possess stridulating organs.
+I examined five males of H. gibbus, and in all these there was a
+well-developed rasp, partially divided into two, on the dorsal surface
+of the terminal abdominal segment; whilst in the same number of females
+there was not even a rudiment of the rasp, the membrane of this
+segment being transparent, and much thinner than in the male. In H.
+cribratostriatus the male has a similar rasp, excepting that it is
+not partially divided into two portions, and the female is completely
+destitute of this 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 independent rasp, or as a scraper for the abdominal rasp, I
+could not decide: the female exhibits no trace
+
+of this latter structure.
+
+Again, in three species of the Lamellicorn genus Oryctes, we have a
+nearly parallel case. In the females of O. 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 surface of this segment, when held in the proper light, is seen
+to be clothed with hairs, which are absent or are represented by
+excessively fine down in the males. It should be noticed that in all
+Coleoptera the effective part of the rasp is destitute of hairs. In O.
+senegalensis the difference between 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; whilst in the
+male these crests in proceeding towards the apex, become more and more
+confluent, regular, and naked; so that three-fourths of the segment is
+covered with extremely fine parallel ribs, which are quite absent in
+the female. In the females, however, of all three species of Oryctes, a
+slight grating or stridulating sound is produced, when the abdomen of a
+softened specimen is pushed backwards and forwards.
+
+In the case of the Heliopathes and Oryctes there can hardly be a doubt
+that the males stridulate in order to call or to excite the females;
+but with most beetles the stridulation apparently serves both sexes as
+a mutual call. Beetles stridulate under various emotions, in the same
+manner as birds use their voices for many purposes besides singing to
+their mates. The great Chiasognathus stridulates in anger or defiance;
+many species do the same from 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 encourage the female in her work, and
+from distress when she is removed. (79. M. P. de la Brulerie, as
+quoted in 'Journal of Travel,' A. Murray, vol. i. 1868, p. 135.) 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 supported by the fact that
+death-ticks (Anobium tessellatum) are well known to answer each other's
+ticking, and, as I have myself observed, a tapping noise artificially
+made. Mr. Doubleday also informs me that he has sometimes observed a
+female ticking (80. According to Mr. Doubleday, "the noise is produced
+by the insect raising itself on its legs as high as it can, and then
+striking its thorax five or six times, in rapid succession, against the
+substance upon which it is sitting." For references on this subject see
+Landois, 'Zeitschrift f�r wissen. Zoolog.' B. xvii. s. 131. Olivier says
+(as quoted by Kirby and Spence, 'Introduction to Entomology,' vol. ii.
+p. 395) that the female of Pimelia striata produces a rather loud sound
+by striking her abdomen against any hard substance, "and that the male,
+obedient to this call, soon attends her, and they pair."), and in an
+hour or two afterwards has found her united with a male, and on one
+occasion surrounded by several males. Finally, it is probable that the
+two sexes of many kinds of beetles were at first enabled to find each
+other by the slight 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.
+
+
+CHAPTER XI.
+
+INSECTS, continued.
+
+ORDER LEPIDOPTERA. (BUTTERFLIES AND MOTHS.)
+
+Courtship of butterflies--Battles--Ticking noise--Colours common to both
+
+sexes, or more brilliant in the males--Examples--Not due to the
+direct action of the conditions of life--Colours adapted for
+protection--Colours of moths--Display--Perceptive powers of the
+Lepidoptera--Variability--Causes of the difference in colour between the
+males and females--Mimicry, female butterflies more brilliantly coloured
+than the males--Bright colours of caterpillars--Summary and concluding
+remarks on the secondary sexual characters of insects--Birds and insects
+compared.
+
+In this great Order the most interesting points for us are the
+differences in colour between the sexes of the same species, and
+between the distinct species of the same genus. Nearly the whole of the
+following chapter will be devoted to this subject; but I will first make
+a few remarks on one or two other points. Several males may often
+be seen pursuing and crowding round the same female. Their courtship
+appears to be a prolonged affair, for I have frequently watched one or
+more males pirouetting round a female until I was tired, without seeing
+the end of the courtship. Mr. A.G. Butler also informs me that he has
+several times watched a male courting a female for a full quarter of
+an hour; but she pertinaciously refused him, and at last settled on the
+ground and closed her wings, so as to escape from his addresses.
+
+Although butterflies are weak and fragile creatures, they are
+pugnacious, and an emperor butterfly (1. Apatura Iris: 'The
+Entomologist's Weekly Intelligence,' 1859, p. 139. For the Bornean
+Butterflies, see C. Collingwood, 'Rambles of a Naturalist,' 1868,
+p. 183.) has been captured with the tips of its wings broken from a
+conflict with another male. Mr. Collingwood, in speaking of the frequent
+battles between the butterflies of Borneo, says, "They whirl round
+each other with the greatest rapidity, and appear to be incited by the
+greatest ferocity."
+
+The Ageronia feronia 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. (2. See my
+'Journal of Researches,' 1845, p. 33. Mr. Doubleday has detected ('Proc.
+Ent. Soc.' March 3, 1845, p. 123) a peculiar membranous sac at the base
+of the front wings, which is probably connected with the production of
+the sound. For the case of Thecophora, see 'Zoological Record,' 1869,
+p. 401. For Mr. Buchanan White's observations, the Scottish Naturalist,
+July 1872, p. 214.)
+
+Some moths also produce sounds; for instance, the males Theocophora
+fovea. On two occasions Mr. F. Buchanan White (3. 'The Scottish
+Naturalist,' July 1872, p. 213.) 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 odour, which is emitted by
+two species of Sphinx moths, is peculiar to the males (4. 'Zoological
+Record,' 1869, p. 347.); 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 colours 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 purpose, or that one sex may be
+attractive to the other? And, again, what is the meaning of the colours
+being widely different in the males and females of certain species,
+and alike in the two sexes of other species of the same genus? Before
+attempting to answer these questions a body of facts must be given.
+
+With our beautiful English butterflies, the admiral, peacock, and
+painted lady (Vanessae), as well as many others, the sexes are alike.
+This is also the case with the magnificent Heliconidae, 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 differ either
+greatly or slightly in colour. No language suffices to describe the
+splendour of the males of some tropical species. Even within the same
+genus we often find species presenting extraordinary differences between
+the sexes, whilst others have their sexes closely alike. Thus in the
+South American genus Epicalia, Mr. Bates, to whom I am indebted for
+most of the following facts, and for looking over this whole discussion,
+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 differently affected by external
+conditions. (5. See also Mr. Bates's paper in 'Proc. Ent. Soc. of
+Philadelphia,' 1865, p. 206. Also Mr. Wallace on the same subject, in
+regard to Diadema, in 'Transactions, Entomological Society of London,'
+1869, p. 278.) In nine of these twelve species the males rank amongst
+the most brilliant of all butterflies, and differ so greatly from the
+comparatively plain females that they were formerly placed in distinct
+genera. The females of these nine species resemble each other in their
+general type of coloration; and they likewise resemble both sexes of the
+species in several allied genera found in various parts of the world.
+Hence we may infer that these nine species, and probably all the others
+of the genus, are descended from an ancestral form which was coloured
+in nearly the same manner. In the tenth species the female still retains
+the same general colouring, but the male resembles her, so that he is
+coloured in a much less gaudy and contrasted manner than the males of
+the previous species. In the eleventh and twelfth species, the females
+depart from the usual type, for they are gaily decorated almost like the
+males, but in a somewhat less degree. Hence in these two latter species
+the bright colours of the males seem to have been transferred to the
+females; whilst in the tenth species the male has either retained or
+recovered the plain colours 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-coloured and nearly alike;
+whilst with the greater number the males are decorated with beautiful
+metallic tints in a diversified manner, and differ much from their
+females. The females throughout the genus retain the same general style
+of colouring, so that they resemble one another much more closely than
+they resemble their own males.
+
+In the genus Papilio, all the species of the Aeneas group are remarkable
+for their conspicuous and strongly contrasted colours, 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 colours, yet in certain species, as in J. oenone,
+the male is rather more bright-coloured than the female, and in a few
+(for instance J. andremiaja) the male is so different from the female
+that he might be mistaken for an entirely distinct species.
+
+Another striking case was pointed out to me in the British Museum by Mr.
+A. Butler, namely, one of the tropical American Theclae, in which both
+sexes are nearly alike and wonderfully splendid; in another species the
+male is coloured in a similarly gorgeous manner, whilst the whole upper
+surface of the female is of a dull uniform brown. Our common little
+English blue butterflies of the genus Lycaena, illustrate the various
+differences in colour between the sexes, almost as well, though not in
+so striking a manner, as the above exotic genera. In Lycaena agestis
+both sexes have wings of a brown colour, bordered with small ocellated
+orange spots, and are thus alike. In L. oegon the wings of the males
+are of a fine blue, bordered with black, whilst those of the female
+are brown, with a similar border, closely resembling the wings of L.
+agestis. Lastly, in L. arion both sexes are of a blue colour 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 shew, 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 colouring 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 coloured more splendidly than the males. In the second
+place, these details have been given to bring clearly before the mind
+that within the same genus, the two sexes frequently present every
+gradation from no difference in colour, 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 colours to the female, or to the male having retained, or perhaps
+recovered, the primordial colours 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 prevalence of the same general type of
+coloration throughout the whole of the same group, we may conclude
+that the causes have generally been the same which have determined the
+brilliant colouring 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 colours to the great heat and moisture of
+these zones; but Mr. Bates (6. 'The Naturalist on the Amazons,' vol.
+i. 1863, p. 19.) 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 conclusive when
+brilliantly-coloured males and plain-coloured females of the same
+species inhabit the same district, feed on the same food, and follow
+exactly the same habits of life. Even when the sexes resemble
+each other, we can hardly believe that their brilliant and
+beautifully-arranged colours are the purposeless result of the nature of
+the tissues and of the action of the surrounding conditions.
+
+With animals of all kinds, whenever colour has been modified for some
+special purpose, this has been, as far 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 whilst 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 coloured so as to
+imitate the objects on which these insects commonly rest. Dr. Rossler,
+I believe, first noticed the similarity of the closed wings of certain
+Vanessae and other butterflies to the bark of trees. Many analogous and
+striking facts could be given. The most interesting one is that recorded
+by Mr. Wallace (7. See the interesting article in the 'Westminster
+Review,' July 1867, p. 10. A woodcut of the Kallima is given by Mr.
+Wallace in 'Hardwicke's Science Gossip,' September 1867, p. 196.) 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, colour and veining, cannot
+be distinguished from a withered leaf with its footstalk. In some other
+cases the lower surfaces of the wings are brilliantly coloured, and
+yet are protective; thus in Thecla rubi the wings when closed are of an
+emerald green, and resemble the young leaves of the bramble, on which
+in spring this butterfly may often be seen seated. It is also remarkable
+that in very many species in which the sexes differ greatly in colour on
+their upper surface, the lower surface is closely similar or identical
+in both sexes, and serves as a protection. (8. Mr. G. Fraser, in
+'Nature,' April 1871, p. 489.)
+
+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 colours on the upper surface
+of such species as our admiral and peacock Vanessae, our white
+cabbage-butterflies (Pieris), or the great swallow-tail Papilio which
+haunts the open fens--for these butterflies are thus rendered visible to
+every living creature. In these species both sexes are alike; but in
+the common brimstone butterfly (Gonepteryx rhamni), the male is of an
+intense yellow, whilst the female is much paler; and in the orange-tip
+(Anthocharis cardamines) 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 colour
+should stand in any relation to ordinary protection. Prof. Weismann
+remarks (9. 'Einfluss der Isolirung auf die Artbildung,' 1872, p. 58.),
+that the female of one of the Lycaenae 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 colour cannot be in any way protective. Nevertheless, it
+is probable that conspicuous colours are indirectly beneficial to many
+species, as a warning that they are unpalatable. For in certain other
+cases, beauty has been gained through the imitation of other beautiful
+species, which inhabit the same district and enjoy an immunity from
+attack by being in some way offensive to their enemies; but then we have
+to account for the beauty of the imitated species.
+
+As Mr. Walsh has remarked to me, the females of our orange-tip
+butterfly, above referred to, and of an American species (Anth. genutia)
+probably shew us the primordial colours of the parent-species of the
+genus; for both sexes of four or five widely-distributed species are
+coloured in nearly the same manner. As in several previous cases, we may
+here infer that it is the males of Anth. cardamines and genutia which
+have departed from the usual type of the genus. In the Anth. sara from
+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 marvellously resembles a pale-coloured leaf; and in our English
+orange-tip, the under surface resembles the flower-head of the wild
+parsley, on which the butterfly often rests at night. (10. See the
+interesting observations by T.W. Wood, 'The Student,' Sept. 1868, p.
+81.) The same reason which compels us to believe that the lower surfaces
+have here been coloured for the sake of protection, leads us to deny
+that the wings have been tipped with bright orange for the same purpose,
+especially when this character is confined to the males.
+
+Most Moths rest motionless during the whole or greater part of the day
+with their wings depressed; and the whole upper surface is often shaded
+and coloured in an admirable manner, as Mr. Wallace has remarked, for
+escaping detection. The front-wings of the Bombycidae and Noctuidae (11.
+Mr. Wallace in 'Hardwicke's Science Gossip,' September 1867, p. 193.),
+when at rest, generally overlap and conceal the hind-wings; so that the
+latter might be brightly coloured without much risk; and they are in
+fact often thus coloured. During flight, moths would often be able to
+escape from their enemies; nevertheless, as the hind-wings are then
+fully exposed to view, their bright colours must generally have been
+acquired at some little risk. But the following fact shews 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 colour of their hind-wings. It would
+naturally be thought that this would be a source of danger; but Mr. J.
+Jenner Weir believes that it actually serves them as a means of escape,
+for birds strike at these brightly coloured and fragile surfaces,
+instead of at the body. For instance, Mr. Weir turned into his aviary a
+vigorous specimen of Triphaena pronuba, which was instantly pursued by a
+robin; but the bird's attention being caught by the coloured wings,
+the moth was not captured until after about fifty attempts, and small
+portions of the wings were repeatedly broken off. He tried the same
+experiment, in the open air, with a swallow and T. fimbria; but the
+large size of this moth probably interfered with its capture. (12. See
+also, on this subject, Mr. Weir's paper in 'Transactions, Entomological
+Society,' 1869, p. 23.) We are thus reminded of a statement made by Mr.
+Wallace (13. 'Westminster Review,' July 1867, p. 16.), 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 colours of many butterflies and of some moths are specially
+arranged for display, so that they may be readily seen. During the night
+colours are not visible, and there can be no doubt that the nocturnal
+moths, taken as a body, are much less gaily decorated than butterflies,
+all of which are diurnal in their habits. But the moths of certain
+families, such as the Zygaenidae, several Sphingidae, Uraniidae, some
+Arctiidae and Saturniidae, fly about during the day or early evening,
+and many of these are extremely beautiful, being far brighter coloured
+than the strictly nocturnal kinds. A few exceptional cases, however, of
+bright-coloured nocturnal species have been recorded. (14. For instance,
+Lithosia; but Prof. Westwood ('Modern Class. of Insects,' vol. ii. p.
+390) seems surprised at this case. On the relative colours of diurnal
+and nocturnal Lepidoptera, see ibid. pp. 333 and 392; also Harris,
+'Treatise on the Insects of New England,' 1842, p. 315.)
+
+There is evidence of another kind in regard to display. Butterflies, as
+before remarked, elevate their wings when at rest, but whilst basking
+in the sunshine often alternately raise and depress them, thus exposing
+both surfaces to full view; and although the lower surface is often
+coloured 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 coloured than the upper. (15. 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 'Transactions of the Linnean
+Society,' vol. xxv. part i. 1865.) In the English fritillaries
+(Argynnis) the lower surface alone is ornamented with shining silver.
+Nevertheless, as a general rule, the upper surface, which is probably
+more fully exposed, is coloured 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 M�ller informs me that three species of Castnia are found
+near his house in S. Brazil: of two of them the hind-wings are obscure,
+and are always covered by the front-wings when these butterflies are at
+rest; but the third species has black hind-wings, beautifully spotted
+with red and white, and these are fully expanded and displayed whenever
+the butterfly rests. Other 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 coloured 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. (16. See Mr. Wormald on this moth: 'Proceedings of the
+Entomological Society,' March 2, 1868.) Mr. Trimen informs me that in
+Guenee's great work, three moths are figured, in which the under surface
+is much the more brilliant. For instance, in the Australian Gastrophora
+the upper surface of the fore-wing is pale greyish-ochreous, while the
+lower surface is magnificently ornamented by an ocellus of cobalt-blue,
+placed in the midst of a black mark, surrounded by orange-yellow, and
+this by bluish-white. But the habits of these three moths are unknown;
+so that no explanation can be given of their unusual style of colouring.
+Mr. Trimen also informs me that the lower surface of the wings in
+certain other Geometrae (17. See also an account of the S. American
+genus Erateina (one of the Geometrae) in 'Transactions, Ent. Soc.' new
+series, vol. v. pl. xv. and xvi.) and quadrifid Noctuae are either more
+variegated or more brightly-coloured than the upper surface; but some
+of these species have the habit of "holding their wings quite erect over
+their backs, retaining them in this position for a considerable time,"
+and thus exposing the under surface to view. Other species, when settled
+on the ground or herbage, now and then suddenly and slightly lift up
+their wings. Hence the lower surface of the wings being brighter than
+the upper surface in certain moths is not so anomalous as it at first
+appears. The 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 (18. 'Proc Ent. Soc. of London,' July
+6, 1868, p. xxvii.) observes that they resemble butterflies in some of
+their movements; "for instance, in the gentle waving up and down of the
+wings as if for display, which is more characteristic of diurnal than of
+nocturnal Lepidoptera."
+
+It is a singular fact that no British moths which are brilliantly
+coloured, and, as far as I can discover, hardly any foreign species,
+differ much in colour according to sex; though this is the case with
+many brilliant butterflies. The male, however, of one American moth,
+the Saturnia Io, is described as having its fore-wings deep yellow,
+curiously marked with purplish-red spots; whilst the wings of the female
+are purple-brown, marked with grey lines. (19. Harris, 'Treatise,' etc.,
+edited by Flint, 1862, p. 395.) The British moths which differ sexually
+in colour are all brown, or of various dull yellow tints, or nearly
+white. In several species the males are much darker than the females
+(20. For instance, I observe in my son's cabinet that the males are
+darker than the females in the Lasiocampa quercus, Odonestis potatoria,
+Hypogymna dispar, Dasychira pudibunda, and Cycnia mendica. In this
+latter species the difference in colour between the two sexes is
+strongly marked; and Mr. Wallace informs me that we here have, as he
+believes, an instance of protective mimicry confined to one sex, as
+will hereafter be more fully explained. The white female of the Cycnia
+resembles the very common Spilosoma menthrasti, both sexes of which are
+white; and Mr. Stainton observed that this latter moth was rejected
+with utter disgust by a whole brood of young turkeys, which were fond
+of eating other moths; so that if the Cycnia was commonly mistaken by
+British birds for the Spilosoma, it would escape being devoured, and
+its white deceptive colour would thus be highly beneficial.), 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 with darker markings. (21. It is remarkable,
+that in the Shetland Islands the male of this moth, instead of differing
+widely from the female, frequently resembles her closely in colour (see
+Mr. MacLachlan, 'Transactions, Entomological Society,' 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 appears in these northern
+islands, the whiteness of the males would not be needed to render them
+visible to the females in the twilight night.) It is probable that
+in these cases the males are thus rendered more conspicuous, and more
+easily seen by the females whilst flying about in the dusk.
+
+From the several foregoing facts it is impossible to admit that the
+brilliant colours of butterflies, and of some few moths, have commonly
+been acquired for the sake of protection. We have seen that their
+colours and elegant patterns are arranged and exhibited as if for
+display. Hence I am led to believe that the females prefer or are most
+excited by the more brilliant males; for on any other supposition the
+males would, as far as we can see, be ornamented to no purpose. We know
+that ants and certain Lamellicorn beetles are capable of feeling an
+attachment for each other, and that ants recognise 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 colours. They certainly discover flowers by colour. 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 endeavour to insert their proboscis
+into them. Fritz M�ller informs me that several kinds of butterflies
+in S. Brazil shew an unmistakable preference for certain colours 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. Collingwood (22. 'Rambles of a Naturalist in the Chinese
+Seas,' 1868, p. 182.) in speaking of the difficulty in collecting
+certain butterflies in the Malay Archipelago, states that "a dead
+specimen pinned upon a conspicuous twig will often arrest an insect of
+the same species in its headlong flight, and bring it down within easy
+reach of the net, especially if it be of the opposite sex."
+
+The courtship of butterflies is, as before remarked, a prolonged affair.
+The males sometimes fight together in rivalry; and many may be seen
+pursuing or crowding round the same female. Unless, then, the females
+prefer one male to another, the pairing must be left to mere chance,
+and this does not appear probable. If, on the other band, the females
+habitually, or even occasionally, prefer the more beautiful males, the
+colours of the latter will have been rendered brighter by degrees, and
+will have been transmitted to both sexes or to one sex, according to 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 frequently be seen paired with battered,
+faded, or dingy males; but this is a circumstance which could hardly
+fail often to follow from the males emerging from their cocoons earlier
+than the females. With moths of the family of the Bombycidae, the sexes
+pair immediately after assuming the imago state; for they cannot feed,
+owing to the rudimentary condition of their mouths. The females, as
+several entomologists have remarked to me, lie in an almost torpid
+state, and appear not to evince the least choice in regard to their
+partners. This is the case with the common silk-moth (B. mori), as I
+have been told by some continental and English breeders. Dr. Wallace,
+who has had great experience in breeding Bombyx cynthia, is convinced
+that the females evince no choice or preference. He has kept above 300
+of these moths together, and has often found the most vigorous females
+mated with stunted males. The reverse appears to occur seldom; for, as
+he believes, the more vigorous males pass over the weakly females, and
+are attracted by those endowed with most vitality. Nevertheless, the
+Bombycidae, though obscurely-coloured, are often beautiful to our eyes
+from their elegant and mottled shades.
+
+I have as yet only referred to the species in which the males are
+brighter coloured 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. Butler shewed me several species of Callidryas in the
+British Museum, in some of which the females equalled, and in others
+greatly surpassed the males in beauty; for the females alone have the
+borders of their wings suffused with crimson and orange, and spotted
+with black. The plainer males of these species closely resemble each
+other, shewing 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. janira which has a conspicuous light-brown
+patch on her wings; and the females of some of the other species are
+brighter coloured than their males. Again, the females of Colias edusa
+and hyale have "orange or yellow spots on the black marginal border,
+represented in the males only by thin streaks"; and in Pieris it is the
+females which "are ornamented with black spots on the fore-wings, and
+these are only partially present in the males." Now the males of many
+butterflies are known to support the females during their marriage
+flight; but in the species just named it is the females which support
+the males; so that the part which the two sexes play is reversed, as is
+their relative beauty. Throughout the animal kingdom the males commonly
+take the more active share in wooing, and their beauty seems to have
+been increased by the females having accepted the more attractive
+individuals; but with these butterflies, the females take the more
+active part in the final marriage ceremony, so that we may suppose 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 foregoing statements have been taken, says in conclusion:
+"Though I am not convinced of the action of sexual selection in
+producing the colours of insects, it cannot be denied that these facts
+are strikingly corroborative of Mr. Darwin's views." (23. 'Nature,'
+April 27, 1871, p. 508. Mr. Meldola quotes Donzel, in 'Soc. Ent. de
+France,' 1837, p. 77, on the flight of butterflies whilst pairing. See
+also Mr. G. Fraser, in 'Nature,' April 20, 1871, p. 489, on the sexual
+differences of several British butterflies.)
+
+As sexual selection primarily depends on variability, a few words must
+be added on this subject. In respect to colour there is no difficulty,
+for any number of highly variable Lepidoptera could be named. One good
+instance will suffice. Mr. Bates shewed me a whole series of specimens
+of Papilio sesostris and P. childrenae; in the latter the males varied
+much in the extent of the beautifully enamelled green patch on the
+fore-wings, and in the size of the white mark, and of the splendid
+crimson stripe on the hind-wings; so that there was a great contrast
+amongst the males between the most and the least gaudy. The male of
+Papilio sesostris is much less beautiful than of P. childrenae; and
+it likewise varies a little in the size of the green patch on the
+fore-wings, and in the occasional appearance of the small crimson stripe
+on the hind-wings, borrowed, as it would seem, from its own female;
+for the females of this and of many other species in the Aeneas group
+possess this crimson stripe. Hence between the brightest specimens of
+P. sesostris and the dullest of P. childrenae, there was but a small
+interval; and it was evident that as far as mere variability is
+concerned, there would be no difficulty in permanently increasing the
+beauty of either species by means of selection. The variability is here
+almost confined to the male sex; but Mr. Wallace and Mr. Bates have
+shewn (24. Wallace on the Papilionidae of the Malayan Region, in
+'Transact. Linn. Soc.' vol. xxv. 1865, pp. 8, 36. A striking case of a
+rare variety, strictly intermediate between two other well-marked
+female varieties, is given by Mr. Wallace. See also Mr. Bates, in 'Proc.
+Entomolog. Soc.' Nov. 19, 1866, p. xl.) that the females of some species
+are extremely variable, the males being nearly constant. In a future
+chapter I shall have occasion to shew 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. (25. Mr. Bates was so kind as to
+lay this subject before the Entomological Society, and I have received
+answers to this effect from several entomologists.) This fact is at
+present inexplicable; but if it should hereafter be found that the
+formation of an ocellus is due to some change in the tissues of the
+wings, for instance, occurring at a very early period of development,
+we might expect, from what we know of the laws of inheritance, that it
+would be transmitted to both sexes, though arising and perfected in one
+sex alone.
+
+On the whole, although many serious objections may be urged, it seems
+probable that most of the brilliantly-coloured species of Lepidoptera
+owe their colours to sexual selection, excepting in certain cases,
+presently to be mentioned, in which conspicuous colours have been gained
+through mimicry as a protection. From the ardour of the male throughout
+the animal kingdom, he is generally willing to accept any female; and it
+is the female which usually exerts a choice. Hence, if sexual selection
+has been efficient with the Lepidoptera, the male, when the sexes
+differ, ought to be the more brilliantly coloured, and this undoubtedly
+is the case. When both sexes are brilliantly coloured and resemble
+each other, the characters acquired by the males appear to have been
+transmitted to both. We are led to this conclusion by cases, even within
+the same genus, of gradation from an extraordinary amount of difference
+to identity in colour between the two sexes.
+
+But it may be asked whether the difference in colour between the sexes
+may not be accounted for by other means besides sexual selection. Thus
+the males and females of the same species of butterfly are in several
+cases known (26. H.W. Bates, 'The Naturalist on the Amazons,' vol. ii.
+1863, p. 228. A.R. Wallace, in 'Transactions, Linnean Society,' vol.
+xxv. 1865, p. 10.) 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 (27. On this whole
+subject see 'The Variation of Animals and Plants under Domestication,'
+1868, vol. ii. chap. xxiii.) 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 colours 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 understand how it is that the females of
+allied species generally resemble one another so much more closely than
+do the males. They thus shew us approximately the primordial colouring
+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 colour thus caused will generally have been masked by
+the brilliant tints gained through sexual selection. When we treat of
+Birds, I shall have to discuss the whole question, as to how far the
+differences in colour between the sexes are due to the males having been
+modified through sexual selection for ornamental purposes, or to the
+females having been modified through natural selection for the sake of
+protection, so that I will here say but little on the subject.
+
+In all the cases in which the more common form of equal inheritance by
+both sexes has prevailed, the selection of bright-coloured males
+would tend to make the females bright-coloured; and the selection
+of dull-coloured females would tend to make the males dull. If both
+processes were carried on simultaneously, they would tend to counteract
+each other; and the final result would depend on whether a greater
+number of females from being well protected by obscure colours, or a
+greater number of males by being brightly-coloured and thus finding
+partners, succeeded in leaving more numerous offspring.
+
+In order to account for the frequent transmission of characters to one
+sex alone, Mr. Wallace expresses his belief that the more common form of
+equal inheritance by both sexes can be changed through natural selection
+into inheritance by one sex alone, but in favour of this view I can
+discover no evidence. We know from what occurs under domestication 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 colours to the males alone,
+and at the same time or subsequently, dull colours 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 requiring the transference of new
+characters to one sex alone, have been carried on with a multitude of
+species,--that the males have been rendered more brilliant by beating
+their rivals, and the females more dull-coloured by having escaped from
+their enemies. The male, for instance, of the common brimstone butterfly
+(Gonepteryx), is of a far more intense yellow than the female, though
+she is equally conspicuous; and it does not seem probable that she
+specially acquired her pale tints as a protection, though it is probable
+that the male acquired his bright colours as a sexual attraction. The
+female of Anthocharis cardamines does not possess the beautiful orange
+wing-tips of the male; consequently she closely resembles the white
+butterflies (Pieris) so common in our 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 colours.
+
+Finally, as we have seen, various considerations lead to the conclusion
+that with the greater number of brilliantly-coloured Lepidoptera it is
+the male which has been chiefly modified through sexual selection; the
+amount of difference between the sexes mostly depending on the form
+of inheritance which has prevailed. Inheritance is governed by so many
+unknown laws or conditions, that it seems to us to act in a capricious
+manner (28. The 'Variation of Animals and Plants under Domestication,'
+vol. ii. chap. xii. p. 17.); and we can thus, to a certain extent,
+understand how it is that with closely allied species the sexes either
+differ to an astonishing degree, or are identical in colour. 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 favour the supposition that we here see females actually
+undergoing the process of transition and losing their brightness for the
+sake of protection; for we have every reason to conclude that at any one
+time the greater number of species are in a fixed condition.
+
+MIMICRY.
+
+This principle was first made clear in an admirable paper by Mr. Bates
+(29. 'Transact. Linn. Soc.' vol. xxiii. 1862, p. 495.), who thus threw a
+flood of light on many obscure problems. It had previously been observed
+that certain butterflies in S. America belonging to quite distinct
+families, resembled the Heliconidae so closely in every stripe and shade
+of colour, that they could not be distinguished save by an experienced
+entomologist. As the Heliconidae are coloured in their usual manner,
+whilst the others depart from the usual colouring of the groups to which
+they belong, it is clear that the latter are the imitators, and the
+Heliconidae the imitated. Mr. Bates further observed that the imitating
+species are comparatively rare, whilst the imitated abound, and that the
+two sets live mingled together. From the fact of the Heliconidae being
+conspicuous and beautiful insects, yet so numerous in individuals and
+species, he concluded that they must be protected from the attacks of
+enemies by some secretion or odour; and this conclusion has now been
+amply confirmed (30. 'Proc. Entomological Soc.' Dec. 3, 1866, p. xlv.),
+especially by Mr. Belt. Hence Mr. Bates inferred that the butterflies
+which imitate the protected species have acquired their present
+marvellously 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
+colours of the imitated, but only of the imitating butterflies. We must
+account for the colours of the former in the same general manner, as in
+the cases previously discussed in this chapter. Since the publication of
+Mr. Bates' paper, similar and equally striking facts have been observed
+by Mr. Wallace in the Malayan region, by Mr. Trimen in South Africa, and
+by Mr. Riley in the United States. (31. Wallace, 'Transact. Linn. Soc.'
+vol. xxv. 1865 p. i.; also, 'Transact. Ent. Soc.' vol. iv. (3rd series),
+1867, p. 301. Trimen, 'Linn. Transact.' vol. xxvi. 1869, p. 497. Riley,
+'Third Annual Report on the Noxious Insects of Missouri,' 1871, pp.
+163-168. This latter essay is valuable, as Mr. Riley here discusses all
+the objections which have been raised against Mr. Bates's theory.)
+
+As some writers have felt much difficulty in understanding how the first
+steps in the process of mimicry could have been effected through natural
+selection, it may be well to remark that the process probably commenced
+long ago between forms not widely dissimilar in colour. In this case
+even a slight variation would be beneficial, if it rendered the one
+species more like the other; and afterwards the imitated species might
+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 ultimately
+assume an appearance or colouring wholly unlike that of the other
+members of the group to which they belonged. It should also be
+remembered that many species of Lepidoptera are liable to considerable
+and abrupt variations in colour. A few instances have been given in this
+chapter; and many more may be found in the papers of Mr. Bates and Mr.
+Wallace.
+
+With several species the sexes are alike, and imitate the two sexes of
+another species. But Mr. Trimen gives, in the paper already referred
+to, three cases in which the sexes of the imitated form differ from each
+other in colour, and the sexes of the imitating form differ in a like
+manner. Several cases have also been recorded where the females alone
+imitate brilliantly-coloured and protected species, the males retaining
+"the normal aspect of their immediate congeners." It is here obvious
+that the successive variations by which the female has been modified
+have been transmitted to her alone. It is, however, probable that some
+of the many successive variations would have been transmitted to, and
+developed in, the males had not such males been eliminated by being thus
+rendered less attractive to the females; so that only those variations
+were preserved which were from the first strictly limited in their
+transmission to the female sex. We have a partial illustration of these
+remarks in a statement by Mr. Belt (32. 'The Naturalist in Nicaragua,'
+1874, p. 385.); 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, whilst all the rest of the wings is barred and
+spotted with black, red and yellow, like the species they mimic. The
+females have not this white patch, and the males usually conceal it by
+covering it with the upper wing, so that I cannot imagine its being
+of any other use to them than as an attraction in courtship, when they
+exhibit it to the females, and thus gratify their deep-seated preference
+for the normal colour of the Order to which the Leptalides belong."
+
+BRIGHT COLOURS OF CATERPILLARS.
+
+Whilst reflecting on the beauty of many butterflies, it occurred to me
+that some caterpillars were splendidly coloured; and as sexual selection
+could not possibly have here acted, it appeared rash to attribute the
+beauty of the mature insect to this agency, unless the bright colours of
+their larvae could be somehow explained. In the first place, it may
+be observed that the colours of caterpillars do not stand in any close
+correlation with those of the mature insect. Secondly, their bright
+colours do not serve in any ordinary manner as a protection. 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 bird.
+
+I then applied to Mr. Wallace, who has an innate genius for solving
+difficulties. After some consideration he replied: "Most caterpillars
+require protection, as may be inferred from some kinds being furnished
+with spines or irritating hairs, and from many being coloured green like
+the leaves on which they feed, or being curiously like the twigs of the
+trees on which they live." Another instance of protection, furnished
+me by Mr. J. Mansel Weale, may be added, namely, that there is a
+caterpillar of a moth which lives on the mimosas in South Africa,
+and fabricates for itself a case quite indistinguishable from the
+surrounding thorns. From such considerations Mr. Wallace thought it
+probable that conspicuously coloured caterpillars were protected by
+having a nauseous taste; but as their skin is 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. Wallace remarks, "distastefulness alone would be
+insufficient to protect a caterpillar unless some outward sign indicated
+to its would-be destroyer that its prey was a disgusting morsel." Under
+these circumstances it would be highly advantageous to a caterpillar to
+be instantaneously and certainly recognised as unpalatable by all birds
+and other animals. Thus the most gaudy colours would be serviceable,
+and might have been gained by variation and the survival of the most
+easily-recognised individuals.
+
+This hypothesis appears at first sight very bold, but when it
+was brought before the Entomological Society (33. 'Proceedings,
+Entomological Society,' Dec. 3, 1866, p. xlv. and March 4, 1867, p.
+lxxx.) it was supported by various statements; and Mr. J. Jenner Weir,
+who keeps a large number of birds in an aviary, informs me that he
+has made many trials, and finds no exception to the rule, that all
+caterpillars of nocturnal and retiring habits with smooth skins, all of
+a green colour, and all which imitate twigs, are greedily devoured by
+his birds. The hairy and spinose kinds are invariably rejected, as
+were four conspicuously-coloured species. When the birds rejected a
+caterpillar, they plainly shewed, by shaking their heads, and cleansing
+their beaks, that they were disgusted by the taste. (34. 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.) Three conspicuous kinds of caterpillars and moths were also
+given to some lizards and frogs, by Mr. A. Butler, and were rejected,
+though other kinds were eagerly eaten. Thus the probability of Mr.
+Wallace's view is confirmed, namely, that certain caterpillars have been
+made conspicuous for their own good, so as to be easily recognised by
+their enemies, on nearly the same principle that poisons are sold in
+coloured bottles by druggists for the good of man. We cannot, however,
+at present thus explain the elegant diversity in the colours 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 colour, 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 REMARKS 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 differ 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
+differences of these kinds.
+
+In almost all the Orders, the males of some species, even of weak and
+delicate kinds, are known to be highly pugnacious; and some few are
+furnished with special weapons for fighting with their rivals. But the
+law of battle does not prevail nearly so widely with insects as with the
+higher animals. Hence it probably arises, that it is in only a few cases
+that the males have been rendered larger and stronger than the females.
+On the contrary, they are usually smaller, so that they may be developed
+within a shorter time, to be ready in large numbers for the emergence of
+the females.
+
+In two families of the Homoptera and in three of the 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 apparently for charming or exciting them in rivalry
+with other males. No one who admits the agency of selection of any kind,
+will, after reading the above discussion, dispute that these musical
+instruments have been acquired through sexual selection. In four other
+Orders the members of one sex, or more commonly of both sexes, are
+provided with organs for producing various sounds, which apparently
+serve merely as call-notes. When both sexes are thus provided, the
+individuals which were able to make the loudest or most continuous noise
+would gain partners before those which were less noisy, so that their
+organs have probably been gained through sexual selection. It is
+instructive to reflect on the wonderful diversity of the means for
+producing sound, possessed by the males alone, or by both sexes, in no
+less than six Orders. We thus learn how effectual sexual selection has
+been in leading to modifications which sometimes, as with the Homoptera,
+relate to important parts of the organisation.
+
+From the reasons assigned in the last chapter, it is probable that the
+great horns possessed by the 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 (Fig. 16), with its polished bronzed coat of mail, and
+its vast complex horns, magnified to the size of a horse, or even of a
+dog, it would be one of the most imposing animals in the world.
+
+The colouring of insects is a complex and obscure subject. When the male
+differs slightly from the female, and neither are brilliantly-coloured,
+it is probable that the sexes have varied in a slightly different
+manner, and that the variations have been transmitted by each sex to
+the same without any benefit or evil thus accruing. When the male is
+brilliantly-coloured and differs conspicuously from the female, as with
+some dragon-flies and many butterflies, it is probable that he owes his
+colours to sexual selection; whilst the female has retained a primordial
+or very ancient type of colouring, slightly modified by the agencies
+before explained. 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
+coloured, there is no doubt that they have been in a multitude of cases
+so coloured for the sake of protection. So it is in some instances when
+both are brightly-coloured, for they thus imitate 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 resemble each other and are both brilliant, especially when the
+colours are arranged for display, we may conclude that they have been
+gained by the male sex as an attraction, and have been transferred to
+the female. We are more especially led to this conclusion whenever the
+same type of coloration prevails throughout a whole group, and we find
+that the males of some species differ widely in colour from the females,
+whilst others differ slightly or not at all with intermediate gradations
+connecting these extreme states.
+
+In the same manner as bright colours have often been partially
+transferred from the males to the females, so it has been with the
+extraordinary horns of many Lamellicorn and some other beetles. So
+again, the sound-producing organs proper to the males of the Homoptera
+and Orthoptera have generally been transferred in a rudimentary, or
+even in a nearly perfect condition, to the females; yet not sufficiently
+perfect to be of any use. It is also an interesting fact, as bearing
+on sexual selection, that the stridulating organs of certain male
+Orthoptera are not fully developed until the last moult; and that the
+colours of certain male dragon-flies are not fully developed until some
+little time after their emergence from the pupal state, and when they
+are ready to breed.
+
+Sexual selection implies that the more attractive individuals are
+preferred by the opposite sex; and as with insects, when the sexes
+differ, it is the male which, with some rare exceptions, is the
+more ornamented, and departs more from the type to which the species
+belongs;--and as it is the male which searches eagerly for the female,
+we must suppose that the females 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 contrivances 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 colours or other ornaments with which the male is decorated.
+
+If we admit that the females of the Homoptera and Orthoptera appreciate
+the musical tones of their male partners, and that the various
+instruments have been perfected through sexual selection, there is
+little improbability in the females of other insects appreciating beauty
+in form or colour, and consequently in such characters having been
+thus gained by the males. But from the circumstance of colour being so
+variable, and from its having been so often modified for the sake of
+protection, it is 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 colour; for we are then left to mere
+analogy. With the Coleoptera, however, as before remarked, it is in
+the great Lamellicorn group, placed by some authors at the head of the
+Order, and in which we sometimes see a mutual attachment between the
+sexes, that we find the males of some species possessing weapons
+for sexual strife, others furnished with wonderful horns, many with
+stridulating organs, and others ornamented with splendid metallic tints.
+Hence it seems 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 colours; and we cannot believe that they would act thus,
+unless the display was of use to them in their courtship.
+
+When we treat of Birds, we shall see that they present in their
+secondary sexual characters the closest analogy with insects. Thus, many
+male birds are highly pugnacious, and some are furnished with special
+weapons for fighting with their rivals. They possess organs which are
+used during the breeding-season for producing vocal and instrumental
+music. They are frequently ornamented with combs, horns, wattles and
+plumes of the most diversified kinds, and are decorated with beautiful
+colours, all 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-coloured 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 hereafter attempt to shew
+in further detail, is sexual selection.
+
+
+CHAPTER XII.
+
+SECONDARY SEXUAL CHARACTERS OF FISHES, AMPHIBIANS, AND REPTILES.
+
+FISHES: Courtship and battles of the males--Larger size of the
+females--Males, bright colours and ornamental appendages; other strange
+characters--Colours and appendages acquired by the males during
+the breeding-season alone--Fishes with both sexes brilliantly
+coloured--Protective colours--The less conspicuous colours 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 colour between the sexes--Vocal
+organs.
+
+REPTILES: Chelonians--Crocodiles--Snakes, colours in some cases
+protective--Lizards, battles of--Ornamental appendages--Strange
+differences in structure between the sexes--Colours--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. Gunther suspects that they
+are brought into action as prehensile organs by the doubling inwards and
+downwards 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. (1. Yarrell's 'Hist.
+of British Fishes,' vol. ii. 1836, pp 417, 425, 436. Dr. Gunther informs
+me that the spines in R. clavata are peculiar to the female.)
+
+The males alone of the capelin (Mallotus villosus, one of 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, whilst she runs
+with great swiftness on the sandy beach, and there deposits her spawn.
+(2. The 'American Naturalist,' April 1871, p. 119.) The widely distinct
+Monacanthus scopas presents a somewhat analogous structure. The male,
+as Dr. Gunther informs me, has a cluster of stiff, straight spines, like
+those of a comb, on the sides of the tail; and these in a specimen six
+inches long were nearly one and a half inches in length; the female
+has in the same place a cluster of bristles, which may be compared with
+those of a tooth-brush. In another species, M. peronii, the male has a
+brush like that possessed by the female of the last species, whilst the
+sides of the tail in the female are smooth. In some other species of
+the same genus the tail can be perceived to be a little roughened in
+the male and perfectly smooth in the female; and lastly in others, both
+sexes have smooth sides.
+
+The males of many fish fight for the possession of the females. Thus the
+male stickleback (Gasterosteus leiurus) has been 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 direction,
+then to his accumulated materials for the nest, then back again in an
+instant; and as she does not advance he endeavours to push her with
+his snout, and then tries to pull her by the tail and side-spine to the
+nest." (3. See Mr. R. Warington's interesting articles in 'Annals and
+Magazine of Natural History,' October 1852, and November 1855.) The
+males are said to be polygamists (4. Noel Humphreys, 'River Gardens,'
+1857.); they are extraordinarily bold and pugnacious, whilst "the
+females are quite pacific." Their battles are at times desperate; "for
+these puny combatants fasten tight on each other for several seconds,
+tumbling over and over again until their strength appears completely
+exhausted." With the rough-tailed stickleback (G. trachurus) the males
+whilst fighting swim round and round each other, biting and endeavouring
+to pierce each other with their raised lateral spines. The same writer
+adds (5. Loudon's 'Magazine of Natural History,' vol. iii. 1830, p.
+331.), "the bite of these little furies is very severe. They also use
+their lateral spines with such fatal effect, that I have seen one during
+a battle absolutely rip his opponent quite open, so that he sank to
+the bottom and died." When a fish is conquered, "his gallant bearing
+forsakes him; his gay colours fade away; and he hides his disgrace among
+his peaceable companions, but is for some time the constant object of
+his conqueror's persecution."
+
+The male salmon is as pugnacious as the little stickleback; and so
+is the male trout, as I hear from Dr. Gunther. Mr. Shaw saw a violent
+contest between two male salmon which lasted the whole day; and Mr. R.
+Buist, Superintendent of Fisheries, informs me that he has often watched
+from the bridge at Perth the males driving away their rivals, whilst 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."
+(6. The 'Field,' June 29, 1867. For Mr. Shaw's Statement, see 'Edinburgh
+Review,' 1843. Another experienced observer (Scrope's 'Days of Salmon
+Fishing,' p. 60) remarks that like the stag, the male would, if he
+could, keep all other males away.) 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.
+
+[Fig. 27. Head of male common salmon (Salmo salar) during the
+breeding-season. [This drawing, as well as all the others in the present
+chapter, have been executed by the well-known artist, Mr. G. Ford, from
+specimens in the British Museum, under the kind superintendence of Dr.
+Gunther.]
+
+Fig. 28. Head of female salmon.]
+
+The most curious point about the male salmon is that during the
+breeding-season, besides a slight change in colour, "the lower jaw
+elongates, and a cartilaginous projection turns upwards from the point,
+which, when the jaws are closed, occupies a deep cavity between the
+intermaxillary bones of the upper jaw." (7. Yarrell, 'History of British
+Fishes,' vol. ii. 1836, p. 10.) (Figs. 27 and 28.) In our salmon this
+change of structure lasts only during the breeding-season; but in the
+Salmo lycaodon of N.W. America the change, as Mr. J.K. Lord (8. 'The
+Naturalist in Vancouver's Island,' vol. i. 1866, p. 54.) 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 projection, and the teeth grow into regular fangs,
+often more than half an inch in length. With the European salmon,
+according to Mr. Lloyd (9. 'Scandinavian Adventures,' vol. i. 1854, pp.
+100, 104.), the temporary hook-like structure serves to strengthen and
+protect the jaws, when one male charges another with wonderful violence;
+but the greatly developed teeth of the male American salmon may be
+compared 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 the thornback (Raia
+clavata) the adult male has sharp, pointed teeth, directed backwards,
+whilst those of the female are broad and flat, and form a pavement; so
+that these teeth differ in the two sexes of the same species more than
+is usual in distinct genera of the same family. The teeth of the male
+become sharp only when he is adult: whilst young they are broad and flat
+like those of the female. As so frequently occurs with secondary sexual
+characters, both sexes of 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. We shall hereafter meet with
+analogous cases in certain birds, in which the male acquires the plumage
+common to both sexes when adult, at a somewhat earlier age than does the
+female. With other species of rays the males even when old never possess
+sharp teeth, and consequently the adults of both sexes are provided with
+broad, flat teeth like those of the young, and like those of the mature
+females of the above-mentioned species. (10. See Yarrell's account of
+the rays in his 'History of British Fishes,' vol. ii. 1836, p. 416, with
+an excellent figure, and pp. 422, 432.) As the rays are bold, strong and
+voracious fish, we may suspect that the males require their sharp teeth
+for fighting with their rivals; but as they possess many parts modified
+and adapted for the prehension of the female, it is possible that their
+teeth may be used for this purpose.
+
+In regard to size, M. Carbonnier (11. As quoted in 'The Farmer,' 1868,
+p. 369.) maintains that the female of almost all fishes is larger than
+the male; and Dr. Gunther 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.
+
+[Fig. 29. Callionymus lyra. Upper figure, male; lower figure, female.
+N.B. The lower figure is more reduced than the upper.]
+
+In many species the male alone is ornamented with bright colours; or
+these are much brighter in the male than the female. The male, also, is
+sometimes provided with 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. Gunther. There is reason to suspect that many tropical fishes
+differ sexually in colour and structure; and there are some striking
+cases with our British fishes. The male Callionymus lyra has been called
+the gemmeous dragonet "from its brilliant gem-like colours." When fresh
+caught from the sea the body is yellow of various shades, striped and
+spotted with vivid blue on the head; the dorsal fins are pale brown
+with dark longitudinal bands; the ventral, caudal, and anal fins
+being bluish-black. The female, or sordid dragonet, was considered by
+Linnaeus, 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 (12. I have drawn up this
+description from Yarrell's 'British Fishes,' vol. i. 1836, pp. 261 and
+266.); but the most striking difference is the extraordinary elongation
+in the male (Fig. 29) of the dorsal fin. Mr. W. Saville Kent remarks
+that this "singular appendage appears from my observations of the
+species in 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." (13. 'Nature,' July
+1873, p. 264.) The young males resemble the adult females in structure
+and colour. Throughout the genus Callionymus (14. 'Catalogue of Acanth.
+Fishes in the British Museum,' by Dr. Gunther, 1861, pp. 138-151.), 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 scorpius, or sea-scorpion, is slenderer and
+smaller than the female. There is also a great difference in colour
+between them. It is difficult, as Mr. Lloyd (15. 'Game Birds of Sweden,'
+etc., 1867, p. 466.) remarks, "for any one, who has not seen this fish
+during the spawning-season, when its hues are brightest, to conceive
+the admixture of brilliant colours with which it, in other respects so
+ill-favoured, is at that time adorned." Both sexes of the Labrus mixtus,
+although very different in colour, are beautiful; the male being orange
+with bright blue stripes, and the female bright red with some black
+spots on the back.
+
+[Fig. 30. Xiphophorus Hellerii. Upper figure, male; lower figure,
+female.]
+
+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 (16. With
+respect to this and the following species I am indebted to Dr. Gunther
+for information: see also his paper on the 'Fishes of Central America,'
+in 'Transact. Zoological Soc.' vol. vi. 1868, p. 485.), the dorsal
+fin is greatly developed and is marked with a row of large, round,
+ocellated, bright-coloured spots; whilst the same fin in the female is
+smaller, of a different shape, and marked only with irregularly curved
+brown spots. In the male the basal margin of the anal fin is also a
+little produced and dark coloured. In the male of an allied form, the
+Xiphophorus Hellerii (Fig. 30), the inferior margin of the caudal fin
+is developed into a long filament, which, as I hear from Dr. Gunther, is
+striped with bright colours. This filament does not contain any muscles,
+and apparently cannot be of any direct use to the fish. As in the case
+of the Callionymus, the males whilst young resemble the adult females in
+colour and structure. Sexual differences such as these may be strictly
+compared with those which are so frequent with gallinaceous birds.
+(17. Dr. Gunther makes this remark; 'Catalogue of Fishes in the British
+Museum,' vol. iii. 1861, p. 141.)
+
+[Fig.31. Plecostomus barbatus. Upper figure, head of male; lower figure,
+female.]
+
+In a siluroid fish, inhabiting the fresh waters of South America, the
+Plecostomus barbatus (18. See Dr. Gunther on this genus, in 'Proceedings
+of the Zoological Society,' 1868, p. 232.) (Fig. 31), the male has its
+mouth and inter-operculum fringed with a beard of stiff hairs, of
+which the female shows hardly a trace. These hairs are of the nature of
+scales. In another species of the same genus, soft flexible 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 probable, but we can hardly suppose that stiff hairs and flexible
+filaments can be useful in any ordinary way to the males alone. In that
+strange monster, the Chimaera monstrosa, the male has a hook-shaped
+bone on the top of the head, directed forwards, with its end rounded
+and covered with sharp spines; in the female "this crown is altogether
+absent," but what its use may be to the male is utterly unknown. (19.
+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.)
+
+The structures as yet referred to are permanent in the male after he has
+arrived at maturity; but with some Blennies, and in another allied genus
+(20. Dr. Gunther, 'Catalogue of Fishes,' vol. iii. pp. 221 and 240.),
+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-coloured. There can be little doubt that this crest serves as
+a temporary sexual ornament, for the female does not exhibit a trace of
+it. In other species of the same genus both sexes possess a crest, and
+in at least one species neither sex is thus provided. In many of the
+Chromidae, for instance in Geophagus and especially in Cichla, the
+males, as I hear from Professor Agassiz (21. See also 'A Journey in
+Brazil,' by Prof. and Mrs. Agassiz, 1868, p. 220.), have a conspicuous
+protuberance on the forehead, which is wholly wanting in the females and
+in the young males. Professor Agassiz adds, "I have often observed these
+fishes at the time of spawning when the protuberance is largest, and
+at other seasons when it is totally wanting, and the two sexes shew no
+difference whatever in the outline of the profile of the head. I never
+could ascertain that it subserves any special function, and the Indians
+on the Amazon know nothing about its use." These protuberances resemble,
+in their periodical appearance, the fleshy carbuncles on the heads
+of certain birds; but whether they serve as ornaments must remain at
+present doubtful.
+
+I hear from Professor Agassiz and Dr. Gunther, that the males of those
+fishes, which differ permanently in colour 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
+colour 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-coloured stripes, which give it the appearance of a
+Labrus, and the body partakes of a golden orange tinge. The females
+are dark in colour, and are commonly called black-fish." (22. Yarrell,
+'History of British Fishes,' vol. ii. 1836, pp. 10, 12, 35.) An
+analogous and even greater change takes place with the Salmo eriox or
+bull trout; the males of the char (S. umbla) are likewise at this season
+rather brighter in colour than the females. (23. W. Thompson, in 'Annals
+and Magazine of Natural History,' vol. vi. 1841, p. 440.) The colours
+of the pike (Esox reticulatus) of the United States, especially of
+the male, become, during the breeding-season, exceedingly intense,
+brilliant, and iridescent. (24. 'The American Agriculturalist,' 1868,
+p. 100.) Another striking instance out of many is afforded by the male
+stickleback (Gasterosteus leiurus), which is described by Mr. Warington
+(25. 'Annals and Mag. of Nat. Hist.' Oct. 1852.), 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 lustre 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 colours all change, the
+throat and belly become of a paler red, the back more green, and the
+glowing tints subside.
+
+With respect to the courtship of fishes, other cases have been observed
+since the first edition of this book appeared, besides that already
+given of the stickleback. Mr. W.S. Kent says that the male of the Labrus
+mixtus, which, as we have seen, differs in colour from the female, makes
+"a deep hollow in the sand of the tank, and then endeavours in the most
+persuasive manner to induce a female of the same species to share it
+with him, swimming backwards and forwards between her and the completed
+nest, and plainly exhibiting the greatest anxiety for her to follow."
+The males of Cantharus lineatus become, during the breeding-season,
+of deep leaden-black; they then retire from the shoal, and excavate
+a hollow as a nest. "Each male now mounts vigilant guard over his
+respective hollow, and vigorously attacks and drives away any other fish
+of the same sex. Towards his companions of the opposite sex his conduct
+is far different; many of the latter are now distended with spawn, and
+these he endeavours 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." (26.
+'Nature,' May 1873, p. 25.)
+
+A more striking case of courtship, as well as of display, by the males
+of a Chinese Macropus has been given by M. Carbonnier, who carefully
+observed these fishes under confinement. (27. 'Bulletin de la Societ�
+d'Acclimat.' Paris, July 1869, and Jan. 1870.) The males are
+most beautifully coloured, more so than the females. During the
+breeding-season they contend for the possession of the females; and,
+in the act of courtship, expand their fins, which are spotted and
+ornamented with brightly coloured 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 "l'�talage de leurs vives couleurs
+chercher a attirer l'attention des femelles, lesquelles ne paraissaient
+indiff�rentes a ce man�ge, elles nageaient avec une molle lenteur vers
+les males et semblaient se complaire dans leur voisinage." After the
+male has won his bride, he makes a little disc of froth by blowing air
+and mucus out of his mouth. He then collects the fertilised ova, dropped
+by the female, in his mouth; and this caused M. Carbonnier much alarm,
+as he thought that they were going to be devoured. But the male soon
+deposits them in the disc of froth, afterwards guarding them, repairing
+the froth, and taking care of the young when hatched. I mention these
+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 difficulty 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.
+
+To return to our more immediate subject. The case stands thus: female
+fishes, as far as I can learn, never willingly spawn except in the
+presence of the males; and the males never fertilise the ova except in
+the presence of the females. The males fight for the possession of the
+females. In many species, the males whilst young resemble the females
+in colour; but when adult become much more brilliant, and retain their
+colours throughout life. In other species the males become brighter than
+the females and otherwise more highly ornamented, only during the season
+of love. The males sedulously court the females, and in one case, as we
+have seen, take pains in displaying their beauty before them. Can it be
+believed that they would thus act to no purpose during their courtship?
+And this would be the case, unless the females exert some choice and
+select those males which please or excite them most. If the female
+exerts such choice, all the above facts on the ornamentation of the
+males become at once intelligible by the aid of sexual selection.
+
+We have next to inquire whether this view of the bright colours of
+certain male fishes having been acquired through sexual selection can,
+through the law of the equal transmission of characters to both sexes,
+be extended to those groups in which the males and females are brilliant
+in the same, or nearly the same degree and manner. In such a genus
+as Labrus, which includes some of the most splendid fishes in the
+world--for instance, the Peacock Labrus (L. pavo), described (28. Bory
+Saint Vincent, in 'Dict. Class. d'Hist. Nat.' tom. ix. 1826, p. 151.),
+with pardonable exaggeration, as formed of polished scales of gold,
+encrusting 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 colour.
+With some fishes, as with many of the lowest animals, splendid colours
+may be the direct result of the nature of their tissues and of the
+surrounding conditions, without the aid of selection of any kind. The
+gold-fish (Cyprinus auratus), judging from the analogy of the golden
+variety of the common carp, is perhaps a case in point, as it may owe
+its splendid colours to a single abrupt variation, due to the conditions
+to which this fish has been subjected under confinement. It is,
+however, more probable that these colours have been intensified through
+artificial selection, as this species has been carefully bred in China
+from a remote period. (29. 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 a variety called the
+fire-fish, from its intensely red colour. It is universally admired, and
+there is not a household where it is not cultivated, IN RIVALRY AS TO
+ITS COLOUR, and as a source of profit.") Under natural conditions it
+does not seem probable that beings so highly organised as fishes, and
+which live under such complex relations, should become brilliantly
+coloured without suffering some evil or receiving some benefit from so
+great a change, and consequently without the intervention of natural
+selection.
+
+What, then, are we to conclude in regard to the many fishes, both sexes
+of which are splendidly coloured? Mr. Wallace (30. 'Westminster Review,'
+July 1867, p. 7.) believes that the species which frequent reefs,
+where corals and other brightly-coloured organisms abound, are brightly
+coloured 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-coloured corals
+or other organisms for the fishes to resemble; yet many species in the
+Amazons are beautifully coloured, and many of the carnivorous Cyprinidae
+in India are ornamented with "bright longitudinal lines of various
+tints." (31. 'Indian Cyprinidae,' by Mr. M'Clelland, 'Asiatic
+Researches,' vol. xix. part ii. 1839, p. 230.) Mr. M'Clelland, in
+describing these fishes, goes so far as to suppose that "the peculiar
+brilliancy of their colours" serves as "a better mark for king-fishers,
+terns, and other birds which are destined to keep the number of these
+fishes in check"; but at the present day few naturalists will admit that
+any animal has been made conspicuous as an aid to its own destruction.
+It is possible that certain fishes may have been rendered conspicuous
+in order to warn birds and beasts of prey that they were unpalatable, as
+explained when treating of caterpillars; but it is not, I believe, known
+that any fish, at least any fresh-water fish, is rejected from being
+distasteful to fish-devouring animals. On the whole, the most probable
+view in regard to the fishes, of which both sexes are brilliantly
+coloured, is that their colours 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 colour or in other ornaments, he alone has
+been modified, the variations being inherited by his male offspring
+alone; or whether the female has been specially modified and rendered
+inconspicuous for the sake of protection, such modifications being
+inherited only by the females. It is impossible to doubt that colour
+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 colours in
+adaptation to surrounding objects, and that within a short time. (32. G.
+Pouchet, 'L'Institut.' Nov. 1, 1871, p. 134.) One of the most striking
+instances ever recorded of an animal being protected by its colour (as
+far as it can be judged of in preserved specimens), as well as by its
+form, is that given by Dr. Gunther (33. 'Proc. Zoolog. Soc.' 1865, p.
+327, pl. xiv. and xv.) of a pipe-fish, which, with its reddish streaming
+filaments, is hardly distinguishable from the sea-weed to which
+it clings with its prehensile tail. But the question now under
+consideration is whether the females alone have been modified for this
+object. We can see that one sex will not be modified through natural
+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 coloured. The ova are fertilised immediately after
+being deposited; and when this process lasts for several days, as in the
+case of the salmon (34. Yarrell, 'British Fishes,' vol. ii. p. 11.), the
+female, during the whole time, is attended by the male. After the
+ova are fertilised they are, in most cases, left unprotected by both
+parents, so that the males and females, as far as oviposition is
+concerned, are equally exposed to danger, and both are equally important
+for the production of fertile ova; consequently the more or less
+brightly-coloured individuals of either sex would be equally liable to
+be destroyed or preserved, and both would have an equal influence on the
+colours 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
+coloured Crenilabrus massa and melops work together in building their
+nests with sea-weed, shells, etc. (35. According to the observations of
+M. Gerbe; see Gunther's 'Record of Zoolog. Literature,' 1865, p. 194.)
+But the males of certain fishes do all the work, and afterwards take
+exclusive charge of the young. This is the case with the dull-coloured
+gobies (36. Cuvier, 'Regne Animal,' vol. ii. 1829, p. 242.), in which
+the sexes are not known to differ in colour, and likewise with the
+sticklebacks (Gasterosteus), in which the males become brilliantly
+coloured during the spawning season. The male of the smooth-tailed
+stickleback (G. leiurus) performs the duties of a nurse with exemplary
+care and vigilance during a long time, and is continually employed in
+gently leading back the young to the nest, when they stray too far. He
+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. (37. See
+Mr. Warington's most interesting description of the habits of the
+Gasterosteus leiurus in 'Annals and Magazine of Nat. History,' November
+1855.)
+
+The males of certain other fishes inhabiting South America 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. (38. Prof. Wyman, in 'Proc. Boston Soc. of Nat. Hist.'
+Sept. 15, 1857. Also Prof. Turner, in 'Journal of Anatomy and
+Physiology,' Nov. 1, 1866, p. 78. Dr. Gunther has likewise described
+other cases.) I am informed by Professor Agassiz that the males of
+the Amazonian species which follow this habit, "not only are generally
+brighter than the females, but the difference is greater at the
+spawning-season than at any other time." The species of Geophagus act in
+the same manner; and in this genus, a conspicuous protuberance becomes
+developed on the forehead of the males during the breeding-season. With
+the various species of Chromids, as Professor Agassiz likewise informs
+me, sexual differences in colour may be observed, "whether they lay
+their eggs in the water among aquatic plants, or deposit them in holes,
+leaving them to come out without further care, or build shallow nests in
+the river mud, over which they sit, as our Pomotis does. It ought also
+to be observed that these sitters are among the brightest species in
+their respective families; for instance, Hygrogonus is bright green,
+with large black ocelli, encircled with the most brilliant red." Whether
+with all the species of Chromids it is the male alone which sits on the
+eggs is not known. It is, however, manifest that the fact of the eggs
+being protected or unprotected by the parents, has had little or no
+influence on the differences in colour 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-coloured males
+would be far more influential on the character of the race, than the
+destruction of the brighter-coloured 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 coloured 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 shew
+great attachment to their young. (39. Yarrell, 'History of British
+Fishes,' vol. ii. 1836, pp. 329, 338.) The sexes do not commonly differ
+much in colour; but Dr. Gunther believes that the male Hippocampi are
+rather brighter than the females. The genus Solenostoma, however, offers
+a curious exceptional case (40. Dr. Gunther, since publishing an account
+of this species in 'The Fishes of Zanzibar,' by Col. Playfair, 1866,
+p. 137, has re-examined the specimens, and has given me the above
+information.), for the female is much more vividly-coloured and spotted
+than the male, and she alone has a marsupial sack and hatches the
+eggs; so that the female of Solenostoma differs from all the other
+Lophobranchii in this latter respect, and from almost all other fishes,
+in being more brightly-coloured 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 coloured 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
+colours of that sex which is the more important of the two for the
+welfare of the offspring, must be in some manner protective. But from
+the large number of fishes, of which the males are either permanently
+or periodically brighter than the females, but whose life is not at all
+more important for the welfare of the species than that of the female,
+this view can hardly be maintained. When we treat of birds we shall meet
+with analogous cases, where there has been a complete inversion of the
+usual attributes of the two sexes, and we shall then give what appears
+to be the probable explanation, namely, that the males have selected
+the more attractive females, instead of the latter having selected, in
+accordance with the usual rule throughout the animal kingdom, the more
+attractive males.
+
+On the whole we may conclude, that with most fishes, in which the sexes
+differ in colour or in other ornamental characters, the males originally
+varied, with their variations transmitted to the same sex, and
+accumulated through sexual selection by attracting or exciting the
+females. In many cases, however, such characters have been transferred,
+either partially or completely, to the females. In other cases, again,
+both sexes have been coloured alike for the sake of protection; but in
+no instance does it appear that the female alone has had her colours or
+other characters specially modified for this latter purpose.
+
+The last point which need be noticed is that fishes are known to make
+various noises, some of which are described as being musical. Dr.
+Dufosse, who has especially attended to this subject, says that the
+sounds are voluntarily produced in several ways by different fishes:
+by the friction of the pharyngeal bones--by the vibration of certain
+muscles attached to the swim bladder, which serves as a resounding
+board--and by the vibration of the intrinsic muscles of the swim
+bladder. By this latter means the Trigla produces pure and long-drawn
+sounds which range over nearly an octave. But the most interesting case
+for us is that of two species of Ophidium, in which the males alone are
+provided with a sound-producing apparatus, consisting of small movable
+bones, with proper muscles, in connection with the swim bladder. (41.
+'Comptes-Rendus,' tom. xlvi. 1858, p. 353; tom. xlvii. 1858, p. 916;
+tom. liv. 1862, p. 393. The noise made by the Umbrinas (Sciaena aquila),
+is said by some authors to be more like that of a flute or organ, than
+drumming: Dr. Zouteveen, in the Dutch translation of this work (vol. ii.
+p. 36), gives some further particulars on the sounds made by fishes.)
+The drumming of the Umbrinas in the European seas is said to be audible
+from a depth of twenty fathoms; and the fishermen of Rochelle assert
+"that the males alone make the noise during the spawning-time; and that
+it is possible by imitating it, to take them without bait." (42. The
+Rev. C. Kingsley, in 'Nature,' May 1870, p. 40.) 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.
+
+AMPHIBIANS.
+
+URODELA.
+
+[Fig. 32. Triton cristatus (half natural size, from Bell's 'British
+Reptiles'). Upper figure, male during the breeding season; lower figure,
+female.]
+
+I will begin with the tailed amphibians. The sexes of salamanders or
+newts often differ much both in colour and structure. In some species
+prehensile claws are developed on the fore-legs of the males during
+the breeding-season: and at this season in the male Triton palmipes the
+hind-feet are provided with a swimming-web, which is almost completely
+absorbed during the winter; so that their feet then resemble those of
+the female. (43. Bell, 'History of British Reptiles,' 2nd ed., 1849, pp.
+156-159.) This structure no doubt aids the male in his eager search and
+pursuit of the female. Whilst courting her he rapidly vibrates the end
+of his tail. With our common newts (Triton punctatus and cristatus) a
+deep, much indented crest is developed along the back and tail of the
+male during the breeding-season, which disappears during the winter. Mr.
+St. George Mivart informs me that it is not furnished with muscles,
+and therefore cannot be used for locomotion. As during the season of
+courtship it becomes edged with bright colours, there can hardly be a
+doubt that it is a masculine ornament. In many species the body presents
+strongly contrasted, though lurid tints, and these become more vivid
+during the breeding-season. The male, for instance, of our common little
+newt (Triton punctatus) is "brownish-grey above, passing into yellow
+beneath, which in the spring becomes a rich bright orange, marked
+everywhere with round dark spots." The edge of the crest also is
+then tipped with bright red or violet. The female is usually of a
+yellowish-brown colour with scattered brown dots, and the lower surface
+is often quite plain. (44. Bell, 'History of British Reptiles,' 2nd
+ed., 1849, pp. 146, 151.) The young are obscurely tinted. The ova are
+fertilised 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 colours and ornamental appendages through sexual
+selection; these being transmitted either to the male offspring alone,
+or to both sexes.
+
+ANURA OR BATRACHIA.
+
+With many frogs and toads the colours evidently serve as a protection,
+such as the bright green tints of tree frogs and the obscure mottled
+shades of many terrestrial species. The most conspicuously-coloured toad
+which I ever saw, the Phryniscus nigricans (45. 'Zoology of the Voyage
+of the "Beagle,"' 1843. Bell, ibid. p. 49.), 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 colours 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 (46. 'The Naturalist
+in Nicaragua,' 1874, p. 321.) 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 colour, Dr. Gunther 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. (47. The male alone of
+the Bufo sikimmensis (Dr. Anderson, 'Proc. Zoolog. Soc.' 1871, p. 204)
+has two plate-like callosities on the thorax and certain rugosities on
+the fingers, which perhaps subserve the same end as the above-mentioned
+prominences.) It is surprising that these animals have not acquired
+more strongly-marked sexual characters; for though cold-blooded their
+passions are strong. Dr. Gunther 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 Professor Hoffman in Giessen fighting all day long during the
+breeding-season, and with so much violence that one had its body ripped
+open.
+
+Frogs and toads offer one interesting sexual difference, namely, in
+the musical powers possessed by the males; but to speak of music,
+when applied to the discordant and overwhelming sounds emitted by male
+bull-frogs and some other species, seems, according to our taste, a
+singularly inappropriate expression. Nevertheless, certain frogs sing in
+a decidedly pleasing manner. Near Rio Janeiro I used often to sit in
+the evening to listen to a number of little 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
+breeding-season, as in the case of the croaking of our common frog. (48.
+Bell, 'History British Reptiles,' 1849, p. 93.) In accordance with this
+fact the vocal organs of the males are more highly-developed than those
+of the females. In some genera the males alone are provided with sacs
+which open into the larynx. (49. J. Bishop, in 'Todd's Cyclopaedia of
+Anatomy and Physiology,' vol. iv. p. 1503.) For instance, in the edible
+frog (Rana esculenta) "the sacs are peculiar to the males, and become,
+when filled with air in the act of croaking, large globular bladders,
+standing out one on each side of the head, near the corners of the
+mouth." The croak of the male is thus rendered exceedingly powerful;
+whilst that of the female is only a slight groaning noise. (50. Bell,
+ibid. pp. 112-114.) In the several genera of the family the vocal organs
+differ considerably in structure, and their development in all cases may
+be attributed to sexual selection.
+
+REPTILES.
+
+CHELONIA.
+
+Tortoises and turtles do not offer well-marked sexual differences. In
+some species, the tail of the male is longer than that of the female. In
+some, the plastron or lower surface of the shell of the male is
+slightly concave in relation to the back of the female. The male of the
+mud-turtle of the United States (Chrysemys picta) has claws on its front
+feet twice as long as those of the female; and these are used when the
+sexes unite. (51. Mr. C.J. Maynard, 'The American Naturalist,' Dec.
+1869, p. 555.) With the huge tortoise of the Galapagos Islands (Testudo
+nigra) the males are said to grow to a larger size than the females:
+during the pairing-season, and at no other time, the male utters a
+hoarse 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.
+(52. See my 'Journal of Researches during the Voyage of the "Beagle,"'
+1845, p. 384.)
+
+With the Testudo elegans of India, it is said "that the combats of the
+males may be heard at some distance, from the noise they produce in
+butting against each other." (53. Dr. Gunther, 'Reptiles of British
+India,' 1864, p. 7.)
+
+CROCODILIA.
+
+The sexes apparently do not differ in colour; nor do I know that the
+males fight together, though this is probable, for some kinds make a
+prodigious display before the females. Bartram (54. 'Travels through
+Carolina,' etc., 1791, p. 128.) 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
+odour is emitted by the submaxillary glands of the crocodile, and
+pervades their haunts. (55. Owen, 'Anatomy of Vertebrates,' vol. i.
+1866, p. 615.)
+
+OPHIDIA.
+
+Dr. Gunther 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 colour, be
+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 rattle-snakes of N. America, the male
+of which, as the keeper in the Zoological Gardens shewed 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." (56. Sir Andrew Smith, 'Zoology of S. Africa:
+Reptilia,' 1849, pl. x.) The male of the Indian Dipsas cynodon, on the
+other hand, is blackish-brown, with the belly partly black, whilst the
+female is reddish or yellowish-olive, with the belly either uniform
+yellowish or marbled with black. In the Tragops dispar of the same
+country the male is bright green, and the female bronze-coloured. (57.
+Dr. A. Gunther, 'Reptiles of British India,' Ray Soc., 1864, pp. 304,
+308.) No doubt the colours of some snakes are protective, as shewn 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
+colours 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 coloured with extreme elegance. The
+colours of certain species are very different in the adult and young
+states. (58. Dr. Stoliczka, 'Journal of Asiatic Society of Bengal,' vol.
+xxxix, 1870, pp. 205, 211.)
+
+During the breeding-season the anal scent-glands of snakes are in active
+function (59. Owen, 'Anatomy of Vertebrates,' vol. i. 1866, p. 615.);
+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 (60.
+'Rambles in Ceylon,' in 'Annals and Magazine of Natural History,' 2nd
+series, vol. ix. 1852, p. 333.) a cobra thrust its head through a narrow
+hole and swallow a toad. "With this encumbrance he could not withdraw
+himself; finding this, he reluctantly disgorged the precious morsel,
+which began to move off; this was too much for snake philosophy to bear,
+and the toad was again seized, and again was the snake, after violent
+efforts to escape, compelled to part with its prey. This time, however,
+a lesson had been learnt, and the toad was seized by one leg, withdrawn,
+and then swallowed in triumph."
+
+The keeper in the Zoological Gardens is positive that certain snakes,
+for instance Crotalus and Python, distinguish him from all other
+persons. Cobras kept together in the same cage apparently feel some
+attachment towards each other. (61. Dr. Gunther, 'Reptiles of British
+India,' 1864, p. 340.)
+
+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 colours in their
+partners, so as to lead to the adornment of the species through sexual
+selection. Nevertheless, it is difficult to account in any other
+manner for the extreme beauty of certain species; for instance, of
+the coral-snakes of S. America, which are of a rich red with black and
+yellow transverse bands. I well remember how much surprise I felt at
+the beauty of the first coral-snake which I saw gliding across a path in
+Brazil. Snakes coloured in this peculiar manner, as Mr. Wallace states
+on the authority of Dr. Gunther (62. 'Westminster Review,' July 1st,
+1867, p. 32.), are found nowhere else in the world except in S. 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 others are quite harmless. The species belonging 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 probably acquired their colours as a protection, on the principle
+of imitation; for they would naturally be thought dangerous by their
+enemies. The cause, however, of the bright colours 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 when this snake is excited these scales are
+rubbed against each other, which produces "a curious prolonged, almost
+hissing sound." (63. Dr. Anderson, 'Proc. Zoolog. Soc.' 1871, p. 196.)
+With respect to the rattling of the rattle-snake, we have at last some
+definite information: for Professor Aughey states (64. The 'American
+Naturalist,' 1873, p. 85.), that on two occasions, being himself unseen,
+he watched from a little distance a rattle-snake coiled up with head
+erect, which continued to rattle at short intervals for half an hour:
+and at last he saw another snake approach, and when they met they
+paired. Hence he is satisfied that one of the uses of the rattle is to
+bring the sexes together. Unfortunately he did not ascertain whether it
+was the male or the female which remained stationary and called for the
+other. But it by no means follows from the above fact that the rattle
+may not be of use to these snakes in other ways, as a warning to animals
+which would otherwise attack them. Nor can I quite disbelieve the
+several accounts which have appeared of their thus paralysing 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 S. America.
+
+LACERTILIA.
+
+The males of some, probably of many kinds of lizards, fight together
+from rivalry. Thus the arboreal Anolis cristatellus of S. America is
+extremely pugnacious: "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 combatants losing his tail,
+which is often devoured by the victor." The male of this species is
+considerably larger than the female (65. Mr. N.L. Austen kept these
+animals alive for a considerable time; see 'Land and Water,' July 1867,
+p. 9.); and this, as far as Dr. Gunther has been able to ascertain,
+is the general rule with lizards of all kinds. The male alone of the
+Cyrtodactylus rubidus of the Andaman Islands possesses pre-anal pores;
+and these pores, judging from analogy, probably serve to emit an odour.
+(66. Stoliczka, 'Journal of the Asiatic Society of Bengal,' vol. xxxiv.
+1870, p. 166.)
+
+[Fig.33. Sitana minor. Male with the gular pouch expanded (from
+Gunther's 'Reptiles of India')']
+
+The sexes often differ greatly in various external characters. The male
+of the above-mentioned Anolis is furnished with a crest which runs along
+the back and tail, and can be erected at 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. Gunther informs me, with the females of many
+Iguanas, Chameleons, and other lizards. In some species, however, the
+crest is equally developed in both sexes, as in the Iguana tuberculata.
+In the genus Sitana, the males alone are furnished with a large throat
+pouch (Fig. 33), which can be folded up like a fan, and is coloured
+blue, black, and red; but these splendid colours are exhibited only
+during the pairing-season. The female does not possess even a rudiment
+of this appendage. In the Anolis cristatellus, according 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 confined 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 colours baffle description, are furnished with skinny appendages
+to the throat "like the wattles of gallinaceous birds." These become
+erected when the animal is excited. They occur in both sexes, but are
+best developed when the male arrives at maturity, at which age the
+middle appendage is sometimes twice as long as the head. Most of the
+species likewise have a low crest running along the neck; and this is
+much more developed in the full-grown males than in the females or young
+males. (67. All the foregoing statements and quotations, in regard to
+Cophotis, Sitana and Draco, as well as the following facts in regard to
+Ceratophora and Chamaeleon, are from Dr. Gunther himself, or from his
+magnificent work on the 'Reptiles of British India,' Ray Soc., 1864, pp.
+122, 130, 135.)
+
+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 impunity"--I presume from despair. (68. Mr.
+Swinhoe, 'Proc. Zoolog. Soc.' 1870, p. 240.)
+
+[Fig. 34. Ceratophora Stoddartii. Upper figure; lower figure, female.]
+
+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 terminal scale forms a minute horn on the summit of the
+flexible appendage; and in a third species (C. Stoddartii, fig. 34) the
+whole appendage is converted into a horn, which is usually of a white
+colour, 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. Gunther has remarked to me, may be compared with the
+combs of gallinaceous birds, and apparently serve as ornaments.
+
+[Fig. 35. Chamaeleo bifurcus. Upper figure, male; lower figure, female.
+
+Fig. 36. Chamaeleo Owenii. Upper figure, male; lower figure, female.]
+
+In the genus Chamaeleon we come to the acme of difference between the
+sexes. The upper part of the skull of the male C. bifurcus (Fig. 35),
+an inhabitant of Madagascar, is produced into two great, solid, bony
+projections, covered with scales like the rest of the head; and of this
+wonderful modification of structure the female exhibits only a rudiment.
+Again, in Chamaeleo Owenii (Fig. 36), from the West Coast of Africa, the
+male bears on his snout and forehead 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 they 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 C. bifurcus, 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 (69. Dr. Buchholz,
+'Monatsbericht K. Preuss. Akad.' Jan. 1874, p. 78.), this is probably
+a correct view. Mr. T.W. Wood also informs me that he once watched two
+individuals of C. pumilus fighting violently on the branch of a tree;
+they flung their heads about and tried to bite each other; they then
+rested for a time and afterwards continued their battle.
+
+With many lizards the sexes differ slightly in colour, the tints and
+stripes of the males being brighter and more distinctly defined than in
+the females. This, for instance, is the case with the above Cophotis
+and with the Acanthodactylus 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 nigrilabris there is a still greater
+difference; the lips also of the male are black, whilst those of the
+female are green. In our common little viviparous lizard (Zootoca
+vivipara) "the under side of the body and base of the tail in the male
+are bright orange, spotted with black; in the female these parts are
+pale-greyish-green without spots." (70. Bell, 'History of British
+Reptiles,' 2nd ed., 1849, p. 40.) We have seen that the males alone of
+Sitana possess a throat-pouch; and this is splendidly tinted with blue,
+black, and red. In the Proctotretus tenuis of Chile the male alone
+is marked with spots of blue, green, and coppery-red. (71. 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, pl. 25 and 39. For the Indian Calotes,
+see 'Reptiles of British India,' by Dr. Gunther, p. 143.) In many cases
+the males retain the same colours throughout the year, but in others
+they become much brighter during the breeding-season; I may give as an
+additional instance the Calotes maria, which at this season has a
+bright red head, the rest of the body being green. (72. Gunther in
+'Proceedings, Zoological Society,' 1870, p. 778, with a coloured
+figure.)
+
+Both sexes of many species are beautifully coloured exactly alike; and
+there is no reason to suppose that such colours are protective. No doubt
+with the bright green kinds which live in the midst of vegetation,
+this colour serves to conceal them; and in N. Patagonia I saw a lizard
+(Proctotretus multimaculatus) 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 colours 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 colours 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.
+
+
+CHAPTER XIII.
+
+SECONDARY SEXUAL CHARACTERS OF BIRDS.
+
+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 the 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 considerable length. Male birds sometimes, though rarely,
+possess special weapons for fighting with each other. They charm the
+female by vocal or instrumental music of the most varied kinds. They
+are ornamented by all sorts of combs, wattles, protuberances, horns,
+air-distended sacks, top-knots, naked shafts, plumes and lengthened
+feathers gracefully springing from all parts of the body. The beak
+and naked skin about the head, and the feathers, are often gorgeously
+coloured. 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 odour, which we may suppose
+serves to charm or excite the female; for that excellent observer, Mr.
+Ramsay (1. 'Ibis,' vol. iii. (new series), 1867, p. 414.), says of the
+Australian musk-duck (Biziura lobata) 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 odour during the pairing-season, that it can be detected long
+before the bird can be seen. (2. Gould, 'Handbook of the Birds of
+Australia,' 1865, vol. ii. p. 383.) On the whole, birds appear to be the
+most aesthetic of all animals, excepting of course man, and they have
+nearly the same taste for the beautiful as we have. This is shewn by our
+enjoyment of the singing of birds, and by our women, both civilised and
+savage, decking their heads with borrowed plumes, and using gems which
+are hardly more brilliantly coloured 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 humming-birds (Grypus), the beak
+of the male is serrated along the margin and hooked at the extremity,
+thus differing much from that of the female. In the Neomorpha of New
+Zealand, there is, as we have seen, a still wider difference in the
+form of the beak in relation to the manner of feeding of the two
+sexes. Something of the same kind has been observed with the goldfinch
+(Carduelis elegans), for I am assured by Mr. J. 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, whilst the
+females more commonly feed on the seeds of the betony or Scrophularia.
+With a slight difference of this kind as a foundation, we can see how
+the beaks of the two sexes might be made to differ greatly through
+natural selection. In some of the above cases, however, it is possible
+that the beaks of the males may have been first modified in relation
+to their contests with other males; and that this afterwards led to
+slightly changed habits of life.
+
+LAW OF BATTLE.
+
+Almost all male birds are extremely pugnacious, using their beaks,
+wings, and legs for fighting together. We see this every spring with our
+robins and sparrows. The smallest of all birds, namely the humming-bird,
+is one of the most quarrelsome. Mr. Gosse (3. Quoted by Mr. Gould,
+'Introduction to the Trochilidae,' 1861, page 29.) 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 or 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 feed." (4. Gould,
+ibid. p. 52.) With waders, the males of the common water-hen (Gallinula
+chloropus) "when pairing, fight violently for the females: they stand
+nearly upright in the water and strike with their feet." Two were seen
+to be thus engaged for half an hour, until one got hold of the head of
+the other, which would have been killed had not the observer interfered;
+the female all the time looking on as a quiet spectator. (5. W.
+Thompson, 'Natural History of Ireland: Birds,' vol. ii. 1850, p.
+327.) Mr. Blyth informs me that the males of an allied bird (Gallicrex
+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 same purpose, for instance, the bulbuls (Pycnonotus hoemorrhous)
+which "fight with great spirit." (6. Jerdon, 'Birds of India,' 1863,
+vol. ii. p. 96.)
+
+[Fig. 37. The Ruff or Machetes pugnax (from Brehm's 'Thierleben').]
+
+The polygamous ruff (Machetes pugnax, Fig. 37) is notorious for his
+extreme pugnacity; and in the spring, the males, which are considerably
+larger than the females, congregate day after day at a particular spot,
+where the females propose to lay their eggs. The fowlers discover these
+spots by the turf being trampled somewhat bare. 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 ruff of
+feathers, however, from its varied and rich colours probably serves in
+chief part as an ornament. Like most pugnacious birds, they seem always
+ready to fight, and when closely confined, often kill each other; but
+Montagu observed that their pugnacity becomes greater during the spring,
+when the long feathers on their necks are fully developed; and at this
+period the least movement by any one bird provokes a general battle. (7.
+Macgillivray, 'History of British Birds,' vol. iv. 1852, pp. 177-181.)
+Of the pugnacity of web-footed birds, two instances will suffice: in
+Guiana "bloody fights occur during the breeding-season between the males
+of the wild musk-duck (Cairina moschata); and where these fights have
+occurred the river is covered for some distance with feathers." (8.
+Sir R. Schomburgk, in 'Journal of Royal Geographic Society,' vol. xiii.
+1843, p. 31.) Birds which seem ill-adapted for fighting engage in fierce
+conflicts; thus the stronger males of the pelican drive away the weaker
+ones, snapping with their huge beaks and giving heavy blows with their
+wings. Male snipe fight together, "tugging and 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 sauratus), although
+"the hens are followed by even half a dozen of their gay suitors." (9.
+'Ornithological Biography,' vol. i. p. 191. For pelicans and snipes, see
+vol. iii. pp. 138, 477.)
+
+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
+Cincloramphus cruralis (allied to our pipits) are by measurement
+actually twice as large as their respective females. (10. Gould,
+'Handbook of Birds of Australia,' vol. i. p. 395; vol. ii. p. 383.) With
+many other birds the females are larger than the males; and, as formerly
+remarked, the explanation often given, namely, that the females have
+most of the work in feeding their young, will not suffice. In some few
+cases, as we shall hereafter see, the females apparently have acquired
+their greater size and strength for the sake of conquering other females
+and obtaining possession of the males.
+
+The males of many gallinaceous birds, especially of the polygamous
+kinds, are furnished with special weapons for fighting with their
+rivals, namely spurs, which can be used with fearful effect. It has been
+recorded by a trustworthy writer (11. Mr. Hewitt, in the 'Poultry Book'
+by Tegetmeier, 1866, p. 137.) 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 cockpit, and the owner laid a wager that
+if the legs could be spliced so that the bird could stand upright, he
+would continue fighting. This was effected on the spot, and the bird
+fought with undaunted courage until he received his death-stroke. In
+Ceylon a closely allied, wild species, the Gallus Stanleyi, is known
+to fight desperately "in defence of his seraglio," so that one of the
+combatants is frequently found dead. (12. Layard, 'Annals and Magazine
+of Natural History,' vol. xiv. 1854, p. 63.) An Indian partridge
+(Ortygornis gularis), the male of which is furnished with strong
+and sharp spurs, is so quarrelsome "that the scars of former fights
+disfigure the breast of almost every bird you kill." (13. Jerdon, 'Birds
+of India,' vol. iii. p. 574.)
+
+The males of almost all gallinaceous birds, even those which are not
+furnished with spurs, engage during the breeding-season in fierce
+conflicts. The Capercailzie and Black-cock (Tetrao urogallus and T.
+tetrix), which are both polygamists, have regular 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 continuously the strangest noises: "he holds his tail up and
+spreads it out like a fan, he lifts up his head and neck with all the
+feathers erect, and stretches his wings from the body. Then he takes a
+few jumps in different directions, sometimes in a circle, and presses
+the under part of his beak so hard against the ground that the chin
+feathers are rubbed off. During these movements he beats his wings
+and turns round and round. The more ardent he grows the more lively he
+becomes, until at last the bird appears like a frantic creature." At
+such times the black-cocks are so absorbed that they become almost blind
+and deaf, but less so than the capercailzie: hence bird after bird may
+be shot on the same spot, or even caught by the hand. After performing
+these antics the males begin to fight: and the same black-cock, in order
+to prove his strength over several antagonists, will visit in the
+course of one morning several Balz-places, which remain the same during
+successive years. (14. Brehm, 'Thierleben,' 1867, B. iv. s. 351. Some
+of the foregoing statements are taken from L. Lloyd, 'The Game Birds of
+Sweden,' etc., 1867, p. 79.)
+
+The peacock with his long train appears more like a dandy than a
+warrior, but he sometimes engages in fierce contests: the Rev. W. Darwin
+Fox informs me that at some little distance from Chester two peacocks
+became so excited whilst fighting, that they flew over the whole city,
+still engaged, until they alighted on the top of St. John's tower.
+
+The spur, in those gallinaceous birds which are thus provided, is
+generally single; but Polyplectron (Fig. 51) has two or more on each
+leg; and one of the Blood-pheasants (Ithaginis cruentus) has been seen
+with five spurs. The spurs are generally confined to the male, being
+represented by mere knobs or 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 (Euplocamus erythrophthalmus) possess
+spurs. In Galloperdix it is usual for the males to have two spurs, and
+for the females to have only one on each leg. (15. Jerdon, 'Birds of
+India': on Ithaginis, vol. iii. p. 523; on Galloperdix, p. 541.)
+Hence spurs may be considered as a masculine structure, which has been
+occasionally more or less transferred to the females. Like most other
+secondary sexual characters, the spurs are highly variable, both in
+number and development, in the same species.
+
+[Fig.38. Palamedea cornuta (from Brehm), shewing the double wing-spurs,
+and the filament on the head.]
+
+Various birds have spurs on their wings. But the Egyptian goose
+(Chenalopex aegyptiacus) has only "bare obtuse knobs," and these
+probably shew us the first steps by which true spurs have been developed
+in other species. In the spur-winged goose, Plectropterus gambensis, the
+males have much larger spurs than the females; and they use them, as
+I am informed by Mr. Bartlett, in fighting together, so that, in
+this case, the wing-spurs serve as sexual weapons; but according to
+Livingstone, they are chiefly used in the defence of the young. The
+Palamedea (Fig. 38) is armed with a pair of spurs on each wing; and
+these are such formidable weapons that a single blow has been known to
+drive a dog howling away. But it does not appear that the spurs in this
+case, or in that of some of the spur-winged rails, are larger in the
+male than in the female. (16. For the Egyptian goose, see Macgillivray,
+'British Birds,' vol. iv. p. 639. For Plectropterus, Livingstone's
+'Travels,' p. 254. For Palamedea, Brehm's 'Thierleben,' B. iv. s. 740.
+See also on this bird Azara, 'Voyages dans l'Amerique merid.' tom. iv.
+1809, pp. 179, 253.) In certain plovers, however, the wing-spurs must be
+considered as a sexual character. Thus in the male of our common peewit
+(Vanellus cristatus) the tubercle on the shoulder of the wing becomes
+more prominent during the breeding-season, and the males fight together.
+In some species of Lobivanellus a similar tubercle becomes developed
+during the breeding-season "into a short horny spur." In the Australian
+L. lobatus both sexes have spurs, but these are much larger in the males
+than in the females. In an allied bird, the Hoplopterus armatus, the
+spurs do not increase in size during the breeding-season; but these
+birds have been seen in Egypt to fight together, in the same manner as
+our peewits, by turning suddenly in the air and striking sideways at
+each other, sometimes with fatal results. Thus also they drive away
+other enemies. (17. See, on our peewit, Mr. R. Carr in 'Land and Water,'
+Aug. 8th, 1868, p. 46. In regard to Lobivanellus, see Jerdon's 'Birds of
+India,' vol. iii. p. 647, and Gould's 'Handbook of Birds of Australia,'
+vol. ii. p. 220. For the Hoplopterus, see Mr. Allen in the 'Ibis,' vol.
+v. 1863, p. 156.)
+
+The season of love is that of battle; but the males of some birds, as of
+the game-fowl and ruff, and even the young males of the wild turkey and
+grouse (18. Audubon, 'Ornithological Biography,' vol. ii. p. 492; vol.
+i. pp. 4-13.), are ready to fight whenever they meet. The presence of
+the female is the teterrima belli causa. The Bengali baboos make the
+pretty little males of the amadavat (Estrelda amandava) fight together
+by placing three small cages in a row, with a female in the middle;
+after a little time the two males are turned loose, and immediately
+a desperate battle ensues. (19. Mr. Blyth, 'Land and Water,' 1867, p.
+212.) When many males congregate at the same appointed spot and fight
+together, as in the case of grouse and various other birds, they are
+generally attended by the females (20. Richardson on Tetrao umbellus,
+'Fauna Bor. Amer.: Birds,' 1831, p. 343. L. Lloyd, 'Game Birds of
+Sweden,' 1867, pp. 22, 79, on the capercailzie and black-cock. Brehm,
+however, asserts ('Thierleben,' B. iv. s. 352) that in Germany the
+grey-hens do not generally attend the Balzen of the black-cocks, but
+this is an exception to the common rule; possibly the hens may lie
+hidden in the surrounding bushes, as is known to be the case with the
+gray-hens in Scandinavia, and with other species in N. America.), which
+afterwards pair with the victorious combatants. But in some cases the
+pairing precedes instead of succeeding the combat: thus according to
+Audubon (21. 'Ornithological Biography,' vol. ii. p. 275.), several
+males of the Virginian goat-sucker (Caprimulgus virgianus) "court, in
+a highly entertaining manner the female, and no sooner has she made her
+choice, than her approved gives chase to all intruders, and drives them
+beyond his dominions." Generally the males try to drive away or kill
+their rivals before they pair. It does not, however, appear that the
+females invariably prefer the victorious males. I have indeed been
+assured by Dr. W. Kovalevsky that the female capercailzie sometimes
+steals away with a young male who has not dared to enter the arena with
+the older cocks, in the same manner as occasionally happens with the
+does of the red-deer in Scotland. When two males contend in presence of
+a single female, the victor, no doubt, commonly gains his desire; but
+some of these battles are caused by wandering males trying to distract
+the peace of an already mated pair. (22. Brehm, 'Thierleben,' etc., B.
+iv. 1867, p. 990. Audubon, 'Ornithological Biography,' vol. ii. p. 492.)
+
+Even with the most pugnacious species it is probable that the pairing
+does not depend exclusively on the mere strength and courage of the
+male; for such males are generally decorated with various ornaments,
+which often become more brilliant during the breeding-season, and which
+are sedulously displayed before the females. The males also endeavour
+to charm or excite their mates by love-notes, songs, and antics; and
+the courtship is, in many instances, a prolonged affair. Hence it is not
+probable that the females are indifferent to the charms of the opposite
+sex, or that they are invariably compelled to yield to the victorious
+males. It is more probable that the females are excited, either before
+or after the conflict, by certain males, and thus unconsciously prefer
+them. In the case of Tetrao umbellus, a good observer (23. 'Land and
+Water,' July 25, 1868, p. 14.) goes so far as to believe that the
+battles of the male "are all a sham, performed to show themselves to the
+greatest advantage before the admiring females who assemble around; for
+I have never been able to find a maimed hero, and seldom more than a
+broken feather." I shall have to recur to this subject, but I may here
+add that with the Tetrao cupido of the United States, about a score
+of males assemble at a particular spot, and, strutting about, make the
+whole air resound with their extraordinary noises. At the first answer
+from a female the males begin to fight furiously, and the weaker give
+way; but then, according to Audubon, both the victors and vanquished
+search for the female, so that the females must either then exert
+a choice, or the battle must be renewed. So, again, with one of the
+field-starlings of the United States (Sturnella ludoviciana) the males
+engage in fierce conflicts, "but at the sight of a female they all fly
+after her as if mad." (24. Audubon's 'Ornithological Biography;' on
+Tetrao cupido, vol. ii. p. 492; on the Sturnus, vol. ii. p. 219.)
+
+VOCAL AND INSTRUMENTAL MUSIC.
+
+With birds the voice serves to express various emotions, such as
+distress, fear, anger, triumph, or mere happiness. It is apparently
+sometimes used to excite terror, as in the case of the hissing noise
+made by some nestling-birds. Audubon (25. 'Ornithological Biography,'
+vol. v. p. 601.), relates that a night-heron (Ardea nycticorax, Linn.),
+which he kept tame, used to hide itself when a cat approached, and then
+"suddenly start up uttering one of the most frightful cries, apparently
+enjoying the cat's alarm and flight." The common domestic cock clucks to
+the hen, and the hen to her chickens, when a dainty morsel is found. The
+hen, when she has laid an egg, "repeats the same note very often, and
+concludes with the sixth above, which she holds for a longer time"
+(26. The Hon. Daines Barrington, 'Philosophical Transactions,' 1773, p.
+252.); and thus she expresses her joy. Some social birds apparently call
+to each other for aid; and as they flit from tree to tree, the flock is
+kept together by chirp answering chirp. During the nocturnal migrations
+of geese and other water-fowl, sonorous clangs from the van may be heard
+in the darkness overhead, answered by clangs in the rear. Certain cries
+serve as danger signals, which, as the sportsman knows to his cost, are
+understood by the same species and by others. The domestic cock crows,
+and the humming-bird chirps, in triumph over a defeated rival. The
+true song, however, of most birds and various strange cries are chiefly
+uttered during the breeding-season, and serve as a charm, or merely as a
+call-note, to the other sex.
+
+Naturalists are much divided with respect to the object of the singing
+of birds. Few more careful observers ever lived than Montagu, and he
+maintained that the "males of song-birds and of many others do not in
+general search for the female, but, on the contrary, their business in
+the spring is to perch on some conspicuous spot, breathing out their
+full and amorous notes, which, by instinct, the female knows,
+and repairs to the spot to choose her mate." (27. 'Ornithological
+Dictionary,' 1833, p. 475.) Mr. Jenner Weir informs me that this is
+certainly the case with the nightingale. Bechstein, who kept birds
+during his whole life, asserts, "that the female canary always chooses
+the best singer, and that in a state of nature the female finch
+selects that male out of a hundred whose notes please her most. (28.
+'Naturgeschichte der Stubenv�gel,' 1840, s. 4. Mr. Harrison Weir
+likewise writes to me:--"I am informed that the best singing males
+generally get a mate first, when they are bred in the same room.") There
+can be no doubt that birds closely attend to each other's song. Mr. Weir
+has told me of the case of a bullfinch which had been taught to pipe a
+German waltz, and who was so good a performer that he cost ten guineas;
+when this bird was first introduced into a room where other birds were
+kept and he began to sing, all the others, consisting of about twenty
+linnets and canaries, ranged themselves on the nearest side of their
+cages, and listened with the greatest interest to the new performer.
+Many naturalists believe that the singing of birds is almost exclusively
+"the effect of rivalry and emulation," and not for the sake of charming
+their mates. This was the opinion of Daines Barrington and White
+of Selborne, who both especially attended to this subject. (29.
+'Philosophical Transactions,' 1773, p. 263. White's 'Natural History
+of Selborne,' 1825, vol. i. p. 246.) Barrington, however, admits that
+"superiority in song gives to birds an amazing ascendancy over others,
+as is well known to bird-catchers."
+
+It is certain that there is an intense degree of rivalry between the
+males in their singing. Bird-fanciers match their birds to see which
+will sing longest; and I was told by Mr. Yarrell that a first-rate bird
+will sometimes sing till he drops down almost dead, or according to
+Bechstein (30. 'Naturgesch. der Stubenv�gel,' 1840, s. 252.), quite dead
+from rupturing a vessel in the lungs. Whatever the cause may be, male
+birds, as I hear from Mr. Weir, often die suddenly during the season of
+song. That the habit of singing is sometimes quite independent of love
+is clear, for a sterile, hybrid canary-bird has been described (31. Mr.
+Bold, 'Zoologist,' 1843-44, p. 659.) as singing whilst viewing itself in
+a mirror, and then dashing at its own image; it likewise attacked with
+fury a female canary, when put into the same cage. The jealousy excited
+by the act of singing is constantly taken advantage of by bird-catchers;
+a male, in good song, is hidden and protected, whilst a stuffed bird,
+surrounded by limed twigs, is exposed to view. In this manner, as Mr.
+Weir informs me, a man has in the course of a single day caught
+fifty, and in one instance, seventy, male chaffinches. The power and
+inclination to sing differ so greatly with birds that although the price
+of an ordinary male chaffinch is only sixpence, Mr. Weir saw one bird
+for which the bird-catcher asked three pounds; the test of a really
+good singer being that it will continue to sing whilst the cage is swung
+round the owner's head.
+
+That male birds should sing from emulation as well as for charming the
+female, is not at all incompatible; and it might have been expected
+that these two habits would have concurred, like those of display and
+pugnacity. Some authors, however, argue that the song of the male cannot
+serve to charm the female, because the females of some few species, such
+as of the canary, robin, lark, and bullfinch, especially when in a state
+of widowhood, as Bechstein remarks, pour forth fairly melodious strains.
+In some of these cases the habit of singing may be in part attributed
+to the females having been highly fed and confined (32. D. Barrington,
+'Philosophical Transactions,' 1773, p. 262. Bechstein, 'Stubenv�gel,'
+1840, s. 4.), for this disturbs all the functions connected with the
+reproduction of the species. Many instances have already been given
+of the partial transference of secondary masculine characters to the
+female, so that it is not at all surprising that the females of some
+species should possess the power of song. It has also been argued,
+that the song of the male cannot serve as a charm, because the males of
+certain species, for instance of the robin, sing during the autumn. (33.
+This is likewise the case with the water-ouzel; see Mr. Hepburn in the
+'Zoologist,' 1845-46, p. 1068.) But nothing is more common than for
+animals to take pleasure in practising whatever instinct they follow
+at other times for some real good. How often do we see birds which fly
+easily, gliding and sailing through the air obviously for pleasure? The
+cat plays with the captured mouse, and the cormorant with the captured
+fish. The weaver-bird (Ploceus), when confined in a cage, amuses itself
+by neatly weaving blades of grass between the wires of its cage. Birds
+which habitually fight during the breeding-season are generally ready
+to fight at all times; and the males of the capercailzie sometimes hold
+their Balzen or leks at the usual place of assemblage during the autumn.
+(34. L. Lloyd, 'Game Birds of Sweden,' 1867, p. 25.) Hence it is not
+at all surprising that male birds should continue singing for their own
+amusement after the season for courtship is over.
+
+As shewn in a previous chapter, singing is to a certain extent an art,
+and is much improved by practice. Birds can be taught various tunes,
+and even the unmelodious sparrow has learnt to sing like a linnet. They
+acquire the song of their foster parents (35. Barrington, ibid. p. 264,
+Bechstein, ibid. s. 5.), and sometimes that of their neighbours. (36.
+Dureau de la Malle gives a curious instance ('Annales des Sc. Nat.' 3rd
+series, Zoolog., tom. x. p. 118) of some wild blackbirds in his garden
+in Paris, which naturally learnt a republican air from a caged bird.)
+All the common songsters belong to the Order of Insessores, and their
+vocal organs are much more complex than those of most other birds;
+yet it is a singular fact that some of the Insessores, such as ravens,
+crows, and magpies, possess the proper apparatus (37. Bishop, in 'Todd's
+Cyclopaedia of Anatomy and Physiology,' vol. iv. p. 1496.), though they
+never sing, and do not naturally modulate their voices to any great
+extent. Hunter asserts (38. As stated by Barrington in 'Philosophical
+Transactions,' 1773, p. 262.) that with the true songsters the muscles
+of the larynx are stronger in the males than in the females; but with
+this slight exception there is no difference in the vocal organs of the
+two sexes, although the males of most species sing so much better and
+more continuously than the females.
+
+It is remarkable that only small birds properly sing. The Australian
+genus Menura, however, must be excepted; for the Menura Alberti, which
+is about the size of a half-grown turkey, not only mocks other birds,
+but "its own whistle is exceedingly beautiful and varied." The males
+congregate and form "corroborying places," where they sing, raising
+and spreading their tails like peacocks, and drooping their wings. (39.
+Gould, 'Handbook to the Birds of Australia,' vol. i. 1865, pp. 308-310.
+See also Mr. T.W. Wood in the 'Student,' April 1870, p. 125.) It is
+also remarkable that birds which sing well are rarely decorated with
+brilliant colours or other ornaments. Of our British birds, excepting
+the bullfinch and goldfinch, the best songsters are plain-coloured. The
+kingfisher, bee-eater, roller, hoopoe, woodpeckers, etc., utter harsh
+cries; and the brilliant birds of the tropics are hardly ever songsters.
+(40. See remarks to this effect in Gould's 'Introduction to the
+Trochilidae,' 1861, p. 22.) Hence bright colours and the power of song
+seem to replace each other. We can perceive that if the plumage did not
+vary in brightness, or if bright colours were dangerous to the species,
+other means would be employed to charm the females; and melody of voice
+offers one such means.
+
+[Fig. 39. Tetrao cupido: male. (T.W. Wood.)]
+
+In some birds the vocal organs differ greatly in the two sexes. In the
+Tetrao cupido (Fig. 39) the male has two bare, orange-coloured sacks,
+one on each side of the neck; and these are largely inflated when
+the male, during the breeding-season, makes his curious hollow
+sound, audible at a great distance. Audubon proved that the sound
+was intimately connected with this apparatus (which reminds us of the
+air-sacks on each side of the mouth of certain male frogs), for he found
+that the sound was much diminished when one of the sacks of a tame bird
+was pricked, and when both were pricked it was altogether stopped. The
+female has "a somewhat similar, though smaller naked space of skin on
+the neck; but this is not capable of inflation." (41. 'The Sportsman
+and Naturalist in Canada,' by Major W. Ross King, 1866, pp. 144-146.
+Mr. T.W. Wood gives in the 'Student' (April 1870, p. 116) an excellent
+account of the attitude and habits of this bird during its courtship. He
+states that the ear-tufts or neck-plumes are erected, so that they
+meet over the crown of the head. See his drawing, Fig. 39.) The male
+of another kind of grouse (Tetrao urophasianus), whilst courting the
+female, has his "bare yellow oesophagus inflated to a prodigious size,
+fully half as large as the body"; and he then utters various grating,
+deep, hollow tones. With his neck-feathers erect, his wings lowered, and
+buzzing on the ground, and his long pointed tail spread out like a fan,
+he displays a variety of grotesque attitudes. The oesophagus of the
+female is not in any way remarkable. (42. Richardson, 'Fauna Bor.
+Americana: Birds,' 1831, p. 359. Audubon, ibid. vol. iv. p. 507.)
+
+[Fig. 40. The Umbrella-bird or Cephalopterus ornatus, male (from
+Brehm).]
+
+It seems now well made out that the great throat pouch of the European
+male bustard (Otis tarda), and of at least four other species, does not,
+as was formerly supposed, serve to hold water, but is connected with
+the utterance during the breeding-season of a peculiar sound resembling
+"oak." (43. The following papers have been lately written on this
+subject: Prof. A. Newton, in the 'Ibis,' 1862, p. 107; Dr. Cullen, ibid.
+1865, p. 145; Mr. Flower, in 'Proc. Zool. Soc.' 1865, p. 747; and Dr.
+Murie, in 'Proc. Zool. Soc.' 1868, p. 471. In this latter paper an
+excellent figure is given of the male Australian Bustard in full display
+with the sack distended. It is a singular fact that the sack is not
+developed in all the males of the same species.) A crow-like bird
+inhabiting South America (see Cephalopterus ornatus, Fig. 40) is called
+the umbrella-bird, from its immense top knot, formed of bare white
+quills surmounted by dark-blue plumes, which it can elevate into a great
+dome no less than five inches in diameter, covering the whole head. This
+bird has on its neck a long, thin, cylindrical fleshy appendage, which
+is thickly clothed with scale-like blue feathers. It probably serves
+in part as an ornament, but likewise as a resounding apparatus; for Mr.
+Bates found that it is connected "with an unusual development of the
+trachea and vocal organs." It is dilated when the bird utters its
+singularly deep, loud and long sustained fluty note. The head-crest
+and neck-appendage are rudimentary in the female. (44. Bates, 'The
+Naturalist on the Amazons,' 1863, vol. ii. p. 284; Wallace, in
+'Proceedings, Zoological Society,' 1850, p. 206. A new species, with a
+still larger neck-appendage (C. penduliger), has lately been discovered,
+see 'Ibis,' vol. i. p. 457.)
+
+The vocal organs of various web-footed and wading birds are
+extraordinarily complex, and differ to a certain extent in the two
+sexes. In some cases the trachea is convoluted, like a French horn, and
+is deeply embedded in the sternum. In the wild swan (Cygnus ferus) it is
+more deeply embedded in the adult male than in the adult female or
+young male. In the male Merganser the enlarged portion of the trachea
+is furnished with an additional pair of muscles. (45. Bishop, in Todd's
+'Cyclopaedia of Anatomy and Physiology,' vol. iv. p. 1499.) In one of
+the ducks, however, namely Anas punctata, the bony enlargement is only a
+little more developed in the male than in the female. (46. Prof. Newton,
+'Proc. Zoolog. Soc.' 1871, p. 651.) But the meaning of these differences
+in the trachea of the two sexes of the Anatidae is not understood; for
+the male is not always the more vociferous; thus with the common
+duck, the male hisses, whilst the female utters a loud quack. (47. The
+spoonbill (Platalea) has its trachea convoluted into a figure of eight,
+and yet this bird (Jerdon, 'Birds of India,' vol. iii. p. 763) is
+mute; but Mr. Blyth informs me that the convolutions are not constantly
+present, so that perhaps they are now tending towards abortion.) In
+both sexes of one of the cranes (Grus virgo) the trachea penetrates the
+sternum, but presents "certain sexual modifications." In the male of the
+black stork there is also a well-marked sexual difference in the length
+and curvature of the bronchi. (48. 'Elements of Comparative Anatomy,'
+by R. Wagner, Eng. translat. 1845, p. 111. With respect to the swan, as
+given above, Yarrell's 'History of British Birds,' 2nd edition, 1845,
+vol. iii. p. 193.) Highly important structures have, therefore, in these
+cases been modified according to sex.
+
+It is often difficult to conjecture whether the many strange cries and
+notes uttered by male birds during the breeding-season serve as a charm
+or merely as a call to the female. The soft cooing of the turtle-dove
+and of many pigeons, it may be presumed, pleases the female. When the
+female of the wild turkey utters her call in the morning, the male
+answers by a note which differs from the gobbling noise made, when with
+erected feathers, rustling wings and distended wattles, he puffs and
+struts before her. (49. C.L. Bonaparte, quoted in the 'Naturalist
+Library: Birds,' vol. xiv. p. 126.) The spel of the black-cock certainly
+serves as a call to the female, for it has been known to bring four or
+five females from a distance to a male under confinement; but as the
+black-cock continues his spel for hours during successive days, and in
+the case of the capercailzie "with an agony of passion," we are led to
+suppose that the females which are present are thus charmed. (50. L.
+Lloyd, 'The Game Birds of Sweden,' etc., 1867, pp. 22, 81.) The voice
+of the common rook is known to alter during the breeding-season, and is
+therefore in some way sexual. (51. Jenner, 'Philosophical Transactions,'
+1824, p. 20.) But what shall we say about the harsh screams of, for
+instance, some kinds of macaws; have these birds as bad taste for
+musical sounds as they apparently have for colour, judging by the
+inharmonious contrast of their bright yellow and blue plumage? It is
+indeed possible that without any advantage being thus gained, the loud
+voices of many male birds may be the result of the inherited effects
+of the continued use of their vocal organs when excited by the strong
+passions of love, jealousy and rage; but to this point we shall recur
+when we treat of quadrupeds.
+
+We have as yet spoken only of the voice, but the males of various birds
+practise, during their courtship, what may be called instrumental
+music. Peacocks and Birds of Paradise rattle their quills together.
+Turkey-cocks scrape their wings against the ground, and some kinds of
+grouse thus produce a buzzing sound. Another North American grouse,
+the Tetrao umbellus, when with his tail erect, his ruffs displayed, "he
+shows off his finery to the females, who lie hid in the neighbourhood,"
+drums by rapidly striking his wings together above his back, according
+to Mr. R. Haymond, and not, as Audubon thought, by striking them against
+his sides. The sound thus produced is compared by some to distant
+thunder, and by others to the quick roll of a drum. The female never
+drums, "but flies directly to the place where the male is thus engaged."
+The male of the Kalij-pheasant, in the Himalayas, often makes a singular
+drumming noise with his wings, not unlike the sound produced by
+shaking a stiff piece of cloth." On the west coast of Africa the little
+black-weavers (Ploceus?) congregate in a small party on the bushes round
+a small open space, and sing and glide through the air with quivering
+wings, "which make a rapid whirring sound like a child's rattle." One
+bird after another thus performs for hours together, but only during
+the courting-season. At this season, and at no other time, the males of
+certain night-jars (Caprimulgus) make a strange booming noise with their
+wings. The various species of woodpeckers strike a sonorous branch with
+their beaks, with so rapid a vibratory movement that "the head appears
+to be in two places at once." The sound thus produced is audible at a
+considerable distance but cannot be described; and I feel sure that its
+source would never be conjectured by any one hearing it for the first
+time. As this jarring sound is made chiefly during the breeding-season,
+it has been considered as a love-song; but it is perhaps more strictly a
+love-call. The female, when driven from her nest, has been observed thus
+to call her mate, who answered in the same manner and soon appeared.
+Lastly, the male hoopoe (Upupa epops) combines vocal and instrumental
+music; for during the breeding-season this bird, as Mr. Swinhoe
+observed, first draws in air, and then taps the end of its beak
+perpendicularly down against a stone or the trunk of a tree, "when the
+breath being forced down the tubular bill produces the correct sound."
+If the beak is not thus struck against some object, the sound is quite
+different. Air is at the same time swallowed, and the oesophagus thus
+becomes much swollen; and this probably acts as a resonator, not
+only with the hoopoe, but with pigeons and other birds. (52. For the
+foregoing facts see, on Birds of Paradise, Brehm, 'Thierleben,' Band
+iii. s. 325. On Grouse, Richardson, 'Fauna Bor. Americ.: Birds,' pp. 343
+and 359; Major W. Ross King, 'The Sportsman in Canada,' 1866, p. 156;
+Mr. Haymond, in Prof. Cox's 'Geol. Survey of Indiana,' p. 227; Audubon,
+'American Ornitholog. Biograph.' vol. i. p. 216. On the Kalij-pheasant,
+Jerdon, 'Birds of India,' vol. iii. p. 533. On the Weavers,
+Livingstone's 'Expedition to the Zambesi,' 1865, p. 425. On Woodpeckers,
+Macgillivray, 'Hist. of British Birds,' vol. iii. 1840, pp. 84, 88, 89,
+and 95. On the Hoopoe, Mr. Swinhoe, in 'Proc. Zoolog. Soc.' June 23,
+1863 and 1871, p. 348. On the Night-jar, Audubon, ibid. vol. ii. p. 255,
+and 'American Naturalist,' 1873, p. 672. The English Night-jar likewise
+makes in the spring a curious noise during its rapid flight.)
+
+[Fig. 41. Outer tail-feather of Scolopax gallinago (from 'Proc. Zool.
+Soc.' 1858).
+
+Fig. 42. Outer tail-feather of Scolopax frenata.
+
+Fig. 43. Outer tail-feather of Scolopax javensis.]
+
+In the foregoing cases sounds are made by the aid of structures already
+present and otherwise necessary; but in the following cases certain
+feathers have been specially modified for the express purpose of
+producing sounds. The drumming, bleating, neighing, or thundering noise
+(as expressed by different observers) made by the common snipe (Scolopax
+gallinago) must have surprised every one who has ever heard it. This
+bird, during the pairing-season, flies to "perhaps a thousand feet in
+height," and after zig-zagging about for a time descends to the earth in
+a curved line, with outspread tail and quivering pinions, and surprising
+velocity. The sound is emitted only during this rapid descent. No one
+was able to explain the cause until M. Meves observed that on each side
+of the tail the outer feathers are peculiarly formed (Fig. 41), having
+a stiff sabre-shaped shaft with the oblique barbs of unusual length, the
+outer webs being strongly bound together. He found that by blowing on
+these feathers, or by fastening them to a long thin stick and waving
+them rapidly through the air, he could reproduce the drumming noise made
+by the living bird. Both sexes are furnished with these feathers, but
+they are generally larger in the male than in the female, and emit a
+deeper note. In some species, as in S. frenata (Fig. 42), four feathers,
+and in S. javensis (Fig. 43), no less than eight on each side of the
+tail are greatly modified. Different tones are emitted by the feathers
+of the different species when waved through the air; and the Scolopax
+Wilsonii of the United States makes a switching noise whilst descending
+rapidly to the earth. (53. See M. Meves' interesting paper in 'Proc.
+Zool. Soc.' 1858, p. 199. For the habits of the snipe, Macgillivray,
+'History of British Birds,' vol. iv. p. 371. For the American snipe,
+Capt. Blakiston, 'Ibis,' vol. v. 1863, p. 131.)
+
+[Fig. 44. Primary wing-feather of a Humming-bird, the Selasphorus
+platycercus (from a sketch by Mr. Salvin). Upper figure, that of male;
+lower figure, corresponding feather of female.]
+
+In the male of the Chamaepetes unicolor (a large gallinaceous bird of
+America), the first primary wing-feather is arched towards the tip
+and is much more attenuated than in the female. In an allied bird,
+the Penelope nigra, Mr. Salvin observed a male, which, whilst it flew
+downwards "with outstretched wings, gave forth a kind of crashing
+rushing noise," like the falling of a tree. (54. Mr. Salvin, in
+'Proceedings, Zoological Society,' 1867, p. 160. I am much indebted to
+this distinguished ornithologist for sketches of the feathers of the
+Chamaepetes, and for other information.) The male alone of one of the
+Indian bustards (Sypheotides auritus) has its primary wing-feathers
+greatly acuminated; and the male of an allied species is known to make a
+humming noise whilst courting the female. (55. Jerdon, 'Birds of India,'
+vol. iii. pp. 618, 621.) In a widely different group of birds, namely
+Humming-birds, the males alone of certain kinds have either the shafts
+of their primary wing-feathers broadly dilated, or the webs abruptly
+excised towards the extremity. The male, for instance, of Selasphorus
+platycercus, when adult, has the first primary wing-feather (Fig. 44),
+thus excised. Whilst flying from flower to flower he makes "a shrill,
+almost whistling noise" (56. Gould, 'Introduction to the Trochilidae,'
+1861, p. 49. Salvin, 'Proceedings, Zoological Society,' 1867, p. 160.);
+but it did not appear to Mr. Salvin that the noise was intentionally
+made.
+
+[Fig. 45. Secondary wing-feathers of Pipra deliciosa (from Mr. Sclater,
+in 'Proc. Zool. Soc.' 1860). The three upper feathers, a, b, c, from the
+male; the three lower corresponding feathers, d, e, f, from the female.
+a and d, fifth secondary wing-feather of male and female, upper surface.
+b and e, sixth secondary, upper surface. c and f, seventh secondary,
+lower surface.]
+
+Lastly, in several species of a sub-genus of Pipra or Manakin, the
+males, as described by Mr. Sclater, have their SECONDARY wing-feathers
+modified in a still more remarkable manner. In the brilliantly-coloured
+P. deliciosa the first three secondaries are thick-stemmed and curved
+towards the body; in the fourth and fifth (Fig. 45, a) the change is
+greater; and in the sixth and seventh (b, c) the shaft "is thickened to
+an extraordinary degree, forming a solid horny lump." The barbs also are
+greatly changed in shape, in comparison with the corresponding feathers
+(d, e, f) in the female. Even the bones of the wing, which support
+these singular feathers in the male, are said by Mr. Fraser to be much
+thickened. These little birds make an extraordinary noise, the first
+"sharp note being not unlike the crack of a whip." (57. Sclater, in
+'Proceedings, Zoological Society,' 1860, p. 90, and in 'Ibis,' vol. iv.
+1862, p. 175. Also Salvin, in 'Ibis,' 1860, p. 37.)
+
+The diversity of the sounds, both vocal and instrumental, made by the
+males of many birds during the breeding-season, and the diversity of the
+means for producing such sounds, are highly remarkable. We thus gain a
+high idea of their importance for sexual purposes, and are reminded of
+the conclusion arrived at as to insects. It is not difficult to imagine
+the steps by which the notes of a bird, primarily used as a mere call or
+for some other purpose, might have been improved into a melodious love
+song. In the case of the modified feathers, by which the drumming,
+whistling, or roaring noises are produced, we know that some birds
+during their courtship flutter, shake, or rattle their unmodified
+feathers together; and if the females were led to select the best
+performers, the males which possessed the strongest or thickest, or most
+attenuated feathers, situated on any part of the body, would be the most
+successful; and thus by slow degrees the feathers might be modified to
+almost any extent. The females, of course, would not notice each slight
+successive alteration in shape, but only the sounds thus produced. It is
+a curious fact that in the same class of animals, sounds so different as
+the drumming of the snipe's tail, the tapping of the woodpecker's beak,
+the harsh trumpet-like cry of certain water-fowl, the cooing of the
+turtle-dove, and the song of the nightingale, should all be pleasing to
+the females of the several species. But we must not judge of the tastes
+of distinct species by a uniform standard; nor must we judge by
+the standard of man's taste. Even with man, we should remember what
+discordant noises, the beating of tom-toms and the shrill notes of
+reeds, please the ears of savages. Sir S. Baker remarks (58. 'The Nile
+Tributaries of Abyssinia,' 1867, p. 203.), that "as the stomach of the
+Arab prefers the raw meat and reeking liver taken hot from the animal,
+so does his ear prefer his equally coarse and discordant music to all
+other."
+
+LOVE ANTICS AND DANCES.
+
+The curious love gestures of some birds have already been incidentally
+noticed; so that little need here be added. In Northern America large
+numbers of a grouse, the Tetrao phasianellus, meet every morning during
+the breeding-season on a selected level spot, and here they run round
+and round in a circle of about fifteen or twenty feet in diameter,
+so that the ground is worn quite bare, like a fairy-ring. In these
+Partridge-dances, as they are called by the hunters, the birds assume
+the strangest attitudes, and run round, some to the left and some to
+the right. Audubon describes the males of a heron (Ardea herodias) as
+walking about on their long legs with great dignity before the
+females, bidding defiance to their rivals. With one of the disgusting
+carrion-vultures (Cathartes jota) the same naturalist states that
+"the gesticulations and parade of the males at the beginning of the
+love-season are extremely ludicrous." Certain birds perform their
+love-antics on the wing, as we have seen with the black African weaver,
+instead of on the ground. During the spring our little white-throat
+(Sylvia cinerea) often rises a few feet or yards in the air above some
+bush, and "flutters with a fitful and fantastic motion, singing all the
+while, and then drops to its perch." The great English bustard throws
+himself into indescribably odd attitudes whilst courting the female, as
+has been figured by Wolf. An allied Indian bustard (Otis bengalensis) at
+such times "rises perpendicularly into the air with a hurried flapping
+of his wings, raising his crest and puffing out the feathers of his neck
+and breast, and then drops to the ground;" he repeats this manoeuvre
+several times, at the same time humming in a peculiar tone. Such females
+as happen to be near "obey this saltatory summons," and when they
+approach he trails his wings and spreads his tail like a turkey-cock.
+(59. For Tetrao phasianellus, see Richardson, 'Fauna, Bor. America,' p.
+361, and for further particulars Capt. Blakiston, 'Ibis,' 1863, p. 125.
+For the Cathartes and Ardea, Audubon, 'Ornithological Biography,' vol.
+ii. p. 51, and vol. iii. p. 89. On the White-throat, Macgillivray,
+'History of British Birds,' vol. ii. p. 354. On the Indian Bustard,
+Jerdon, 'Birds of India,' vol. iii. p. 618.)
+
+[Fig. 46. Bower-bird, Chlamydera maculata, with bower (from Brehm).]
+
+But the most curious case is afforded by three allied genera of
+Australian birds, the famous Bower-birds,--no doubt the co-descendants
+of some ancient species which first acquired the strange instinct of
+constructing bowers for performing their love-antics. The bowers (Fig.
+46), which, as we shall hereafter see, are decorated with feathers,
+shells, bones, and leaves, are built on the ground for the sole purpose
+of courtship, for their nests are formed in trees. Both sexes assist in
+the erection of the bowers, but the male is the principal workman. So
+strong is this instinct that it is practised under confinement, and Mr.
+Strange has described (60. Gould, 'Handbook to the Birds of Australia,'
+vol. i. pp. 444, 449, 455. The bower of the Satin Bower-bird may be seen
+in the Zoological Society's Gardens, Regent's Park.) the habits of some
+Satin Bower-birds which he kept in an aviary in New South Wales. "At
+times the male will chase the female all over the aviary, then go to the
+bower, pick up a gay feather or a large leaf, utter a curious kind of
+note, set all his feathers erect, run round the bower and become so
+excited that his eyes appear ready to start from his head; he continues
+opening first one wing then the other, uttering a low, whistling note,
+and, like the domestic cock, seems to be picking up something from
+the ground, until at last the female goes gently towards him." Captain
+Stokes has described the habits and "play-houses" of another species,
+the Great Bower-bird, which was seen "amusing itself by flying backwards
+and forwards, taking a shell alternately from each side, and carrying
+it through the archway in its mouth." These curious structures, formed
+solely as halls of assemblage, where both sexes amuse themselves and pay
+their court, must cost the birds much labour. The bower, for instance,
+of the Fawn-breasted species, is nearly four feet in length, eighteen
+inches in height, and is raised on a thick platform of sticks.
+
+DECORATION.
+
+I will first discuss the cases in which the males are ornamented either
+exclusively or in a much higher degree than the females, and in a
+succeeding chapter those in which both sexes are equally ornamented,
+and finally the rare cases in which the female is somewhat more
+brightly-coloured than the male. As with the artificial ornaments used
+by savage and civilised men, so with the natural ornaments of birds, the
+head is the chief seat of decoration. (61. See remarks to this effect,
+on the 'Feeling of Beauty among Animals,' by Mr. J. Shaw, in the
+'Athenaeum,' Nov. 24th, 1866, p. 681.) The ornaments, as mentioned
+at the commencement of this chapter, are wonderfully diversified. The
+plumes on the front or back of the head consist of variously-shaped
+feathers, sometimes capable of erection or expansion, by which their
+beautiful colours are fully displayed. Elegant ear-tufts (Fig. 39) are
+occasionally present. The head is sometimes covered with velvety down,
+as with the pheasant; or is naked and vividly coloured. The throat,
+also, is sometimes ornamented with a beard, wattles, or caruncles.
+Such appendages are generally brightly-coloured, and no doubt serve as
+ornaments, though not always ornamental in our eyes; for whilst the male
+is in the act of courting the female, they often swell and assume vivid
+tints, as in the male turkey. At such times the fleshy appendages about
+the head of the male Tragopan pheasant (Ceriornis Temminckii) swell into
+a large lappet on the throat and into two horns, one on each side of the
+splendid top-knot; and these are then coloured of the most intense blue
+which I have ever beheld. (62. See Dr. Murie's account with coloured
+figures in 'Proceedings, Zoological Society,' 1872, p. 730.) The African
+hornbill (Bucorax abyssinicus) inflates the scarlet bladder-like wattle
+on its neck, and with its wings drooping and tail expanded "makes quite
+a grand appearance." (63. Mr. Monteiro, 'Ibis,' vol. iv. 1862, p. 339.)
+Even the iris of the eye is sometimes more brightly-coloured in the male
+than in the female; and this is frequently the case with the beak, for
+instance, in our common blackbird. In Buceros corrugatus, the whole beak
+and immense casque are coloured more conspicuously in the male than
+in the female; and "the oblique grooves upon the sides of the lower
+mandible are peculiar to the male sex." (64. 'Land and Water,' 1868, p.
+217.)
+
+The head, again, often supports fleshy appendages, filaments, and solid
+protuberances. These, if not common to both sexes, are always confined
+to the males. The solid protuberances have been described in detail
+by Dr. W. Marshall (65. 'Ueber die Sch�delh�cker,' etc., 'Niederland.
+Archiv. fur Zoologie,' B. I. Heft 2, 1872.), who shews that they are
+formed either of cancellated bone coated with skin, or of dermal and
+other tissues. With mammals true horns are always supported on the
+frontal bones, but with birds various bones have been modified for this
+purpose; and in species of the same group the protuberances may
+have cores of bone, or be quite destitute of them, with intermediate
+gradations connecting these two extremes. Hence, as Dr. Marshall justly
+remarks, variations of the most different kinds have served for the
+development through sexual selection of these ornamental appendages.
+Elongated feathers or plumes spring from almost every part of the body.
+The feathers on the throat and breast are sometimes developed into
+beautiful ruffs and collars. The tail-feathers are frequently increased
+in length; as we see in the tail-coverts of the peacock, and in the tail
+itself of the Argus pheasant. With the peacock even the bones of the
+tail have been modified to support the heavy tail-coverts. (66. Dr. W.
+Marshall, '�ber den Vogelschwanz,' ibid. B. I. Heft 2, 1872.) The body
+of the Argus is not larger than that of a fowl; yet the length from the
+end of the beak to the extremity of the tail is no less than five feet
+three inches (67. Jardine's 'Naturalist Library: Birds,' vol. xiv. p.
+166.), and that of the beautifully ocellated secondary wing-feathers
+nearly three feet. In a small African night-jar (Cosmetornis
+vexillarius) one of the primary wing-feathers, during the
+breeding-season, attains a length of twenty-six inches, whilst the bird
+itself is only ten inches in length. In another closely-allied genus of
+night-jars, the shafts of the elongated wing-feathers are naked, except
+at the extremity, where there is a disc. (68. Sclater, in the 'Ibis,'
+vol. vi. 1864, p. 114; Livingstone, 'Expedition to the Zambesi,' 1865,
+p. 66.) Again, in another genus of night-jars, the tail-feathers are
+even still more prodigiously developed. In general the feathers of the
+tail are more often elongated than those of the wings, as any
+great elongation of the latter impedes flight. We thus see that in
+closely-allied birds ornaments of the same kind have been gained by the
+males through the development of widely different feathers.
+
+It is a curious fact that the feathers of species belonging to very
+distinct groups have been modified in almost exactly the same peculiar
+manner. Thus the wing-feathers in one of the above-mentioned night-jars
+are bare along the shaft, and terminate in a disc; or are, as they are
+sometimes called, spoon or racket-shaped. Feathers of this kind occur in
+the tail of a motmot (Eumomota superciliaris), of a king-fisher, finch,
+humming-bird, parrot, several Indian drongos (Dicrurus and Edolius, in
+one of which the disc stands vertically), and in the tail of certain
+birds of paradise. In these latter birds, similar feathers, beautifully
+ocellated, ornament the head, as is likewise the case with some
+gallinaceous birds. In an Indian bustard (Sypheotides auritus) the
+feathers forming the ear-tufts, which are about four inches in length,
+also terminate in discs. (69. Jerdon, 'Birds of India,' vol. iii. p.
+620.) It is a most singular fact that the motmots, as Mr. Salvin has
+clearly shewn (70. 'Proceedings, Zoological Society,' 1873, p. 429.),
+give to their tail feathers the racket-shape by biting off the barbs,
+and, further, that this continued mutilation has produced a certain
+amount of inherited effect.
+
+[Fig. 47. Paradisea Papuana (T.W. Wood).]
+
+Again, the barbs of the feathers in various widely-distinct birds are
+filamentous or plumose, as with some herons, ibises, birds of paradise,
+and Gallinaceae. In other cases the barbs disappear, leaving the shafts
+bare from end to end; and these in the tail of the Paradisea apoda
+attain a length of thirty-four inches (71. Wallace, in 'Annals and
+Magazine of Natural History,' vol. xx. 1857, p. 416, and in his 'Malay
+Archipelago,' vol. ii. 1869, p. 390.): in P. Papuana (Fig. 47) they are
+much shorter and thin. Smaller feathers when thus denuded appear like
+bristles, as on the breast of the turkey-cock. As any fleeting fashion
+in dress comes to be admired by man, so with birds a change of almost
+any kind in the structure or colouring of the feathers in the male
+appears to have been admired by the female. The fact of the feathers in
+widely distinct groups having been modified in an analogous manner
+no doubt depends primarily on all the feathers having nearly the same
+structure and manner of development, and consequently tending to vary in
+the same manner. We often see a tendency to analogous variability in
+the plumage of our domestic breeds belonging to distinct species. Thus
+top-knots have appeared in several species. In an extinct variety of the
+turkey, the top-knot consisted of bare quills surmounted with plumes of
+down, so that they somewhat resembled the racket-shaped feathers above
+described. In certain breeds of the pigeon and fowl the feathers are
+plumose, with some tendency in the shafts to be naked. In the Sebastopol
+goose the scapular feathers are greatly elongated, curled, or even
+spirally twisted, with the margins plumose. (72. See my work on 'The
+Variation of Animals and Plants under Domestication,' vol. i. pp. 289,
+293.)
+
+In regard to colour, hardly anything need here be said, for every one
+knows how splendid are the tints of many birds, and how harmoniously
+they are combined. The colours are often metallic and iridescent.
+Circular spots are sometimes surrounded by one or more differently
+shaded zones, and are thus converted into ocelli. Nor need much be said
+on the wonderful difference between the sexes of many birds. The
+common peacock offers a striking instance. Female birds of paradise are
+obscurely coloured and destitute of all ornaments, whilst the males
+are probably the most highly decorated of all birds, and in so many
+different ways that they must be seen to be appreciated. The elongated
+and golden-orange plumes which spring from beneath the wings of the
+Paradisea apoda, when vertically erected and made to vibrate, are
+described as forming a sort of halo, in the centre of which the head
+"looks like a little emerald sun with its rays formed by the two
+plumes." (73. Quoted from M. de Lafresnaye in 'Annals and Mag. of
+Natural History,' vol. xiii. 1854, p. 157: see also Mr. Wallace's
+much fuller account in vol. xx. 1857, p. 412, and in his 'Malay
+Archipelago.') In another most beautiful species the head is bald,
+"and of a rich cobalt blue, crossed by several lines of black velvety
+feathers." (74. Wallace, 'The Malay Archipelago,' vol. ii. 1869, p.
+405.)
+
+[Fig. 48. Lophornis ornatus, male and female (from Brehm).
+
+Fig. 49. Spathura underwoodi, male and female (from Brehm).]
+
+Male humming-birds (Figs. 48 and 49) almost vie with birds of paradise
+in their beauty, as every one will admit who has seen Mr. Gould's
+splendid volumes, or his rich collection. It is very remarkable in how
+many different ways these birds are ornamented. Almost every part
+of their plumage has been taken advantage of, and modified; and the
+modifications have been carried, as Mr. Gould shewed me, to a wonderful
+extreme in some species belonging to nearly every sub-group. Such cases
+are curiously like those which we see in our fancy breeds, reared by man
+for the sake of ornament; certain individuals originally varied in
+one character, and other individuals of the same species in other
+characters; and these have been seized on by man and much augmented--as
+shewn by the tail of the fantail-pigeon, the hood of the jacobin,
+the beak and wattle of the carrier, and so forth. The sole difference
+between these cases is that in the one, the result is due to man's
+selection, whilst in the other, as with humming-birds, birds of
+paradise, etc., it is due to the selection by the females of the more
+beautiful males.
+
+I will mention only one other bird, remarkable from the extreme contrast
+in colour between the sexes, namely the famous bell-bird (Chasmorhynchus
+niveus) of S. America, the note of which can be distinguished at the
+distance of nearly three miles, and astonishes every one when first
+hearing it. The male is pure white, whilst the female is dusky-green;
+and white is a very rare colour in terrestrial species of moderate size
+and inoffensive habits. The male, also, as described by Waterton, has a
+spiral tube, nearly three inches in length, which rises from the base of
+the beak. It is jet-black, dotted over with minute downy feathers. This
+tube can be inflated with air, through a communication with the palate;
+and when not inflated hangs down on one side. The genus consists of four
+species, the males of which are very distinct, whilst the females, as
+described by Mr. Sclater in a very interesting paper, closely resemble
+each other, thus offering an excellent instance of the common rule that
+within the same group the males differ much more from each other than
+do the females. In a second species (C. nudicollis) the male is likewise
+snow-white, with the exception of a large space of naked skin on the
+throat and round the eyes, which during the breeding-season is of a fine
+green colour. In a third species (C. tricarunculatus) the head and neck
+alone of the male are white, the rest of the body being chestnut-brown,
+and the male of this species is provided with three filamentous
+projections half as long as the body--one rising from the base of
+the beak, and the two others from the corners of the mouth. (75. Mr.
+Sclater, 'Intellectual Observer,' Jan. 1867. Waterton's 'Wanderings,'
+p. 118. See also Mr. Salvin's interesting paper, with a plate, in the
+'Ibis,' 1865, p. 90.)
+
+The coloured plumage and certain other ornaments of the adult males are
+either retained for life, or are periodically renewed during the summer
+and breeding-season. At this same season the beak and naked skin about
+the head frequently change colour, as with some herons, ibises, gulls,
+one of the bell-birds just noticed, etc. In the white ibis, the cheeks,
+the inflatable skin of the throat, and the basal portion of the beak
+then become crimson. (76. 'Land and Water,' 1867, p. 394.) In one of
+the rails, Gallicrex cristatus, a large red caruncle is developed during
+this period on the head of the male. So it is with a thin horny crest
+on the beak of one of the pelicans, P. erythrorhynchus; for, after the
+breeding-season, these horny crests are shed, like horns from the heads
+of stags, and the shore of an island in a lake in Nevada was found
+covered with these curious exuviae. (77. Mr. D.G. Elliot, in 'Proc.
+Zool. Soc.' 1869, p. 589.)
+
+Changes of colour in the plumage according to the season depend, firstly
+on a double annual moult, secondly on an actual change of colour in the
+feathers themselves, and thirdly on their dull-coloured margins being
+periodically shed, or on these three processes more or less combined.
+The shedding of the deciduary margins may be compared with the shedding
+of their down by very young birds; for the down in most cases
+arises from the summits of the first true feathers. (78. Nitzsch's
+'Pterylography,' edited by P.L. Sclater, Ray Society, 1867, p. 14.)
+
+With respect to the birds which annually undergo a double moult,
+there are, firstly, some kinds, for instance snipes, swallow-plovers
+(Glareolae), and curlews, in which the two sexes resemble each other,
+and do not change colour at any season. I do not know whether the winter
+plumage is thicker and warmer than the summer plumage, but warmth seems
+the most probable end attained of a double moult, where there is no
+change of colour. Secondly, there are birds, for instance, certain
+species of Totanus and other Grallatores, the sexes of which resemble
+each other, but in which the summer and winter plumage differ slightly
+in colour. The difference, however, in these cases is so small that it
+can hardly be an advantage to them; and it may, perhaps, be attributed
+to the direct action of the different conditions to which the birds are
+exposed during the two seasons. Thirdly, there are many other birds the
+sexes of which are alike, but which are widely different in their summer
+and winter plumage. Fourthly, there are birds the sexes of which differ
+from each other in colour; but the females, though moulting twice,
+retain the same colours throughout the year, whilst the males undergo
+a change of colour, sometimes a great one, as with certain bustards.
+Fifthly and lastly, there are birds the sexes of which differ from each
+other in both their summer and winter plumage; but the male undergoes
+a greater amount of change at each recurrent season than the female--of
+which the ruff (Machetes pugnax) offers a good instance.
+
+With respect to the cause or purpose of the differences in colour
+between the summer and winter plumage, this may in some instances,
+as with the ptarmigan (79. The brown mottled summer plumage of the
+ptarmigan is of as much importance to it, as a protection, as the white
+winter plumage; for in Scandinavia during the spring, when the snow has
+disappeared, this bird is known to suffer greatly from birds of prey,
+before it has acquired its summer dress: see Wilhelm von Wright, in
+Lloyd, 'Game Birds of Sweden,' 1867, p. 125.), serve during both seasons
+as a protection. When the difference between the two plumages is slight
+it may perhaps be attributed, as already remarked, to the direct action
+of the conditions of life. But with many birds there can hardly be a
+doubt that the summer plumage is ornamental, even when both sexes are
+alike. We may conclude that this is the case with many herons,
+egrets, etc., for they acquire their beautiful plumes only during
+the breeding-season. Moreover, such plumes, top-knots, etc., though
+possessed by both sexes, are occasionally a little more developed in
+the male than in the female; and they resemble the plumes and ornaments
+possessed by the males alone of other birds. It is also known that
+confinement, by affecting the reproductive system of male birds,
+frequently checks the development of their secondary sexual characters,
+but has no immediate influence on any other characters; and I am
+informed by Mr. Bartlett that eight or nine specimens of the Knot
+(Tringa canutus) retained their unadorned winter plumage in the
+Zoological Gardens throughout the year, from which fact we may infer
+that the summer plumage, though common to both sexes, partakes of the
+nature of the exclusively masculine plumage of many other birds. (80.
+In regard to the previous statements on moulting, see, on snipes,
+etc., Macgillivray, 'Hist. Brit. Birds,' vol. iv. p. 371; on Glareolae,
+curlews, and bustards, Jerdon, 'Birds of India,' vol. iii. pp. 615, 630,
+683; on Totanus, ibid. p. 700; on the plumes of herons, ibid. p. 738,
+and Macgillivray, vol. iv. pp. 435 and 444, and Mr. Stafford Allen, in
+the 'Ibis,' vol. v. 1863, p. 33.)
+
+From the foregoing facts, more especially from neither sex of certain
+birds changing colour during either annual moult, or changing so
+slightly that the change can hardly be of any service to them, and
+from the females of other species moulting twice yet retaining the same
+colours throughout the year, we may conclude that the habit of annually
+moulting twice has not been acquired in order that the male should
+assume an ornamental character during the breeding-season; but that the
+double moult, having been originally acquired for some distinct purpose,
+has subsequently been taken advantage of in certain cases for gaining a
+nuptial plumage.
+
+It appears at first sight a surprising circumstance that some
+closely-allied species should regularly undergo a double annual moult,
+and others only a single one. The ptarmigan, for instance, moults twice
+or even thrice in the year, and the blackcock only once: some of the
+splendidly coloured honey-suckers (Nectariniae) of India and some
+sub-genera of obscurely coloured pipits (Anthus) have a double, whilst
+others have only a single annual moult. (81. On the moulting of the
+ptarmigan, see Gould's 'Birds of Great Britain.' On the honey-suckers,
+Jerdon, 'Birds of India,' vol. i. pp. 359, 365, 369. On the moulting of
+Anthus, see Blyth, in 'Ibis,' 1867, p. 32.) But the gradations in the
+manner of moulting, which are known to occur with various birds, shew
+us how species, or whole groups, might have originally acquired their
+double annual moult, or having once gained the habit, have again lost
+it. With certain bustards and plovers the vernal moult is far from
+complete, some feathers being renewed, and some changed in colour.
+There is also reason to believe that with certain bustards and rail-like
+birds, which properly undergo a double moult, some of the older males
+retain their nuptial plumage throughout the year. A few highly modified
+feathers may merely be added during the spring to the plumage, as occurs
+with the disc-formed tail-feathers of certain drongos (Bhringa) in
+India, and with the elongated feathers on the back, neck, and crest
+of certain herons. By such steps as these, the vernal moult might
+be rendered more and more complete, until a perfect double moult was
+acquired. Some of the birds of paradise retain their nuptial feathers
+throughout the year, and thus have only a single moult; others cast them
+directly after the breeding-season, and thus have a double moult; and
+others again cast them at this season during the first year, but not
+afterwards; so that these latter species are intermediate in their
+manner of moulting. There is also a great difference with many birds in
+the length of time during which the two annual plumages are retained; so
+that the one might come to be retained for the whole year, and the other
+completely lost. Thus in the spring Machetes pugnax retains his ruff for
+barely two months. In Natal the male widow-bird (Chera progne) acquires
+his fine plumage and long tail-feathers in December or January, and
+loses them in March; so that they are retained only for about three
+months. Most species, which undergo a double moult, keep their
+ornamental feathers for about six months. The male, however, of the wild
+Gallus bankiva retains his neck-hackles for nine or ten months; and when
+these are cast off, the underlying black feathers on the neck are fully
+exposed to view. But with the domesticated descendant of this species,
+the neck-hackles of the male are immediately replaced by new ones; so
+that we here see, as to part of the plumage, a double moult changed
+under domestication into a single moult. (82. For the foregoing
+statements in regard to partial moults, and on old males retaining
+their nuptial plumage, see Jerdon, on bustards and plovers, in 'Birds
+of India,' vol. iii. pp. 617, 637, 709, 711. Also Blyth in 'Land and
+Water,' 1867, p. 84. On the moulting of Paradisea, see an interesting
+article by Dr. W. Marshall, 'Archives Neerlandaises,' tom. vi. 1871.
+On the Vidua, 'Ibis,' vol. iii. 1861, p. 133. On the Drongo-shrikes,
+Jerdon, ibid. vol. i. p. 435. On the vernal moult of the Herodias
+bubulcus, Mr. S.S. Allen, in 'Ibis,' 1863, p. 33. On Gallus bankiva,
+Blyth, in 'Annals and Mag. of Natural History,' vol. i. 1848, p.
+455; see, also, on this subject, my 'Variation of Animals under
+Domestication,' vol. i. p. 236.)
+
+The common drake (Anas boschas), after the breeding-season, is well
+known to lose his male plumage for a period of three months, during
+which time he assumes that of the female. The male pin-tail duck (Anas
+acuta) loses his plumage for the shorter period of six weeks or two
+months; and Montagu remarks that "this double moult within so short a
+time is a most extraordinary circumstance, that seems to bid defiance
+to all human reasoning." But the believer in the gradual modification of
+species will be far from feeling surprise at finding gradations of all
+kinds. If the male pin-tail were to acquire his new plumage within a
+still shorter period, the new male feathers would almost necessarily be
+mingled with the old, and both with some proper to the female; and this
+apparently is the case with the male of a not distantly-allied bird,
+namely the Merganser serrator, for the males are said to "undergo
+a change of plumage, which assimilates them in some measure to the
+female." By a little further acceleration in the process, the double
+moult would be completely lost. (83. See Macgillivray, 'Hist. British
+Birds' (vol. v. pp. 34, 70, and 223), on the moulting of the Anatidae,
+with quotations from Waterton and Montagu. Also Yarrell, 'History of
+British Birds,' vol. iii. p. 243.)
+
+Some male birds, as before stated, become more brightly coloured in the
+spring, not by a vernal moult, but either by an actual change of colour
+in the feathers, or by their obscurely-coloured deciduary margins being
+shed. Changes of colour thus caused may last for a longer or shorter
+time. In the Pelecanus onocrotalus a beautiful rosy tint, with
+lemon-coloured marks on the breast, overspreads the whole plumage in
+the spring; but these tints, as Mr. Sclater states, "do not last long,
+disappearing generally in about six weeks or two months after they have
+been attained." Certain finches shed the margins of their feathers
+in the spring, and then become brighter coloured, while other finches
+undergo no such change. Thus the Fringilla tristis of the United States
+(as well as many other American species) exhibits its bright colours
+only when the winter is past, whilst our goldfinch, which exactly
+represents this bird in habits, and our siskin, which represents it
+still more closely in structure, undergo no such annual change. But
+a difference of this kind in the plumage of allied species is not
+surprising, for with the common linnet, which belongs to the same
+family, the crimson forehead and breast are displayed only during
+the summer in England, whilst in Madeira these colours are retained
+throughout the year. (84. On the pelican, see Sclater, in 'Proc.
+Zool. Soc.' 1868, p. 265. On the American finches, see Audubon,
+'Ornithological Biography,' vol. i. pp. 174, 221, and Jerdon, 'Birds of
+India,' vol. ii. p. 383. On the Fringilla cannabina of Madeira, Mr. E.
+Vernon Harcourt, 'Ibis,' vol. v. 1863, p. 230.)
+
+DISPLAY BY MALE BIRDS OF THEIR PLUMAGE.
+
+Ornaments of all kinds, whether permanently or temporarily gained,
+are sedulously displayed by the males, and apparently serve to excite,
+attract, or fascinate the females. But the males will sometimes
+display their ornaments, when not in the presence of the females, as
+occasionally occurs with grouse at their balz-places, and as may be
+noticed with the peacock; this latter bird, however, evidently wishes
+for a spectator of some kind, and, as I have often seen, will shew
+off his finery before poultry, or even pigs. (85. See also 'Ornamental
+Poultry,' by Rev. E.S. Dixon, 1848, p. 8.) All naturalists who have
+closely attended to the habits of birds, whether in a state of nature
+or under confinement, are unanimously of opinion that the males take
+delight in displaying their beauty. Audubon frequently speaks of the
+male as endeavouring in various ways to charm the female. Mr. Gould,
+after describing some peculiarities in a male humming-bird, says he
+has no doubt that it has the power of displaying them to the greatest
+advantage before the female. Dr. Jerdon (86. 'Birds of India,'
+introduct., vol. i. p. xxiv.; on the peacock, vol. iii. p. 507. See
+Gould's 'Introduction to Trochilidae,' 1861, pp. 15 and 111.) insists
+that the beautiful plumage of the male serves "to fascinate and attract
+the female." Mr. Bartlett, at the Zoological Gardens, expressed himself
+to me in the strongest terms to the same effect.
+
+[Fig. 50. Rupicola crocea, male (T.W. Wood).]
+
+It must be a grand sight in the forests of India "to come suddenly on
+twenty or thirty pea-fowl, the males displaying their gorgeous trains,
+and strutting about in all the pomp of pride before the gratified
+females." The wild turkey-cock erects his glittering plumage, expands
+his finely-zoned tail and barred wing-feathers, and altogether, with his
+crimson and blue wattles, makes a superb, though, to our eyes, grotesque
+appearance. Similar facts have already been given with respect to grouse
+of various kinds. Turning to another Order: The male Rupicola crocea
+(Fig. 50) is one of the most beautiful birds in the world, being of
+a splendid orange, with some of the feathers curiously truncated and
+plumose. The female is brownish-green, shaded with red, and has a much
+smaller crest. Sir R. Schomburgk has described their courtship; he
+found one of their meeting-places where ten males and two females were
+present. The space was from four to five feet in diameter, and appeared
+to have been cleared of every blade of grass and smoothed as if by human
+hands. A male "was capering, to the apparent delight of several others.
+Now spreading its wings, throwing up its head, or opening its tail like
+a fan; now strutting about with a hopping gait until tired, when it
+gabbled some kind of note, and was relieved by another. Thus three
+of them successively took the field, and then, with self-approbation,
+withdrew to rest." The Indians, in order to obtain their skins, wait at
+one of the meeting-places till the birds are eagerly engaged in dancing,
+and then are able to kill with their poisoned arrows four or five males,
+one after the other. (87. 'Journal of R. Geograph. Soc.' vol. x. 1840,
+p. 236.) With birds of paradise a dozen or more full-plumaged males
+congregate in a tree to hold a dancing-party, as it is called by the
+natives: and here they fly about, raise their wings, elevate their
+exquisite plumes, and make them vibrate, and the whole tree seems, as
+Mr. Wallace remarks, to be filled with waving plumes. When thus engaged,
+they become so absorbed that a skilful archer may shoot nearly the whole
+party. These birds, when kept in confinement in the Malay Archipelago,
+are said to take much care in keeping their feathers clean; often
+spreading them out, examining them, and removing every speck of dirt.
+One observer, who kept several pairs alive, did not doubt that the
+display of the male was intended to please the female. (88. 'Annals and
+Mag. of Nat. Hist.' vol. xiii. 1854, p. 157; also Wallace, ibid. vol.
+xx. 1857, p. 412, and 'The Malay Archipelago,' vol. ii. 1869, p. 252.
+Also Dr. Bennett, as quoted by Brehm, 'Thierleben,' B. iii. s. 326.)
+
+[Fig. 51. Polyplectron chinquis, male (T.W. Wood).]
+
+The Gold and Amherst pheasants during their courtship not only expand
+and raise their splendid frills, but twist them, as I have myself seen,
+obliquely towards the female on whichever side she may be standing,
+obviously in order that a large surface may be displayed before her.
+(89. Mr. T.W. Wood has given ('The Student,' April 1870, p. 115) a
+full account of this manner of display, by the Gold pheasant and by
+the Japanese pheasant, Ph. versicolor; and he calls it the lateral
+or one-sided display.) They likewise turn their beautiful tails and
+tail-coverts a little towards the same side. Mr. Bartlett has observed a
+male Polyplectron (Fig. 51) in the act of courtship, and has shewn me
+a specimen stuffed in the attitude then assumed. The tail and
+wing-feathers of this bird are ornamented with beautiful ocelli, like
+those on the peacock's train. Now when the peacock displays himself, he
+expands and erects his tail transversely to his body, for he stands in
+front of the female, and has to shew off, at the same time, his rich
+blue throat and breast. But the breast of the Polyplectron is obscurely
+coloured, and the ocelli are not confined to the tail-feathers.
+Consequently the Polyplectron does not stand in front of the female; but
+he erects and expands his tail-feathers a little obliquely, lowering the
+expanded wing on the same side, and raising that on the opposite side.
+In this attitude the ocelli over the whole body are exposed at the same
+time before the eyes of the admiring female in one grand bespangled
+expanse. To whichever side she may turn, the expanded wings and the
+obliquely-held tail are turned towards her. The male Tragopan pheasant
+acts in nearly the same manner, for he raises the feathers of the body,
+though not the wing itself, on the side which is opposite to the
+female, and which would otherwise be concealed, so that nearly all the
+beautifully spotted feathers are exhibited at the same time.
+
+[Fig. 52. Side view of male Argus pheasant, whilst displaying before the
+female. Observed and sketched from nature by T.W. Wood.]
+
+The Argus pheasant affords a much more remarkable case. The immensely
+developed secondary wing-feathers are confined to the male; and each is
+ornamented with a row of from twenty to twenty-three ocelli, above an
+inch in diameter. These feathers are also elegantly marked with oblique
+stripes and rows of spots of a dark colour, like those on the skin of a
+tiger and leopard combined. These beautiful ornaments are hidden until
+the male shows himself off before the female. He then erects his tail,
+and expands his wing-feathers into a great, almost upright, circular fan
+or shield, which is carried in front of the body. The neck and head are
+held on one side, so that they are concealed by the fan; but the bird in
+order to see the female, before whom he is displaying himself, sometimes
+pushes his head between two of the long wing-feathers (as Mr. Bartlett
+has seen), and then presents a grotesque appearance. This must be a
+frequent habit with the bird in a state of nature, for Mr. Bartlett
+and his son on examining some perfect skins sent from the East, found a
+place between two of the feathers which was much frayed, as if the head
+had here frequently been pushed through. Mr. Wood thinks that the male
+can also peep at the female on one side, beyond the margin of the fan.
+
+The ocelli on the wing-feathers are wonderful objects; for they are
+so shaded that, as the Duke of Argyll remarks (90. 'The Reign of Law,'
+1867, p. 203.), they stand out like balls lying loosely within sockets.
+When I looked at the specimen in the British Museum, which is mounted
+with the wings expanded and trailing downwards, I was however greatly
+disappointed, for the ocelli appeared flat, or even concave. But Mr.
+Gould soon made the case clear to me, for he held the feathers erect, in
+the position in which they would naturally be displayed, and now, from
+the light shining on them from above, each ocellus at once resembled
+the ornament called a ball and socket. These feathers have been shown to
+several artists, and all have expressed their admiration at the perfect
+shading. It may well be asked, could such artistically shaded ornaments
+have been formed by means of sexual selection? But it will be convenient
+to defer giving an answer to this question until we treat in the next
+chapter of the principle of gradation.
+
+The foregoing remarks relate to the secondary wing-feathers, but the
+primary wing-feathers, which in most gallinaceous birds are uniformly
+coloured, are in the Argus pheasant equally wonderful. They are of a
+soft brown tint with numerous dark spots, each of which consists of two
+or three black dots with a surrounding dark zone. But the chief ornament
+is a space parallel to the dark-blue shaft, which in outline forms a
+perfect second feather lying within the true feather. This inner part is
+coloured of a lighter chestnut, and is thickly dotted with minute white
+points. I have shewn this feather to several persons, and many have
+admired it even more than the ball and socket feathers, and have
+declared that it was more like a work of art than of nature. Now these
+feathers are quite hidden on all ordinary occasions, but are fully
+displayed, together with the long secondary feathers, when they are all
+expanded together so as to form the great fan or shield.
+
+The case of the male Argus pheasant is eminently interesting, because it
+affords good evidence that the most refined beauty may serve as a sexual
+charm, and for no other purpose. We must conclude that this is the case,
+as the secondary and primary wing-feathers are not at all displayed, and
+the ball and socket ornaments are not exhibited in full perfection until
+the male assumes the attitude of courtship. The Argus pheasant does not
+possess brilliant colours, so that his success in love appears to depend
+on the great size of his plumes, and on the elaboration of the most
+elegant patterns. Many will declare that it is utterly incredible that
+a female bird should be able to appreciate fine shading and exquisite
+patterns. It is undoubtedly a marvellous fact that she should possess
+this almost human degree of taste. He who thinks that he can safely
+gauge the discrimination and taste of the lower animals may deny that
+the female Argus pheasant can appreciate such refined beauty; but he
+will then be compelled to admit that the extraordinary attitudes assumed
+by the male during the act of courtship, by which the wonderful beauty
+of his plumage is fully displayed, are purposeless; and this is a
+conclusion which I for one will never admit.
+
+Although so many pheasants and allied gallinaceous birds carefully
+display their plumage before the females, it is remarkable, as Mr.
+Bartlett informs me, that this is not the case with the dull-coloured
+Eared and Cheer pheasants (Crossoptilon auritum and Phasianus
+wallichii); so that these birds seem conscious that they have little
+beauty to display. Mr. Bartlett has never seen the males of either
+of these species fighting together, though he has not had such good
+opportunities for observing the Cheer as the Eared pheasant. Mr.
+Jenner Weir, also, finds that all male birds with rich or
+strongly-characterised plumage are more quarrelsome than the
+dull-coloured species belonging to the same groups. The goldfinch, for
+instance, is far more pugnacious than the linnet, and the blackbird
+than the thrush. Those birds which undergo a seasonal change of plumage
+likewise become much more pugnacious at the period when they are most
+gaily ornamented. No doubt the males of some obscurely-coloured birds
+fight desperately together, but it appears that when sexual selection
+has been highly influential, and has given bright colours to the males
+of any species, it has also very often given a strong tendency to
+pugnacity. We shall meet with nearly analogous cases when we treat of
+mammals. On the other hand, with birds the power of song and brilliant
+colours have rarely been both acquired by the males of the same species;
+but in this case the advantage gained would have been the same, namely
+success in charming the female. Nevertheless it must be owned that the
+males of several brilliantly coloured birds have had their feathers
+specially modified for the sake of producing instrumental music, though
+the beauty of this cannot be compared, at least according to our taste,
+with that of the vocal music of many songsters.
+
+We will now turn to male birds which are not ornamented in any high
+degree, but which nevertheless display during their courtship whatever
+attractions they may possess. These cases are in some respects more
+curious than the foregoing, and have been but little noticed. I owe the
+following facts to Mr. Weir, who has long kept confined birds of many
+kinds, including all the British Fringillidae and Emberizidae. The facts
+have been selected from a large body of valuable notes kindly sent me by
+him. The bullfinch makes his advances in front of the female, and then
+puffs out his breast, so that many more of the crimson feathers are seen
+at once than otherwise would be the case. At the same time he twists and
+bows his black tail from side to side in a ludicrous manner. The male
+chaffinch also stands in front of the female, thus shewing his red
+breast and "blue bell," as the fanciers call his head; the wings at
+the same time being slightly expanded, with the pure white bands on the
+shoulders thus rendered conspicuous. The common linnet distends his rosy
+breast, slightly expands his brown wings and tail, so as to make the
+best of them by exhibiting their white edgings. We must, however, be
+cautious in concluding that the wings are spread out solely for display,
+as some birds do so whose wings are not beautiful. This is the case with
+the domestic cock, but it is always the wing on the side opposite to the
+female which is expanded, and at the same time scraped on the ground.
+The male goldfinch behaves differently from all other finches: his
+wings are beautiful, the shoulders being black, with the dark-tipped
+wing-feathers spotted with white and edged with golden yellow. When
+he courts the female, he sways his body from side to side, and quickly
+turns his slightly expanded wings first to one side, then to the other,
+with a golden flashing effect. Mr. Weir informs me that no other British
+finch turns thus from side to side during his courtship, not even the
+closely-allied male siskin, for he would not thus add to his beauty.
+
+Most of the British Buntings are plain coloured birds; but in the
+spring the feathers on the head of the male reed-bunting (Emberiza
+schoeniculus) acquire a fine black colour by the abrasion of the dusky
+tips; and these are erected during the act of courtship. Mr. Weir has
+kept two species of Amadina from Australia: the A. castanotis is a very
+small and chastely coloured finch, with a dark tail, white rump, and
+jet-black upper tail-coverts, each of the latter being marked with three
+large conspicuous oval spots of white. (91. For the description of these
+birds, see Gould's 'Handbook to the Birds of Australia,' vol. i. 1865,
+p. 417.) This species, when courting the female, slightly spreads
+out and vibrates these parti-coloured tail-coverts in a very peculiar
+manner. The male Amadina Lathami behaves very differently, exhibiting
+before the female his brilliantly spotted breast, scarlet rump, and
+scarlet upper tail-coverts. I may here add from Dr. Jerdon that the
+Indian bulbul (Pycnonotus hoemorrhous) has its under tail-coverts of
+a crimson colour, and these, it might be thought, could never be well
+exhibited; but the bird "when excited often spreads them out laterally,
+so that they can be seen even from above." (92. 'Birds of India,' vol.
+ii. p. 96.) The crimson under tail-coverts of some other birds, as
+with one of the woodpeckers, Picus major, can be seen without any such
+display. The common pigeon has iridescent feathers on the breast,
+and every one must have seen how the male inflates his breast whilst
+courting the female, thus shewing them off to the best advantage. One
+of the beautiful bronze-winged pigeons of Australia (Ocyphaps lophotes)
+behaves, as described to me by Mr. Weir, very differently: the male,
+whilst standing before the female, lowers his head almost to the ground,
+spreads out and raises his tail, and half expands his wings. He then
+alternately and slowly raises and depresses his body, so that the
+iridescent metallic feathers are all seen at once, and glitter in the
+sun.
+
+Sufficient facts have now been given to shew with what care male birds
+display their various charms, and this they do with the utmost skill.
+Whilst preening their feathers, they have frequent opportunities for
+admiring themselves, and of studying how best to exhibit their beauty.
+But as all the males of the same species display themselves in exactly
+the same manner, it appears that actions, at first perhaps intentional,
+have become instinctive. If so, we ought not to accuse birds of
+conscious vanity; yet when we see a peacock strutting about, with
+expanded and quivering tail-feathers, he seems the very emblem of pride
+and vanity.
+
+The various ornaments possessed by the males are certainly of the
+highest importance to them, for in some cases they have been acquired
+at the expense of greatly impeded powers of flight or of running. The
+African night-jar (Cosmetornis), which during the pairing-season has
+one of its primary wing-feathers developed into a streamer of very great
+length, is thereby much retarded in its flight, although at other times
+remarkable for its swiftness. The "unwieldy size" of the secondary
+wing-feathers of the male Argus pheasant is said "almost entirely to
+deprive the bird of flight." The fine plumes of male birds of paradise
+trouble them during a high wind. The extremely long tail-feathers of the
+male widow-birds (Vidua) of Southern Africa render "their flight heavy;"
+but as soon as these are cast off they fly as well as the females. As
+birds always breed when food is abundant, the males probably do not
+suffer much inconvenience in searching for food from their impeded
+powers of movement; but there can hardly be a doubt that they must be
+much more liable to be struck down by birds of prey. Nor can we doubt
+that the long train of the peacock and the long tail and wing-feathers
+of the Argus pheasant must render them an easier prey to any prowling
+tiger-cat than would otherwise be the case. Even the bright colours of
+many male birds cannot fail to make them conspicuous to their enemies
+of all kinds. Hence, as Mr. Gould has remarked, it probably is that such
+birds are generally of a shy disposition, as if conscious that their
+beauty was a source of danger, and are much more difficult to discover
+or approach, than the sombre coloured and comparatively tame females or
+than the young and as yet unadorned males. (93. On the Cosmetornis, see
+Livingstone's 'Expedition to the Zambesi,' 1865, p. 66. On the Argus
+pheasant, Jardine's 'Nat. Hist. Lib.: Birds,' vol. xiv. p. 167. On Birds
+of Paradise, Lesson, quoted by Brehm, 'Thierleben,' B. iii. s. 325.
+On the widow-bird, Barrow's 'Travels in Africa,' vol. i. p. 243, and
+'Ibis,' vol. iii. 1861 p. 133. Mr. Gould, on the shyness of male birds,
+'Handbook to Birds of Australia,' vol. i. 1865, pp. 210, 457.)
+
+It is a more curious fact that the males of some birds which are
+provided with special weapons for battle, and which in a state of
+nature are so pugnacious that they often kill each other, suffer from
+possessing certain ornaments. Cock-fighters trim the hackles and cut off
+the combs and gills of their cocks; and the birds are then said to be
+dubbed. An undubbed bird, as Mr. Tegetmeier insists, "is at a fearful
+disadvantage; the comb and gills offer an easy hold to his adversary's
+beak, and as a cock always strikes where he holds, when once he has
+seized his foe, he has him entirely in his power. Even supposing that
+the bird is not killed, the loss of blood suffered by an undubbed cock
+is much greater than that sustained by one that has been trimmed." (94.
+Tegetmeier, 'The Poultry Book,' 1866, p. 139.) Young turkey-cocks in
+fighting always seize hold of each other's wattles; and I presume that
+the old birds fight in the same manner. It may perhaps be objected that
+the comb and wattles are not ornamental, and cannot be of service to the
+birds in this way; but even to our eyes, the beauty of the glossy black
+Spanish cock is much enhanced by his white face and crimson comb; and
+no one who has ever seen the splendid blue wattles of the male Tragopan
+pheasant distended in courtship can for a moment doubt that beauty is
+the object gained. From the foregoing facts we clearly see that
+the plumes and other ornaments of the males must be of the highest
+importance to them; and we further see that beauty is even sometimes
+more important than success in battle.
+
+
+CHAPTER XIV.
+
+BIRDS--continued.
+
+Choice exerted by the female--Length of courtship--Unpaired
+birds--Mental qualities and taste for the beautiful--Preference or
+antipathy shewn by the female for particular males--Variability of
+birds--Variations sometimes abrupt--Laws of variation--Formation of
+ocelli--Gradations of character--Case of Peacock, Argus pheasant, and
+Urosticte.
+
+When the sexes differ in beauty or in the power of singing, or in
+producing what I have called instrumental music, it is almost invariably
+the male who surpasses the female. These qualities, as we have just
+seen, are evidently of high importance to the male. When they are gained
+for only a part of the year it is always before the breeding-season. It
+is the male alone who elaborately displays his varied attractions,
+and often performs strange antics on the ground or in the air, in the
+presence of the female. Each male drives away, or if he can, kills
+his rivals. Hence we may conclude that it is the object of the male to
+induce the female to pair with him, and for this purpose he tries to
+excite or charm her in various ways; and this is the opinion of all
+those who have carefully studied the habits of living birds. But
+there remains a question which has an all important bearing on sexual
+selection, namely, does every male of the same species excite and
+attract the female equally? Or does she exert a choice, and prefer
+certain males? This latter question can be answered in the affirmative
+by much direct and indirect evidence. It is far more difficult to decide
+what qualities determine the choice of the females; but here again we
+have some direct and indirect evidence that it is to a large extent the
+external attractions of the male; though no doubt his vigour, courage,
+and other mental qualities come into play. We will begin with the
+indirect evidence.
+
+LENGTH OF COURTSHIP.
+
+The lengthened period during which both sexes of certain birds meet day
+after day at an appointed place probably depends partly on the courtship
+being a prolonged affair, and partly on reiteration in the act of
+pairing. Thus in Germany and Scandinavia the balzen or leks of the
+black-cocks last from the middle of March, all through April into May.
+As many as forty or fifty, or even more birds congregate at the leks;
+and the same place is often frequented during successive years. The lek
+of the capercailzie lasts from the end of March to the middle or even
+end of May. In North America "the partridge dances" of the Tetrao
+phasianellus "last for a month or more." Other kinds of grouse, both
+in North America and Eastern Siberia (1. Nordman describes ('Bull. Soc.
+Imp. des Nat. Moscou,' 1861, tom. xxxiv. p. 264) the balzen of Tetrao
+urogalloides in Amur Land. He estimated the number of birds assembled
+at above a hundred, not counting the females, which lie hid in
+the surrounding bushes. The noises uttered differ from those of T.
+urogallus.), follow nearly the same habits. The fowlers discover the
+hillocks where the ruffs congregate by the grass being trampled bare,
+and this shews that the same spot is long frequented. The Indians of
+Guiana are well acquainted with the cleared arenas, where they expect to
+find the beautiful cocks of the Rock; and the natives of New Guinea
+know the trees where from ten to twenty male birds of paradise in full
+plumage congregate. In this latter case it is not expressly stated that
+the females meet on the same trees, but the hunters, if not specially
+asked, would probably not mention their presence, as their skins are
+valueless. Small parties of an African weaver (Ploceus) congregate,
+during the breeding-season, and perform for hours their graceful
+evolutions. Large numbers of the Solitary snipe (Scolopax major)
+assemble during dusk in a morass; and the same place is frequented for
+the same purpose during successive years; here they may be seen running
+about "like so many large rats," puffing out their feathers, flapping
+their wings, and uttering the strangest cries. (2. With respect to the
+assemblages of the above named grouse, see Brehm, 'Thierleben,' B.
+iv. s. 350; also L. Lloyd, 'Game Birds of Sweden,' 1867, pp. 19, 78.
+Richardson, 'Fauna Bor. Americana: Birds,' p. 362. References in regard
+to the assemblages of other birds have already been given. On Paradisea,
+see Wallace, in 'Annals and Mag. of Nat. Hist.' vol. xx. 1857, p. 412.
+On the snipe, Lloyd, ibid. p. 221.)
+
+Some of the above birds,--the black-cock, capercailzie, pheasant-grouse,
+ruff, solitary snipe, and perhaps others,--are, as is believed,
+polygamists. With such birds it might have been thought that the
+stronger males would simply have driven away the weaker, and then at
+once have taken possession of as many females as possible; but if it
+be indispensable for the male to excite or please the female, we can
+understand the length of the courtship and the congregation of so many
+individuals of both sexes at the same spot. Certain strictly monogamous
+species likewise hold nuptial assemblages; this seems to be the case
+in Scandinavia with one of the ptarmigans, and their leks last from the
+middle of March to the middle of May. In Australia the lyre-bird (Menura
+superba) forms "small round hillocks," and the M. Alberti scratches
+for itself shallow holes, or, as they are called by the natives,
+"corroborying places," where it is believed both sexes assemble. The
+meetings of the M. superba are sometimes very large; and an account has
+lately been published (3. Quoted by Mr. T.W. Wood, in the 'Student,'
+April 1870, p. 125.) by a traveller, who heard in a valley beneath him,
+thickly covered with scrub, "a din which completely astonished" him;
+on crawling onwards he beheld, to his amazement, about one hundred and
+fifty of the magnificent lyre-cocks, "ranged in order of battle, and
+fighting with indescribable fury." The bowers of the Bower-birds are
+the resort of both sexes during the breeding-season; and "here the males
+meet and contend with each other for the favours of the female, and here
+the latter assemble and coquet with the males." With two of the genera,
+the same bower is resorted to during many years. (4. Gould, 'Handbook
+to the Birds of Australia,' vol. i. pp. 300, 308, 448, 451. On the
+ptarmigan, above alluded to, see Lloyd, ibid. p. 129.)
+
+The common magpie (Corvus pica, Linn.), as I have been informed by the
+Rev. W. Darwin Fox, used to assemble from all parts of Delamere Forest,
+in order to celebrate the "great magpie marriage." Some years ago these
+birds abounded in extraordinary numbers, so that a gamekeeper killed in
+one morning nineteen males, and another killed by a single shot seven
+birds at roost together. They then had the habit of assembling very
+early in the spring at particular spots, where they could be seen in
+flocks, chattering, sometimes fighting, bustling and flying about the
+trees. The whole affair was evidently considered by the birds as one of
+the highest importance. Shortly after the meeting they all separated,
+and were then observed by Mr. Fox and others to be paired for the
+season. In any district in which a species does not exist in large
+numbers, great assemblages cannot, of course, be held, and the same
+species may have different habits in different countries. For instance,
+I have heard of only one instance, from Mr. Wedderburn, of a regular
+assemblage of black game in Scotland, yet these assemblages are so well
+known in Germany and Scandinavia that they have received special names.
+
+UNPAIRED BIRDS.
+
+From the facts now given, we may conclude that the courtship of birds
+belonging to widely different groups, is often a prolonged, delicate,
+and troublesome affair. There is even reason to suspect, improbable
+as this will at first appear, that some males and females of the same
+species, inhabiting the same district, do not always please each other,
+and consequently do not pair. Many accounts have been published of
+either the male or female of a pair having been shot, and quickly
+replaced by another. This has been observed more frequently with the
+magpie than with any other bird, owing perhaps to its conspicuous
+appearance and nest. The illustrious Jenner states that in Wiltshire one
+of a pair was daily shot no less than seven times successively, "but all
+to no purpose, for the remaining magpie soon found another mate"; and
+the last pair reared their young. A new partner is generally found
+on the succeeding day; but Mr. Thompson gives the case of one being
+replaced on the evening of the same day. Even after the eggs are
+hatched, if one of the old birds is destroyed a mate will often be
+found; this occurred after an interval of two days, in a case recently
+observed by one of Sir J. Lubbock's keepers. (5. On magpies, Jenner, in
+'Philosophical Transactions,' 1824, p. 21. Macgillivray, 'Hist. British
+Birds,' vol. i. p. 570. Thompson, in 'Annals and Magazine of Natural
+History,' vol. viii. 1842, p. 494.) The first and most obvious
+conjecture is that male magpies must be much more numerous than females;
+and that in the above cases, as well as in many others which could be
+given, the males alone had been killed. This apparently holds good in
+some instances, for the gamekeepers in Delamere Forest assured Mr.
+Fox that the magpies and carrion-crows which they formerly killed in
+succession in large numbers near their nests, were all males; and they
+accounted for this fact by the males being easily killed whilst bringing
+food to the sitting females. Macgillivray, however, gives, on the
+authority of an excellent observer, an instance of three magpies
+successively killed on the same nest, which were all females; and
+another case of six magpies successively killed whilst sitting on the
+same eggs, which renders it probable that most of them were females;
+though, as I hear from Mr. Fox, the male will sit on the eggs when the
+female is killed.
+
+Sir J. Lubbock's gamekeeper has repeatedly shot, but how often he could
+not say, one of a pair of jays (Garrulus glandarius), and has never
+failed shortly afterwards to find the survivor re-matched. Mr. Fox, Mr.
+F. Bond, and others have shot one of a pair of carrion-crows (Corvus
+corone), but the nest was soon again tenanted by a pair. These birds are
+rather common; but the peregrine-falcon (Falco peregrinus) is rare, yet
+Mr. Thompson states that in Ireland "if either an old male or female be
+killed in the breeding-season (not an uncommon circumstance),
+another mate is found within a very few days, so that the eyries,
+notwithstanding such casualties, are sure to turn out their complement
+of young." Mr. Jenner Weir has known the same thing with the
+peregrine-falcons at Beachy Head. The same observer informs me that
+three kestrels (Falco tinnunculus), all males, were killed one after
+the other whilst attending the same nest; two of these were in mature
+plumage, but the third was in the plumage of the previous year. Even
+with the rare golden eagle (Aquila chrysaetos), Mr. Birkbeck was assured
+by a trustworthy gamekeeper in Scotland, that if one is killed, another
+is soon found. So with the white owl (Strix flammea), "the survivor
+readily found a mate, and the mischief went on."
+
+White of Selborne, who gives the case of the owl, adds that he knew a
+man, who from believing that partridges when paired were disturbed by
+the males fighting, used to shoot them; and though he had widowed the
+same female several times, she always soon found a fresh partner. This
+same naturalist ordered the sparrows, which deprived the house-martins
+of their nests, to be shot; but the one which was left, "be it cock or
+hen, presently procured a mate, and so for several times following." I
+could add analogous cases relating to the chaffinch, nightingale, and
+redstart. With respect to the latter bird (Phoenicura ruticilla), a
+writer expresses much surprise how the sitting female could so soon have
+given effectual notice that she was a widow, for the species was not
+common in the neighbourhood. Mr. Jenner Weir has mentioned to me a
+nearly similar case; at Blackheath he never sees or hears the note of
+the wild bullfinch, yet when one of his caged males has died, a wild
+one in the course of a few days has generally come and perched near the
+widowed female, whose call-note is not loud. I will give only one other
+fact, on the authority of this same observer; one of a pair of starlings
+(Sturnus vulgaris) was shot in the morning; by noon a new mate was
+found; this was again shot, but before night the pair was complete; so
+that the disconsolate widow or widower was thrice consoled during the
+same day. Mr. Engleheart also informs me that he used during several
+years to shoot one of a pair of starlings which built in a hole in
+a house at Blackheath; but the loss was always immediately repaired.
+During one season he kept an account, and found that he had shot
+thirty-five birds from the same nest; these consisted of both males and
+females, but in what proportion he could not say: nevertheless, after
+all this destruction, a brood was reared. (6. On the peregrine falcon,
+see Thompson, 'Nat. Hist. of Ireland: Birds,' vol. i. 1849, p. 39. On
+owls, sparrows, and partridges, see White, 'Nat. Hist. of Selborne,'
+edit. of 1825, vol. i. p. 139. On the Phoenicura, see Loudon's 'Mag. of
+Nat. Hist.' vol. vii. 1834, p. 245. Brehm ('Thierleben,' B. iv. s. 991)
+also alludes to cases of birds thrice mated during the same day.)
+
+These facts well deserve attention. How is it that there are birds
+enough ready to replace immediately a lost mate of either sex? Magpies,
+jays, carrion-crows, partridges, and some other birds, are always seen
+during the spring in pairs, and never by themselves; and these offer
+at first sight the most perplexing cases. But birds of the same sex,
+although of course not truly paired, sometimes live in pairs or in small
+parties, as is known to be the case with pigeons and partridges. Birds
+also sometimes live in triplets, as has been observed with starlings,
+carrion-crows, parrots, and partridges. With partridges two females have
+been known to live with one male, and two males with one female. In all
+such cases it is probable that the union would be easily broken; and one
+of the three would readily pair with a widow or widower. The males of
+certain birds may occasionally be heard pouring forth their love-song
+long after the proper time, shewing that they have either lost or never
+gained a mate. Death from accident or disease of one of a pair would
+leave the other free and single; and there is reason to believe that
+female birds during the breeding-season are especially liable to
+premature death. Again, birds which have had their nests destroyed, or
+barren pairs, or retarded individuals, would easily be induced to desert
+their mates, and would probably be glad to take what share they could
+of the pleasures and duties of rearing offspring although not their own.
+(7. See White ('Nat. Hist. of Selborne,' 1825, vol. i. p. 140) on the
+existence, early in the season, of small coveys of male partridges, of
+which fact I have heard other instances. See Jenner, on the retarded
+state of the generative organs in certain birds, in 'Phil. Transact.'
+1824. In regard to birds living in triplets, I owe to Mr. Jenner Weir
+the cases of the starlings and parrots, and to Mr. Fox, of partridges;
+on carrion-crows, see the 'Field,' 1868, p. 415. On various male birds
+singing after the proper period, see Rev. L. Jenyns, 'Observations in
+Natural History,' 1846, p. 87.) Such contingencies as these probably
+explain most of the foregoing cases. (8. The following case has been
+given ('The Times,' Aug. 6, 1868) by the Rev. F.O. Morris, on the
+authority of the Hon. and Rev. O.W. Forester. "The gamekeeper here found
+a hawk's nest this year, with five young ones on it. He took four and
+killed them, but left one with its wings clipped as a decoy to destroy
+the old ones by. They were both shot next day, in the act of feeding the
+young one, and the keeper thought it was done with. The next day he came
+again and found two other charitable hawks, who had come with an adopted
+feeling to succour the orphan. These two he killed, and then left the
+nest. On returning afterwards he found two more charitable individuals
+on the same errand of mercy. One of these he killed; the other he also
+shot, but could not find. No more came on the like fruitless errand.")
+Nevertheless, it is a strange fact that within the same district, during
+the height of the breeding-season, there should be so many males and
+females always ready to repair the loss of a mated bird. Why do not
+such spare birds immediately pair together? Have we not some reason to
+suspect, and the suspicion has occurred to Mr. Jenner Weir, that as the
+courtship of birds appears to be in many cases prolonged and tedious, so
+it occasionally happens that certain males and females do not
+succeed, during the proper season, in exciting each other's love, and
+consequently do not pair? This suspicion will appear somewhat less
+improbable after we have seen what strong antipathies and preferences
+female birds occasionally evince towards particular males.
+
+MENTAL QUALITIES OF BIRDS, AND THEIR TASTE FOR THE BEAUTIFUL.
+
+Before we further discuss the question whether the females select the
+more attractive males or accept the first whom they may encounter, it
+will be advisable briefly to consider the mental powers of birds. Their
+reason is generally, and perhaps justly, ranked as low; yet some facts
+could be given leading to an opposite conclusion. (9. I am indebted to
+Prof. Newton for the following passage from Mr. Adam's 'Travels of
+a Naturalist,' 1870, p. 278. Speaking of Japanese nut-hatches in
+confinement, he says: "Instead of the more yielding fruit of the
+yew, which is the usual food of the nut-hatch of Japan, at one time I
+substituted hard hazel-nuts. As the bird was unable to crack them, he
+placed them one by one in his water-glass, evidently with the notion
+that they would in time become softer--an interesting proof of
+intelligence on the part of these birds.") Low powers of reasoning,
+however, are compatible, as we see with mankind, with strong affections,
+acute perception, and a taste for the beautiful; and it is with these
+latter qualities that we are here concerned. It has often been said that
+parrots become so deeply attached to each other that when one dies the
+other pines for a long time; but Mr. Jenner Weir thinks that with
+most birds the strength of their affection has been much exaggerated.
+Nevertheless when one of a pair in a state of nature has been shot, the
+survivor has been heard for days afterwards uttering a plaintive call;
+and Mr. St. John gives various facts proving the attachment of mated
+birds. (10. 'A Tour in Sutherlandshire,' vol. i. 1849, p. 185. Dr.
+Buller says ('Birds of New Zealand,' 1872, p. 56) that a male King Lory
+was killed; and the female "fretted and moped, refused her food, and
+died of a broken heart.") Mr. Bennett relates (11. 'Wanderings in New
+South Wales,' vol. ii. 1834, p. 62.) that in China after a drake of the
+beautiful mandarin Teal had been stolen, the duck remained disconsolate,
+though sedulously courted by another mandarin drake, who displayed
+before her all his charms. After an interval of three weeks the stolen
+drake was recovered, and instantly the pair recognised each other with
+extreme joy. On the other hand, starlings, as we have seen, may be
+consoled thrice in the same day for the loss of their mates. Pigeons
+have such excellent local memories, that they have been known to return
+to their former homes after an interval of nine months, yet, as I hear
+from Mr. Harrison Weir, if a pair which naturally would remain mated
+for life be separated for a few weeks during the winter, and afterwards
+matched with other birds, the two when brought together again, rarely,
+if ever, recognise each other.
+
+Birds sometimes exhibit benevolent feelings; they will feed the deserted
+young ones even of distinct species, but this perhaps ought to be
+considered as a mistaken instinct. They will feed, as shewn in an
+earlier part of this work, adult birds of their own species which have
+become blind. Mr. Buxton gives a curious account of a parrot which took
+care of a frost-bitten and crippled bird of a distinct species, cleansed
+her feathers, and defended her from the attacks of the other parrots
+which roamed freely about his garden. It is a still more curious fact
+that these birds apparently evince some sympathy for the pleasures of
+their fellows. When a pair of cockatoos made a nest in an acacia tree,
+"it was ridiculous to see the extravagant interest taken in the matter
+by the others of the same species." These parrots, also, evinced
+unbounded curiosity, and clearly had "the idea of property and
+possession." (12. 'Acclimatization of Parrots,' by C. Buxton, M.P.,
+'Annals and Mag. of Nat. Hist.' Nov. 1868, p. 381.) They have good
+memories, for in the Zoological Gardens they have plainly recognised
+their former masters after an interval of some months.
+
+Birds possess acute powers of observation. Every mated bird, of
+course, recognises its fellow. Audubon states that a certain number
+of mocking-thrushes (Mimus polyglottus) remain all the year round in
+Louisiana, whilst others migrate to the Eastern States; these latter,
+on their return, are instantly recognised, and always attacked, by
+their southern brethren. Birds under confinement distinguish different
+persons, as is proved by the strong and permanent antipathy or
+affection which they shew, without any apparent cause, towards certain
+individuals. I have heard of numerous instances with jays, partridges,
+canaries, and especially bullfinches. Mr. Hussey has described in how
+extraordinary a manner a tamed partridge recognised everybody: and
+its likes and dislikes were very strong. This bird seemed "fond of gay
+colours, and no new gown or cap could be put on without catching his
+attention." (13. The 'Zoologist,' 1847-48, p. 1602.) Mr. Hewitt has
+described the habits of some ducks (recently descended from wild birds),
+which, at the approach of a strange dog or cat, would rush headlong into
+the water, and exhaust themselves in their attempts to escape; but they
+knew Mr. Hewitt's own dogs and cats so well that they would lie down
+and bask in the sun close to them. They always moved away from a strange
+man, and so they would from the lady who attended them if she made any
+great change in her dress. Audubon relates that he reared and tamed
+a wild turkey which always ran away from any strange dog; this bird
+escaped into the woods, and some days afterwards Audubon saw, as
+he thought, a wild turkey, and made his dog chase it; but, to his
+astonishment, the bird did not run away, and the dog, when he came up,
+did not attack the bird, for they mutually recognised each other as old
+friends. (14. Hewitt on wild ducks, 'Journal of Horticulture,' Jan. 13,
+1863, p. 39. Audubon on the wild turkey, 'Ornithological Biography,'
+vol. i. p. 14. On the mocking-thrush, ibid. vol. i. p. 110.)
+
+Mr. Jenner Weir is convinced that birds pay particular attention to the
+colours of other birds, sometimes out of jealousy, and sometimes as a
+sign of kinship. Thus he turned a reed-bunting (Emberiza schoeniculus),
+which had acquired its black head-dress, into his aviary, and the
+new-comer was not noticed by any bird, except by a bullfinch, which is
+likewise black-headed. This bullfinch was a very quiet bird, and had
+never before quarrelled with any of its comrades, including another
+reed-bunting, which had not as yet become black-headed: but the
+reed-bunting with a black head was so unmercifully treated that it had
+to be removed. Spiza cyanea, during the breeding-season, is of a bright
+blue colour; and though generally peaceable, it attacked S. ciris, which
+has only the head blue, and completely scalped the unfortunate bird. Mr.
+Weir was also obliged to turn out a robin, as it fiercely attacked all
+the birds in his aviary with any red in their plumage, but no other
+kinds; it actually killed a red-breasted crossbill, and nearly killed
+a goldfinch. On the other hand, he has observed that some birds, when
+first introduced, fly towards the species which resemble them most in
+colour, and settle by their sides.
+
+As male birds display their fine plumage and other ornaments with
+so much care before the females, it is obviously probable that these
+appreciate the beauty of their suitors. It is, however, difficult to
+obtain direct evidence of their capacity to appreciate beauty. When
+birds gaze at themselves in a looking-glass (of which many instances
+have been recorded) we cannot feel sure that it is not from jealousy of
+a supposed rival, though this is not the conclusion of some observers.
+In other cases it is difficult to distinguish between mere curiosity and
+admiration. It is perhaps the former feeling which, as stated by Lord
+Lilford (15. The 'Ibis,' vol. ii. 1860, p. 344.), attracts the ruff
+towards any bright object, so that, in the Ionian Islands, "it will dart
+down to a bright-coloured handkerchief, regardless of repeated shots."
+The common lark is drawn down from the sky, and is caught in large
+numbers, by a small mirror made to move and glitter in the sun. Is it
+admiration or curiosity which leads the magpie, raven, and some other
+birds to steal and secrete bright objects, such as silver articles or
+jewels?
+
+Mr. Gould states that certain humming-birds decorate the outsides of
+their nests "with the utmost taste; they instinctively fasten thereon
+beautiful pieces of flat lichen, the larger pieces in the middle, and
+the smaller on the part attached to the branch. Now and then a pretty
+feather is intertwined or fastened to the outer sides, the stem being
+always so placed that the feather stands out beyond the surface." The
+best evidence, however, of a taste for the beautiful is afforded by the
+three genera of Australian bower-birds already mentioned. Their bowers
+(Fig. 46), where the sexes congregate and play strange antics, are
+variously constructed, but what most concerns us is, that they are
+decorated by the several species in a different manner. The Satin
+bower-bird collects gaily-coloured articles, such as the blue
+tail-feathers of parrakeets, bleached bones and shells, which it sticks
+between the twigs or arranges at the entrance. Mr. Gould found in
+one bower a neatly-worked stone tomahawk and a slip of blue cotton,
+evidently procured from a native encampment. These objects are
+continually re-arranged, and carried about by the birds whilst at play.
+The bower of the Spotted bower-bird "is beautifully lined with tall
+grasses, so disposed that the heads nearly meet, and the decorations are
+very profuse." Round stones are used to keep the grass-stems in their
+proper places, and to make divergent paths leading to the bower. The
+stones and shells are often brought from a great distance. The Regent
+bird, as described by Mr. Ramsay, ornaments its short bower with
+bleached land-shells belonging to five or six species, and with "berries
+of various colours, blue, red, and black, which give it when fresh a
+very pretty appearance. Besides these there were several newly-picked
+leaves and young shoots of a pinkish colour, the whole showing a decided
+taste for the beautiful." Well may Mr. Gould say that "these highly
+decorated halls of assembly must be regarded as the most wonderful
+instances of bird-architecture yet discovered;" and the taste, as we
+see, of the several species certainly differs. (16. On the ornamented
+nests of humming-birds, Gould, 'Introduction to the Trochilidae,' 1861,
+p. 19. On the bower-birds, Gould, 'Handbook to the Birds of Australia,'
+1865, vol. i. pp. 444-461. Ramsay, in the 'Ibis,' 1867, p. 456.)
+
+PREFERENCE FOR PARTICULAR MALES BY THE FEMALES.
+
+Having made these preliminary remarks on the discrimination and taste
+of birds, I will give all the facts known to me which bear on the
+preference shewn by the female for particular males. It is certain that
+distinct species of birds occasionally pair in a state of nature and
+produce hybrids. Many instances could be given: thus Macgillivray
+relates how a male blackbird and female thrush "fell in love with each
+other," and produced offspring. (17. 'History of Brit. Birds,' vol.
+ii. p. 92.) Several years ago eighteen cases had been recorded of the
+occurrence in Great Britain of hybrids between the black grouse and
+pheasant (18. 'Zoologist,' 1853-1854, p. 3946.); but most of these cases
+may perhaps be accounted for by solitary birds not finding one of their
+own species to pair with. With other birds, as Mr. Jenner Weir has
+reason to believe, hybrids are sometimes the result of the casual
+intercourse of birds building in close proximity. But these remarks do
+not apply to the many recorded instances of tamed or domestic birds,
+belonging to distinct species, which have become absolutely fascinated
+with each other, although living with their own species. Thus Waterton
+(19. Waterton, 'Essays on Nat. Hist.' 2nd series, pp. 42 and 117. For
+the following statements see on the wigeon, 'Loudon's Mag. of Nat.
+Hist.' vol. ix. p. 616; L. Lloyd, 'Scandinavian Adventures,' vol. i.
+1854, p. 452. Dixon, 'Ornamental and Domestic Poultry,' p. 137;
+Hewitt, in 'Journal of Horticulture,' Jan. 13, 1863, p. 40; Bechstein,
+'Stubenv�gel,' 1840, s. 230. Mr. J. Jenner Weir has lately given me an
+analogous case with ducks of two species.) states that out of a flock
+of twenty-three Canada geese, a female paired with a solitary Bernicle
+gander, although so different in appearance and size; and they produced
+hybrid offspring. A male wigeon (Mareca penelope), living with females
+of the same species, has been known to pair with a pintail duck,
+Querquedula acuta. Lloyd describes the remarkable attachment between
+a shield-drake (Tadorna vulpanser) and a common duck. Many additional
+instances could be given; and the Rev. E.S. Dixon remarks that "those
+who have kept many different species of geese together well know what
+unaccountable attachments they are frequently forming, and that they
+are quite as likely to pair and rear young with individuals of a race
+(species) apparently the most alien to themselves as with their own
+stock."
+
+The Rev. W.D. Fox informs me that he possessed at the same time a pair
+of Chinese geese (Anser cygnoides), and a common gander with three
+geese. The two lots kept quite separate, until the Chinese gander
+seduced one of the common geese to live with him. Moreover, of the young
+birds hatched from the eggs of the common geese, only four were pure,
+the other eighteen proving hybrids; so that the Chinese gander seems to
+have had prepotent charms over the common gander. I will give only one
+other case; Mr. Hewitt states that a wild duck, reared in captivity,
+"after breeding a couple of seasons with her own mallard, at once shook
+him off on my placing a male Pintail on the water. It was evidently
+a case of love at first sight, for she swam about the new-comer
+caressingly, though he appeared evidently alarmed and averse to her
+overtures of affection. From that hour she forgot her old partner.
+Winter passed by, and the next spring the pintail seemed to have become
+a convert to her blandishments, for they nested and produced seven or
+eight young ones."
+
+What the charm may have been in these several cases, beyond mere
+novelty, we cannot even conjecture. Colour, however, sometimes comes
+into play; for in order to raise hybrids from the siskin (Fringilla
+spinus) and the canary, it is much the best plan, according to
+Bechstein, to place birds of the same tint together. Mr. Jenner Weir
+turned a female canary into his aviary, where there were male linnets,
+goldfinches, siskins, greenfinches, chaffinches, and other birds, in
+order to see which she would choose; but there never was any doubt,
+and the greenfinch carried the day. They paired and produced hybrid
+offspring.
+
+The fact of the female preferring to pair with one male rather than with
+another of the same species is not so likely to excite attention, as
+when this occurs, as we have just seen, between distinct species. The
+former cases can best be observed with domesticated or confined birds;
+but these are often pampered by high feeding, and sometimes have their
+instincts vitiated to an extreme degree. Of this latter fact I could
+give sufficient proofs with pigeons, and especially with fowls, but they
+cannot be here related. Vitiated instincts may also account for some of
+the hybrid unions above mentioned; but in many of these cases the birds
+were allowed to range freely over large ponds, and there is no reason to
+suppose that they were unnaturally stimulated by high feeding.
+
+With respect to birds in a state of nature, the first and most obvious
+supposition which will occur to every one is that the female at the
+proper season accepts the first male whom she may encounter; but she
+has at least the opportunity for exerting a choice, as she is almost
+invariably pursued by many males. Audubon--and we must remember that he
+spent a long life in prowling about the forests of the United States and
+observing the birds--does not doubt that the female deliberately chooses
+her mate; thus, speaking of a woodpecker, he says the hen is followed by
+half-a-dozen gay suitors, who continue performing strange antics, "until
+a marked preference is shewn for one." The female of the red-winged
+starling (Agelaeus phoeniceus) is likewise pursued by several males,
+"until, becoming fatigued, she alights, receives their addresses, and
+soon makes a choice." He describes also how several male night-jars
+repeatedly plunge through the air with astonishing rapidity, suddenly
+turning, and thus making a singular noise; "but no sooner has the female
+made her choice than the other males are driven away." With one of the
+vultures (Cathartes aura) of the United States, parties of eight, ten,
+or more males and females assemble on fallen logs, "exhibiting the
+strongest desire to please mutually," and after many caresses, each male
+leads off his partner on the wing. Audubon likewise carefully observed
+the wild flocks of Canada geese (Anser canadensis), and gives a graphic
+description of their love-antics; he says that the birds which had
+been previously mated "renewed their courtship as early as the month of
+January, while the others would be contending or coquetting for hours
+every day, until all seemed satisfied with the choice they had made,
+after which, although they remained together, any person could easily
+perceive that they were careful to keep in pairs. I have observed also
+that the older the birds the shorter were the preliminaries of their
+courtship. The bachelors and old maids whether in regret, or not caring
+to be disturbed by the bustle, quietly moved aside and lay down at some
+distance from the rest." (20. Audubon, 'Ornithological Biography,' vol.
+i. pp. 191, 349; vol. ii. pp. 42, 275; vol. iii. p. 2.) Many similar
+statements with respect to other birds could be cited from this same
+observer.
+
+Turning now to domesticated and confined birds, I will commence by
+giving what little I have learnt respecting the courtship of fowls.
+I have received long letters on this subject from Messrs. Hewitt and
+Tegetmeier, and almost an essay from the late Mr. Brent. It will be
+admitted by every one that these gentlemen, so well known from their
+published works, are careful and experienced observers. They do not
+believe that the females prefer certain males on account of the beauty
+of their plumage; but some allowance must be made for the artificial
+state under which these birds have long been kept. Mr. Tegetmeier is
+convinced that a gamecock, though disfigured by being dubbed and with
+his hackles trimmed, would be accepted as readily as a male retaining
+all his natural ornaments. Mr. Brent, however, admits that the beauty of
+the male probably aids in exciting the female; and her acquiescence is
+necessary. Mr. Hewitt is convinced that the union is by no means left to
+mere chance, for the female almost invariably prefers the most vigorous,
+defiant, and mettlesome male; hence it is almost useless, as he remarks,
+"to attempt true breeding if a game-cock in good health and condition
+runs the locality, for almost every hen on leaving the roosting-place
+will resort to the game-cock, even though that bird may not actually
+drive away the male of her own variety." Under ordinary circumstances
+the males and females of the fowl seem to come to a mutual understanding
+by means of certain gestures, described to me by Mr. Brent. But hens
+will often avoid the officious attentions of young males. Old hens, and
+hens of a pugnacious disposition, as the same writer informs me, dislike
+strange males, and will not yield until well beaten into compliance.
+Ferguson, however, describes how a quarrelsome hen was subdued by the
+gentle courtship of a Shanghai cock. (21. 'Rare and Prize Poultry,'
+1854, p. 27.)
+
+There is reason to believe that pigeons of both sexes prefer pairing
+with birds of the same breed; and dovecot-pigeons dislike all the
+highly improved breeds. (22. 'Variation of Animals and Plants under
+Domestication,' vol. ii. p. 103.) Mr. Harrison Weir has lately heard
+from a trustworthy observer, who keeps blue pigeons, that these drive
+away all other coloured varieties, such as white, red, and yellow;
+and from another observer, that a female dun carrier could not, after
+repeated trials, be matched with a black male, but immediately paired
+with a dun. Again, Mr. Tegetmeier had a female blue turbit that
+obstinately refused to pair with two males of the same breed, which were
+successively shut up with her for weeks; but on being let out she would
+have immediately accepted the first blue dragon that offered. As she
+was a valuable bird, she was then shut up for many weeks with a silver
+(i.e., very pale blue) male, and at last mated with him. Nevertheless,
+as a general rule, colour appears to have little influence on the
+pairing of pigeons. Mr. Tegetmeier, at my request, stained some of his
+birds with magenta, but they were not much noticed by the others.
+
+Female pigeons occasionally feel a strong antipathy towards certain
+males, without any assignable cause. Thus MM. Boitard and Corbie, whose
+experience extended over forty-five years, state: "Quand une femelle
+�prouve de l'antipathie pour un m�le avec lequel on veut l'accoupler,
+malgr� tous les feux de l'amour, malgr� l'alpiste et le chenevis dont
+on la nourrit pour augmenter son ardeur, malgr� un emprisonnement de six
+mois et m�me d'un an, elle refuse constamment ses caresses; les avances
+empress�es, les agaceries, les tournoiemens, les tendres roucoulemens,
+rien ne peut lui plaire ni l'�mouvoir; gonfl�e, boudeuse, blottie dans
+un coin de sa prison, elle n'en sort que pour boire et manger, ou
+pour repousser avec une esp�ce de rage des caresses devenues trop
+pressantes." (23. Boitard and Corbie, 'Les Pigeons,' etc., 1824, p.
+12. Prosper Lucas ('Trait� de l'H�r�d. Nat.' tom. ii. 1850, p. 296) has
+himself observed nearly similar facts with pigeons.) On the other hand,
+Mr. Harrison Weir has himself observed, and has heard from several
+breeders, that a female pigeon will occasionally take a strong fancy for
+a particular male, and will desert her own mate for him. Some females,
+according to another experienced observer, Riedel (24. Die Taubenzucht,
+1824, s. 86.), are of a profligate disposition, and prefer almost any
+stranger to their own mate. Some amorous males, called by our English
+fanciers "gay birds," are so successful in their gallantries, that, as
+Mr. H. Weir informs me, they must be shut up on account of the mischief
+which they cause.
+
+Wild turkeys in the United States, according to Audubon, "sometimes pay
+their addresses to the domesticated females, and are generally received
+by them with great pleasure." So that these females apparently prefer
+the wild to their own males. (25. 'Ornithological Biography,' vol. i. p.
+13. See to the same effect, Dr. Bryant, in Allen's 'Mammals and Birds of
+Florida,' p. 344.)
+
+Here is a more curious case. Sir R. Heron during many years kept an
+account of the habits of the peafowl, which he bred in large numbers. He
+states that "the hens have frequently great preference to a particular
+peafowl. They were all so fond of an old pied cock, that one year, when
+he was confined, though still in view, they were constantly assembled
+close to the trellice-walls of his prison, and would not suffer a
+japanned peacock to touch them. On his being let out in the autumn,
+the oldest of the hens instantly courted him and was successful in her
+courtship. The next year he was shut up in a stable, and then the hens
+all courted his rival." (26. 'Proceedings, Zoological Society,' 1835,
+p. 54. The japanned peacock is considered by Mr. Sclater as a distinct
+species, and has been named Pavo nigripennis; but the evidence seems
+to me to show that it is only a variety.) This rival was a japanned or
+black-winged peacock, to our eyes a more beautiful bird than the common
+kind.
+
+Lichtenstein, who was a good observer and had excellent opportunities of
+observation at the Cape of Good Hope, assured Rudolphi that the female
+widow-bird (Chera progne) disowns the male when robbed of the long
+tail-feathers with which he is ornamented during the breeding-season.
+I presume that this observation must have been made on birds under
+confinement. (27. Rudolphi, 'Beitr�ge zur Anthropologie,' 1812, s. 184.)
+Here is an analogous case; Dr. Jaeger (28. 'Die Darwin'sche Theorie,
+und ihre Stellung zu Moral und Religion,' 1869, s. 59.), director of the
+Zoological Gardens of Vienna, states that a male silver-pheasant, who
+had been triumphant over all other males and was the accepted lover of
+the females, had his ornamental plumage spoiled. He was then immediately
+superseded by a rival, who got the upper hand and afterwards led the
+flock.
+
+It is a remarkable fact, as shewing how important colour is in the
+courtship of birds, that Mr. Boardman, a well-known collector and
+observer of birds for many years in the Northern United States, has
+never in his large experience seen an albino paired with another bird;
+yet he has had opportunities of observing many albinos belonging to
+several species. (29. This statement is given by Mr. A. Leith Adams, in
+his 'Field and Forest Rambles,' 1873, p. 76, and accords with his own
+experience.) It can hardly be maintained that albinos in a state
+of nature are incapable of breeding, as they can be raised with the
+greatest facility under confinement. It appears, therefore, that we must
+attribute the fact that they do not pair to their rejection by their
+normally coloured comrades.
+
+Female birds not only exert a choice, but in some few cases they court
+the male, or even fight together for his possession. Sir R. Heron states
+that with peafowl, the first advances are always made by the female;
+something of the same kind takes place, according to Audubon, with the
+older females of the wild turkey. With the capercailzie, the females
+flit round the male whilst he is parading at one of the places of
+assemblage, and solicit his attention. (30. In regard to peafowl, see
+Sir R. Heron, 'Proc. Zoolog. Soc.' 1835, p. 54, and the Rev. E.S. Dixon,
+'Ornamental Poultry,' 1848, p. 8. For the turkey, Audubon, ibid. p. 4.
+For the capercailzie, Lloyd, 'Game Birds of Sweden,' 1867, p. 23.) We
+have seen that a tame wild-duck seduced an unwilling pintail drake after
+a long courtship. Mr. Bartlett believes that the Lophophorus, like
+many other gallinaceous birds, is naturally polygamous, but two females
+cannot be placed in the same cage with a male, as they fight so much
+together. The following instance of rivalry is more surprising as it
+relates to bullfinches, which usually pair for life. Mr. Jenner Weir
+introduced a dull-coloured and ugly female into his aviary, and she
+immediately attacked another mated female so unmercifully that the
+latter had to be separated. The new female did all the courtship, and
+was at last successful, for she paired with the male; but after a time
+she met with a just retribution, for, ceasing to be pugnacious, she
+was replaced by the old female, and the male then deserted his new and
+returned to his old love.
+
+In all ordinary cases the male is so eager that he will accept any
+female, and does not, as far as we can judge, prefer one to the other;
+but, as we shall hereafter see, exceptions to this rule apparently occur
+in some few groups. With domesticated birds, I have heard of only one
+case of males shewing any preference for certain females, namely,
+that of the domestic cock, who, according to the high authority of Mr.
+Hewitt, prefers the younger to the older hens. On the other hand, in
+effecting hybrid unions between the male pheasant and common hens,
+Mr. Hewitt is convinced that the pheasant invariably prefers the older
+birds. He does not appear to be in the least influenced by their colour;
+but "is most capricious in his attachments" (31. Mr. Hewitt, quoted
+in Tegetmeier's 'Poultry Book,' 1866, p. 165.): from some inexplicable
+cause he shews the most determined aversion to certain hens, which no
+care on the part of the breeder can overcome. Mr. Hewitt informs me that
+some hens are quite unattractive even to the males of their own species,
+so that they may be kept with several cocks during a whole season, and
+not one egg out of forty or fifty will prove fertile. On the other hand,
+with the long-tailed duck (Harelda glacialis), "it has been remarked,"
+says M. Ekstrom, "that certain females are much more courted than the
+rest. Frequently, indeed, one sees an individual surrounded by six or
+eight amorous males." Whether this statement is credible, I know not;
+but the native sportsmen shoot these females in order to stuff them as
+decoys. (32. Quoted in Lloyd's 'Game Birds of Sweden,' p. 345.)
+
+With respect to female birds feeling a preference for particular males,
+we must bear in mind that we can judge of choice being exerted only by
+analogy. If an inhabitant of another planet were to behold a number of
+young rustics at a fair courting a pretty girl, and quarrelling about
+her like birds at one of their places of assemblage, he would, by the
+eagerness of the wooers to please her and to display their finery, infer
+that she had the power of choice. Now with birds the evidence stands
+thus: they have acute powers of observation, and they seem to have some
+taste for the beautiful both in colour and sound. It is certain that
+the females occasionally exhibit, from unknown causes, the strongest
+antipathies and preferences for particular males. When the sexes differ
+in colour or in other ornaments the males with rare exceptions are
+the more decorated, either permanently or temporarily during the
+breeding-season. They sedulously display their various ornaments, exert
+their voices, and perform strange antics in the presence of the females.
+Even well-armed males, who, it might be thought, would altogether depend
+for success on the law of battle, are in most cases highly ornamented;
+and their ornaments have been acquired at the expense of some loss
+of power. In other cases ornaments have been acquired, at the cost of
+increased risk from birds and beasts of prey. With various species
+many individuals of both sexes congregate at the same spot, and their
+courtship is a prolonged affair. There is even reason to suspect that
+the males and females within the same district do not always succeed in
+pleasing each other and pairing.
+
+What then are we to conclude from these facts and considerations? Does
+the male parade his charms with so much pomp and rivalry for no purpose?
+Are we not justified in believing that the female exerts a choice, and
+that she receives the addresses of the male who pleases her most? It is
+not probable that she consciously deliberates; but she is most excited
+or attracted by the most beautiful, or melodious, or gallant males.
+Nor need it be supposed that the female studies each stripe or spot
+of colour; that the peahen, for instance, admires each detail in the
+gorgeous train of the peacock--she is probably struck only by the
+general effect. Nevertheless, after hearing how carefully the male Argus
+pheasant displays his elegant primary wing-feathers, and erects his
+ocellated plumes in the right position for their full effect; or again,
+how the male goldfinch alternately displays his gold-bespangled wings,
+we ought not to feel too sure that the female does not attend to each
+detail of beauty. We can judge, as already remarked, of choice being
+exerted, only from analogy; and the mental powers of birds do not
+differ fundamentally from ours. From these various considerations we may
+conclude that the pairing of birds is not left to chance; but that those
+males, which are best able by their various charms to please or excite
+the female, are under ordinary circumstances accepted. If this be
+admitted, there is not much difficulty in understanding how male birds
+have gradually acquired their ornamental characters. All animals present
+individual differences, and as man can modify his domesticated birds by
+selecting the individuals which appear to him the most beautiful, so
+the habitual or even occasional preference by the female of the more
+attractive males would almost certainly lead to their modification; and
+such modifications might in the course of time be augmented to almost
+any extent, compatible with the existence of the species.
+
+VARIABILITY OF BIRDS, AND ESPECIALLY OF THEIR SECONDARY SEXUAL
+CHARACTERS.
+
+Variability and inheritance are the foundations for the work of
+selection. That domesticated birds have varied greatly, their variations
+being inherited, is certain. That birds in a state of nature have been
+modified into distinct races is now universally admitted. (33.
+According to Dr. Blasius ('Ibis,' vol. ii. 1860, p. 297), there are 425
+indubitable species of birds which breed in Europe, besides sixty
+forms, which are frequently regarded as distinct species. Of the latter,
+Blasius thinks that only ten are really doubtful, and that the other
+fifty ought to be united with their nearest allies; but this shews
+that there must be a considerable amount of variation with some of our
+European birds. It is also an unsettled point with naturalists, whether
+several North American birds ought to be ranked as specifically distinct
+from the corresponding European species. So again many North American
+forms which until lately were named as distinct species, are now
+considered to be local races.) Variations may be divided into two
+classes; those which appear to our ignorance to arise spontaneously, and
+those which are directly related to the surrounding conditions, so that
+all or nearly all the individuals of the same species are similarly
+modified. Cases of the latter kind have recently been observed with
+care by Mr. J.A. Allen (34. 'Mammals and Birds of East Florida,' also
+an 'Ornithological Reconnaissance of Kansas,' etc. Notwithstanding the
+influence of climate on the colours of birds, it is difficult to account
+for the dull or dark tints of almost all the species inhabiting certain
+countries, for instance, the Galapagos Islands under the equator, the
+wide temperate plains of Patagonia, and, as it appears, Egypt (see Mr.
+Hartshorne in the 'American Naturalist,' 1873, p. 747). These countries
+are open, and afford little shelter to birds; but it seems doubtful
+whether the absence of brightly coloured species can be explained on
+the principle of protection, for on the Pampas, which are equally open,
+though covered by green grass, and where the birds would be equally
+exposed to danger, many brilliant and conspicuously coloured species are
+common. I have sometimes speculated whether the prevailing dull tints
+of the scenery in the above named countries may not have affected the
+appreciation of bright colours by the birds inhabiting them.), who shews
+that in the United States many species of birds gradually become more
+strongly coloured in proceeding southward, and more lightly coloured in
+proceeding westward to the arid plains of the interior. Both sexes seem
+generally to be affected in a like manner, but sometimes one sex more
+than the other. This result is not incompatible with the belief that
+the colours of birds are mainly due to the accumulation of successive
+variations through sexual selection; for even after the sexes have been
+greatly differentiated, climate might produce an equal effect on both
+sexes, or a greater effect on one sex than on the other, owing to some
+constitutional difference.
+
+Individual differences between the members of the same species are
+admitted by every one to occur under a state of nature. Sudden and
+strongly marked variations are rare; it is also doubtful whether
+if beneficial they would often be preserved through selection and
+transmitted to succeeding generations. (35. 'Origin of Species' fifth
+edit. 1869, p.104. I had always perceived, that rare and strongly-marked
+deviations of structure, deserving to be called monstrosities, could
+seldom be preserved through natural selection, and that the preservation
+of even highly-beneficial variations would depend to a certain extent on
+chance. I had also fully appreciated the importance of mere individual
+differences, and this led me to insist so strongly on the importance
+of that unconscious form of selection by man, which follows from the
+preservation of the most valued individuals of each breed, without any
+intention on his part to modify the characters of the breed. But until I
+read an able article in the 'North British Review' (March 1867, p. 289,
+et seq.), which has been of more use to me than any other Review, I
+did not see how great the chances were against the preservation of
+variations, whether slight or strongly pronounced, occurring only in
+single individuals.) Nevertheless, it may be worth while to give the
+few cases which I have been able to collect, relating chiefly to
+colour,--simple albinism and melanism being excluded. Mr. Gould is
+well known to admit the existence of few varieties, for he esteems very
+slight differences as specific; yet he states (36. 'Introduction to the
+Trochlidae,' p. 102.) that near Bogota certain humming-birds belonging
+to the genus Cynanthus are divided into two or three races or varieties,
+which differ from each other in the colouring of the tail--"some having
+the whole of the feathers blue, while others have the eight central
+ones tipped with beautiful green." It does not appear that intermediate
+gradations have been observed in this or the following cases. In the
+males alone of one of the Australian parrakeets "the thighs in some
+are scarlet, in others grass-green." In another parrakeet of the
+same country "some individuals have the band across the wing-coverts
+bright-yellow, while in others the same part is tinged with red." (37.
+Gould, 'Handbook to Birds of Australia,' vol. ii. pp. 32 and 68.) In
+the United States some few of the males of the scarlet tanager (Tanagra
+rubra) have "a beautiful transverse band of glowing red on the smaller
+wing-coverts" (38. Audubon, 'Ornithological Biography,' 1838, vol. iv.
+p. 389.); but this variation seems to be somewhat rare, so that its
+preservation through sexual selection would follow only under usually
+favourable circumstances. In Bengal the Honey buzzard (Pernis cristata)
+has either a small rudimental crest on its head, or none at all: so
+slight a difference, however, would not have been worth notice, had not
+this same species possessed in Southern India a well-marked occipital
+crest formed of several graduated feathers." (39. Jerdon, 'Birds of
+India,' vol. i. p. 108; and Mr. Blyth, in 'Land and Water,' 1868, p.
+381.)
+
+The following case is in some respects more interesting. A pied variety
+of the raven, with the head, breast, abdomen, and parts of the wings and
+tail-feathers white, is confined to the Feroe Islands. It is not very
+rare there, for Graba saw during his visit from eight to ten living
+specimens. Although the characters of this variety are not quite
+constant, yet it has been named by several distinguished ornithologists
+as a distinct species. The fact of the pied birds being pursued and
+persecuted with much clamour by the other ravens of the island was the
+chief cause which led Brunnich to conclude that they were specifically
+distinct; but this is now known to be an error. (40. Graba, 'Tagebuch
+Reise nach Faro,' 1830, ss. 51-54. Macgillivray, 'History of British
+Birds,' vol. iii. p. 745, 'Ibis,' vol. v. 1863, p. 469.) This case seems
+analogous to that lately given of albino birds not pairing from being
+rejected by their comrades.
+
+In various parts of the northern seas a remarkable variety of the common
+Guillemot (Uria troile) is found; and in Feroe, one out of every five
+birds, according to Graba's estimation, presents this variation. It is
+characterised (41. Graba, ibid. s. 54. Macgillivray, ibid. vol. v. p.
+327.) by a pure white ring round the eye, with a curved narrow white
+line, an inch and a half in length, extending back from the ring.
+This conspicuous character has caused the bird to be ranked by several
+ornithologists as a distinct species under the name of U. lacrymans, but
+it is now known to be merely a variety. It often pairs with the common
+kind, yet intermediate gradations have never been seen; nor is this
+surprising, for variations which appear suddenly, are often, as I
+have elsewhere shewn (42. 'Variation of Animals and Plants under
+Domestication,' vol. ii. p. 92.), transmitted either unaltered or not
+at all. We thus see that two distinct forms of the same species may
+co-exist in the same district, and we cannot doubt that if the one
+had possessed any advantage over the other, it would soon have been
+multiplied to the exclusion of the latter. If, for instance, the male
+pied ravens, instead of being persecuted by their comrades, had been
+highly attractive (like the above pied peacock) to the black female
+ravens their numbers would have rapidly increased. And this would have
+been a case of sexual selection.
+
+With respect to the slight individual differences which are common, in a
+greater or less degree, to all the members of the same species, we have
+every reason to believe that they are by far the most important for the
+work of selection. Secondary sexual characters are eminently liable to
+vary, both with animals in a state of nature and under domestication.
+(43. On these points see also 'Variation of Animals and Plants under
+Domestication,' vol. i. p. 253; vol ii. pp. 73, 75.) There is also
+reason to believe, as we have seen in our eighth chapter, that
+variations are more apt to occur in the male than in the female sex. All
+these contingencies are highly favourable for sexual selection. Whether
+characters thus acquired are transmitted to one sex or to both sexes,
+depends, as we shall see in the following chapter, on the form of
+inheritance which prevails.
+
+It is sometimes difficult to form an opinion whether certain slight
+differences between the sexes of birds are simply the result of
+variability with sexually-limited inheritance, without the aid of sexual
+selection, or whether they have been augmented through this latter
+process. I do not here refer to the many instances where the male
+displays splendid colours or other ornaments, of which the female
+partakes to a slight degree; for these are almost certainly due to
+characters primarily acquired by the male having been more or less
+transferred to the female. But what are we to conclude with respect to
+certain birds in which, for instance, the eyes differ slightly in colour
+in the two sexes? (44. See, for instance, on the irides of a Podica and
+Gallicrex in 'Ibis,' vol. ii. 1860, p. 206; and vol. v. 1863, p. 426.)
+In some cases the eyes differ conspicuously; thus with the storks of the
+genus Xenorhynchus, those of the male are blackish-hazel, whilst those
+of the females are gamboge-yellow; with many hornbills (Buceros), as I
+hear from Mr. Blyth (45. See also Jerdon, 'Birds of India,' vol. i. pp.
+243-245.), the males have intense crimson eyes, and those of the females
+are white. In the Buceros bicornis, the hind margin of the casque and a
+stripe on the crest of the beak are black in the male, but not so in the
+female. Are we to suppose that these black marks and the crimson colour
+of the eyes have been preserved or augmented through sexual selection
+in the males? This is very doubtful; for Mr. Bartlett shewed me in the
+Zoological Gardens that the inside of the mouth of this Buceros is
+black in the male and flesh-coloured in the female; and their external
+appearance or beauty would not be thus affected. I observed in Chile
+(46. 'Zoology of the Voyage of H.M.S. "Beagle,"' 1841, p. 6.) that the
+iris in the condor, when about a year old, is dark-brown, but changes
+at maturity into yellowish-brown in the male, and into bright red in the
+female. The male has also a small, longitudinal, leaden-coloured, fleshy
+crest or comb. The comb of many gallinaceous birds is highly ornamental,
+and assumes vivid colours during the act of courtship; but what are we
+to think of the dull-coloured comb of the condor, which does not appear
+to us in the least ornamental? The same question may be asked in regard
+to various other characters, such as the knob on the base of the beak
+of the Chinese goose (Anser cygnoides), which is much larger in the male
+than in the female. No certain answer can be given to these questions;
+but we ought to be cautious in assuming that knobs and various fleshy
+appendages cannot be attractive to the female, when we remember that
+with savage races of man various hideous deformities--deep scars on the
+face with the flesh raised into protuberances, the septum of the nose
+pierced by sticks or bones, holes in the ears and lips stretched widely
+open--are all admired as ornamental.
+
+Whether or not unimportant differences between the sexes, such as those
+just specified, have been preserved through sexual selection, these
+differences, as well as all others, must primarily depend on the laws of
+variation. On the principle of correlated development, the plumage often
+varies on different parts of the body, or over the whole body, in the
+same manner. We see this well illustrated in certain breeds of the fowl.
+In all the breeds the feathers on the neck and loins of the males
+are elongated, and are called hackles; now when both sexes acquire a
+top-knot, which is a new character in the genus, the feathers on the
+head of the male become hackle-shaped, evidently on the principle of
+correlation; whilst those on the head of the female are of the ordinary
+shape. The colour also of the hackles forming the top-knot of the male,
+is often correlated with that of the hackles on the neck and loins,
+as may be seen by comparing these feathers in the golden and
+silver-spangled Polish, the Houdans, and Creve-coeur breeds. In some
+natural species we may observe exactly the same correlation in the
+colours of these same feathers, as in the males of the splendid Gold and
+Amherst pheasants.
+
+The structure of each individual feather generally causes any change
+in its colouring to be symmetrical; we see this in the various laced,
+spangled, and pencilled breeds of the fowl; and on the principle of
+correlation the feathers over the whole body are often coloured in the
+same manner. We are thus enabled without much trouble to rear breeds
+with their plumage marked almost as symmetrically as in natural species.
+In laced and spangled fowls the coloured margins of the feathers are
+abruptly defined; but in a mongrel raised by me from a black Spanish
+cock glossed with green, and a white game-hen, all the feathers
+were greenish-black, excepting towards their extremities, which were
+yellowish-white; but between the white extremities and the black bases,
+there was on each feather a symmetrical, curved zone of dark-brown. In
+some instances the shaft of the feather determines the distribution of
+the tints; thus with the body-feathers of a mongrel from the same black
+Spanish cock and a silver-spangled Polish hen, the shaft, together with
+a narrow space on each side, was greenish-black, and this was surrounded
+by a regular zone of dark-brown, edged with brownish-white. In these
+cases we have feathers symmetrically shaded, like those which give
+so much elegance to the plumage of many natural species. I have also
+noticed a variety of the common pigeon with the wing-bars symmetrically
+zoned with three bright shades, instead of being simply black on a
+slaty-blue ground, as in the parent-species.
+
+In many groups of birds the plumage is differently coloured in the
+several species, yet certain spots, marks, or stripes are retained by
+all. Analogous cases occur with the breeds of the pigeon, which usually
+retain the two wing-bars, though they may be coloured red, yellow,
+white, black, or blue, the rest of the plumage being of some wholly
+different tint. Here is a more curious case, in which certain marks are
+retained, though coloured in a manner almost exactly the opposite
+of what is natural; the aboriginal pigeon has a blue tail, with the
+terminal halves of the outer webs of the two outer tail feathers white;
+now there is a sub-variety having a white instead of a blue tail, with
+precisely that part black which is white in the parent-species. (47.
+Bechstein, 'Naturgeschichte Deutschlands,' B. iv. 1795, s. 31, on a
+sub-variety of the Monck pigeon.)
+
+FORMATION AND VARIABILITY OF THE OCELLI OR EYE-LIKE SPOTS ON THE PLUMAGE
+OF BIRDS.
+
+[Fig. 53. Cyllo leda, Linn., from a drawing by Mr. Trimen, shewing the
+extreme range of variation in the ocelli. A. Specimen, from Mauritius,
+upper surface of fore-wing. A1. Specimen, from Natal, ditto. B.
+Specimen, from Java, upper surface of hind-wing. B1. Specimen, from
+Mauritius, ditto.]
+
+As no ornaments are more beautiful than the ocelli on the feathers of
+various birds, on the hairy coats of some mammals, on the scales of
+reptiles and fishes, on the skin of amphibians, on the wings of many
+Lepidoptera and other insects, they deserve to be especially noticed.
+An ocellus consists of a spot within a ring of another colour, like
+the pupil within the iris, but the central spot is often surrounded
+by additional concentric zones. The ocelli on the tail-coverts of the
+peacock offer a familiar example, as well as those on the wings of the
+peacock-butterfly (Vanessa). Mr. Trimen has given me a description of a
+S. African moth (Gynanisa isis), allied to our Emperor moth, in which
+a magnificent ocellus occupies nearly the whole surface of each hinder
+wing; it consists of a black centre, including a semi-transparent
+crescent-shaped mark, surrounded by successive, ochre-yellow, black,
+ochre-yellow, pink, white, pink, brown, and whitish zones. Although we
+do not know the steps by which these wonderfully beautiful and complex
+ornaments have been developed, the process has probably been a simple
+one, at least with insects; for, as Mr. Trimen writes to me, "no
+characters of mere marking or coloration are so unstable in the
+Lepidoptera as the ocelli, both in number and size." Mr. Wallace,
+who first called my attention to this subject, shewed me a series of
+specimens of our common meadow-brown butterfly (Hipparchia janira)
+exhibiting numerous gradations from a simple minute black spot to an
+elegantly-shaded ocellus. In a S. African butterfly (Cyllo leda, Linn.),
+belonging to the same family, the ocelli are even still more variable.
+In some specimens (A, Fig. 53) large spaces on the upper surface of the
+wings are coloured black, and include irregular white marks; and from
+this state a complete gradation can be traced into a tolerably perfect
+ocellus (A1), and this results from the contraction of the irregular
+blotches of colour. In another series of specimens a gradation can be
+followed from excessively minute white dots, surrounded by a scarcely
+visible black line (B), into perfectly symmetrical and large ocelli
+(B1). (48. This woodcut has been engraved from a beautiful drawing,
+most kindly made for me by Mr. Trimen; see also his description of the
+wonderful amount of variation in the coloration and shape of the wings
+of this butterfly, in his 'Rhopalocera Africae Australis,' p. 186.) In
+cases like these, the development of a perfect ocellus does not require
+a long course of variation and selection.
+
+With birds and many other animals, it seems to follow from the
+comparison of allied species that circular spots are often generated
+by the breaking up and contraction of stripes. In the Tragopan pheasant
+faint white lines in the female represent the beautiful white spots
+in the male (49. Jerdon, 'Birds of India,' vol. iii. p. 517.); and
+something of the same kind may be observed in the two sexes of the Argus
+pheasant. However this may be, appearances strongly favour the belief
+that on the one hand, a dark spot is often formed by the colouring
+matter being drawn towards a central point from a surrounding zone,
+which latter is thus rendered lighter; and, on the other hand, that
+a white spot is often formed by the colour being driven away from a
+central point, so that it accumulates in a surrounding darker zone. In
+either case an ocellus is the result. The colouring matter seems to be a
+nearly constant quantity, but is redistributed, either centripetally
+or centrifugally. The feathers of the common guinea-fowl offer a good
+instance of white spots surrounded by darker zones; and wherever the
+white spots are large and stand near each other, the surrounding dark
+zones become confluent. In the same wing-feather of the Argus pheasant
+dark spots may be seen surrounded by a pale zone, and white spots by a
+dark zone. Thus the formation of an ocellus in its most elementary state
+appears to be a simple affair. By what further steps the more complex
+ocelli, which are surrounded by many successive zones of colour, have
+been generated, I will not pretend to say. But the zoned feathers of
+the mongrels from differently coloured fowls, and the extraordinary
+variability of the ocelli on many Lepidoptera, lead us to conclude that
+their formation is not a complex process, but depends on some slight and
+graduated change in the nature of the adjoining tissues.
+
+GRADATION OF SECONDARY SEXUAL CHARACTERS.
+
+[Fig. 54. Feather of Peacock, about two-thirds of natural size, drawn
+by Mr. Ford. The transparent zone is represented by the outermost white
+zone, confined to the upper end of the disc.]
+
+Cases of gradation are important, as shewing us that highly complex
+ornaments may be acquired by small successive steps. In order to
+discover the actual steps by which the male of any existing bird has
+acquired his magnificent colours or other ornaments, we ought to
+behold the long line of his extinct progenitors; but this is obviously
+impossible. We may, however, generally gain a clue by comparing all the
+species of the same group, if it be a large one; for some of them will
+probably retain, at least partially, traces of their former characters.
+Instead of entering on tedious details respecting various groups, in
+which striking instances of gradation could be given, it seems the best
+plan to take one or two strongly marked cases, for instance that of the
+peacock, in order to see if light can be thrown on the steps by which
+this bird has become so splendidly decorated. The peacock is chiefly
+remarkable from the extraordinary length of his tail-coverts; the tail
+itself not being much elongated. The barbs along nearly the whole length
+of these feathers stand separate or are decomposed; but this is the
+case with the feathers of many species, and with some varieties of the
+domestic fowl and pigeon. The barbs coalesce towards the extremity of
+the shaft forming the oval disc or ocellus, which is certainly one of
+the most beautiful objects in the world. It consists of an iridescent,
+intensely blue, indented centre, surrounded by a rich green zone, this
+by a broad coppery-brown zone, and this by five other narrow zones of
+slightly different iridescent shades. A trifling character in the disc
+deserves notice; the barbs, for a space along one of the concentric
+zones are more or less destitute of their barbules, so that a part of
+the disc is surrounded by an almost transparent zone, which gives it a
+highly finished aspect. But I have elsewhere described (50. 'Variation
+of Animals and Plants under Domestication,' vol. i. p. 254.) an exactly
+analogous variation in the hackles of a sub-variety of the game-cock, in
+which the tips, having a metallic lustre, "are separated from the lower
+part of the feather by a symmetrically shaped transparent zone, composed
+of the naked portions of the barbs." The lower margin or base of the
+dark-blue centre of the ocellus is deeply indented on the line of the
+shaft. The surrounding zones likewise shew traces, as may be seen in the
+drawing (Fig. 54), of indentations, or rather breaks. These indentations
+are common to the Indian and Javan peacocks (Pavo cristatus and P.
+muticus); and they seem to deserve particular attention, as probably
+connected with the development of the ocellus; but for a long time I
+could not conjecture their meaning.
+
+If we admit the principle of gradual evolution, there must formerly have
+existed many species which presented every successive step between
+the wonderfully elongated tail-coverts of the peacock and the short
+tail-coverts of all ordinary birds; and again between the magnificent
+ocelli of the former, and the simpler ocelli or mere coloured spots on
+other birds; and so with all the other characters of the peacock. Let
+us look to the allied Gallinaceae for any still-existing gradations. The
+species and sub-species of Polyplectron inhabit countries adjacent to
+the native land of the peacock; and they so far resemble this bird that
+they are sometimes called peacock-pheasants. I am also informed by Mr.
+Bartlett that they resemble the peacock in their voice and in some of
+their habits. During the spring the males, as previously described,
+strut about before the comparatively plain-coloured females, expanding
+and erecting their tail and wing-feathers, which are ornamented with
+numerous ocelli. I request the reader to turn back to the drawing (Fig.
+51) of a Polyplectron; In P. napoleonis the ocelli are confined to the
+tail, and the back is of a rich metallic blue; in which respects this
+species approaches the Java peacock. P. hardwickii possesses a peculiar
+top-knot, which is also somewhat like that of the Java peacock. In all
+the species the ocelli on the wings and tail are either circular
+or oval, and consist of a beautiful, iridescent, greenish-blue or
+greenish-purple disc, with a black border. This border in P. chinquis
+shades into brown, edged with cream colour, so that the ocellus is here
+surrounded with variously shaded, though not bright, concentric zones.
+The unusual length of the tail-coverts is another remarkable character
+in Polyplectron; for in some of the species they are half, and in others
+two-thirds as long as the true tail-feathers. The tail-coverts are
+ocellated as in the peacock. Thus the several species of Polyplectron
+manifestly make a graduated approach to the peacock in the length of
+their tail-coverts, in the zoning of the ocelli, and in some other
+characters.
+
+[Fig. 55. Part of a tail-covert of Polyplectron chinquis, with the two
+ocelli of natural size.
+
+Fig. 56. Part of a tail-covert of Polyplectron malaccense, with the two
+ocelli, partially confluent, of natural size.]
+
+Notwithstanding this approach, the first species of Polyplectron which
+I examined almost made me give up the search; for I found not only
+that the true tail-feathers, which in the peacock are quite plain, were
+ornamented with ocelli, but that the ocelli on all the feathers differed
+fundamentally from those of the peacock, in there being two on the same
+feather (Fig. 55), one on each side of the shaft. Hence I concluded
+that the early progenitors of the peacock could not have resembled a
+Polyplectron. But on continuing my search, I observed that in some
+of the species the two ocelli stood very near each other; that in the
+tail-feathers of P. hardwickii they touched each other; and, finally,
+that on the tail-coverts of this same species as well as of P.
+malaccense (Fig. 56) they were actually confluent. As the central part
+alone is confluent, an indentation is left at both the upper and lower
+ends; and the surrounding coloured zones are likewise indented. A
+single ocellus is thus formed on each tail-covert, though still plainly
+betraying its double origin. These confluent ocelli differ from the
+single ocelli of the peacock in having an indentation at both ends,
+instead of only at the lower or basal end. The explanation, however, of
+this difference is not difficult; in some species of Polyplectron the
+two oval ocelli on the same feather stand parallel to each other; in
+other species (as in P. chinquis) they converge towards one end; now
+the partial confluence of two convergent ocelli would manifestly leave a
+much deeper indentation at the divergent than at the convergent end. It
+is also manifest that if the convergence were strongly pronounced and
+the confluence complete, the indentation at the convergent end would
+tend to disappear.
+
+The tail-feathers in both species of the peacock are entirely destitute
+of ocelli, and this apparently is related to their being covered up
+and concealed by the long tail-coverts. In this respect they differ
+remarkably from the tail-feathers of Polyplectron, which in most of
+the species are ornamented with larger ocelli than those on the
+tail-coverts. Hence I was led carefully to examine the tail-feathers of
+the several species, in order to discover whether their ocelli shewed
+any tendency to disappear; and to my great satisfaction, this appeared
+to be so. The central tail-feathers of P. napoleonis have the two ocelli
+on each side of the shaft perfectly developed; but the inner ocellus
+becomes less and less conspicuous on the more exterior tail-feathers,
+until a mere shadow or rudiment is left on the inner side of the
+outermost feather. Again, in P. malaccense, the ocelli on the
+tail-coverts are, as we have seen, confluent; and these feathers are of
+unusual length, being two-thirds of the length of the tail-feathers,
+so that in both these respects they approach the tail-coverts of the
+peacock. Now in P. malaccense, the two central tail-feathers alone are
+ornamented, each with two brightly-coloured ocelli, the inner ocellus
+having completely disappeared from all the other tail-feathers.
+Consequently the tail-coverts and tail-feathers of this species of
+Polyplectron make a near approach in structure and ornamentation to the
+corresponding feathers of the peacock.
+
+As far, then, as gradation throws light on the steps by which the
+magnificent train of the peacock has been acquired, hardly anything more
+is needed. If we picture to ourselves a progenitor of the peacock in an
+almost exactly intermediate condition between the existing peacock, with
+his enormously elongated tail-coverts, ornamented with single ocelli,
+and an ordinary gallinaceous bird with short tail-coverts,
+merely spotted with some colour, we shall see a bird allied to
+Polyplectron--that is, with tail-coverts, capable of erection and
+expansion, ornamented with two partially confluent ocelli, and long
+enough almost to conceal the tail-feathers, the latter having already
+partially lost their ocelli. The indentation of the central disc and of
+the surrounding zones of the ocellus, in both species of peacock, speaks
+plainly in favour of this view, and is otherwise inexplicable. The males
+of Polyplectron are no doubt beautiful birds, but their beauty, when
+viewed from a little distance, cannot be compared with that of the
+peacock. Many female progenitors of the peacock must, during a long
+line of descent, have appreciated this superiority; for they have
+unconsciously, by the continued preference for the most beautiful males,
+rendered the peacock the most splendid of living birds.
+
+ARGUS PHEASANT.
+
+Another excellent case for investigation is offered by the ocelli on the
+wing-feathers of the Argus pheasant, which are shaded in so wonderful a
+manner as to resemble balls lying loose within sockets, and consequently
+differ from ordinary ocelli. No one, I presume, will attribute the
+shading, which has excited the admiration of many experienced artists,
+to chance--to the fortuitous concourse of atoms of colouring matter.
+That these ornaments should have been formed through the selection of
+many successive variations, not one of which was originally intended to
+produce the ball-and-socket effect, seems as incredible as that one of
+Raphael's Madonnas should have been formed by the selection of chance
+daubs of paint made by a long succession of young artists, not one of
+whom intended at first to draw the human figure. In order to discover
+how the ocelli have been developed, we cannot look to a long line of
+progenitors, nor to many closely-allied forms, for such do not now
+exist. But fortunately the several feathers on the wing suffice to
+give us a clue to the problem, and they prove to demonstration that
+a gradation is at least possible from a mere spot to a finished
+ball-and-socket ocellus.
+
+[Fig. 57. Part of secondary wing-feather of Argus pheasant, shewing
+two perfect ocelli, a and b. A, B, C, D, etc., are dark stripes running
+obliquely down, each to an ocellus. [Much of the web on both sides,
+especially to the left of the shaft, has been cut off.]
+
+Fig.59. Portion of one of the secondary wing-feathers near to the body,
+shewing the so-called elliptic ornaments. The right-hand figure is given
+merely as a diagram for the sake of the letters of reference. A, B,
+C, D, etc. Rows of spots running down to and forming the elliptic
+ornaments. b. Lowest spot or mark in row B. c. The next succeeding spot
+or mark in the same row. d. Apparently a broken prolongation of the spot
+c. in the same row B.]
+
+The wing-feathers, bearing the ocelli, are covered with dark stripes
+(Fig. 57) or with rows of dark spots (Fig. 59), each stripe or row of
+spots running obliquely down the outer side of the shaft to one of the
+ocelli. The spots are generally elongated in a line transverse to the
+row in which they stand. They often become confluent either in the line
+of the row--and then they form a longitudinal stripe--or transversely,
+that is, with the spots in the adjoining rows, and then they form
+transverse stripes. A spot sometimes breaks up into smaller spots, which
+still stand in their proper places.
+
+It will be convenient first to describe a perfect ball-and-socket
+ocellus. This consists of an intensely black circular ring, surrounding
+a space shaded so as exactly to resemble a ball. The figure here given
+has been admirably drawn by Mr. Ford and well engraved, but a woodcut
+cannot exhibit the exquisite shading of the original. The ring is almost
+always slightly broken or interrupted (Fig. 57) at a point in the upper
+half, a little to the right of and above the white shade on the enclosed
+ball; it is also sometimes broken towards the base on the right hand.
+These little breaks have an important meaning. The ring is always
+much thickened, with the edges ill-defined towards the left-hand upper
+corner, the feather being held erect, in the position in which it is
+here drawn. Beneath this thickened part there is on the surface of the
+ball an oblique almost pure-white mark, which shades off downwards
+into a pale-leaden hue, and this into yellowish and brown tints, which
+insensibly become darker and darker towards the lower part of the ball.
+It is this shading which gives so admirably the effect of light shining
+on a convex surface. If one of the balls be examined, it will be seen
+that the lower part is of a brown tint and is indistinctly separated by
+a curved oblique line from the upper part, which is yellower and more
+leaden; this curved oblique line runs at right angles to the longer axis
+of the white patch of light, and indeed of all the shading; but this
+difference in colour, which cannot of course be shewn in the woodcut,
+does not in the least interfere with the perfect shading of the ball.
+It should be particularly observed that each ocellus stands in obvious
+connection either with a dark stripe, or with a longitudinal row of dark
+spots, for both occur indifferently on the same feather. Thus in Fig. 57
+stripe A runs to ocellus a; B runs to ocellus b; stripe C is broken
+in the upper part, and runs down to the next succeeding ocellus, not
+represented in the woodcut; D to the next lower one, and so with the
+stripes E and F. Lastly, the several ocelli are separated from each
+other by a pale surface bearing irregular black marks.
+
+[Fig. 58. Basal part of the secondary wing feather, nearest to the
+body.]
+
+I will next describe the other extreme of the series, namely, the first
+trace of an ocellus. The short secondary wing-feather (Fig. 58),
+nearest to the body, is marked like the other feathers, with oblique,
+longitudinal, rather irregular, rows of very dark spots. The basal spot,
+or that nearest the shaft, in the five lower rows (excluding the lowest
+one) is a little larger than the other spots of the same row, and a
+little more elongated in a transverse direction. It differs also from
+the other spots by being bordered on its upper side with some dull
+fulvous shading. But this spot is not in any way more remarkable than
+those on the plumage of many birds, and might easily be overlooked. The
+next higher spot does not differ at all from the upper ones in the same
+row. The larger basal spots occupy exactly the same relative position on
+these feathers as do the perfect ocelli on the longer wing-feathers.
+
+By looking to the next two or three succeeding wing-feathers,
+an absolutely insensible gradation can be traced from one of the
+last-described basal spots, together with the next higher one in the
+same row, to a curious ornament, which cannot be called an ocellus,
+and which I will name, from the want of a better term, an "elliptic
+ornament." These are shewn in the accompanying figure (Fig. 59). We here
+see several oblique rows, A, B, C, D, etc. (see the lettered diagram on
+the right hand), of dark spots of the usual character. Each row of spots
+runs down to and is connected with one of the elliptic ornaments, in
+exactly the same manner as each stripe in Fig. 57 runs down to and is
+connected with one of the ball-and-socket ocelli. Looking to any one
+row, for instance, B, in Fig. 59, the lowest mark (b) is thicker and
+considerably longer than the upper spots, and has its left extremity
+pointed and curved upwards. This black mark is abruptly bordered on its
+upper side by a rather broad space of richly shaded tints, beginning
+with a narrow brown zone, which passes into orange, and this into a pale
+leaden tint, with the end towards the shaft much paler. These shaded
+tints together fill up the whole inner space of the elliptic ornament.
+The mark (b) corresponds in every respect with the basal shaded spot
+of the simple feather described in the last paragraph (Fig. 58), but is
+more highly developed and more brightly coloured. Above and to the right
+of this spot (b, Fig. 59), with its bright shading, there is a long
+narrow, black mark (c), belonging to the same row, and which is arched
+a little downwards so as to face (b). This mark is sometimes broken into
+two portions. It is also narrowly edged on the lower side with a fulvous
+tint. To the left of and above c, in the same oblique direction, but
+always more or less distinct from it, there is another black mark (d).
+This mark is generally sub-triangular and irregular in shape, but in
+the one lettered in the diagram it is unusually narrow, elongated, and
+regular. It apparently consists of a lateral and broken prolongation of
+the mark (c), together with its confluence with a broken and prolonged
+part of the next spot above; but I do not feel sure of this. These three
+marks, b, c, and d, with the intervening bright shades, form together
+the so-called elliptic ornament. These ornaments placed parallel to
+the shaft, manifestly correspond in position with the ball-and-socket
+ocelli. Their extremely elegant appearance cannot be appreciated in the
+drawing, as the orange and leaden tints, contrasting so well with the
+black marks, cannot be shewn.
+
+[Fig. 60. An ocellus in an intermediate condition between the elliptic
+ornament and the perfect ball-and-socket ocellus.]
+
+Between one of the elliptic ornaments and a perfect ball-and-socket
+ocellus, the gradation is so perfect that it is scarcely possible to
+decide when the latter term ought to be used. The passage from the one
+into the other is effected by the elongation and greater curvature
+in opposite directions of the lower black mark (b, Fig. 59), and more
+especially of the upper one (c), together with the contraction of the
+elongated sub-triangular or narrow mark (d), so that at last these three
+marks become confluent, forming an irregular elliptic ring. This ring is
+gradually rendered more and more circular and regular, increasing at
+the same time in diameter. I have here given a drawing (Fig. 60) of the
+natural size of an ocellus not as yet quite perfect. The lower part
+of the black ring is much more curved than is the lower mark in the
+elliptic ornament (b, Fig. 59). The upper part of the ring consists
+of two or three separate portions; and there is only a trace of the
+thickening of the portion which forms the black mark above the white
+shade. This white shade itself is not as yet much concentrated;
+and beneath it the surface is brighter coloured than in a perfect
+ball-and-socket ocellus. Even in the most perfect ocelli traces of the
+junction of three or four elongated black marks, by which the ring has
+been formed, may often be detected. The irregular sub-triangular or
+narrow mark (d, Fig. 59), manifestly forms, by its contraction and
+equalisation, the thickened portion of the ring above the white shade
+on a perfect ball-and-socket ocellus. The lower part of the ring is
+invariably a little thicker than the other parts (Fig. 57), and this
+follows from the lower black mark of the elliptic ornament (b, Fig. 59)
+having originally been thicker than the upper mark (c). Every step can
+be followed in the process of confluence and modification; and the black
+ring which surrounds the ball of the ocellus is unquestionably formed
+by the union and modification of the three black marks, b, c, d, of
+the elliptic ornament. The irregular zigzag black marks between the
+successive ocelli (Fig. 57) are plainly due to the breaking up of the
+somewhat more regular but similar marks between the elliptic ornaments.
+
+The successive steps in the shading of the ball-and-socket ocelli can be
+followed out with equal clearness. The brown, orange, and pale-leadened
+narrow zones, which border the lower black mark of the elliptic
+ornament, can be seen gradually to become more and more softened
+and shaded into each other, with the upper lighter part towards the
+left-hand corner rendered still lighter, so as to become almost white,
+and at the same time more contracted. But even in the most perfect
+ball-and-socket ocelli a slight difference in the tints, though not
+in the shading, between the upper and lower parts of the ball can be
+perceived, as before noticed; and the line of separation is oblique,
+in the same direction as the bright coloured shades of the elliptic
+ornaments. Thus almost every minute detail in the shape and colouring of
+the ball-and-socket ocelli can be shewn to follow from gradual changes
+in the elliptic ornaments; and the development of the latter can be
+traced by equally small steps from the union of two almost simple spots,
+the lower one (Fig. 58) having some dull fulvous shading on its upper
+side.
+
+[Fig. 61. Portion near summit of one of the secondary wing-feathers,
+bearing perfect ball-and-socket ocelli. a. Ornamented upper part. b.
+Uppermost, imperfect ball-and-socket ocellus. (The shading above the
+white mark on the summit of the ocellus is here a little too dark.) c.
+Perfect ocellus.]
+
+The extremities of the longer secondary feathers which bear the perfect
+ball-and-socket ocelli, are peculiarly ornamented (Fig. 61). The oblique
+longitudinal stripes suddenly cease upwards and become confused; and
+above this limit the whole upper end of the feather (a) is covered with
+white dots, surrounded by little black rings, standing on a dark ground.
+The oblique stripe belonging to the uppermost ocellus (b) is barely
+represented by a very short irregular black mark with the usual, curved,
+transverse base. As this stripe is thus abruptly cut off, we can perhaps
+understand from what has gone before, how it is that the upper thickened
+part of the ring is here absent; for, as before stated, this thickened
+part apparently stands in some relation with a broken prolongation from
+the next higher spot. From the absence of the upper and thickened
+part of the ring, the uppermost ocellus, though perfect in all other
+respects, appears as if its top had been obliquely sliced off. It would,
+I think, perplex any one, who believes that the plumage of the Argus
+pheasant was created as we now see it, to account for the imperfect
+condition of the uppermost ocellus. I should add that on the secondary
+wing-feather farthest from the body all the ocelli are smaller and less
+perfect than on the other feathers, and have the upper part of the ring
+deficient, as in the case just mentioned. The imperfection here seems
+to be connected with the fact that the spots on this feather shew less
+tendency than usual to become confluent into stripes; they are, on the
+contrary, often broken up into smaller spots, so that two or three rows
+run down to the same ocellus.
+
+There still remains another very curious point, first observed by Mr.
+T.W. Wood (51. The 'Field,' May 28, 1870.), which deserves attention. In
+a photograph, given me by Mr. Ward, of a specimen mounted as in the
+act of display, it may be seen that on the feathers which are held
+perpendicularly, the white marks on the ocelli, representing light
+reflected from a convex surface, are at the upper or further end, that
+is, are directed upwards; and the bird whilst displaying himself on the
+ground would naturally be illuminated from above. But here comes the
+curious point; the outer feathers are held almost horizontally, and
+their ocelli ought likewise to appear as if illuminated from above, and
+consequently the white marks ought to be placed on the upper sides of
+the ocelli; and, wonderful as is the fact, they are thus placed! Hence
+the ocelli on the several feathers, though occupying very different
+positions with respect to the light, all appear as if illuminated from
+above, just as an artist would have shaded them. Nevertheless they are
+not illuminated from strictly the same point as they ought to be; for
+the white marks on the ocelli of the feathers which are held almost
+horizontally, are placed rather too much towards the further end; that
+is, they are not sufficiently lateral. We have, however, no right to
+expect absolute perfection in a part rendered ornamental through sexual
+selection, any more than we have in a part modified through natural
+selection for real use; for instance, in that wondrous organ the human
+eye. And we know what Helmholtz, the highest authority in Europe on the
+subject, has said about the human eye; that if an optician had sold him
+an instrument so carelessly made, he would have thought himself
+fully justified in returning it. (52. 'Popular Lectures on Scientific
+Subjects,' Eng. trans. 1873, pp. 219, 227, 269, 390.)
+
+We have now seen that a perfect series can be followed, from simple
+spots to the wonderful ball-and-socket ornaments. Mr. Gould, who kindly
+gave me some of these feathers, fully agrees with me in the completeness
+of the gradation. It is obvious that the stages in development exhibited
+by the feathers on the same bird do not at all necessarily shew us the
+steps passed through by the extinct progenitors of the species; but they
+probably give us the clue to the actual steps, and they at least prove
+to demonstration that a gradation is possible. Bearing in mind how
+carefully the male Argus pheasant displays his plumes before the female,
+as well as the many facts rendering it probable that female birds
+prefer the more attractive males, no one who admits the agency of
+sexual selection in any case will deny that a simple dark spot with
+some fulvous shading might be converted, through the approximation and
+modification of two adjoining spots, together with some slight increase
+of colour, into one of the so-called elliptic ornaments. These latter
+ornaments have been shewn to many persons, and all have admitted
+that they are beautiful, some thinking them even more so than the
+ball-and-socket ocelli. As the secondary plumes became lengthened
+through sexual selection, and as the elliptic ornaments increased in
+diameter, their colours apparently became less bright; and then the
+ornamentation of the plumes had to be gained by an improvement in the
+pattern and shading; and this process was carried on until the
+wonderful ball-and-socket ocelli were finally developed. Thus we can
+understand--and in no other way as it seems to me--the present condition
+and origin of the ornaments on the wing-feathers of the Argus pheasant.
+
+From the light afforded by the principle of gradation--from what we know
+of the laws of variation--from the changes which have taken place in
+many of our domesticated birds--and, lastly, from the character (as
+we shall hereafter see more clearly) of the immature plumage of young
+birds--we can sometimes indicate, with a certain amount of confidence,
+the probable steps by which the males have acquired their brilliant
+plumage and various ornaments; yet in many cases we are involved in
+complete darkness. Mr. Gould several years ago pointed out to me a
+humming-bird, the Urosticte benjamini, remarkable for the curious
+differences between the sexes. The male, besides a splendid gorget, has
+greenish-black tail-feathers, with the four CENTRAL ones tipped with
+white; in the female, as with most of the allied species, the three
+OUTER tail-feathers on each side are tipped with white, so that the male
+has the four central, whilst the female has the six exterior feathers
+ornamented with white tips. What makes the case more curious is that,
+although the colouring of the tail differs remarkably in both sexes of
+many kinds of humming-birds, Mr. Gould does not know a single species,
+besides the Urosticte, in which the male has the four central feathers
+tipped with white.
+
+The Duke of Argyll, in commenting on this case (53. 'The Reign of
+Law,' 1867, p. 247.), passes over sexual selection, and asks, "What
+explanation does the law of natural selection give of such specific
+varieties as these?" He answers "none whatever"; and I quite agree with
+him. But can this be so confidently said of sexual selection? Seeing in
+how many ways the tail-feathers of humming-birds differ, why should not
+the four central feathers have varied in this one species alone, so as
+to have acquired white tips? The variations may have been gradual, or
+somewhat abrupt as in the case recently given of the humming-birds
+near Bogota, in which certain individuals alone have the "central
+tail-feathers tipped with beautiful green." In the female of the
+Urosticte I noticed extremely minute or rudimental white tips to the two
+outer of the four central black tail-feathers; so that here we have an
+indication of change of some kind in the plumage of this species. If we
+grant the possibility of the central tail-feathers of the male varying
+in whiteness, there is nothing strange in such variations having
+been sexually selected. The white tips, together with the small white
+ear-tufts, certainly add, as the Duke of Argyll admits, to the beauty of
+the male; and whiteness is apparently appreciated by other birds, as may
+be inferred from such cases as the snow-white male of the Bell-bird. The
+statement made by Sir R. Heron should not be forgotten, namely, that his
+peahens, when debarred from access to the pied peacock, would not unite
+with any other male, and during that season produced no offspring. Nor
+is it strange that variations in the tail-feathers of the Urosticte
+should have been specially selected for the sake of ornament, for the
+next succeeding genus in the family takes its name of Metallura from
+the splendour of these feathers. We have, moreover, good evidence that
+humming-birds take especial pains in displaying their tail-feathers;
+Mr. Belt (54. 'The Naturalist in Nicaragua,' 1874, p. 112.), after
+describing the beauty of the Florisuga mellivora, says, "I have seen
+the female sitting on a branch, and two males displaying their charms in
+front of her. One would shoot up like a rocket, then suddenly expanding
+the snow-white tail, like an inverted parachute, slowly descend in
+front of her, turning round gradually to shew off back and front...The
+expanded white tail covered more space than all the rest of the bird,
+and was evidently the grand feature in the performance. Whilst one male
+was descending, the other would shoot up and come slowly down expanded.
+The entertainment would end in a fight between the two performers;
+but whether the most beautiful or the most pugnacious was the accepted
+suitor, I know not." Mr. Gould, after describing the peculiar plumage
+of the Urosticte, adds, "that ornament and variety is the sole object,
+I have myself but little doubt." (55. 'Introduction to the Trochilidae,'
+1861, p. 110.) If this be admitted, we can perceive that the males which
+during former times were decked in the most elegant and novel manner
+would have gained an advantage, not in the ordinary struggle for life,
+but in rivalry with other males, and would have left a larger number of
+offspring to inherit their newly-acquired beauty.
+
+
+CHAPTER XV.
+
+Birds--continued.
+
+Discussion as to why the males alone of some species, and both sexes
+of others, are brightly coloured--On sexually-limited inheritance,
+as applied to various structures and to brightly-coloured
+plumage--Nidification in relation to colour--Loss of nuptial plumage
+during the winter.
+
+We have in this chapter to consider why the females of many birds have
+not acquired the same ornaments as the male; and why, on the other
+hand, both sexes of many other birds are equally, or almost equally,
+ornamented? In the following chapter we shall consider the few cases in
+which the female is more conspicuously coloured than the male.
+
+In my 'Origin of Species' (1. Fourth edition, 1866, p. 241.) I briefly
+suggested that the long tail of the peacock would be inconvenient and
+the conspicuous black colour of the male capercailzie dangerous, to
+the female during the period of incubation: and consequently that the
+transmission of these characters from the male to the female offspring
+had been checked through natural selection. I still think that this may
+have occurred in some few instances: but after mature reflection on
+all the facts which I have been able to collect, I am now inclined
+to believe that when the sexes differ, the successive variations have
+generally been from the first limited in their transmission to the same
+sex in which they first arose. Since my remarks appeared, the subject of
+sexual coloration has been discussed in some very interesting papers by
+Mr. Wallace (2. 'Westminster Review,' July 1867. 'Journal of Travel,'
+vol. i. 1868, p. 73.), who believes that in almost all cases the
+successive variations tended at first to be transmitted equally to both
+sexes; but that the female was saved, through natural selection, from
+acquiring the conspicuous colours of the male, owing to the danger which
+she would thus have incurred during incubation.
+
+This view necessitates a tedious discussion on a difficult point,
+namely, whether the transmission of a character, which is at first
+inherited by both sexes can be subsequently limited in its transmission
+to one sex alone by means of natural selection. We must bear in mind,
+as shewn in the preliminary chapter on sexual selection, that characters
+which are limited in their development to one sex are always latent
+in the other. An imaginary illustration will best aid us in seeing the
+difficulty of the case; we may suppose that a fancier wished to make a
+breed of pigeons, in which the males alone should be coloured of a
+pale blue, whilst the females retained their former slaty tint. As with
+pigeons characters of all kinds are usually transmitted to both sexes
+equally, the fancier would have to try to convert this latter form of
+inheritance into sexually-limited transmission. All that he could do
+would be to persevere in selecting every male pigeon which was in the
+least degree of a paler blue; and the natural result of this process,
+if steadily carried on for a long time, and if the pale variations were
+strongly inherited or often recurred, would be to make his whole
+stock of a lighter blue. But our fancier would be compelled to match,
+generation after generation, his pale blue males with slaty females, for
+he wishes to keep the latter of this colour. The result would generally
+be the production either of a mongrel piebald lot, or more probably the
+speedy and complete loss of the pale-blue tint; for the primordial slaty
+colour would be transmitted with prepotent force. Supposing, however,
+that some pale-blue males and slaty females were produced during each
+successive generation, and were always crossed together, then the slaty
+females would have, if I may use the expression, much blue blood in
+their veins, for their fathers, grandfathers, etc., will all have been
+blue birds. Under these circumstances it is conceivable (though I know
+of no distinct facts rendering it probable) that the slaty females might
+acquire so strong a latent tendency to pale-blueness, that they would
+not destroy this colour in their male offspring, their female offspring
+still inheriting the slaty tint. If so, the desired end of making
+a breed with the two sexes permanently different in colour might be
+gained.
+
+The extreme importance, or rather necessity in the above case of the
+desired character, namely, pale-blueness, being present though in a
+latent state in the female, so that the male offspring should not
+be deteriorated, will be best appreciated as follows: the male of
+Soemmerring's pheasant has a tail thirty-seven inches in length, whilst
+that of the female is only eight inches; the tail of the male common
+pheasant is about twenty inches, and that of the female twelve inches
+long. Now if the female Soemmerring pheasant with her SHORT tail were
+crossed with the male common pheasant, there can be no doubt that the
+male hybrid offspring would have a much LONGER tail than that of the
+pure offspring of the common pheasant. On the other hand, if the
+female common pheasant, with a tail much longer than that of the female
+Soemmerring pheasant, were crossed with the male of the latter, the male
+hybrid offspring would have a much SHORTER tail than that of the pure
+offspring of Soemmerring's pheasant. (3. Temminck says that the tail of
+the female Phasianus Soemmerringii is only six inches long, 'Planches
+coloriees,' vol. v. 1838, pp. 487 and 488: the measurements above
+given were made for me by Mr. Sclater. For the common pheasant, see
+Macgillivray, 'History of British Birds,' vol. i. pp. 118-121.)
+
+Our fancier, in order to make his new breed with the males of a
+pale-blue tint, and the females unchanged, would have to continue
+selecting the males during many generations; and each stage of paleness
+would have to be fixed in the males, and rendered latent in the females.
+The task would be an extremely difficult one, and has never been tried,
+but might possibly be successfully carried out. The chief obstacle would
+be the early and complete loss of the pale-blue tint, from the necessity
+of reiterated crosses with the slaty female, the latter not having at
+first any LATENT tendency to produce pale-blue offspring.
+
+On the other hand, if one or two males were to vary ever so slightly
+in paleness, and the variations were from the first limited in their
+transmission to the male sex, the task of making a new breed of the
+desired kind would be easy, for such males would simply have to be
+selected and matched with ordinary females. An analogous case has
+actually occurred, for there are breeds of the pigeon in Belgium (4. Dr.
+Chapuis, 'Le Pigeon Voyageur Belge,' 1865, p. 87.) in which the males
+alone are marked with black striae. So again Mr. Tegetmeier has recently
+shewn (5. The 'Field,' Sept. 1872.) that dragons not rarely produce
+silver-coloured birds, which are almost always hens; and he himself has
+bred ten such females. It is on the other hand a very unusual event when
+a silver male is produced; so that nothing would be easier, if desired,
+than to make a breed of dragons with blue males and silver females.
+This tendency is indeed so strong that when Mr. Tegetmeier at last got a
+silver male and matched him with one of the silver females, he
+expected to get a breed with both sexes thus coloured; he was however
+disappointed, for the young male reverted to the blue colour of his
+grandfather, the young female alone being silver. No doubt with patience
+this tendency to reversion in the males, reared from an occasional
+silver male matched with a silver hen, might be eliminated, and then
+both sexes would be coloured alike; and this very process has been
+followed with success by Mr. Esquilant in the case of silver turbits.
+
+With fowls, variations of colour, limited in their transmission to the
+male sex, habitually occur. When this form of inheritance prevails,
+it might well happen that some of the successive variations would be
+transferred to the female, who would then slightly resemble the male,
+as actually occurs in some breeds. Or again, the greater number, but not
+all, of the successive steps might be transferred to both sexes, and the
+female would then closely resemble the male. There can hardly be a
+doubt that this is the cause of the male pouter pigeon having a somewhat
+larger crop, and of the male carrier pigeon having somewhat larger
+wattles, than their respective females; for fanciers have not selected
+one sex more than the other, and have had no wish that these characters
+should be more strongly displayed in the male than in the female, yet
+this is the case with both breeds.
+
+The same process would have to be followed, and the same difficulties
+encountered, if it were desired to make a breed with the females alone
+of some new colour.
+
+Lastly, our fancier might wish to make a breed with the two sexes
+differing from each other, and both from the parent species. Here the
+difficulty would be extreme, unless the successive variations were from
+the first sexually limited on both sides, and then there would be
+no difficulty. We see this with the fowl; thus the two sexes of the
+pencilled Hamburghs differ greatly from each other, and from the two
+sexes of the aboriginal Gallus bankiva; and both are now kept constant
+to their standard of excellence by continued selection, which would be
+impossible unless the distinctive characters of both were limited in
+their transmission.
+
+The Spanish fowl offers a more curious case; the male has an immense
+comb, but some of the successive variations, by the accumulation of
+which it was acquired, appear to have been transferred to the female;
+for she has a comb many times larger than that of the females of the
+parent species. But the comb of the female differs in one respect from
+that of the male, for it is apt to lop over; and within a recent period
+it has been ordered by the fancy that this should always be the case,
+and success has quickly followed the order. Now the lopping of the comb
+must be sexually limited in its transmission, otherwise it would prevent
+the comb of the male from being perfectly upright, which would be
+abhorrent to every fancier. On the other hand, the uprightness of
+the comb in the male must likewise be a sexually-limited character,
+otherwise it would prevent the comb of the female from lopping over.
+
+From the foregoing illustrations, we see that even with almost unlimited
+time at command, it would be an extremely difficult and complex, perhaps
+an impossible process, to change one form of transmission into the other
+through selection. Therefore, without distinct evidence in each case, I
+am unwilling to admit that this has been effected in natural species. On
+the other hand, by means of successive variations, which were from the
+first
+
+sexually limited in their transmission, there would not be the least
+difficulty in rendering a male bird widely different in colour or in
+any other character from the female; the latter being left unaltered, or
+slightly altered, or specially modified for the sake of protection.
+
+As bright colours are of service to the males in their rivalry with
+other males, such colours would be selected whether or not they were
+transmitted exclusively to the same sex. Consequently the females might
+be expected often to partake of the brightness of the males to a greater
+or less degree; and this occurs with a host of species. If all the
+successive variations were transmitted equally to both sexes, the
+females would be indistinguishable from the males; and this likewise
+occurs with many birds. If, however, dull colours were of high
+importance for the safety of the female during incubation, as with many
+ground birds, the females which varied in brightness, or which received
+through inheritance from the males any marked accession of brightness,
+would sooner or later be destroyed. But the tendency in the males to
+continue for an indefinite period transmitting to their female offspring
+their own brightness, would have to be eliminated by a change in the
+form of inheritance; and this, as shewn by our previous illustration,
+would be extremely difficult. The more probable result of the
+long-continued destruction of the more brightly-coloured females,
+supposing the equal form of transmission to prevail, would be the
+lessening or annihilation of the bright colours of the males, owing to
+their continual crossing with the duller females. It would be tedious to
+follow out all the other possible results; but I may remind the reader
+that if sexually-limited variations in brightness occurred in the
+females, even if they were not in the least injurious to them and
+consequently were not eliminated, yet they would not be favoured or
+selected, for the male usually accepts any female, and does not select
+the more attractive individuals; consequently these variations would be
+liable to be lost, and would have little influence on the character of
+the race; and this will aid in accounting for the females being commonly
+duller-coloured than the males.
+
+In the eighth chapter instances were given, to which many might here
+be added, of variations occurring at various ages, and inherited at the
+corresponding age. It was also shewn that variations which occur late
+in life are commonly transmitted to the same sex in which they first
+appear; whilst variations occurring early in life are apt to be
+transmitted to both sexes; not that all the cases of sexually-limited
+transmission can thus be accounted for. It was further shewn that if
+a male bird varied by becoming brighter whilst young, such variations
+would be of no service until the age for reproduction had arrived, and
+there was competition between rival males. But in the case of birds
+living on the ground and commonly in need of the protection of dull
+colours, bright tints would be far more dangerous to the young and
+inexperienced than to the adult males. Consequently the males which
+varied in brightness whilst young would suffer much destruction and be
+eliminated through natural selection; on the other hand, the males which
+varied in this manner when nearly mature, notwithstanding that they
+were exposed to some additional danger, might survive, and from being
+favoured through sexual selection, would procreate their kind. As a
+relation often exists between the period of variation and the form of
+transmission, if the bright-coloured young males were destroyed and the
+mature ones were successful in their courtship, the males alone would
+acquire brilliant colours and would transmit them exclusively to their
+male offspring. But I by no means wish to maintain that the influence
+of age on the form of transmission, is the sole cause of the great
+difference in brilliancy between the sexes of many birds.
+
+When the sexes of birds differ in colour, it is interesting to determine
+whether the males alone have been modified by sexual selection, the
+females having been left unchanged, or only partially and indirectly
+thus changed; or whether the females have been specially modified
+through natural selection for the sake of protection. I will therefore
+discuss this question at some length, even more fully than its intrinsic
+importance deserves; for various curious collateral points may thus be
+conveniently considered.
+
+Before we enter on the subject of colour, more especially in reference
+to Mr. Wallace's conclusions, it may be useful to discuss some other
+sexual differences under a similar point of view. A breed of
+fowls formerly existed in Germany (6. Bechstein, 'Naturgeschichte
+Deutschlands,' 1793, B. iii. 339.) in which the hens were furnished with
+spurs; they were good layers, but they so greatly disturbed their nests
+with their spurs that they could not be allowed to sit on their own
+eggs. Hence at one time it appeared to me probable that with the females
+of the wild Gallinaceae the development of spurs had been checked
+through natural selection, from the injury thus caused to their nests.
+This seemed all the more probable, as wing-spurs, which would not be
+injurious during incubation, are often as well-developed in the female
+as in the male; though in not a few cases they are rather larger in the
+male. When the male is furnished with leg-spurs the female almost always
+exhibits rudiments of them,--the rudiment sometimes consisting of a
+mere scale, as in Gallus. Hence it might be argued that the females had
+aboriginally been furnished with well-developed spurs, but that these
+had subsequently been lost through disuse or natural selection. But if
+this view be admitted, it would have to be extended to innumerable
+other cases; and it implies that the female progenitors of the existing
+spur-bearing species were once encumbered with an injurious appendage.
+
+In some few genera and species, as in Galloperdix, Acomus, and the
+Javan peacock (Pavo muticus), the females, as well as the males, possess
+well-developed leg-spurs. Are we to infer from this fact that they
+construct a different sort of nest from that made by their nearest
+allies, and not liable to be injured by their spurs; so that the spurs
+have not been removed? Or are we to suppose that the females of these
+several species especially require spurs for their defence? It is a more
+probable conclusion that both the presence and absence of spurs in the
+females result from different laws of inheritance having prevailed,
+independently of natural selection. With the many females in which spurs
+appear as rudiments, we may conclude that some few of the successive
+variations, through which they were developed in the males, occurred
+very early in life, and were consequently transferred to the females.
+In the other and much rarer cases, in which the females possess fully
+developed spurs, we may conclude that all the successive variations were
+transferred to them; and that they gradually acquired and inherited the
+habit of not disturbing their nests.
+
+The vocal organs and the feathers variously modified for producing
+sound, as well as the proper instincts for using them, often differ in
+the two sexes, but are sometimes the same in both. Can such differences
+be accounted for by the males having acquired these organs and
+instincts, whilst the females have been saved from inheriting them,
+on account of the danger to which they would have been exposed by
+attracting the attention of birds or beasts of prey? This does not
+seem to me probable, when we think of the multitude of birds which with
+impunity gladden the country with their voices during the spring.
+(7. Daines Barrington, however, thought it probable ('Philosophical
+Transactions,' 1773, p. 164) that few female birds sing, because the
+talent would have been dangerous to them during incubation. He adds,
+that a similar view may possibly account for the inferiority of the
+female to the male in plumage.) It is a safer conclusion that, as vocal
+and instrumental organs are of special service only to the males during
+their courtship, these organs were developed through sexual selection
+and their constant use in that sex alone--the successive variations and
+the effects of use having been from the first more or less limited in
+transmission to the male offspring.
+
+Many analogous cases could be adduced; those for instance of the plumes
+on the head being generally longer in the male than in the female,
+sometimes of equal length in both sexes, and occasionally absent in the
+female,--these several cases occurring in the same group of birds. It
+would be difficult to account for such a difference between the sexes by
+the female having been benefited by possessing a slightly shorter crest
+than the male, and its consequent diminution or complete suppression
+through natural selection. But I will take a more favourable case,
+namely the length of the tail. The long train of the peacock would have
+been not only inconvenient but dangerous to the peahen during the period
+of incubation and whilst accompanying her young. Hence there is not the
+least a priori improbability in the development of her tail having been
+checked through natural selection. But the females of various pheasants,
+which apparently are exposed on their open nests to as much danger as
+the peahen, have tails of considerable length. The females as well as
+the males of the Menura superba have long tails, and they build a domed
+nest, which is a great anomaly in so large a bird. Naturalists have
+wondered how the female Menura could manage her tail during incubation;
+but it is now known (8. Mr. Ramsay, in 'Proc. Zoolog. Soc.' 1868, p.
+50.) that she "enters the nest head first, and then turns round with
+her tail sometimes over her back, but more often bent round by her side.
+Thus in time the tail becomes quite askew, and is a tolerable guide
+to the length of time the bird has been sitting." Both sexes of an
+Australian kingfisher (Tanysiptera sylvia) have the middle tail-feathers
+greatly lengthened, and the female makes her nest in a hole; and as I am
+informed by Mr. R.B. Sharpe these feathers become much crumpled during
+incubation.
+
+In these two latter cases the great length of the tail-feathers must be
+in some degree inconvenient to the female; and as in both species the
+tail-feathers of the female are somewhat shorter than those of the
+male, it might be argued that their full development had been prevented
+through natural selection. But if the development of the tail of
+the peahen had been checked only when it became inconveniently or
+dangerously great, she would have retained a much longer tail than she
+actually possesses; for her tail is not nearly so long, relatively to
+the size of her body, as that of many female pheasants, nor longer
+than that of the female turkey. It must also be borne in mind that,
+in accordance with this view, as soon as the tail of the peahen became
+dangerously long, and its development was consequently checked, she
+would have continually reacted on her male progeny, and thus have
+prevented the peacock from acquiring his present magnificent train. We
+may therefore infer that the length of the tail in the peacock and its
+shortness in the peahen are the result of the requisite variations in
+the male having been from the first transmitted to the male offspring
+alone.
+
+We are led to a nearly similar conclusion with respect to the length
+of the tail in the various species of pheasants. In the Eared pheasant
+(Crossoptilon auritum) the tail is of equal length in both sexes, namely
+sixteen or seventeen inches; in the common pheasant it is about twenty
+inches long in the male and twelve in the female; in Soemmerring's
+pheasant, thirty-seven inches in the male and only eight in the female;
+and lastly in Reeve's pheasant it is sometimes actually seventy-two
+inches long in the male and sixteen in the female. Thus in the several
+species, the tail of the female differs much in length, irrespectively
+of that of the male; and this can be accounted for, as it seems to me,
+with much more probability, by the laws of inheritance,--that is by the
+successive variations having been from the first more or less closely
+limited in their transmission to the male sex than by the agency of
+natural selection, resulting from the length of tail being more or less
+injurious to the females of these several allied species.
+
+We may now consider Mr. Wallace's arguments in regard to the sexual
+coloration of birds. He believes that the bright tints originally
+acquired through sexual selection by the males would in all, or almost
+all cases, have been transmitted to the females, unless the transference
+had been checked through natural selection. I may here remind the reader
+that various facts opposed to this view have already been given under
+reptiles, amphibians, fishes and lepidoptera. Mr. Wallace rests his
+belief chiefly, but not exclusively, as we shall see in the next
+chapter, on the following statement (9. 'Journal of Travel,' edited by
+A. Murray, vol. i. 1868, p. 78.), that when both sexes are coloured in a
+very conspicuous manner, the nest is of such a nature as to conceal the
+sitting bird; but when there is a marked contrast of colour between the
+sexes, the male being gay and the female dull-coloured, the nest is open
+and exposes the sitting bird to view. This coincidence, as far as it
+goes, certainly seems to favour the belief that the females which sit on
+open nests have been specially modified for the sake of protection;
+but we shall presently see that there is another and more probable
+explanation, namely, that conspicuous females have acquired the instinct
+of building domed nests oftener than dull-coloured birds. Mr. Wallace
+admits that there are, as might have been expected, some exceptions to
+his two rules, but it is a question whether the exceptions are not so
+numerous as seriously to invalidate them.
+
+There is in the first place much truth in the Duke of Argyll's remark
+(10. 'Journal of Travel,' edited by A. Murray, vol. i. 1868, p. 281.)
+that a large domed nest is more conspicuous to an enemy, especially to
+all tree-haunting carnivorous animals, than a smaller open nest. Nor
+must we forget that with many birds which build open nests, the male
+sits on the eggs and aids the female in feeding the young: this is the
+case, for instance, with Pyranga aestiva (11. Audubon, 'Ornithological
+Biography,' vol. i. p. 233.), one of the most splendid birds in
+the United States, the male being vermilion, and the female light
+brownish-green. Now if brilliant colours had been extremely dangerous to
+birds whilst sitting on their open nests, the males in these cases
+would have suffered greatly. It might, however, be of such paramount
+importance to the male to be brilliantly coloured, in order to beat his
+rivals, that this may have more than compensated some additional danger.
+
+Mr. Wallace admits that with the King-crows (Dicrurus), Orioles, and
+Pittidae, the females are conspicuously coloured, yet build open nests;
+but he urges that the birds of the first group are highly pugnacious
+and could defend themselves; that those of the second group take extreme
+care in concealing their open nests, but this does not invariably hold
+good (12. Jerdon, 'Birds of India,' vol. ii. p. 108. Gould's 'Handbook
+of the Birds of Australia,' vol. i. p. 463.); and that with the birds of
+the third group the females are brightly coloured chiefly on the under
+surface. Besides these cases, pigeons which are sometimes brightly, and
+almost always conspicuously coloured, and which are notoriously liable
+to the attacks of birds of prey, offer a serious exception to the rule,
+for they almost always build open and exposed nests. In another large
+family, that of the humming-birds, all the species build open nests, yet
+with some of the most gorgeous species the sexes are alike; and in
+the majority, the females, though less brilliant than the males,
+are brightly coloured. Nor can it be maintained that all female
+humming-birds, which are brightly coloured, escape detection by their
+tints being green, for some display on their upper surfaces red, blue,
+and other colours. (13. For instance, the female Eupetomena macroura
+has the head and tail dark blue with reddish loins; the female Lampornis
+porphyrurus is blackish-green on the upper surface, with the lores and
+sides of the throat crimson; the female Eulampis jugularis has the top
+of the head and back green, but the loins and the tail are crimson. Many
+other instances of highly conspicuous females could be given. See Mr.
+Gould's magnificent work on this family.)
+
+In regard to birds which build in holes or construct domed nests, other
+advantages, as Mr. Wallace remarks, besides concealment are gained,
+such as shelter from the rain, greater warmth, and in hot countries
+protection from the sun (14. Mr. Salvin noticed in Guatemala ('Ibis,'
+1864, p. 375) that humming-birds were much more unwilling to leave their
+nests during very hot weather, when the sun was shining brightly, as
+if their eggs would be thus injured, than during cool, cloudy, or rainy
+weather.); so that it is no valid objection to his view that many birds
+having both sexes obscurely coloured build concealed nests. (15. I may
+specify, as instances of dull-coloured birds building concealed nests,
+the species belonging to eight Australian genera described in Gould's
+'Handbook of the Birds of Australia,' vol. i. pp. 340, 362, 365, 383,
+387, 389, 391, 414.) The female Horn-bill (Buceros), for instance, of
+India and Africa is protected during incubation with extraordinary care,
+for she plasters up with her own excrement the orifice of the hole in
+which she sits on her eggs, leaving only a small orifice through which
+the male feeds her; she is thus kept a close prisoner during the whole
+period of incubation (16. Mr. C. Horne, 'Proc. Zoolog. Soc.' 1869. p.
+243.); yet female horn-bills are not more conspicuously coloured than
+many other birds of equal size which build open nests. It is a more
+serious objection to Mr. Wallace's view, as is admitted by him, that
+in some few groups the males are brilliantly coloured and the females
+obscure, and yet the latter hatch their eggs in domed nests. This is the
+case with the Grallinae of Australia, the Superb Warblers (Maluridae) of
+the same country, the Sun-birds (Nectariniae), and with several of the
+Australian Honey-suckers or Meliphagidae. (17. On the nidification and
+colours of these latter species, see Gould's 'Handbook to the Birds of
+Australia,' vol. i. pp. 504, 527.)
+
+If we look to the birds of England we shall see that there is no close
+and general relation between the colours of the female and the nature
+of the nest which is constructed. About forty of our British birds
+(excluding those of large size which could defend themselves) build in
+holes in banks, rocks, or trees, or construct domed nests. If we take
+the colours of the female goldfinch, bullfinch, or blackbird, as a
+standard of the degree of conspicuousness, which is not highly dangerous
+to the sitting female, then out of the above forty birds the females of
+only twelve can be considered as conspicuous to a dangerous degree, the
+remaining twenty-eight being inconspicuous. (18. I have consulted, on
+this subject, Macgillivray's 'British Birds,' and though doubts may be
+entertained in some cases in regard to the degree of concealment of
+the nest, and to the degree of conspicuousness of the female, yet the
+following birds, which all lay their eggs in holes or in domed nests,
+can hardly be considered, by the above standard, as conspicuous: Passer,
+2 species; Sturnus, of which the female is considerably less brilliant
+than the male; Cinclus; Motallica boarula (?); Erithacus (?); Fruticola,
+2 sp.; Saxicola; Ruticilla, 2 sp.; Sylvia, 3 sp.; Parus, 3 sp.;
+Mecistura; Anorthura; Certhia; Sitta; Yunx; Muscicapa, 2 sp.; Hirundo,
+3 sp.; and Cypselus. The females of the following 12 birds may be
+considered as conspicuous according to the same standard, viz., Pastor,
+Motacilla alba, Parus major and P. caeruleus, Upupa, Picus, 4 sp.,
+Coracias, Alcedo, and Merops.) Nor is there any close relation within
+the same genus between a well-pronounced difference in colour between
+the sexes, and the nature of the nest constructed. Thus the male house
+sparrow (Passer domesticus) differs much from the female, the
+male tree-sparrow (P. montanus) hardly at all, and yet both build
+well-concealed nests. The two sexes of the common fly-catcher (Muscicapa
+grisola) can hardly be distinguished, whilst the sexes of the pied
+fly-catcher (M. luctuosa) differ considerably, and both species build
+in holes or conceal their nests. The female blackbird (Turdus merula)
+differs much, the female ring-ouzel (T. torquatus) differs less, and the
+female common thrush (T. musicus) hardly at all from their respective
+males; yet all build open nests. On the other hand, the not very
+distantly-allied water-ouzel (Cinclus aquaticus) builds a domed nest,
+and the sexes differ about as much as in the ring-ouzel. The black and
+red grouse (Tetrao tetrix and T. scoticus) build open nests in equally
+well-concealed spots, but in the one species the sexes differ greatly,
+and in the other very little.
+
+Notwithstanding the foregoing objections, I cannot doubt, after reading
+Mr. Wallace's excellent essay, that looking to the birds of the world,
+a large majority of the species in which the females are conspicuously
+coloured (and in this case the males with rare exceptions are equally
+conspicuous), build concealed nests for the sake of protection. Mr.
+Wallace enumerates (19. 'Journal of Travel,' edited by A. Murray, vol.
+i. p. 78.) a long series of groups in which this rule holds good; but
+it will suffice here to give, as instances, the more familiar groups of
+kingfishers, toucans, trogons, puff-birds (Capitonidae), plantain-eaters
+(Musophagae, woodpeckers, and parrots. Mr. Wallace believes that in
+these groups, as the males gradually acquired through sexual selection
+their brilliant colours, these were transferred to the females and were
+not eliminated by natural selection, owing to the protection which they
+already enjoyed from their manner of nidification. According to this
+view, their present manner of nesting was acquired before their present
+colours. But it seems to me much more probable that in most cases,
+as the females were gradually rendered more and more brilliant from
+partaking of the colours of the male, they were gradually led to change
+their instincts (supposing that they originally built open nests), and
+to seek protection by building domed or concealed nests. No one who
+studies, for instance, Audubon's account of the differences in the nests
+of the same species in the Northern and Southern United States (20. See
+many statements in the 'Ornithological Biography.' See also some curious
+observations on the nests of Italian birds by Eugenio Bettoni, in the
+'Atti della Societ� Italiana,' vol. xi. 1869, p. 487.), will feel any
+great difficulty in admitting that birds, either by a change (in the
+strict sense of the word) of their habits, or through the natural
+selection of so-called spontaneous variations of instinct, might readily
+be led to modify their manner of nesting.
+
+This way of viewing the relation, as far as it holds good, between the
+bright colours of female birds and their manner of nesting, receives
+some support from certain cases occurring in the Sahara Desert. Here, as
+in most other deserts, various birds, and many other animals, have
+had their colours adapted in a wonderful manner to the tints of the
+surrounding surface. Nevertheless there are, as I am informed by the
+Rev. Mr. Tristram, some curious exceptions to the rule; thus the male of
+the Monticola cyanea is conspicuous from his bright blue colour, and
+the female almost equally conspicuous from her mottled brown and white
+plumage; both sexes of two species of Dromolaea are of a lustrous black;
+so that these three species are far from receiving protection from their
+colours, yet they are able to survive, for they have acquired the habit
+of taking refuge from danger in holes or crevices in the rocks.
+
+With respect to the above groups in which the females are conspicuously
+coloured and build concealed nests, it is not necessary to suppose that
+each separate species had its nidifying instinct specially modified;
+but only that the early progenitors of each group were gradually led
+to build domed or concealed nests, and afterwards transmitted this
+instinct, together with their bright colours, to their modified
+descendants. As far as it can be trusted, the conclusion is interesting,
+that sexual selection together with equal or nearly equal inheritance
+by both sexes, have indirectly determined the manner of nidification of
+whole groups of birds.
+
+According to Mr. Wallace, even in the groups in which the females, from
+being protected in domed nests during incubation, have not had their
+bright colours eliminated through natural selection, the males often
+differ in a slight, and occasionally in a considerable degree from the
+females. This is a significant fact, for such differences in colour must
+be accounted for by some of the variations in the males having been from
+the first limited in transmission to the same sex; as it can hardly be
+maintained that these differences, especially when very slight, serve as
+a protection to the female. Thus all the species in the splendid group
+of the Trogons build in holes; and Mr. Gould gives figures (21. See his
+Monograph of the Trogonidae, 1st edition.) of both sexes of twenty-five
+species, in all of which, with one partial exception, the sexes differ
+sometimes slightly, sometimes conspicuously, in colour,--the males being
+always finer than the females, though the latter are likewise beautiful.
+All the species of kingfishers build in holes, and with most of the
+species the sexes are equally brilliant, and thus far Mr. Wallace's rule
+holds good; but in some of the Australian species the colours of
+the females are rather less vivid than those of the male; and in one
+splendidly-coloured species, the sexes differ so much that they were
+at first thought to be specifically distinct. (22. Namely, Cyanalcyon,
+Gould's 'Handbook to the Birds of Australia,' vol. i. p. 133; see, also,
+pp. 130, 136.) Mr. R.B. Sharpe, who has especially studied this group,
+has shewn me some American species (Ceryle) in which the breast of the
+male is belted with black. Again, in Carcineutes, the difference between
+the sexes is conspicuous: in the male the upper surface is dull-blue
+banded with black, the lower surface being partly fawn-coloured, and
+there is much red about the head; in the female the upper surface is
+reddish-brown banded with black, and the lower surface white with black
+markings. It is an interesting fact, as shewing how the same peculiar
+style of sexual colouring often characterises allied forms, that in
+three species of Dacelo the male differs from the female only in the
+tail being dull-blue banded with black, whilst that of the female is
+brown with blackish bars; so that here the tail differs in colour in the
+two sexes in exactly the same manner as the whole upper surface in the
+two sexes of Carcineutes.
+
+With parrots, which likewise build in holes, we find analogous cases:
+in most of the species, both sexes are brilliantly coloured and
+indistinguishable, but in not a few species the males are coloured
+rather more vividly than the females, or even very differently from
+them. Thus, besides other strongly-marked differences, the whole under
+surface of the male King Lory (Aprosmictus scapulatus) is scarlet,
+whilst the throat and chest of the female is green tinged with red: in
+the Euphema splendida there is a similar difference, the face and wing
+coverts moreover of the female being of a paler blue than in the male.
+(23. Every gradation of difference between the sexes may be followed
+in the parrots of Australia. See Gould's 'Handbook,' etc., vol. ii.
+pp. 14-102.) In the family of the tits (Parinae), which build concealed
+nests, the female of our common blue tomtit (Parus caeruleus), is "much
+less brightly coloured" than the male: and in the magnificent Sultan
+yellow tit of India the difference is greater. (24. Macgillivray's
+'British Birds,' vol. ii. p. 433. Jerdon, 'Birds of India,' vol. ii. p.
+282.)
+
+Again, in the great group of the woodpeckers (25. All the following
+facts are taken from M. Malherbe's magnificent 'Monographie des
+Picidees,' 1861.), the sexes are generally nearly alike, but in the
+Megapicus validus all those parts of the head, neck, and breast, which
+are crimson in the male are pale brown in the female. As in several
+woodpeckers the head of the male is bright crimson, whilst that of the
+female is plain, it occurred to me that this colour might possibly make
+the female dangerously conspicuous, whenever she put her head out of
+the hole containing her nest, and consequently that this colour, in
+accordance with Mr. Wallace's belief, had been eliminated. This view is
+strengthened by what Malherbe states with respect to Indopicus carlotta;
+namely, that the young females, like the young males, have some crimson
+about their heads, but that this colour disappears in the adult female,
+whilst it is intensified in the adult male. Nevertheless the following
+considerations render this view extremely doubtful: the male takes a
+fair share in incubation (26. Audubon's 'Ornithological Biography,'
+vol. ii. p. 75; see also the 'Ibis,' vol. i. p. 268.), and would be thus
+almost equally exposed to danger; both sexes of many species have their
+heads of an equally bright crimson; in other species the difference
+between the sexes in the amount of scarlet is so slight that it can
+hardly make any appreciable difference in the danger incurred; and
+lastly, the colouring of the head in the two sexes often differs
+slightly in other ways.
+
+The cases, as yet given, of slight and graduated differences in colour
+between the males and females in the groups, in which as a general rule
+the sexes resemble each other, all relate to species which build domed
+or concealed nests. But similar gradations may likewise be observed in
+groups in which the sexes as a general rule resemble each other, but
+which build open nests.
+
+As I have before instanced the Australian parrots, so I may here
+instance, without giving any details, the Australian pigeons. (27.
+Gould's 'Handbook to the Birds of Australia,' vol. ii. pp. 109-149.) It
+deserves especial notice that in all these cases the slight differences
+in plumage between the sexes are of the same general nature as the
+occasionally greater differences. A good illustration of this fact has
+already been afforded by those kingfishers in which either the tail
+alone or the whole upper surface of the plumage differs in the same
+manner in the two sexes. Similar cases may be observed with parrots and
+pigeons. The differences in colour between the sexes of the same species
+are, also, of the same general nature as the differences in colour
+between the distinct species of the same group. For when in a group in
+which the sexes are usually alike, the male differs considerably from
+the female, he is not coloured in a quite new style. Hence we may infer
+that within the same group the special colours of both sexes when they
+are alike, and the colours of the male, when he differs slightly or even
+considerably from the female, have been in most cases determined by the
+same general cause; this being sexual selection.
+
+It is not probable, as has already been remarked, that differences in
+colour between the sexes, when very slight, can be of service to the
+female as a protection. Assuming, however, that they are of service,
+they might be thought to be cases of transition; but we have no reason
+to believe that many species at any one time are undergoing change.
+Therefore we can hardly admit that the numerous females which differ
+very slightly in colour from their males are now all commencing to
+become obscure for the sake of protection. Even if we consider somewhat
+more marked sexual differences, is it probable, for instance, that the
+head of the female chaffinch,--the crimson on the breast of the female
+bullfinch,--the green of the female greenfinch,--the crest of the female
+golden-crested wren, have all been rendered less bright by the slow
+process of selection for the sake of protection? I cannot think so; and
+still less with the slight differences between the sexes of those birds
+which build concealed nests. On the other hand, the differences in
+colour between the sexes, whether great or small, may to a large extent
+be explained on the principle of the successive variations, acquired by
+the males through sexual selection, having been from the first more or
+less limited in their transmission to the females. That the degree of
+limitation should differ in different species of the same group will not
+surprise any one who has studied the laws of inheritance, for they are
+so complex that they appear to us in our ignorance to be capricious in
+their action. (28. See remarks to this effect in 'Variation of Animals
+and Plants under Domestication,' vol. ii. chap. xii.)
+
+As far as I can discover there are few large groups of birds in which
+all the species have both sexes alike and brilliantly coloured, but
+I hear from Mr. Sclater, that this appears to be the case with the
+Musophagae or plantain-eaters. Nor do I believe that any large group
+exists in which the sexes of all the species are widely dissimilar
+in colour: Mr. Wallace informs me that the chatterers of S. America
+(Cotingidae) offer one of the best instances; but with some of the
+species, in which the male has a splendid red breast, the female
+exhibits some red on her breast; and the females of other species shew
+traces of the green and other colours of the males. Nevertheless we have
+a near approach to close sexual similarity or dissimilarity throughout
+several groups: and this, from what has just been said of the
+fluctuating nature of inheritance, is a somewhat surprising
+circumstance. But that the same laws should largely prevail with allied
+animals is not surprising. The domestic fowl has produced a great number
+of breeds and sub-breeds, and in these the sexes generally differ in
+plumage; so that it has been noticed as an unusual circumstance when
+in certain sub-breeds they resemble each other. On the other hand, the
+domestic pigeon has likewise produced a vast number of distinct breeds
+and sub-breeds, and in these, with rare exceptions, the two sexes are
+identically alike.
+
+Therefore if other species of Gallus and Columba were domesticated and
+varied, it would not be rash to predict that similar rules of sexual
+similarity and dissimilarity, depending on the form of transmission,
+would hold good in both cases. In like manner the same form of
+transmission has generally prevailed under nature throughout the same
+groups, although marked exceptions to this rule occur. Thus within the
+same family or even genus, the sexes may be identically alike, or very
+different in colour. Instances have already been given in the same
+genus, as with sparrows, fly-catchers, thrushes and grouse. In the
+family of pheasants the sexes of almost all the species are wonderfully
+dissimilar, but are quite alike in the eared pheasant or Crossoptilon
+auritum. In two species of Chloephaga, a genus of geese, the male cannot
+be distinguished from the females, except by size; whilst in two others,
+the sexes are so unlike that they might easily be mistaken for distinct
+species. (29. The 'Ibis,' vol. vi. 1864, p. 122.)
+
+The laws of inheritance can alone account for the following cases, in
+which the female acquires, late in life, certain characters proper to
+the male, and ultimately comes to resemble him more or less completely.
+Here protection can hardly have come into play. Mr. Blyth informs me
+that the females of Oriolus melanocephalus and of some allied species,
+when sufficiently mature to breed, differ considerably in plumage from
+the adult males; but after the second or third moults they differ only
+in their beaks having a slight greenish tinge. In the dwarf bitterns
+(Ardetta), according to the same authority, "the male acquires his final
+livery at the first moult, the female not before the third or fourth
+moult; in the meanwhile she presents an intermediate garb, which is
+ultimately exchanged for the same livery as that of the male." So again
+the female Falco peregrinus acquires her blue plumage more slowly
+than the male. Mr. Swinhoe states that with one of the Drongo shrikes
+(Dicrurus macrocercus) the male, whilst almost a nestling, moults his
+soft brown plumage and becomes of a uniform glossy greenish-black; but
+the female retains for a long time the white striae and spots on the
+axillary feathers; and does not completely assume the uniform black
+colour of the male for three years. The same excellent observer remarks
+that in the spring of the second year the female spoon-bill (Platalea)
+of China resembles the male of the first year, and that apparently it is
+not until the third spring that she acquires the same adult plumage as
+that possessed by the male at a much earlier age. The female Bombycilla
+carolinensis differs very little from the male, but the appendages,
+which like beads of red sealing-wax ornament the wing-feathers (30. When
+the male courts the female, these ornaments are vibrated, and "are shewn
+off to great advantage," on the outstretched wings: A. Leith Adams,
+'Field and Forest Rambles,' 1873, p. 153.), are not developed in her
+so early in life as in the male. In the male of an Indian parrakeet
+(Palaeornis javanicus) the upper mandible is coral-red from his earliest
+youth, but in the female, as Mr. Blyth has observed with caged and wild
+birds, it is at first black and does not become red until the bird is
+at least a year old, at which age the sexes resemble each other in all
+respects. Both sexes of the wild turkey are ultimately furnished with
+a tuft of bristles on the breast, but in two-year-old birds the tuft is
+about four inches long in the male and hardly apparent in the female;
+when, however, the latter has reached her fourth year, it is from four
+to five inches in length. (31. On Ardetta, Translation of Cuvier's
+'Regne Animal,' by Mr. Blyth, footnote, p. 159. On the Peregrine Falcon,
+Mr. Blyth, in Charlesworth's 'Mag. of Nat. Hist.' vol. i. 1837, p. 304.
+On Dicrurus, 'Ibis,' 1863, p. 44. On the Platalea, 'Ibis,' vol. vi.
+1864, p. 366. On the Bombycilla, Audubon's 'Ornitholog. Biography,' vol.
+i. p. 229. On the Palaeornis, see, also, Jerdon, 'Birds of India,' vol.
+i. p. 263. On the wild turkey, Audubon, ibid. vol. i. p. 15; but I hear
+from Judge Caton that in Illinois the female very rarely acquires a
+tuft. Analogous cases with the females of Petrocossyphus are given by
+Mr. R. Sharpe, 'Proceedings of the Zoological Society,' 1872, p. 496.)
+
+
+These cases must not be confounded with those where diseased or old
+females abnormally assume masculine characters, nor with those where
+fertile females, whilst young, acquire the characters of the male,
+through variation or some unknown cause. (32. Of these latter cases
+Mr. Blyth has recorded (Translation of Cuvier's 'Regne Animal,' p. 158)
+various instances with Lanius, Ruticilla, Linaria, and Anas. Audubon has
+also recorded a similar case ('Ornitholog. Biography,' vol. v. p. 519)
+with Pyranga aestiva.) But all these cases have so much in common that
+they depend, according to the hypothesis of pangenesis, on gemmules
+derived from each part of the male being present, though latent, in
+the female; their development following on some slight change in the
+elective affinities of her constituent tissues.
+
+A few words must be added on changes of plumage in relation to the
+season of the year. From reasons formerly assigned there can be little
+doubt that the elegant plumes, long pendant feathers, crests, etc., of
+egrets, herons, and many other birds, which are developed and retained
+only during the summer, serve for ornamental and nuptial purposes,
+though common to both sexes. The female is thus rendered more
+conspicuous during the period of incubation than during the winter; but
+such birds as herons and egrets would be able to defend themselves. As,
+however, plumes would probably be inconvenient and certainly of no use
+during the winter, it is possible that the habit of moulting twice in
+the year may have been gradually acquired through natural selection for
+the sake of casting off inconvenient ornaments during the winter. But
+this view cannot be extended to the many waders, whose summer and winter
+plumages differ very little in colour. With defenceless species, in
+which both sexes, or the males alone, become extremely conspicuous
+during the breeding-season,--or when the males acquire at this season
+such long wing or tail-feathers as to impede their flight, as with
+Cosmetornis and Vidua,--it certainly at first appears highly probable
+that the second moult has been gained for the special purpose of
+throwing off these ornaments. We must, however, remember that many
+birds, such as some of the Birds of Paradise, the Argus pheasant and
+peacock, do not cast their plumes during the winter; and it can hardly
+be maintained that the constitution of these birds, at least of the
+Gallinaceae, renders a double moult impossible, for the ptarmigan moults
+thrice in the year. (33. See Gould's 'Birds of Great Britain.') Hence
+it must be considered as doubtful whether the many species which moult
+their ornamental plumes or lose their bright colours during the winter,
+have acquired this habit on account of the inconvenience or danger which
+they would otherwise have suffered.
+
+I conclude, therefore, that the habit of moulting twice in the year was
+in most or all cases first acquired for some distinct purpose, perhaps
+for gaining a warmer winter covering; and that variations in the plumage
+occurring during the summer were accumulated through sexual selection,
+and transmitted to the offspring at the same season of the year; that
+such variations were inherited either by both sexes or by the males
+alone, according to the form of inheritance which prevailed. This
+appears more probable than that the species in all cases originally
+tended to retain their ornamental plumage during the winter, but
+were saved from this through natural selection, resulting from the
+inconvenience or danger thus caused.
+
+I have endeavoured in this chapter to shew that the arguments are not
+trustworthy in favour of the view that weapons, bright colours,
+and various ornaments, are now confined to the males owing to the
+conversion, by natural selection, of the equal transmission of
+characters to both sexes, into transmission to the male sex alone. It
+is also doubtful whether the colours of many female birds are due to the
+preservation, for the sake of protection, of variations which were from
+the first limited in their transmission to the female sex. But it will
+be convenient to defer any further discussion on this subject until I
+treat, in the following chapter, of the differences in plumage between
+the young and old.
+
+
+CHAPTER XVI.
+
+BIRDS--concluded.
+
+The immature plumage in relation to the character of the plumage in both
+sexes when adult--Six classes of cases--Sexual differences between the
+males of closely-allied or representative species--The female assuming
+the characters of the male--Plumage of the young in relation to the
+summer and winter plumage of the adults--On the increase of beauty in
+the birds of the world--Protective colouring--Conspicuously coloured
+birds--Novelty appreciated--Summary of the four chapters on Birds.
+
+We must now consider the transmission of characters, as limited by
+age, in reference to sexual selection. The truth and importance of
+the principle of inheritance at corresponding ages need not here be
+discussed, as enough has already been said on the subject. Before giving
+the several rather complex rules or classes of cases, under which the
+differences in plumage between the young and the old, as far as known to
+me, may be included, it will be well to make a few preliminary remarks.
+
+With animals of all kinds when the adults differ in colour from the
+young, and the colours of the latter are not, as far as we can see,
+of any special service, they may generally be attributed, like various
+embryological structures, to the retention of a former character. But
+this view can be maintained with confidence, only when the young of
+several species resemble each other closely, and likewise resemble other
+adult species belonging to the same group; for the latter are the living
+proofs that such a state of things was formerly possible. Young lions
+and pumas are marked with feeble stripes or rows of spots, and as many
+allied species both young and old are similarly marked, no believer
+in evolution will doubt that the progenitor of the lion and puma was
+a striped animal, and that the young have retained vestiges of the
+stripes, like the kittens of black cats, which are not in the least
+striped when grown up. Many species of deer, which when mature are not
+spotted, are whilst young covered with white spots, as are likewise some
+few species in the adult state. So again the young in the whole family
+of pigs (Suidae), and in certain rather distantly allied animals, such
+as the tapir, are marked with dark longitudinal stripes; but here we
+have a character apparently derived from an extinct progenitor, and now
+preserved by the young alone. In all such cases the old have had their
+colours changed in the course of time, whilst the young have remained
+but little altered, and this has been effected through the principle of
+inheritance at corresponding ages.
+
+This same principle applies to many birds belonging to various groups,
+in which the young closely resemble each other, and differ much from
+their respective adult parents. The young of almost all the Gallinaceae,
+and of some distantly allied birds such as ostriches, are covered with
+longitudinally striped down; but this character points back to a state
+of things so remote that it hardly concerns us. Young cross-bills
+(Loxia) have at first straight beaks like those of other finches, and
+in their immature striated plumage they resemble the mature red-pole and
+female siskin, as well as the young of the goldfinch, greenfinch,
+and some other allied species. The young of many kinds of buntings
+(Emberiza) resemble one another, and likewise the adult state of the
+common bunting, E. miliaria. In almost the whole large group of thrushes
+the young have their breasts spotted--a character which is retained
+throughout life by many species, but is quite lost by others, as by the
+Turdus migratorius. So again with many thrushes, the feathers on the
+back are mottled before they are moulted for the first time, and this
+character is retained for life by certain eastern species. The young of
+many species of shrikes (Lanius), of some woodpeckers, and of an Indian
+pigeon (Chalcophaps indicus), are transversely striped on the under
+surface; and certain allied species or whole genera are similarly
+marked when adult. In some closely-allied and resplendent Indian cuckoos
+(Chrysococcyx), the mature species differ considerably from one another
+in colour, but the young cannot be distinguished. The young of an Indian
+goose (Sarkidiornis melanonotus) closely resemble in plumage an allied
+genus, Dendrocygna, when mature. (1. In regard to thrushes, shrikes, and
+woodpeckers, see Mr. Blyth, in Charlesworth's 'Mag. of Nat. Hist.' vol.
+i. 1837, p. 304; also footnote to his translation of Cuvier's 'Regne
+Animal,' p. 159. I give the case of Loxia on Mr. Blyth's information.
+On thrushes, see also Audubon, 'Ornith. Biog.' vol. ii. p. 195. On
+Chrysococcyx and Chalcophaps, Blyth, as quoted in Jerdon's 'Birds of
+India,' vol. iii. p. 485. On Sarkidiornis, Blyth, in 'Ibis,' 1867, p.
+175.) Similar facts will hereafter be given in regard to certain herons.
+Young black-grouse (Tetrao tetrix) resemble the young as well as the old
+of certain other species, for instance the red-grouse or T. scoticus.
+Finally, as Mr. Blyth, who has attended closely to this subject, has
+well remarked, the natural affinities of many species are best exhibited
+in their immature plumage; and as the true affinities of all organic
+beings depend on their descent from a common progenitor, this remark
+strongly confirms the belief that the immature plumage approximately
+shews us the former or ancestral condition of the species.
+
+Although many young birds, belonging to various families, thus give us
+a glimpse of the plumage of their remote progenitors, yet there are many
+other birds, both dull-coloured and bright-coloured, in which the young
+closely resemble their parents. In such cases the young of the different
+species cannot resemble each other more closely than do the parents; nor
+can they strikingly resemble allied forms when adult. They give us but
+little insight into the plumage of their progenitors, excepting in so
+far that, when the young and the old are coloured in the same general
+manner throughout a whole group of species, it is probable that their
+progenitors were similarly coloured.
+
+We may now consider the classes of cases, under which the differences
+and resemblances between the plumage of the young and the old, in both
+sexes or in one sex alone, may be grouped. Rules of this kind were first
+enounced by Cuvier; but with the progress of knowledge they require some
+modification and amplification. This I have attempted to do, as far as
+the extreme complexity of the subject permits, from information derived
+from various sources; but a full essay on this subject by some competent
+ornithologist is much needed. In order to ascertain to what extent each
+rule prevails, I have tabulated the facts given in four great works,
+namely, by Macgillivray on the birds of Britain, Audubon on those
+of North America, Jerdon on those of India, and Gould on those of
+Australia. I may here premise, first, that the several cases or rules
+graduate into each other; and secondly, that when the young are said to
+resemble their parents, it is not meant that they are identically alike,
+for their colours are almost always less vivid, and the feathers are
+softer and often of a different shape.
+
+RULES OR CLASSES OF CASES.
+
+I. When the adult male is more beautiful or conspicuous than the adult
+female, the young of both sexes in their first plumage closely
+resemble the adult female, as with the common fowl and peacock; or, as
+occasionally occurs, they resemble her much more closely than they do
+the adult male.
+
+II. When the adult female is more conspicuous than the adult male, as
+sometimes though rarely occurs, the young of both sexes in their first
+plumage resemble the adult male.
+
+III. When the adult male resembles the adult female, the young of both
+sexes have a peculiar first plumage of their own, as with the robin.
+
+IV. When the adult male resembles the adult female, the young of
+both sexes in their first plumage resemble the adults, as with the
+kingfisher, many parrots, crows, hedge-warblers.
+
+V. When the adults of both sexes have a distinct winter and summer
+plumage, whether or not the male differs from the female, the young
+resemble the adults of both sexes in their winter dress, or much more
+rarely in their summer dress, or they resemble the females alone. Or
+the young may have an intermediate character; or again they may differ
+greatly from the adults in both their seasonal plumages.
+
+VI. In some few cases the young in their first plumage differ from each
+other according to sex; the young males resembling more or less closely
+the adult males, and the young females more or less closely the adult
+females.
+
+CLASS I.
+
+In this class, the young of both sexes more or less closely resemble the
+adult female, whilst the adult male differs from the adult female, often
+in the most conspicuous manner. Innumerable instances in all Orders
+could be given; it will suffice to call to mind the common pheasant,
+duck, and house-sparrow. The cases under this class graduate into
+others. Thus the two sexes when adult may differ so slightly, and the
+young so slightly from the adults, that it is doubtful whether such
+cases ought to come under the present, or under the third or fourth
+classes. So again the young of the two sexes, instead of being quite
+alike, may differ in a slight degree from each other, as in our sixth
+class. These transitional cases, however, are few, or at least are not
+strongly pronounced, in comparison with those which come strictly under
+the present class.
+
+The force of the present law is well shewn in those groups, in which, as
+a general rule, the two sexes and the young are all alike; for when
+in these groups the male does differ from the female, as with certain
+parrots, kingfishers, pigeons, etc., the young of both sexes resemble
+the adult female. (2. See, for instance, Mr. Gould's account ('Handbook
+to the Birds of Australia,' vol. i. p. 133) of Cyanalcyon (one of the
+Kingfishers), in which, however, the young male, though resembling the
+adult female, is less brilliantly coloured. In some species of Dacelo
+the males have blue tails, and the females brown ones; and Mr. R.B.
+Sharpe informs me that the tail of the young male of D. gaudichaudi is
+at first brown. Mr. Gould has described (ibid. vol. ii. pp. 14, 20, 37)
+the sexes and the young of certain black Cockatoos and of the King Lory,
+with which the same rule prevails. Also Jerdon ('Birds of India,' vol.
+i. p. 260) on the Palaeornis rosa, in which the young are more like the
+female than the male. See Audubon ('Ornithological Biography,' vol. ii.
+p. 475) on the two sexes and the young of Columba passerina.) We see the
+same fact exhibited still more clearly in certain anomalous cases; thus
+the male of Heliothrix auriculata (one of the humming-birds) differs
+conspicuously from the female in having a splendid gorget and fine
+ear-tufts, but the female is remarkable from having a much longer tail
+than that of the male; now the young of both sexes resemble (with the
+exception of the breast being spotted with bronze) the adult female in
+all other respects, including the length of her tail, so that the tail
+of the male actually becomes shorter as he reaches maturity, which is a
+most unusual circumstance. (3. I owe this information to Mr. Gould, who
+shewed me the specimens; see also his 'Introduction to the Trochilidae,'
+1861, p. 120.) Again, the plumage of the male goosander (Mergus
+merganser) is more conspicuously coloured than that of the female, with
+the scapular and secondary wing-feathers much longer; but differently
+from what occurs, as far as I know, in any other bird, the crest of
+the adult male, though broader than that of the female, is considerably
+shorter, being only a little above an inch in length; the crest of the
+female being two and a half inches long. Now the young of both sexes
+entirely resemble the adult female, so that their crests are actually
+of greater length, though narrower, than in the adult male. (4.
+Macgillivray, 'Hist. Brit. Birds,' vol. v. pp. 207-214.)
+
+When the young and the females closely resemble each other and both
+differ from the males, the most obvious conclusion is that the males
+alone have been modified. Even in the anomalous cases of the Heliothrix
+and Mergus, it is probable that originally both adult sexes were
+furnished--the one species with a much elongated tail, and the other
+with a much elongated crest--these characters having since been
+partially lost by the adult males from some unexplained cause, and
+transmitted in their diminished state to their male offspring alone,
+when arrived at the corresponding age of maturity. The belief that
+in the present class the male alone has been modified, as far as the
+differences between the male and the female together with her young are
+concerned, is strongly supported by some remarkable facts recorded by
+Mr. Blyth (5. See his admirable paper in the 'Journal of the Asiatic
+Soc. of Bengal,' vol. xix. 1850, p. 223; see also Jerdon, 'Birds of
+India,' vol. i. introduction, p. xxix. In regard to Tanysiptera, Prof.
+Schlegel told Mr. Blyth that he could distinguish several distinct
+races, solely by comparing the adult males.), with respect to
+closely-allied species which represent each other in distinct countries.
+For with several of these representative species the adult males have
+undergone a certain amount of change and can be distinguished;
+the females and the young from the distinct countries being
+indistinguishable, and therefore absolutely unchanged. This is the
+case with certain Indian chats (Thamnobia), with certain honey-suckers
+(Nectarinia), shrikes (Tephrodornis), certain kingfishers (Tanysiptera),
+Kalij pheasants (Gallophasis), and tree-partridges (Arboricola).
+
+In some analogous cases, namely with birds having a different summer
+and winter plumage, but with the two sexes nearly alike, certain
+closely-allied species can easily be distinguished in their summer or
+nuptial plumage, yet are indistinguishable in their winter as well as in
+their immature plumage. This is the case with some of the closely-allied
+Indian wagtails or Motacillae. Mr. Swinhoe (6. See also Mr. Swinhoe, in
+'Ibis,' July 1863, p. 131; and a previous paper, with an extract from
+a note by Mr. Blyth, in 'Ibis,' January, 1861, p. 25.) informs me that
+three species of Ardeola, a genus of herons, which represent one another
+on separate continents, are "most strikingly different" when ornamented
+with their summer plumes, but are hardly, if at all, distinguishable
+during the winter. The young also of these three species in their
+immature plumage closely resemble the adults in their winter dress.
+This case is all the more interesting, because with two other species of
+Ardeola both sexes retain, during the winter and summer, nearly the same
+plumage as that possessed by the three first species during the winter
+and in their immature state; and this plumage, which is common to
+several distinct species at different ages and seasons, probably shews
+us how the progenitors of the genus were coloured. In all these cases,
+the nuptial plumage which we may assume was originally acquired by the
+adult males during the breeding-season, and transmitted to the adults
+of both sexes at the corresponding season, has been modified, whilst the
+winter and immature plumages have been left unchanged.
+
+The question naturally arises, how is it that in these latter cases the
+winter plumage of both sexes, and in the former cases the plumage of the
+adult females, as well as the immature plumage of the young, have not
+been at all affected? The species which represent each other in distinct
+countries will almost always have been exposed to somewhat different
+conditions, but we can hardly attribute to this action the modification
+of the plumage in the males alone, seeing that the females and the
+young, though similarly exposed, have not been affected. Hardly any fact
+shews us more clearly how subordinate in importance is the direct action
+of the conditions of life, in comparison with the accumulation through
+selection of indefinite variations, than the surprising difference
+between the sexes of many birds; for both will have consumed the same
+food, and have been exposed to the same climate. Nevertheless we are not
+precluded from believing that in the course of time new conditions
+may produce some direct effect either on both sexes, or from their
+constitutional differences chiefly on one sex. We see only that this
+is subordinate in importance to the accumulated results of selection.
+Judging, however, from a wide-spread analogy, when a species
+migrates into a new country (and this must precede the formation of
+representative species), the changed conditions to which they will
+almost always have been exposed will cause them to undergo a certain
+amount of fluctuating variability. In this case sexual selection, which
+depends on an element liable to change--the taste or admiration of the
+female--will have had new shades of colour or other differences to act
+on and accumulate; and as sexual selection is always at work, it
+would (from what we know of the results on domestic animals of man's
+unintentional selection), be surprising if animals inhabiting separate
+districts, which can never cross and thus blend their newly-acquired
+characters, were not, after a sufficient lapse of time, differently
+modified. These remarks likewise apply to the nuptial or summer plumage,
+whether confined to the males, or common to both sexes.
+
+Although the females of the above closely-allied or representative
+species, together with their young, differ hardly at all from one
+another, so that the males alone can be distinguished, yet the females
+of most species within the same genus obviously differ from each other.
+The differences, however, are rarely as great as between the males. We
+see this clearly in the whole family of the Gallinaceae: the females,
+for instance, of the common and Japan pheasant, and especially of
+the gold and Amherst pheasant --of the silver pheasant and the wild
+fowl--resemble one another very closely in colour, whilst the males
+differ to an extraordinary degree. So it is with the females of most of
+the Cotingidae, Fringillidae, and many other families. There can indeed
+be no doubt that, as a general rule, the females have been less
+modified than the males. Some few birds, however, offer a singular
+and inexplicable exception; thus the females of Paradisea apoda and P.
+papuana differ from each other more than do their respective males (7.
+Wallace, 'The Malay Archipelago,' vol. ii. 1869, p. 394.); the female
+of the latter species having the under surface pure white, whilst
+the female P. apoda is deep brown beneath. So, again, as I hear from
+Professor Newton, the males of two species of Oxynotus (shrikes), which
+represent each other in the islands of Mauritius and Bourbon (8. These
+species are described with coloured figures, by M. F. Pollen, in 'Ibis,'
+1866, p. 275.), differ but little in colour, whilst the females differ
+much. In the Bourbon species the female appears to have partially
+retained an immature condition of plumage, for at first sight she "might
+be taken for the young of the Mauritian species." These differences may
+be compared with those inexplicable ones, which occur independently of
+man's selection in certain sub-breeds of the game-fowl, in which
+the females are very different, whilst the males can hardly be
+distinguished. (9. 'Variation of Animals,' etc., vol. i. p. 251.)
+
+As I account so largely by sexual selection for the differences between
+the males of allied species, how can the differences between the females
+be accounted for in all ordinary cases? We need not here consider the
+species which belong to distinct genera; for with these, adaptation to
+different habits of life, and other agencies, will have come into play.
+In regard to the differences between the females within the same genus,
+it appears to me almost certain, after looking through various large
+groups, that the chief agent has been the greater or less transference
+to the female of the characters acquired by the males through sexual
+selection. In the several British finches, the two sexes differ either
+very slightly or considerably; and if we compare the females of the
+greenfinch, chaffinch, goldfinch, bullfinch, crossbill, sparrow, etc.,
+we shall see that they differ from one another chiefly in the points in
+which they partially resemble their respective males; and the colours
+of the males may safely be attributed to sexual selection. With many
+gallinaceous species the sexes differ to an extreme degree, as with the
+peacock, pheasant, and fowl, whilst with other species there has been a
+partial or even complete transference of character from the male to the
+female. The females of the several species of Polyplectron exhibit in
+a dim condition, and chiefly on the tail, the splendid ocelli of their
+males. The female partridge differs from the male only in the red mark
+on her breast being smaller; and the female wild turkey only in
+her colours being much duller. In the guinea-fowl the two sexes are
+indistinguishable. There is no improbability in the plain, though
+peculiarly spotted plumage of this latter bird having been acquired
+through sexual selection by the males, and then transmitted to
+both sexes; for it is not essentially different from the much more
+beautifully spotted plumage, characteristic of the males alone of the
+Tragopan pheasants.
+
+It should be observed that, in some instances, the transference of
+characters from the male to the female has been effected apparently at
+a remote period, the male having subsequently undergone great changes,
+without transferring to the female any of his later-gained characters.
+For instance, the female and the young of the black-grouse (Tetrao
+tetrix) resemble pretty closely both sexes and the young of the
+red-grouse (T. scoticus); and we may consequently infer that the
+black-grouse is descended from some ancient species, of which both sexes
+were coloured in nearly the same manner as the red-grouse. As both
+sexes of this latter species are more distinctly barred during the
+breeding-season than at any other time, and as the male differs slightly
+from the female in his more strongly-pronounced red and brown tints (10.
+Macgillivray, 'History of British Birds,' vol. i. pp. 172-174.), we may
+conclude that his plumage has been influenced by sexual selection,
+at least to a certain extent. If so, we may further infer that nearly
+similar plumage of the female black-grouse was similarly produced at
+some former period. But since this period the male black-grouse has
+acquired his fine black plumage, with his forked and outwardly-curled
+tail-feathers; but of these characters there has hardly been any
+transference to the female, excepting that she shews in her tail a trace
+of the curved fork.
+
+We may therefore conclude that the females of distinct though allied
+species have often had their plumage rendered more or less different by
+the transference in various degrees of characters acquired by the males
+through sexual selection, both during former and recent times. But it
+deserves especial attention that brilliant colours have been transferred
+much more rarely than other tints. For instance, the male of the
+red-throated blue-breast (Cyanecula suecica) has a rich blue breast,
+including a sub-triangular red mark; now marks of nearly the same shape
+have been transferred to the female, but the central space is fulvous
+instead of red, and is surrounded by mottled instead of blue feathers.
+The Gallinaceae offer many analogous cases; for none of the species,
+such as partridges, quails, guinea-fowls, etc., in which the colours of
+the plumage have been largely transferred from the male to the female,
+are brilliantly coloured. This is well exemplified with the pheasants,
+in which the male is generally so much more brilliant than the female;
+but with the Eared and Cheer pheasants (Crossoptilon auritum and
+Phasianus wallichii) the sexes closely resemble each other and their
+colours are dull. We may go so far as to believe that if any part of
+the plumage in the males of these two pheasants had been brilliantly
+coloured, it would not have been transferred to the females. These facts
+strongly support Mr. Wallace's view that with birds which are exposed to
+much danger during incubation, the transference of bright colours from
+the male to the female has been checked through natural selection. We
+must not, however, forget that another explanation, before given, is
+possible; namely, that the males which varied and became bright, whilst
+they were young and inexperienced, would have been exposed to much
+danger, and would generally have been destroyed; the older and more
+cautious males, on the other hand, if they varied in a like manner,
+would not only have been able to survive, but would have been favoured
+in their rivalry with other males. Now variations occurring late in life
+tend to be transmitted exclusively to the same sex, so that in this case
+extremely bright tints would not have been transmitted to the females.
+On the other hand, ornaments of a less conspicuous kind, such as
+those possessed by the Eared and Cheer pheasants, would not have been
+dangerous, and if they appeared during early youth, would generally have
+been transmitted to both sexes.
+
+In addition to the effects of the partial transference of characters
+from the males to the females, some of the differences between the
+females of closely allied species may be attributed to the direct or
+definite action of the conditions of life. (11. See, on this
+subject, chap. xxiii. in the 'Variation of Animals and Plants under
+Domestication.') With the males, any such action would generally have
+been masked by the brilliant colours gained through sexual selection;
+but not so with the females. Each of the endless diversities in plumage
+which we see in our domesticated birds is, of course, the result of some
+definite cause; and under natural and more uniform conditions, some one
+tint, assuming that it was in no way injurious, would almost certainly
+sooner or later prevail. The free intercrossing of the many individuals
+belonging to the same species would ultimately tend to make any change
+of colour, thus induced, uniform in character.
+
+No one doubts that both sexes of many birds have had their colours
+adapted for the sake of protection; and it is possible that the females
+alone of some species may have been modified for this end. Although it
+would be a difficult, perhaps an impossible process, as shewn in the
+last chapter, to convert one form of transmission into another through
+selection, there would not be the least difficulty in adapting
+the colours of the female, independently of those of the male, to
+surrounding objects, through the accumulation of variations which were
+from the first limited in their transmission to the female sex. If the
+variations were not thus limited, the bright tints of the male would
+be deteriorated or destroyed. Whether the females alone of many species
+have been thus specially modified, is at present very doubtful. I wish
+I could follow Mr. Wallace to the full extent; for the admission would
+remove some difficulties. Any variations which were of no service to the
+female as a protection would be at once obliterated, instead of being
+lost simply by not being selected, or from free intercrossing, or from
+being eliminated when transferred to the male and in any way injurious
+to him. Thus the plumage of the female would be kept constant in
+character. It would also be a relief if we could admit that the obscure
+tints of both sexes of many birds had been acquired and preserved for
+the sake of protection,--for example, of the hedge-warbler or kitty-wren
+(Accentor modularis and Troglodytes vulgaris), with respect to which we
+have no sufficient evidence of the action of sexual selection. We ought,
+however, to be cautious in concluding that colours which appear to us
+dull, are not attractive to the females of certain species; we should
+bear in mind such cases as that of the common house-sparrow, in which
+the male differs much from the female, but does not exhibit any bright
+tints. No one probably will dispute that many gallinaceous birds which
+live on the open ground, have acquired their present colours, at least
+in part, for the sake of protection. We know how well they are thus
+concealed; we know that ptarmigans, whilst changing from their winter to
+their summer plumage, both of which are protective, suffer greatly from
+birds of prey. But can we believe that the very slight differences in
+tints and markings between, for instance, the female black-grouse
+and red-grouse serve as a protection? Are partridges, as they are now
+coloured, better protected than if they had resembled quails? Do the
+slight differences between the females of the common pheasant, the Japan
+and gold pheasants, serve as a protection, or might not their plumages
+have been interchanged with impunity? From what Mr. Wallace has observed
+of the habits of certain gallinaceous birds in the East, he thinks that
+such slight differences are beneficial. For myself, I will only say that
+I am not convinced.
+
+Formerly when I was inclined to lay much stress on protection as
+accounting for the duller colours of female birds, it occurred to me
+that possibly both sexes and the young might aboriginally have been
+equally bright coloured; but that subsequently, the females from
+the danger incurred during incubation, and the young from being
+inexperienced, had been rendered dull as a protection. But this view
+is not supported by any evidence, and is not probable; for we thus
+in imagination expose during past times the females and the young to
+danger, from which it has subsequently been necessary to shield their
+modified descendants. We have, also, to reduce, through a gradual
+process of selection, the females and the young to almost exactly the
+same tints and markings, and to transmit them to the corresponding sex
+and period of life. On the supposition that the females and the young
+have partaken during each stage of the process of modification of a
+tendency to be as brightly coloured as the males, it is also a somewhat
+strange fact that the females have never been rendered dull-coloured
+without the young participating in the same change; for there are no
+instances, as far as I can discover, of species with the females dull
+and the young bright coloured. A partial exception, however, is offered
+by the young of certain woodpeckers, for they have "the whole upper part
+of the head tinged with red," which afterwards either decreases into a
+mere circular red line in the adults of both sexes, or quite disappears
+in the adult females. (12. Audubon, 'Ornith. Biography,' vol. i. p. 193.
+Macgillivray, 'History of British Birds,' vol. iii. p. 85. See also the
+case before given of Indopicus carlotta.)
+
+Finally, with respect to our present class of cases, the most probable
+view appears to be that successive variations in brightness or in other
+ornamental characters, occurring in the males at a rather late period
+of life have alone been preserved; and that most or all of these
+variations, owing to the late period of life at which they appeared,
+have been from the first transmitted only to the adult male offspring.
+Any variations in brightness occurring in the females or in the young,
+would have been of no service to them, and would not have been selected;
+and moreover, if dangerous, would have been eliminated. Thus the females
+and the young will either have been left unmodified, or (as is much
+more common) will have been partially modified by receiving through
+transference from the males some of his successive variations. Both
+sexes have perhaps been directly acted on by the conditions of life
+to which they have long been exposed: but the females from not being
+otherwise much modified, will best exhibit any such effects. These
+changes and all others will have been kept uniform by the free
+intercrossing of many individuals. In some cases, especially with
+ground birds, the females and the young may possibly have been modified,
+independently of the males, for the sake of protection, so as to have
+acquired the same dull-coloured plumage.
+
+CLASS II.
+
+WHEN THE ADULT FEMALE IS MORE CONSPICUOUS THAN THE ADULT MALE, THE YOUNG
+OF BOTH SEXES IN THEIR FIRST PLUMAGE RESEMBLE THE ADULT MALE.
+
+This class is exactly the reverse of the last, for the females are here
+brighter coloured or more conspicuous than the males; and the young,
+as far as they are known, resemble the adult males instead of the adult
+females. But the difference between the sexes is never nearly so great
+as with many birds in the first class, and the cases are comparatively
+rare. Mr. Wallace, who first called attention to the singular relation
+which exists between the less bright colours of the males and their
+performing the duties of incubation, lays great stress on this point
+(13. 'Westminster Review,' July 1867, and A. Murray, 'Journal of
+Travel,' 1868, p. 83.), as a crucial test that obscure colours have
+been acquired for the sake of protection during the period of nesting.
+A different view seems to me more probable. As the cases are curious and
+not numerous, I will briefly give all that I have been able to find.
+
+In one section of the genus Turnix, quail-like birds, the female is
+invariably larger than the male (being nearly twice as large in one of
+the Australian species), and this is an unusual circumstance with
+the Gallinaceae. In most of the species the female is more distinctly
+coloured and brighter than the male (14. For the Australian species, see
+Gould's 'Handbook,' etc., vol. ii. pp. 178, 180, 186, and 188. In the
+British Museum specimens of the Australian Plain-wanderer (Pedionomus
+torquatus) may be seen, shewing similar sexual differences.), but in
+some few species the sexes are alike. In Turnix taigoor of India the
+male "wants the black on the throat and neck, and the whole tone of the
+plumage is lighter and less pronounced than that of the female." The
+female appears to be noisier, and is certainly much more pugnacious than
+the male; so that the females and not the males are often kept by the
+natives for fighting, like game-cocks. As male birds are exposed by the
+English bird-catchers for a decoy near a trap, in order to catch other
+males by exciting their rivalry, so the females of this Turnix are
+employed in India. When thus exposed the females soon begin their "loud
+purring call, which can be heard a long way off, and any females within
+ear-shot run rapidly to the spot, and commence fighting with the caged
+bird." In this way from twelve to twenty birds, all breeding females,
+may be caught in the course of a single day. The natives assert that the
+females after laying their eggs associate in flocks, and leave the males
+to sit on them. There is no reason to doubt the truth of this assertion,
+which is supported by some observations made in China by Mr. Swinhoe.
+(15. Jerdon, 'Birds of India,' vol. iii. p. 596. Mr. Swinhoe, in 'Ibis,'
+1865, p. 542; 1866, pp. 131, 405.) Mr. Blyth believes, that the young of
+both sexes resemble the adult male.
+
+[Fig. 62. Rhynchaea capensis (from Brehm).]
+
+The females of the three species of Painted Snipes (Rhynchaea, Fig. 62)
+"are not only larger but much more richly coloured than the males." (16.
+Jerdon, 'Birds of India,' vol. iii. p. 677.) With all other birds in
+which the trachea differs in structure in the two sexes it is more
+developed and complex in the male than in the female; but in the
+Rhynchaea australis it is simple in the male, whilst in the female it
+makes four distinct convolutions before entering the lungs. (17. Gould's
+'Handbook to the Birds of Australia,' vol. ii. p. 275.) The female
+therefore of this species has acquired an eminently masculine character.
+Mr. Blyth ascertained, by examining many specimens, that the trachea is
+not convoluted in either sex of R. bengalensis, which species resembles
+R. australis so closely, that it can hardly be distinguished except by
+its shorter toes. This fact is another striking instance of the law that
+secondary sexual characters are often widely different in closely-allied
+forms, though it is a very rare circumstance when such differences
+relate to the female sex. The young of both sexes of R. bengalensis
+in their first plumage are said to resemble the mature male. (18. 'The
+Indian Field,' Sept. 1858, p. 3.) There is also reason to believe that
+the male undertakes the duty of incubation, for Mr. Swinhoe (19.
+'Ibis,' 1866, p. 298.) found the females before the close of the summer
+associated in flocks, as occurs with the females of the Turnix.
+
+The females of Phalaropus fulicarius and P. hyperboreus are larger, and
+in their summer plumage "more gaily attired than the males." But
+the difference in colour between the sexes is far from conspicuous.
+According to Professor Steenstrup, the male alone of P. fulicarius
+undertakes the duty of incubation; this is likewise shewn by the state
+of his breast-feathers during the breeding-season. The female of the
+dotterel plover (Eudromias morinellus) is larger than the male, and has
+the red and black tints on the lower surface, the white crescent on the
+breast, and the stripes over the eyes, more strongly pronounced. The
+male also takes at least a share in hatching the eggs; but the female
+likewise attends to the young. (20. For these several statements, see
+Mr. Gould's 'Birds of Great Britain.' Prof. Newton informs me that he
+has long been convinced, from his own observations and from those of
+others, that the males of the above-named species take either the whole
+or a large share of the duties of incubation, and that they "shew
+much greater devotion towards their young, when in danger, than do the
+females." So it is, as he informs me, with Limosa lapponica and some
+few other Waders, in which the females are larger and have more strongly
+contrasted colours than the males.) I have not been able to discover
+whether with these species the young resemble the adult males more
+closely than the adult females; for the comparison is somewhat difficult
+to make on account of the double moult.
+
+Turning now to the ostrich Order: the male of the common cassowary
+(Casuarius galeatus) would be thought by any one to be the female, from
+his smaller size and from the appendages and naked skin about his head
+being much less brightly coloured; and I am informed by Mr. Bartlett
+that in the Zoological Gardens, it is certainly the male alone who
+sits on the eggs and takes care of the young. (21. The natives of Ceram
+(Wallace, 'Malay Archipelago,' vol. ii. p. 150) assert that the male and
+female sit alternately on the eggs; but this assertion, as Mr. Bartlett
+thinks, may be accounted for by the female visiting the nest to lay her
+eggs.) The female is said by Mr. T.W. Wood (22. The 'Student,' April
+1870, p. 124.) to exhibit during the breeding-season a most pugnacious
+disposition; and her wattles then become enlarged and more brilliantly
+coloured. So again the female of one of the emus (Dromoeus irroratus) is
+considerably larger than the male, and she possesses a slight top-knot,
+but is otherwise indistinguishable in plumage. She appears, however, "to
+have greater power, when angry or otherwise excited, of erecting, like
+a turkey-cock, the feathers of her neck and breast. She is usually the
+more courageous and pugilistic. She makes a deep hollow guttural
+boom especially at night, sounding like a small gong. The male has a
+slenderer frame and is more docile, with no voice beyond a suppressed
+hiss when angry, or a croak." He not only performs the whole duty of
+incubation, but has to defend the young from their mother; "for as soon
+as she catches sight of her progeny she becomes violently agitated, and
+notwithstanding the resistance of the father appears to use her utmost
+endeavours to destroy them. For months afterwards it is unsafe to put
+the parents together, violent quarrels being the inevitable result, in
+which the female generally comes off conqueror." (23. See the excellent
+account of the habits of this bird under confinement, by Mr. A.W.
+Bennett, in 'Land and Water,' May 1868, p. 233.) So that with this emu
+we have a complete reversal not only of the parental and incubating
+instincts, but of the usual moral qualities of the two sexes; the
+females being savage, quarrelsome, and noisy, the males gentle and good.
+The case is very different with the African ostrich, for the male is
+somewhat larger than the female and has finer plumes with more strongly
+contrasted colours; nevertheless he undertakes the whole duty of
+incubation. (24. Mr. Sclater, on the incubation of the Struthiones,
+'Proc. Zool. Soc.' June 9, 1863. So it is with the Rhea darwinii:
+Captain Musters says ('At Home with the Patagonians,' 1871, p. 128),
+that the male is larger, stronger and swifter than the female, and of
+slightly darker colours; yet he takes sole charge of the eggs and of the
+young, just as does the male of the common species of Rhea.)
+
+I will specify the few other cases known to me, in which the female is
+more conspicuously coloured than the male, although nothing is known
+about the manner of incubation. With the carrion-hawk of the Falkland
+Islands (Milvago leucurus) I was much surprised to find by dissection
+that the individuals, which had all their tints strongly pronounced,
+with the cere and legs orange-coloured, were the adult females; whilst
+those with duller plumage and grey legs were the males or the young. In
+an Australian tree-creeper (Climacteris erythrops) the female differs
+from the male in "being adorned with beautiful, radiated, rufous
+markings on the throat, the male having this part quite plain." Lastly,
+in an Australian night-jar "the female always exceeds the male in size
+and in the brilliance of her tints; the males, on the other hand, have
+two white spots on the primaries more conspicuous than in the female."
+(25. For the Milvago, see 'Zoology of the Voyage of the "Beagle,"
+Birds,' 1841, p. 16. For the Climacteris and night-jar (Eurostopodus),
+see Gould's 'Handbook to the Birds of Australia,' vol. i. pp. 602
+and 97. The New Zealand shieldrake (Tadorna variegata) offers a quite
+anomalous case; the head of the female is pure white, and her back is
+redder than that of the male; the head of the male is of a rich
+dark bronzed colour, and his back is clothed with finely pencilled
+slate-coloured feathers, so that altogether he may be considered as the
+more beautiful of the two. He is larger and more pugnacious than the
+female, and does not sit on the eggs. So that in all these respects
+this species comes under our first class of cases; but Mr. Sclater
+('Proceedings of the Zoological Society,' 1866, p. 150) was much
+surprised to observe that the young of both sexes, when about three
+months old, resembled in their dark heads and necks the adult males,
+instead of the adult females; so that it would appear in this case that
+the females have been modified, whilst the males and the young have
+retained a former state of plumage.)
+
+We thus see that the cases in which female birds are more conspicuously
+coloured than the males, with the young in their immature plumage
+resembling the adult males instead of the adult females, as in the
+previous class, are not numerous, though they are distributed in
+various Orders. The amount of difference, also, between the sexes is
+incomparably less than that which frequently occurs in the last class;
+so that the cause of the difference, whatever it may have been, has here
+acted on the females either less energetically or less persistently than
+on the males in the last class. Mr. Wallace believes that the males have
+had their colours rendered less conspicuous for the sake of protection
+during the period of incubation; but the difference between the sexes
+in hardly any of the foregoing cases appears sufficiently great for this
+view to be safely accepted. In some of the cases, the brighter tints of
+the female are almost confined to the lower surface, and the males, if
+thus coloured, would not have been exposed to danger whilst sitting on
+the eggs. It should also be borne in mind that the males are not only
+in a slight degree less conspicuously coloured than the females, but are
+smaller and weaker. They have, moreover, not only acquired the maternal
+instinct of incubation, but are less pugnacious and vociferous than the
+females, and in one instance have simpler vocal organs. Thus an almost
+complete transposition of the instincts, habits, disposition, colour,
+size, and of some points of structure, has been effected between the two
+sexes.
+
+Now if we might assume that the males in the present class have lost
+some of that ardour which is usual to their sex, so that they no longer
+search eagerly for the females; or, if we might assume that the females
+have become much more numerous than the males--and in the case of one
+Indian Turnix the females are said to be "much more commonly met with
+than the males" (26. Jerdon, 'Birds of India,' vol. iii. p. 598.)--then
+it is not improbable that the females would have been led to court the
+males, instead of being courted by them. This indeed is the case to a
+certain extent with some birds, as we have seen with the peahen, wild
+turkey, and certain kinds of grouse. Taking as our guide the habits
+of most male birds, the greater size and strength as well as the
+extraordinary pugnacity of the females of the Turnix and emu, must
+mean that they endeavour to drive away rival females, in order to gain
+possession of the male; and on this view all the facts become clear; for
+the males would probably be most charmed or excited by the females
+which were the most attractive to them by their bright colours, other
+ornaments, or vocal powers. Sexual selection would then do its work,
+steadily adding to the attractions of the females; the males and the
+young being left not at all, or but little modified.
+
+CLASS III.
+
+WHEN THE ADULT MALE RESEMBLES THE ADULT FEMALE, THE YOUNG OF BOTH SEXES
+HAVE A PECULIAR FIRST PLUMAGE OF THEIR OWN.
+
+In this class the sexes when adult resemble each other, and differ from
+the young. This occurs with many birds of many kinds. The male robin
+can hardly be distinguished from the female, but the young are widely
+different, with their mottled dusky-olive and brown plumage. The male
+and female of the splendid scarlet ibis are alike, whilst the young
+are brown; and the scarlet colour, though common to both sexes, is
+apparently a sexual character, for it is not well developed in either
+sex under confinement; and a loss of colour often occurs with brilliant
+males when they are confined. With many species of herons the young
+differ greatly from the adults; and the summer plumage of the latter,
+though common to both sexes, clearly has a nuptial character. Young
+swans are slate-coloured, whilst the mature birds are pure white; but
+it would be superfluous to give additional instances. These differences
+between the young and the old apparently depend, as in the last two
+classes, on the young having retained a former or ancient state of
+plumage, whilst the old of both sexes have acquired a new one. When the
+adults are bright coloured, we may conclude from the remarks just made
+in relation to the scarlet ibis and to many herons, and from the analogy
+of the species in the first class, that such colours have been
+acquired through sexual selection by the nearly mature males; but that,
+differently from what occurs in the first two classes, the transmission,
+though limited to the same age, has not been limited to the same sex.
+Consequently, the sexes when mature resemble each other and differ from
+the young.
+
+CLASS IV.
+
+WHEN THE ADULT MALE RESEMBLES THE ADULT FEMALE, THE YOUNG OF BOTH SEXES
+IN THEIR FIRST PLUMAGE RESEMBLE THE ADULTS.
+
+In this class the young and the adults of both sexes, whether
+brilliantly or obscurely coloured, resemble each other. Such cases are,
+I think, more common than those in the last class. We have in England
+instances in the kingfisher, some woodpeckers, the jay, magpie, crow,
+and many small dull-coloured birds, such as the hedge-warbler or
+kitty-wren. But the similarity in plumage between the young and the old
+is never complete, and graduates away into dissimilarity. Thus the
+young of some members of the kingfisher family are not only less vividly
+coloured than the adults, but many of the feathers on the lower surface
+are edged with brown (27. Jerdon, 'Birds of India,' vol. i. pp. 222,
+228. Gould's 'Handbook to the Birds of Australia,' vol. i. pp. 124,
+130.),--a vestige probably of a former state of the plumage. Frequently
+in the same group of birds, even within the same genus, for instance
+in an Australian genus of parrakeets (Platycercus), the young of some
+species closely resemble, whilst the young of other species differ
+considerably, from their parents of both sexes, which are alike. (28.
+Gould, ibid. vol. ii. pp. 37, 46, 56.) Both sexes and the young of
+the common jay are closely similar; but in the Canada jay (Perisoreus
+canadensis) the young differ so much from their parents that they
+were formerly described as distinct species. (29. Audubon, 'Ornith.
+Biography,' vol. ii. p. 55.)
+
+I may remark before proceeding that, under the present and next two
+classes of cases, the facts are so complex and the conclusions so
+doubtful, that any one who feels no especial interest in the subject had
+better pass them over.
+
+The brilliant or conspicuous colours which characterise many birds
+in the present class, can rarely or never be of service to them as a
+protection; so that they have probably been gained by the males through
+sexual selection, and then transferred to the females and the young.
+It is, however, possible that the males may have selected the more
+attractive females; and if these transmitted their characters to their
+offspring of both sexes, the same results would follow as from the
+selection of the more attractive males by the females. But there is
+evidence that this contingency has rarely, if ever, occurred in any of
+those groups of birds in which the sexes are generally alike; for, if
+even a few of the successive variations had failed to be transmitted
+to both sexes, the females would have slightly exceeded the males in
+beauty. Exactly the reverse occurs under nature; for, in almost every
+large group in which the sexes generally resemble each other, the males
+of some few species are in a slight degree more brightly coloured than
+the females. It is again possible that the females may have selected the
+more beautiful males, these males having reciprocally selected the more
+beautiful females; but it is doubtful whether this double process of
+selection would be likely to occur, owing to the greater eagerness of
+one sex than the other, and whether it would be more efficient than
+selection on one side alone. It is, therefore, the most probable
+view that sexual selection has acted, in the present class, as far as
+ornamental characters are concerned, in accordance with the general rule
+throughout the animal kingdom, that is, on the males; and that these
+have transmitted their gradually-acquired colours, either equally or
+almost equally, to their offspring of both sexes.
+
+Another point is more doubtful, namely, whether the successive
+variations first appeared in the males after they had become nearly
+mature, or whilst quite young. In either case sexual selection must have
+acted on the male when he had to compete with rivals for the possession
+of the female; and in both cases the characters thus acquired have been
+transmitted to both sexes and all ages. But these characters if acquired
+by the males when adult, may have been transmitted at first to the
+adults alone, and at some subsequent period transferred to the young.
+For it is known that, when the law of inheritance at corresponding ages
+fails, the offspring often inherit characters at an earlier age than
+that at which they first appeared in their parents. (30. 'Variation
+of Animals and Plants under Domestication,' vol. ii. p. 79.) Cases
+apparently of this kind have been observed with birds in a state of
+nature. For instance Mr. Blyth has seen specimens of Lanius rufus and of
+Colymbus glacialis which had assumed whilst young, in a quite anomalous
+manner, the adult plumage of their parents. (31. 'Charlesworth's
+Magazine of Natural History,' vol. i. 1837, pp. 305, 306.) Again,
+the young of the common swan (Cygnus olor) do not cast off their dark
+feathers and become white until eighteen months or two years old; but
+Dr. F. Forel has described the case of three vigorous young birds, out
+of a brood of four, which were born pure white. These young birds were
+not albinos, as shewn by the colour of their beaks and legs, which
+nearly resembled the same parts in the adults. (32. 'Bulletin de la Soc.
+Vaudoise des Sc. Nat.' vol. x. 1869, p. 132. The young of the Polish
+swan, Cygnus immutabilis of Yarrell, are always white; but this species,
+as Mr. Sclater informs me, is believed to be nothing more than a variety
+of the domestic swan (Cygnus olor).)
+
+It may be worth while to illustrate the above three modes by which, in
+the present class, the two sexes and the young may have come to resemble
+each other, by the curious case of the genus Passer. (33. I am indebted
+to Mr. Blyth for information in regard to this genus. The sparrow of
+Palestine belongs to the sub-genus Petronia.) In the house-sparrow (P.
+domesticus) the male differs much from the female and from the young.
+The young and the females are alike, and resemble to a large extent both
+sexes and the young of the sparrow of Palestine (P. brachydactylus), as
+well as of some allied species. We may therefore assume that the female
+and young of the house-sparrow approximately shew us the plumage of the
+progenitor of the genus. Now with the tree-sparrow (P. montanus) both
+sexes and the young closely resemble the male of the house-sparrow; so
+that they have all been modified in the same manner, and all depart
+from the typical colouring of their early progenitor. This may have been
+effected by a male ancestor of the tree-sparrow having varied, firstly,
+when nearly mature; or, secondly, whilst quite young, and by having
+in either case transmitted his modified plumage to the females and the
+young; or, thirdly, he may have varied when adult and transmitted his
+plumage to both adult sexes, and, owing to the failure of the law of
+inheritance at corresponding ages, at some subsequent period to his
+young.
+
+It is impossible to decide which of these three modes has generally
+prevailed throughout the present class of cases. That the males varied
+whilst young, and transmitted their variations to their offspring of
+both sexes, is the most probable. I may here add that I have, with
+little success, endeavoured, by consulting various works, to decide
+how far the period of variation in birds has generally determined the
+transmission of characters to one sex or to both. The two rules,
+often referred to (namely, that variations occurring late in life are
+transmitted to one and the same sex, whilst those which occur early in
+life are transmitted to both sexes), apparently hold good in the first
+(34. For instance, the males of Tanagra aestiva and Fringilla cyanea
+require three years, the male of Fringilla ciris four years, to complete
+their beautiful plumage. (See Audubon, 'Ornith. Biography,' vol. i. pp.
+233, 280, 378). The Harlequin duck takes three years (ibid. vol. iii. p.
+614). The male of the Gold pheasant, as I hear from Mr. Jenner Weir,
+can be distinguished from the female when about three months old, but
+he does not acquire his full splendour until the end of the September in
+the following year.), second, and fourth classes of cases; but they fail
+in the third, often in the fifth (35. Thus the Ibis tantalus and Grus
+americanus take four years, the Flamingo several years, and the Ardea
+ludovicana two years, before they acquire their perfect plumage. See
+Audubon, ibid. vol. i. p. 221; vol. iii. pp. 133, 139, 211.), and in
+the sixth small class. They apply, however, as far as I can judge, to
+a considerable majority of the species; and we must not forget
+the striking generalisation by Dr. W. Marshall with respect to the
+protuberances on the heads of birds. Whether or not the two rules
+generally hold good, we may conclude from the facts given in the eighth
+chapter, that the period of variation is one important element in
+determining the form of transmission.
+
+With birds it is difficult to decide by what standard we ought to judge
+of the earliness or lateness of the period of variation, whether by
+the age in reference to the duration of life, or to the power of
+reproduction, or to the number of moults through which the species
+passes. The moulting of birds, even within the same family, sometimes
+differs much without any assignable cause. Some birds moult so early,
+that nearly all the body feathers are cast off before the first
+wing-feathers are fully grown; and we cannot believe that this was
+the primordial state of things. When the period of moulting has been
+accelerated, the age at which the colours of the adult plumage are first
+developed will falsely appear to us to be earlier than it really is.
+This may be illustrated by the practice followed by some bird-fanciers,
+who pull out a few feathers from the breast of nestling bullfinches,
+and from the head or neck of young gold-pheasants, in order to ascertain
+their sex; for in the males, these feathers are immediately replaced by
+coloured ones. (36. Mr. Blyth, in Charlesworth's 'Magazine of Natural
+History,' vol. i. 1837, p. 300. Mr. Bartlett has informed me in regard
+to gold pheasants.) The actual duration of life is known in but few
+birds, so that we can hardly judge by this standard. And, with reference
+to the period at which the power of reproduction is gained, it is a
+remarkable fact that various birds occasionally breed whilst retaining
+their immature plumage. (37. I have noticed the following cases in
+Audubon's 'Ornith. Biography.' The redstart of America (Muscapica
+ruticilla, vol. i. p. 203). The Ibis tantalus takes four years to come
+to full maturity, but sometimes breeds in the second year (vol. iii.
+p. 133). The Grus americanus takes the same time, but breeds before
+acquiring its full plumage (vol. iii. p. 211). The adults of Ardea
+caerulea are blue, and the young white; and white, mottled, and mature
+blue birds may all be seen breeding together (vol. iv. p. 58): but Mr.
+Blyth informs me that certain herons apparently are dimorphic, for white
+and coloured individuals of the same age may be observed. The Harlequin
+duck (Anas histrionica, Linn.) takes three years to acquire its full
+plumage, though many birds breed in the second year (vol. iii. p.
+614). The White-headed Eagle (Falco leucocephalus, vol. iii. p. 210) is
+likewise known to breed in its immature state. Some species of Oriolus
+(according to Mr. Blyth and Mr. Swinhoe, in 'Ibis,' July 1863, p. 68)
+likewise breed before they attain their full plumage.)
+
+The fact of birds breeding in their immature plumage seems opposed to
+the belief that sexual selection has played as important a part, as
+I believe it has, in giving ornamental colours, plumes, etc., to the
+males, and, by means of equal transmission, to the females of many
+species. The objection would be a valid one, if the younger and less
+ornamented males were as successful in winning females and propagating
+their kind, as the older and more beautiful males. But we have no reason
+to suppose that this is the case. Audubon speaks of the breeding of the
+immature males of Ibis tantalus as a rare event, as does Mr. Swinhoe, in
+regard to the immature males of Oriolus. (38. See footnote 37 above.) If
+the young of any species in their immature plumage were more successful
+in winning partners than the adults, the adult plumage would probably
+soon be lost, as the males would prevail, which retained their immature
+dress for the longest period, and thus the character of the species
+would ultimately be modified. (39. Other animals, belonging to quite
+distinct classes, are either habitually or occasionally capable of
+breeding before they have fully acquired their adult characters. This
+is the case with the young males of the salmon. Several amphibians
+have been known to breed whilst retaining their larval structure. Fritz
+M�ller has shewn ('Facts and arguments for Darwin,' Eng. trans. 1869,
+p. 79) that the males of several amphipod crustaceans become sexually
+mature whilst young; and I infer that this is a case of premature
+breeding, because they have not as yet acquired their fully-developed
+claspers. All such facts are highly interesting, as bearing on one means
+by which species may undergo great modifications of character.) If, on
+the other hand, the young never succeeded in obtaining a female, the
+habit of early reproduction would perhaps be sooner or later eliminated,
+from being superfluous and entailing waste of power.
+
+The plumage of certain birds goes on increasing in beauty during many
+years after they are fully mature; this is the case with the train of
+the peacock, with some of the birds of paradise, and with the crest
+and plumes of certain herons, for instance, the Ardea ludovicana. (40.
+Jerdon, 'Birds of India,' vol. iii. p. 507, on the peacock. Dr. Marshall
+thinks that the older and more brilliant males of birds of paradise,
+have an advantage over the younger males; see 'Archives Neerlandaises,'
+tom. vi. 1871.--On Ardea, Audubon, ibid. vol. iii. p. 139.) But it
+is doubtful whether the continued development of such feathers is the
+result of the selection of successive beneficial variations (though
+this is the most probable view with birds of paradise) or merely of
+continuous growth. Most fishes continue increasing in size, as long as
+they are in good health and have plenty of food; and a somewhat similar
+law may prevail with the plumes of birds.
+
+CLASS V.
+
+WHEN THE ADULTS OF BOTH SEXES HAVE A DISTINCT WINTER AND SUMMER PLUMAGE,
+WHETHER OR NOT THE MALE DIFFERS FROM THE FEMALE, THE YOUNG RESEMBLE THE
+ADULTS OF BOTH SEXES IN THEIR WINTER DRESS, OR MUCH MORE RARELY IN THEIR
+SUMMER DRESS, OR THEY RESEMBLE THE FEMALES ALONE. OR THE YOUNG MAY HAVE
+AN INTERMEDIATE CHARACTER; OR, AGAIN, THEY MAY DIFFER GREATLY FROM THE
+ADULTS IN BOTH THEIR SEASONAL PLUMAGES.
+
+The cases in this class are singularly complex; nor is this surprising,
+as they depend on inheritance, limited in a greater or less degree in
+three different ways, namely, by sex, age, and the season of the year.
+In some cases the individuals of the same species pass through at least
+five distinct states of plumage. With the species, in which the male
+differs from the female during the summer season alone, or, which is
+rarer, during both seasons (41. For illustrative cases, see vol. iv.
+of Macgillivray's 'History of British Birds;' on Tringa, etc., pp. 229,
+271; on the Machetes, p. 172; on the Charadrius hiaticula, p. 118; on
+the Charadrius pluvialis, p. 94.), the young generally resemble
+the females,--as with the so-called goldfinch of North America, and
+apparently with the splendid Maluri of Australia. (42. For the goldfinch
+of N. America, Fringilla tristis, Linn., see Audubon, 'Ornithological
+Biography,' vol. i. p. 172. For the Maluri, Gould's 'Handbook of the
+Birds of Australia,' vol. i. p. 318.) With those species, the sexes
+of which are alike during both the summer and winter, the young may
+resemble the adults, firstly, in their winter dress; secondly, and this
+is of much rarer occurrence, in their summer dress; thirdly, they may
+be intermediate between these two states; and, fourthly, they may differ
+greatly from the adults at all seasons. We have an instance of the first
+of these four cases in one of the egrets of India (Buphus coromandus),
+in which the young and the adults of both sexes are white during the
+winter, the adults becoming golden-buff during the summer.
+
+With the gaper (Anastomus oscitans) of India we have a similar case, but
+the colours are reversed: for the young and the adults of both sexes are
+grey and black during the winter, the adults becoming white during
+the summer. (43. I am indebted to Mr. Blyth for information as to the
+Buphus; see also Jerdon, 'Birds of India,' vol. iii. p. 749. On the
+Anastomus, see Blyth, in 'Ibis,' 1867, p. 173.) As an instance of the
+second case, the young of the razor-bill (Alca torda, Linn.), in an
+early state of plumage, are coloured like the adults during the summer;
+and the young of the white-crowned sparrow of North America (Fringilla
+leucophrys), as soon as fledged, have elegant white stripes on their
+heads, which are lost by the young and the old during the winter. (44.
+On the Alca, see Macgillivray, 'Hist. Brit. Birds,' vol. v. p. 347. On
+the Fringilla leucophrys, Audubon, ibid. vol. ii. p. 89. I shall have
+hereafter to refer to the young of certain herons and egrets being
+white.) With respect to the third case, namely, that of the young having
+an intermediate character between the summer and winter adult plumages,
+Yarrell (45. 'History of British Birds,' vol. i. 1839, p. 159.) insists
+that this occurs with many waders. Lastly, in regard to the young
+differing greatly from both sexes in their adult summer and winter
+plumages, this occurs with some herons and egrets of North America and
+India,--the young alone being white.
+
+I will make only a few remarks on these complicated cases. When the
+young resemble the females in their summer dress, or the adults of both
+sexes in their winter dress, the cases differ from those given under
+Classes I. and III. only in the characters originally acquired by
+the males during the breeding-season, having been limited in their
+transmission to the corresponding season. When the adults have a
+distinct summer and winter plumage, and the young differ from both, the
+case is more difficult to understand. We may admit as probable that
+the young have retained an ancient state of plumage; we can account by
+sexual selection for the summer or nuptial plumage of the adults, but
+how are we to account for their distinct winter plumage? If we could
+admit that this plumage serves in all cases as a protection, its
+acquirement would be a simple affair; but there seems no good reason for
+this admission. It may be suggested that the widely different conditions
+of life during the winter and summer have acted in a direct manner
+on the plumage; this may have had some effect, but I have not much
+confidence in so great a difference as we sometimes see between the two
+plumages, having been thus caused. A more probable explanation is, that
+an ancient style of plumage, partially modified through the transference
+of some characters from the summer plumage, has been retained by the
+adults during the winter. Finally, all the cases in our present class
+apparently depend on characters acquired by the adult males, having been
+variously limited in their transmission according to age, season, and
+sex; but it would not be worth while to attempt to follow out these
+complex relations.
+
+CLASS VI.
+
+THE YOUNG IN THEIR FIRST PLUMAGE DIFFER FROM EACH OTHER ACCORDING TO
+SEX; THE YOUNG MALES RESEMBLING MORE OR LESS CLOSELY THE ADULT MALES,
+AND THE YOUNG FEMALES MORE OR LESS CLOSELY THE ADULT FEMALES.
+
+The cases in the present class, though occurring in various groups, are
+not numerous; yet it seems the most natural thing that the young should
+at first somewhat resemble the adults of the same sex, and gradually
+become more and more like them. The adult male blackcap (Sylvia
+atricapilla) has a black head, that of the female being reddish-brown;
+and I am informed by Mr. Blyth, that the young of both sexes can be
+distinguished by this character even as nestlings. In the family of
+thrushes an unusual number of similar cases have been noticed; thus, the
+male blackbird (Turdus merula) can be distinguished in the nest from the
+female. The two sexes of the mocking bird (Turdus polyglottus, Linn.)
+differ very little from each other, yet the males can easily be
+distinguished at a very early age from the females by showing more pure
+white. (46. Audubon, 'Ornith. Biography,' vol. i. p. 113.) The males
+of a forest-thrush and of a rock-thrush (Orocetes erythrogastra and
+Petrocincla cyanea) have much of their plumage of a fine blue, whilst
+the females are brown; and the nestling males of both species have their
+main wing and tail-feathers edged with blue whilst those of the female
+are edged with brown. (47. Mr. C.A. Wright, in 'Ibis,' vol. vi. 1864, p.
+65. Jerdon, 'Birds of India,' vol. i. p. 515. See also on the blackbird,
+Blyth in Charlesworth's 'Magazine of Natural History,' vol. i. 1837,
+p. 113.) In the young blackbird the wing-feathers assume their mature
+character and become black after the others; on the other hand, in the
+two species just named the wing-feathers become blue before the others.
+The most probable view with reference to the cases in the present
+class is that the males, differently from what occurs in Class I., have
+transmitted their colours to their male offspring at an earlier age than
+that at which they were first acquired; for, if the males had
+varied whilst quite young, their characters would probably have been
+transmitted to both sexes. (48. The following additional cases may be
+mentioned; the young males of Tanagra rubra can be distinguished from
+the young females (Audubon, 'Ornith. Biography,' vol. iv. p. 392), and
+so it is within the nestlings of a blue nuthatch, Dendrophila frontalis
+of India (Jerdon, 'Birds of India,' vol. i. p. 389). Mr. Blyth also
+informs me that the sexes of the stonechat, Saxicola rubicola, are
+distinguishable at a very early age. Mr. Salvin gives ('Proc. Zoolog.
+Soc.' 1870, p. 206) the case of a humming-bird, like the following one
+of Eustephanus.)
+
+In Aithurus polytmus, a humming-bird, the male is splendidly coloured
+black and green, and two of the tail-feathers are immensely lengthened;
+the female has an ordinary tail and inconspicuous colours; now the young
+males, instead of resembling the adult female, in accordance with the
+common rule, begin from the first to assume the colours proper to
+their sex, and their tail-feathers soon become elongated. I owe this
+information to Mr. Gould, who has given me the following more striking
+and as yet unpublished case. Two humming-birds belonging to the genus
+Eustephanus, both beautifully coloured, inhabit the small island of Juan
+Fernandez, and have always been ranked as specifically distinct. But
+it has lately been ascertained that the one which is of a rich
+chestnut-brown colour with a golden-red head, is the male, whilst the
+other which is elegantly variegated with green and white with a metallic
+green head is the female. Now the young from the first somewhat resemble
+the adults of the corresponding sex, the resemblance gradually becoming
+more and more complete.
+
+In considering this last case, if as before we take the plumage of the
+young as our guide, it would appear that both sexes have been rendered
+beautiful independently; and not that one sex has partially transferred
+its beauty to the other. The male apparently has acquired his bright
+colours through sexual selection in the same manner as, for instance,
+the peacock or pheasant in our first class of cases; and the female in
+the same manner as the female Rhynchaea or Turnix in our second class of
+cases. But there is much difficulty in understanding how this could have
+been effected at the same time with the two sexes of the same species.
+Mr. Salvin states, as we have seen in the eighth chapter, that with
+certain humming-birds the males greatly exceed the females in number,
+whilst with other species inhabiting the same country the females
+greatly exceed the males. If, then, we might assume that during some
+former lengthened period the males of the Juan Fernandez species
+had greatly exceeded the females in number, but that during another
+lengthened period the females had far exceeded the males, we could
+understand how the males at one time, and the females at another, might
+have been rendered beautiful by the selection of the brighter coloured
+individuals of either sex; both sexes transmitting their characters to
+their young at a rather earlier age than usual. Whether this is the true
+explanation I will not pretend to say; but the case is too remarkable to
+be passed over without notice.
+
+We have now seen in all six classes, that an intimate relation exists
+between the plumage of the young and the adults, either of one sex or
+both. These relations are fairly well explained on the principle that
+one sex--this being in the great majority of cases the male--first
+acquired through variation and sexual selection bright colours or other
+ornaments, and transmitted them in various ways, in accordance with
+the recognised laws of inheritance. Why variations have occurred at
+different periods of life, even sometimes with species of the same
+group, we do not know, but with respect to the form of transmission, one
+important determining cause seems to be the age at which the variations
+first appear.
+
+From the principle of inheritance at corresponding ages, and from any
+variations in colour which occurred in the males at an early age
+not being then selected--on the contrary being often eliminated as
+dangerous--whilst similar variations occurring at or near the period
+of reproduction have been preserved, it follows that the plumage of the
+young will often have been left unmodified, or but little modified.
+We thus get some insight into the colouring of the progenitors of our
+existing species. In a vast number of species in five out of our six
+classes of cases, the adults of one sex or of both are bright coloured,
+at least during the breeding-season, whilst the young are invariably
+less brightly coloured than the adults, or are quite dull coloured;
+for no instance is known, as far as I can discover, of the young of
+dull-coloured species displaying bright colours, or of the young of
+bright-coloured species being more brilliant than their parents. In
+the fourth class, however, in which the young and the old resemble each
+other, there are many species (though by no means all), of which the
+young are bright-coloured, and as these form old groups, we may infer
+that their early progenitors were likewise bright. With this exception,
+if we look to the birds of the world, it appears that their beauty has
+been much increased since that period, of which their immature plumage
+gives us a partial record.
+
+ON THE COLOUR OF THE PLUMAGE IN RELATION TO PROTECTION.
+
+It will have been seen that I cannot follow Mr. Wallace in the belief
+that dull colours, when confined to the females, have been in most cases
+specially gained for the sake of protection. There can, however, be
+no doubt, as formerly remarked, that both sexes of many birds have had
+their colours modified, so as to escape the notice of their enemies; or
+in some instances, so as to approach their prey unobserved, just as
+owls have had their plumage rendered soft, that their flight may not be
+overheard. Mr. Wallace remarks (49. 'Westminster Review,' July 1867,
+p. 5.) that "it is only in the tropics, among forests which never lose
+their foliage, that we find whole groups of birds, whose chief colour
+is green." It will be admitted by every one, who has ever tried,
+how difficult it is to distinguish parrots in a leaf-covered tree.
+Nevertheless, we must remember that many parrots are ornamented with
+crimson, blue, and orange tints, which can hardly be protective.
+Woodpeckers are eminently arboreal, but besides green species, there are
+many black, and black-and-white kinds--all the species being apparently
+exposed to nearly the same dangers. It is therefore probable that with
+tree-haunting birds, strongly-pronounced colours have been acquired
+through sexual selection, but that a green tint has been acquired
+oftener than any other, from the additional advantage of protection.
+
+In regard to birds which live on the ground, every one admits that they
+are coloured so as to imitate the surrounding surface. How difficult
+it is to see a partridge, snipe, woodcock, certain plovers, larks, and
+night-jars when crouched on ground. Animals inhabiting deserts offer the
+most striking cases, for the bare surface affords no concealment, and
+nearly all the smaller quadrupeds, reptiles, and birds depend for safety
+on their colours. Mr. Tristram has remarked in regard to the inhabitants
+of the Sahara, that all are protected by their "isabelline or
+sand-colour." (50. 'Ibis,' 1859, vol. i. p. 429, et seq. Dr. Rohlfs,
+however, remarks to me in a letter that according to his experience of
+the Sahara, this statement is too strong.) Calling to my recollection
+the desert-birds of South America, as well as most of the ground-birds
+of Great Britain, it appeared to me that both sexes in such cases are
+generally coloured nearly alike. Accordingly, I applied to Mr. Tristram
+with respect to the birds of the Sahara, and he has kindly given me the
+following information. There are twenty-six species belonging to fifteen
+genera, which manifestly have their plumage coloured in a protective
+manner; and this colouring is all the more striking, as with most of
+these birds it differs from that of their congeners. Both sexes of
+thirteen out of the twenty-six species are coloured in the same manner;
+but these belong to genera in which this rule commonly prevails, so that
+they tell us nothing about the protective colours being the same in both
+sexes of desert-birds. Of the other thirteen species, three belong to
+genera in which the sexes usually differ from each other, yet here they
+have the sexes alike. In the remaining ten species, the male differs
+from the female; but the difference is confined chiefly to the under
+surface of the plumage, which is concealed when the bird crouches on the
+ground; the head and back being of the same sand-coloured hue in the
+two sexes. So that in these ten species the upper surfaces of both sexes
+have been acted on and rendered alike, through natural selection, for
+the sake of protection; whilst the lower surfaces of the males alone
+have been diversified, through sexual selection, for the sake of
+ornament. Here, as both sexes are equally well protected, we clearly
+see that the females have not been prevented by natural selection from
+inheriting the colours of their male parents; so that we must look to
+the law of sexually-limited transmission.
+
+In all parts of the world both sexes of many soft-billed birds,
+especially those which frequent reeds or sedges, are obscurely coloured.
+No doubt if their colours had been brilliant, they would have been much
+more conspicuous to their enemies; but whether their dull tints have
+been specially gained for the sake of protection seems, as far as I
+can judge, rather doubtful. It is still more doubtful whether such dull
+tints can have been gained for the sake of ornament. We must, however,
+bear in mind that male birds, though dull-coloured, often differ much
+from their females (as with the common sparrow), and this leads to the
+belief that such colours have been gained through sexual selection, from
+being attractive. Many of the soft-billed birds are songsters; and a
+discussion in a former chapter should not be forgotten, in which it was
+shewn that the best songsters are rarely ornamented with bright tints.
+It would appear that female birds, as a general rule, have selected
+their mates either for their sweet voices or gay colours, but not for
+both charms combined. Some species, which are manifestly coloured for
+the sake of protection, such as the jack-snipe, woodcock, and night-jar,
+are likewise marked and shaded, according to our standard of taste, with
+extreme elegance. In such cases we may conclude that both natural and
+sexual selection have acted conjointly for protection and ornament.
+Whether any bird exists which does not possess some special attraction,
+by which to charm the opposite sex, may be doubted. When both sexes
+are so obscurely coloured that it would be rash to assume the agency of
+sexual selection, and when no direct evidence can be advanced shewing
+that such colours serve as a protection, it is best to own complete
+ignorance of the cause, or, which comes to nearly the same thing, to
+attribute the result to the direct action of the conditions of life.
+
+Both sexes of many birds are conspicuously, though not brilliantly
+coloured, such as the numerous black, white, or piebald species; and
+these colours are probably the result of sexual selection. With the
+common blackbird, capercailzie, blackcock, black scoter-duck (Oidemia),
+and even with one of the birds of paradise (Lophorina atra), the males
+alone are black, whilst the females are brown or mottled; and there
+can hardly be a doubt that blackness in these cases has been a sexually
+selected character. Therefore it is in some degree probable that the
+complete or partial blackness of both sexes in such birds as crows,
+certain cockatoos, storks, and swans, and many marine birds, is likewise
+the result of sexual selection, accompanied by equal transmission to
+both sexes; for blackness can hardly serve in any case as a protection.
+With several birds, in which the male alone is black, and in others in
+which both sexes are black, the beak or skin about the head is brightly
+coloured, and the contrast thus afforded adds much to their beauty; we
+see this in the bright yellow beak of the male blackbird, in the crimson
+skin over the eyes of the blackcock and capercailzie, in the brightly
+and variously coloured beak of the scoter-drake (Oidemia), in the red
+beak of the chough (Corvus graculus, Linn.), of the black swan, and
+the black stork. This leads me to remark that it is not incredible that
+toucans may owe the enormous size of their beaks to sexual selection,
+for the sake of displaying the diversified and vivid stripes of colour,
+with which these organs are ornamented. (51. No satisfactory explanation
+has ever been offered of the immense size, and still less of the
+bright colours, of the toucan's beak. Mr. Bates ('The Naturalist on the
+Amazons,' vol. ii. 1863, p. 341) states that they use their beaks for
+reaching fruit at the extreme tips of the branches; and likewise, as
+stated by other authors, for extracting eggs and young birds from the
+nests of other birds. But, as Mr. Bates admits, the beak "can scarcely
+be considered a very perfectly-formed instrument for the end to which it
+is applied." The great bulk of the beak, as shewn by its breadth, depth,
+as well as length, is not intelligible on the view, that it serves
+merely as an organ of prehension. Mr. Belt believes ('The Naturalist in
+Nicaragua,' p. 197) that the principal use of the beak is as a defence
+against enemies, especially to the female whilst nesting in a hole in a
+tree.) The naked skin, also, at the base of the beak and round the eyes
+is likewise often brilliantly coloured; and Mr. Gould, in speaking
+of one species (52. Rhamphastos carinatus, Gould's 'Monograph of
+Ramphastidae.'), says that the colours of the beak "are doubtless in the
+finest and most brilliant state during the time of pairing." There is
+no greater improbability that toucans should be encumbered with immense
+beaks, though rendered as light as possible by their cancellated
+structure, for the display of fine colours (an object falsely appearing
+to us unimportant), than that the male Argus pheasant and some other
+birds should be encumbered with plumes so long as to impede their
+flight.
+
+In the same manner, as the males alone of various species are black,
+the females being dull-coloured; so in a few cases the males alone are
+either wholly or partially white, as with the several bell-birds
+of South America (Chasmorhynchus), the Antarctic goose (Bernicla
+antarctica), the silver pheasant, etc., whilst the females are brown
+or obscurely mottled. Therefore, on the same principle as before, it is
+probable that both sexes of many birds, such as white cockatoos, several
+egrets with their beautiful plumes, certain ibises, gulls, terns, etc.,
+have acquired their more or less completely white plumage through sexual
+selection. In some of these cases the plumage becomes white only at
+maturity. This is the case with certain gannets, tropic-birds, etc.,
+and with the snow-goose (Anser hyperboreus). As the latter breeds on
+the "barren grounds," when not covered with snow, and as it migrates
+southward during the winter, there is no reason to suppose that its
+snow-white adult plumage serves as a protection. In the Anastomus
+oscitans, we have still better evidence that the white plumage is a
+nuptial character, for it is developed only during the summer; the young
+in their immature state, and the adults in their winter dress, being
+grey and black. With many kinds of gulls (Larus), the head and neck
+become pure white during the summer, being grey or mottled during the
+winter and in the young state. On the other hand, with the smaller
+gulls, or sea-mews (Gavia), and with some terns (Sterna), exactly the
+reverse occurs; for the heads of the young birds during the first year,
+and of the adults during the winter, are either pure white, or much
+paler coloured than during the breeding-season. These latter cases offer
+another instance of the capricious manner in which sexual selection
+appears often to have acted. (53. On Larus, Gavia, and Sterna, see
+Macgillivray, 'History of British Birds,' vol. v. pp. 515, 584, 626. On
+the Anser hyperboreus, Audubon, 'Ornithological Biography,' vol. iv. p.
+562. On the Anastomus, Mr. Blyth, in 'Ibis,' 1867, p. 173.)
+
+That aquatic birds have acquired a white plumage so much oftener than
+terrestrial birds, probably depends on their large size and strong
+powers of flight, so that they can easily defend themselves or escape
+from birds of prey, to which moreover they are not much exposed.
+Consequently, sexual selection has not here been interfered with or
+guided for the sake of protection. No doubt with birds which roam over
+the open ocean, the males and females could find each other much
+more easily, when made conspicuous either by being perfectly white or
+intensely black; so that these colours may possibly serve the same end
+as the call-notes of many land-birds. (54. It may be noticed that with
+vultures, which roam far and wide high in the air, like marine birds
+over the ocean, three or four species are almost wholly or largely
+white, and that many others are black. So that here again conspicuous
+colours may possibly aid the sexes in finding each other during the
+breeding-season.) A white or black bird when it discovers and flies down
+to a carcase floating on the sea or cast up on the beach, will be seen
+from a great distance, and will guide other birds of the same and other
+species, to the prey; but as this would be a disadvantage to the first
+finders, the individuals which were the whitest or blackest would not
+thus procure more food than the less strongly coloured individuals.
+Hence conspicuous colours cannot have been gradually acquired for this
+purpose through natural selection.
+
+As sexual selection depends on so fluctuating an element as taste, we
+can understand how it is that, within the same group of birds having
+nearly the same habits, there should exist white or nearly white, as
+well as black, or nearly black species,--for instance, both white and
+black cockatoos, storks, ibises, swans, terns, and petrels. Piebald
+birds likewise sometimes occur in the same groups together with black
+and white species; for instance, the black-necked swan, certain terns,
+and the common magpie. That a strong contrast in colour is agreeable to
+birds, we may conclude by looking through any large collection, for the
+sexes often differ from each other in the male having the pale parts
+of a purer white, and the variously coloured dark parts of still darker
+tints than the female.
+
+It would even appear that mere novelty, or slight changes for the sake
+of change, have sometimes acted on female birds as a charm, like changes
+of fashion with us. Thus the males of some parrots can hardly be said to
+be more beautiful than the females, at least according to our taste, but
+they differ in such points, as in having a rose-coloured collar instead
+of "a bright emeraldine narrow green collar"; or in the male having a
+black collar instead of "a yellow demi-collar in front," with a pale
+roseate instead of a plum-blue head. (55. See Jerdon on the genus
+Palaeornis, 'Birds of India,' vol. i. pp. 258-260.) As so many male
+birds have elongated tail-feathers or elongated crests for their chief
+ornament, the shortened tail, formerly described in the male of a
+humming-bird, and the shortened crest of the male goosander, seem like
+one of the many changes of fashion which we admire in our own dresses.
+
+Some members of the heron family offer a still more curious case of
+novelty in colouring having, as it appears, been appreciated for the
+sake of novelty. The young of the Ardea asha are white, the adults being
+dark slate-coloured; and not only the young, but the adults in their
+winter plumage, of the allied Buphus coromandus are white, this colour
+changing into a rich golden-buff during the breeding-season. It is
+incredible that the young of these two species, as well as of some other
+members of the same family (56. The young of Ardea rufescens and A.
+caerulea of the United States are likewise white, the adults
+being coloured in accordance with their specific names. Audubon
+('Ornithological Biography,' vol. iii. p. 416; vol. iv. p. 58) seems
+rather pleased at the thought that this remarkable change of plumage
+will greatly "disconcert the systematists."), should for any special
+purpose have been rendered pure white and thus made conspicuous to their
+enemies; or that the adults of one of these two species should have been
+specially rendered white during the winter in a country which is never
+covered with snow. On the other hand we have good reason to believe that
+whiteness has been gained by many birds as a sexual ornament. We may
+therefore conclude that some early progenitor of the Ardea asha and the
+Buphus acquired a white plumage for nuptial purposes, and transmitted
+this colour to their young; so that the young and the old became white
+like certain existing egrets; and that the whiteness was afterwards
+retained by the young, whilst it was exchanged by the adults for more
+strongly-pronounced tints. But if we could look still further back to
+the still earlier progenitors of these two species, we should probably
+see the adults dark-coloured. I infer that this would be the case, from
+the analogy of many other birds, which are dark whilst young, and when
+adult are white; and more especially from the case of the Ardea gularis,
+the colours of which are the reverse of those of A. asha, for the young
+are dark-coloured and the adults white, the young having retained a
+former state of plumage. It appears therefore that, during a long line
+of descent, the adult progenitors of the Ardea asha, the Buphus, and of
+some allies, have undergone the following changes of colour: first, a
+dark shade; secondly, pure white; and thirdly, owing to another change
+of fashion (if I may so express myself), their present slaty, reddish,
+or golden-buff tints. These successive changes are intelligible only on
+the principle of novelty having been admired by birds for its own sake.
+
+Several writers have objected to the whole theory of sexual selection,
+by assuming that with animals and savages the taste of the female for
+certain colours or other ornaments would not remain constant for many
+generations; that first one colour and then another would be admired,
+and consequently that no permanent effect could be produced. We may
+admit that taste is fluctuating, but it is not quite arbitrary. It
+depends much on habit, as we see in mankind; and we may infer that this
+would hold good with birds and other animals. Even in our own dress, the
+general character lasts long, and the changes are to a certain extent
+graduated. Abundant evidence will be given in two places in a future
+chapter, that savages of many races have admired for many generations
+the same cicatrices on the skin, the same hideously perforated lips,
+nostrils, or ears, distorted heads, etc.; and these deformities present
+some analogy to the natural ornaments of various animals. Nevertheless,
+with savages such fashions do not endure for ever, as we may infer
+from the differences in this respect between allied tribes on the same
+continent. So again the raisers of fancy animals certainly have admired
+for many generations and still admire the same breeds; they earnestly
+desire slight changes, which are considered as improvements, but any
+great or sudden change is looked at as the greatest blemish. With birds
+in a state of nature we have no reason to suppose that they would admire
+an entirely new style of coloration, even if great and sudden variations
+often occurred, which is far from being the case. We know that dovecot
+pigeons do not willingly associate with the variously coloured fancy
+breeds; that albino birds do not commonly get partners in marriage;
+and that the black ravens of the Feroe Islands chase away their piebald
+brethren. But this dislike of a sudden change would not preclude their
+appreciating slight changes, any more than it does in the case of man.
+Hence with respect to taste, which depends on many elements, but partly
+on habit and partly on a love of novelty, there seems no improbability
+in animals admiring for a very long period the same general style of
+ornamentation or other attractions, and yet appreciating slight changes
+in colours, form, or sound.
+
+SUMMARY OF THE FOUR CHAPTERS ON BIRDS.
+
+Most male birds are highly pugnacious during the breeding-season, and
+some possess weapons adapted for fighting with their rivals. But the
+most pugnacious and the best armed males rarely or never depend for
+success solely on their power to drive away or kill their rivals, but
+have special means for charming the female. With some it is the power of
+song, or of giving forth strange cries, or instrumental music, and the
+males in consequence differ from the females in their vocal organs, or
+in the structure of certain feathers. From the curiously diversified
+means for producing various sounds, we gain a high idea of the
+importance of this means of courtship. Many birds endeavour to charm the
+females by love-dances or antics, performed on the ground or in the air,
+and sometimes at prepared places. But ornaments of many kinds, the
+most brilliant tints, combs and wattles, beautiful plumes, elongated
+feathers, top-knots, and so forth, are by far the commonest means. In
+some cases mere novelty appears to have acted as a charm. The ornaments
+of the males must be highly important to them, for they have been
+acquired in not a few cases at the cost of increased danger from
+enemies, and even at some loss of power in fighting with their rivals.
+The males of very many species do not assume their ornamental dress
+until they arrive at maturity, or they assume it only during the
+breeding-season, or the tints then become more vivid. Certain ornamental
+appendages become enlarged, turgid, and brightly coloured during the act
+of courtship. The males display their charms with elaborate care and to
+the best effect; and this is done in the presence of the females. The
+courtship is sometimes a prolonged affair, and many males and females
+congregate at an appointed place. To suppose that the females do not
+appreciate the beauty of the males, is to admit that their splendid
+decorations, all their pomp and display, are useless; and this is
+incredible. Birds have fine powers of discrimination, and in some few
+instances it can be shewn that they have a taste for the beautiful. The
+females, moreover, are known occasionally to exhibit a marked preference
+or antipathy for certain individual males.
+
+If it be admitted that the females prefer, or are unconsciously excited
+by the more beautiful males, then the males would slowly but surely be
+rendered more and more attractive through sexual selection. That it is
+this sex which has been chiefly modified, we may infer from the fact
+that, in almost every genus where the sexes differ, the males differ
+much more from one another than do the females; this is well shewn in
+certain closely-allied representative species, in which the females can
+hardly be distinguished, whilst the males are quite distinct. Birds in
+a state of nature offer individual differences which would amply
+suffice for the work of sexual selection; but we have seen that they
+occasionally present more strongly marked variations which recur so
+frequently that they would immediately be fixed, if they served to
+allure the female. The laws of variation must determine the nature of
+the initial changes, and will have largely influenced the final result.
+The gradations, which may be observed between the males of allied
+species, indicate the nature of the steps through which they have
+passed. They explain also in the most interesting manner how certain
+characters have originated, such as the indented ocelli on the
+tail-feathers of the peacock, and the ball-and-socket ocelli on the
+wing-feathers of the Argus pheasant. It is evident that the brilliant
+colours, top-knots, fine plumes, etc., of many male birds cannot have
+been acquired as a protection; indeed, they sometimes lead to danger.
+That they are not due to the direct and definite action of the
+conditions of life, we may feel assured, because the females have been
+exposed to the same conditions, and yet often differ from the males
+to an extreme degree. Although it is probable that changed conditions
+acting during a lengthened period have in some cases produced a definite
+effect on both sexes, or sometimes on one sex alone, the more important
+result will have been an increased tendency to vary or to present more
+strongly-marked individual differences; and such differences will have
+afforded an excellent ground-work for the action of sexual selection.
+
+The laws of inheritance, irrespectively of selection, appear to have
+determined whether the characters acquired by the males for the sake of
+ornament, for producing various sounds, and for fighting together,
+have been transmitted to the males alone or to both sexes, either
+permanently, or periodically during certain seasons of the year. Why
+various characters should have been transmitted sometimes in one way
+and sometimes in another, is not in most cases known; but the period of
+variability seems often to have been the determining cause. When the two
+sexes have inherited all characters in common they necessarily resemble
+each other; but as the successive variations may be differently
+transmitted, every possible gradation may be found, even within the same
+genus, from the closest similarity to the widest dissimilarity between
+the sexes. With many closely-allied species, following nearly the same
+habits of life, the males have come to differ from each other chiefly
+through the action of sexual selection; whilst the females have come
+to differ chiefly from partaking more or less of the characters thus
+acquired by the males. The effects, moreover, of the definite action of
+the conditions of life, will not have been masked in the females, as
+in the males, by the accumulation through sexual selection of
+strongly-pronounced colours and other ornaments. The individuals of both
+sexes, however affected, will have been kept at each successive period
+nearly uniform by the free intercrossing of many individuals.
+
+With species, in which the sexes differ in colour, it is possible or
+probable that some of the successive variations often tended to be
+transmitted equally to both sexes; but that when this occurred the
+females were prevented from acquiring the bright colours of the males,
+by the destruction which they suffered during incubation. There is no
+evidence that it is possible by natural selection to convert one form of
+transmission into another. But there would not be the least difficulty
+in rendering a female dull-coloured, the male being still kept
+bright-coloured, by the selection of successive variations, which were
+from the first limited in their transmission to the same sex. Whether
+the females of many species have actually been thus modified, must at
+present remain doubtful. When, through the law of the equal transmission
+of characters to both sexes, the females were rendered as conspicuously
+coloured as the males, their instincts appear often to have been
+modified so that they were led to build domed or concealed nests.
+
+In one small and curious class of cases the characters and habits of the
+two sexes have been completely transposed, for the females are larger,
+stronger, more vociferous and brighter coloured than the males. They
+have, also, become so quarrelsome that they often fight together for the
+possession of the males, like the males of other pugnacious species
+for the possession of the females. If, as seems probable, such females
+habitually drive away their rivals, and by the display of their
+bright colours or other charms endeavour to attract the males, we can
+understand how it is that they have gradually been rendered, by sexual
+selection and sexually-limited transmission, more beautiful than the
+males--the latter being left unmodified or only slightly modified.
+
+Whenever the law of inheritance at corresponding ages prevails but not
+that of sexually-limited transmission, then if the parents vary late
+in life--and we know that this constantly occurs with our poultry, and
+occasionally with other birds--the young will be left unaffected,
+whilst the adults of both sexes will be modified. If both these laws of
+inheritance prevail and either sex varies late in life, that sex alone
+will be modified, the other sex and the young being unaffected. When
+variations in brightness or in other conspicuous characters occur early
+in life, as no doubt often happens, they will not be acted on through
+sexual selection until the period of reproduction arrives; consequently
+if dangerous to the young, they will be eliminated through natural
+selection. Thus we can understand how it is that variations arising late
+in life have so often been preserved for the ornamentation of the males;
+the females and the young being left almost unaffected, and therefore
+like each other. With species having a distinct summer and winter
+plumage, the males of which either resemble or differ from the females
+during both seasons or during the summer alone, the degrees and kinds of
+resemblance between the young and the old are exceedingly complex; and
+this complexity apparently depends on characters, first acquired by the
+males, being transmitted in various ways and degrees, as limited by age,
+sex, and season.
+
+As the young of so many species have been but little modified in colour
+and in other ornaments, we are enabled to form some judgment with
+respect to the plumage of their early progenitors; and we may infer that
+the beauty of our existing species, if we look to the whole class, has
+been largely increased since that period, of which the immature plumage
+gives us an indirect record. Many birds, especially those which live
+much on the ground, have undoubtedly been obscurely coloured for the
+sake of protection. In some instances the upper exposed surface of the
+plumage has been thus coloured in both sexes, whilst the lower surface
+in the males alone has been variously ornamented through sexual
+selection. Finally, from the facts given in these four chapters, we may
+conclude that weapons for battle, organs for producing sound, ornaments
+of many kinds, bright and conspicuous colours, have generally been
+acquired by the males through variation and sexual selection, and
+have been transmitted in various ways according to the several laws
+of inheritance--the females and the young being left comparatively
+but little modified. (57. I am greatly indebted to the kindness of Mr.
+Sclater for having looked over these four chapters on birds, and the
+two following ones on mammals. In this way I have been saved from making
+mistakes about the names of the species, and from stating anything as
+a fact which is known to this distinguished naturalist to be erroneous.
+But, of course, he is not at all answerable for the accuracy of the
+statements quoted by me from various authorities.)
+
+
+CHAPTER XVII.
+
+SECONDARY SEXUAL CHARACTERS OF MAMMALS.
+
+The law of battle--Special weapons, confined to the males--Cause of
+absence of weapons in the female--Weapons common to both sexes, yet
+primarily acquired by the male--Other uses of such weapons--Their
+high importance--Greater size of the male--Means of defence--On the
+preference shown by either sex in the pairing of quadrupeds.
+
+With mammals the male appears to win the female much more through the
+law of battle than through the display of his charms. The most timid
+animals, not provided with any special weapons for fighting, engage in
+desperate conflicts during the season of love. Two male hares have been
+seen to fight together until one was killed; male moles often fight,
+and sometimes with fatal results; male squirrels engage in frequent
+contests, "and often wound each other severely"; as do male beavers, so
+that "hardly a skin is without scars." (1. See Waterton's account of
+two hares fighting, 'Zoologist,' vol. i. 1843, p. 211. On moles, Bell,
+'Hist. of British Quadrupeds,' 1st ed., p. 100. On squirrels, Audubon
+and Bachman, Viviparous Quadrupeds of N. America, 1846, p. 269. On
+beavers, Mr. A.H. Green, in 'Journal of Linnean Society, Zoology,'
+vol. x. 1869, p. 362.) I observed the same fact with the hides of the
+guanacoes in Patagonia; and on one occasion several were so absorbed in
+fighting that they fearlessly rushed close by me. Livingstone speaks of
+the males of the many animals in Southern Africa as almost invariably
+shewing the scars received in former contests.
+
+The law of battle prevails with aquatic as with terrestrial mammals. It
+is notorious how desperately male seals fight, both with their teeth and
+claws, during the breeding-season; and their hides are likewise often
+covered with scars. Male sperm-whales are very jealous at this season;
+and in their battles "they often lock their jaws together, and turn
+on their sides and twist about"; so that their lower jaws often become
+distorted. (2. On the battles of seals, see Capt. C. Abbott in 'Proc.
+Zool. Soc.' 1868, p. 191; Mr. R. Brown, ibid. 1868, p. 436; also L.
+Lloyd, 'Game Birds of Sweden,' 1867, p. 412; also Pennant. On the
+sperm-whale see Mr. J.H. Thompson, in 'Proc. Zool. Soc.' 1867, p. 246.)
+
+All male animals which are furnished with special weapons for fighting,
+are well known to engage in fierce battles. The courage and the
+desperate conflicts of stags have often been described; their
+skeletons have been found in various parts of the world, with the horns
+inextricably locked together, shewing how miserably the victor and
+vanquished had perished. (3. See Scrope ('Art of Deer-stalking,' p.
+17) on the locking of the horns with the Cervus elaphus. Richardson, in
+'Fauna Bor. Americana,' 1829, p. 252, says that the wapiti, moose, and
+reindeer have been found thus locked together. Sir A. Smith found at the
+Cape of Good Hope the skeletons of two gnus in the same condition.)
+No animal in the world is so dangerous as an elephant in must. Lord
+Tankerville has given me a graphic description of the battles between
+the wild bulls in Chillingham Park, the descendants, degenerated in size
+but not in courage, of the gigantic Bos primigenius. In 1861 several
+contended for mastery; and it was observed that two of the younger bulls
+attacked in concert the old leader of the herd, overthrew and disabled
+him, so that he was believed by the keepers to be lying mortally wounded
+in a neighbouring wood. But a few days afterwards one of the young bulls
+approached the wood alone; and then the "monarch of the chase," who had
+been lashing himself up for vengeance, came out and, in a short time,
+killed his antagonist. He then quietly joined the herd, and long held
+undisputed sway. Admiral Sir B.J. Sulivan informs me that, when he lived
+in the Falkland Islands, he imported a young English stallion, which
+frequented the hills near Port William with eight mares. On these hills
+there were two wild stallions, each with a small troop of mares; "and it
+is certain that these stallions would never have approached each other
+without fighting. Both had tried singly to fight the English horse and
+drive away his mares, but had failed. One day they came in TOGETHER and
+attacked him. This was seen by the capitan who had charge of the horses,
+and who, on riding to the spot, found one of the two stallions engaged
+with the English horse, whilst the other was driving away the mares, and
+had already separated four from the rest. The capitan settled the matter
+by driving the whole party into the corral, for the wild stallions would
+not leave the mares."
+
+Male animals which are provided with efficient cutting or tearing teeth
+for the ordinary purposes of life, such as the carnivora, insectivora,
+and rodents, are seldom furnished with weapons especially adapted for
+fighting with their rivals. The case is very different with the males
+of many other animals. We see this in the horns of stags and of certain
+kinds of antelopes in which the females are hornless. With many animals
+the canine teeth in the upper or lower jaw, or in both, are much larger
+in the males than in the females, or are absent in the latter, with
+the exception sometimes of a hidden rudiment. Certain antelopes, the
+musk-deer, camel, horse, boar, various apes, seals, and the walrus,
+offer instances. In the females of the walrus the tusks are sometimes
+quite absent. (4. Mr. Lamont ('Seasons with the Sea-Horses,' 1861, p.
+143) says that a good tusk of the male walrus weighs 4 pounds, and is
+longer than that of the female, which weighs about 3 pounds. The males
+are described as fighting ferociously. On the occasional absence of
+the tusks in the female, see Mr. R. Brown, 'Proceedings, Zoological
+Society,' 1868, p. 429.) In the male elephant of India and in the male
+dugong (5. Owen, 'Anatomy of Vertebrates,' vol. iii. p. 283.) the upper
+incisors form offensive weapons. In the male narwhal the left canine
+alone is developed into the well-known, spirally-twisted, so-called
+horn, which is sometimes from nine to ten feet in length. It is believed
+that the males use these horns for fighting together; for "an unbroken
+one can rarely be got, and occasionally one may be found with the point
+of another jammed into the broken place." (6. Mr. R. Brown, in 'Proc.
+Zool. Soc.' 1869, p. 553. See Prof. Turner, in 'Journal of Anat. and
+Phys.' 1872, p. 76, on the homological nature of these tusks. Also Mr.
+J.W. Clarke on two tusks being developed in the males, in 'Proceedings
+of the Zoological Society,' 1871, p. 42.) The tooth on the opposite
+side of the head in the male consists of a rudiment about ten inches in
+length, which is embedded in the jaw; but sometimes, though rarely, both
+are equally developed on the two sides. In the female both are always
+rudimentary. The male cachalot has a larger head than that of the
+female, and it no doubt aids him in his aquatic battles. Lastly, the
+adult male ornithorhynchus is provided with a remarkable apparatus,
+namely a spur on the foreleg, closely resembling the poison-fang of a
+venomous snake; but according to Harting, the secretion from the gland
+is not poisonous; and on the leg of the female there is a hollow,
+apparently for the reception of the spur. (7. Owen on the cachalot and
+Ornithorhynchus, ibid. vol. iii. pp. 638, 641. Harting is quoted by Dr.
+Zouteveen in the Dutch translation of this work, vol. ii. p. 292.)
+
+When the males are provided with weapons which in the females are
+absent, there can be hardly a doubt that these serve for fighting with
+other males; and that they were acquired through sexual selection, and
+were transmitted to the male sex alone. It is not probable, at least
+in most cases, that the females have been prevented from acquiring such
+weapons, on account of their being useless, superfluous, or in some
+way injurious. On the contrary, as they are often used by the males for
+various purposes, more especially as a defence against their enemies, it
+is a surprising fact that they are so poorly developed, or quite absent,
+in the females of so many animals. With female deer the development
+during each recurrent season of great branching horns, and with female
+elephants the development of immense tusks, would be a great waste
+of vital power, supposing that they were of no use to the females.
+Consequently, they would have tended to be eliminated in the female
+through natural selection; that is, if the successive variations were
+limited in their transmission to the female sex, for otherwise the
+weapons of the males would have been injuriously affected, and this
+would have been a greater evil. On the whole, and from the consideration
+of the following facts, it seems probable that when the various weapons
+differ in the two sexes, this has generally depended on the kind of
+transmission which has prevailed.
+
+As the reindeer is the one species in the whole family of Deer, in which
+the female is furnished with horns, though they are somewhat smaller,
+thinner, and less branched than in the male, it might naturally be
+thought that, at least in this case, they must be of some special
+service to her. The female retains her horns from the time when they are
+fully developed, namely, in September, throughout the winter until April
+or May, when she brings forth her young. Mr. Crotch made particular
+enquiries for me in Norway, and it appears that the females at this
+season conceal themselves for about a fortnight in order to bring forth
+their young, and then reappear, generally hornless. In Nova Scotia,
+however, as I hear from Mr. H. Reeks, the female sometimes retains her
+horns longer. The male on the other hand casts his horns much earlier,
+towards the end of November. As both sexes have the same requirements
+and follow the same habits of life, and as the male is destitute of
+horns during the winter, it is improbable that they can be of any
+special service to the female during this season, which includes the
+larger part of the time during which she is horned. Nor is it probable
+that she can have inherited horns from some ancient progenitor of the
+family of deer, for, from the fact of the females of so many species in
+all quarters of the globe not having horns, we may conclude that this
+was the primordial character of the group. (8. On the structure and
+shedding of the horns of the reindeer, Hoffberg, 'Amoenitates Acad.'
+vol. iv. 1788, p. 149. See Richardson, 'Fauna Bor. Americana,' p. 241,
+in regard to the American variety or species: also Major W. Ross King,
+'The Sportsman in Canada,' 1866, p. 80.
+
+The horns of the reindeer are developed at a most unusually early
+age; but what the cause of this may be is not known. The effect has
+apparently been the transference of the horns to both sexes. We should
+bear in mind that horns are always transmitted through the female, and
+that she has a latent capacity for their development, as we see in
+old or diseased females. (9. Isidore Geoffroy St.-Hilaire, 'Essais de
+Zoolog. G�n�rale,' 1841, p. 513. Other masculine characters, besides
+the horns, are sometimes similarly transferred to the female; thus Mr.
+Boner, in speaking of an old female chamois ('Chamois Hunting in the
+Mountains of Bavaria,' 1860, 2nd ed., p. 363), says, "not only was the
+head very male-looking, but along the back there was a ridge of long
+hair, usually to be found only in bucks.") Moreover the females of
+some other species of deer exhibit, either normally or occasionally,
+rudiments of horns; thus the female of Cervulus moschatus has "bristly
+tufts, ending in a knob, instead of a horn"; and "in most specimens of
+the female wapiti (Cervus canadensis) there is a sharp bony protuberance
+in the place of the horn." (10. On the Cervulus, Dr. Gray, 'Catalogue
+of Mammalia in the British Museum,' part iii. p. 220. On the Cervus
+canadensis or wapiti, see Hon. J.D. Caton, 'Ottawa Academy of Nat.
+Sciences,' May 1868, p. 9.) From these several considerations we may
+conclude that the possession of fairly well-developed horns by the
+female reindeer, is due to the males having first acquired them
+as weapons for fighting with other males; and secondarily to their
+development from some unknown cause at an unusually early age in the
+males, and their consequent transference to both sexes.
+
+Turning to the sheath-horned ruminants: with antelopes a graduated
+series can be formed, beginning with species, the females of which are
+completely destitute of horns--passing on to those which have horns so
+small as to be almost rudimentary (as with the Antilocapra americana, in
+which species they are present in only one out of four or five females
+(11. I am indebted to Dr. Canfield for this information; see also
+his paper in the 'Proceedings of the Zoological Society,' 1866, p.
+105.))--to those which have fairly developed horns, but manifestly
+smaller and thinner than in the male and sometimes of a different shape
+(12. For instance the horns of the female Ant. euchore resemble those
+of a distinct species, viz. the Ant. dorcas var. Corine, see Desmarest,
+'Mammalogie,' p. 455.),--and ending with those in which both sexes have
+horns of equal size. As with the reindeer, so with antelopes, there
+exists, as previously shewn, a relation between the period of the
+development of the horns and their transmission to one or both sexes; it
+is therefore probable that their presence or absence in the females of
+some species, and their more or less perfect condition in the females
+of other species, depends, not on their being of any special use, but
+simply on inheritance. It accords with this view that even in the same
+restricted genus both sexes of some species, and the males alone of
+others, are thus provided. It is also a remarkable fact that, although
+the females of Antilope bezoartica are normally destitute of horns, Mr.
+Blyth has seen no less than three females thus furnished; and there was
+no reason to suppose that they were old or diseased.
+
+In all the wild species of goats and sheep the horns are larger in the
+male than in the female, and are sometimes quite absent in the latter.
+(13. Gray, 'Catalogue of Mammalia, the British Museum,' part iii. 1852,
+p. 160.) In several domestic breeds of these two animals, the males
+alone are furnished with horns; and in some breeds, for instance, in the
+sheep of North Wales, though both sexes are properly horned, the ewes
+are very liable to be hornless. I have been informed by a trustworthy
+witness, who purposely inspected a flock of these same sheep during
+the lambing season, that the horns at birth are generally more fully
+developed in the male than in the female. Mr. J. Peel crossed his Lonk
+sheep, both sexes of which always bear horns, with hornless Leicesters
+and hornless Shropshire Downs; and the result was that the male
+offspring had their horns considerably reduced, whilst the females were
+wholly destitute of them. These several facts indicate that, with sheep,
+the horns are a much less firmly fixed character in the females than
+in the males; and this leads us to look at the horns as properly of
+masculine origin.
+
+With the adult musk-ox (Ovibos moschatus) the horns of the male are
+larger than those of the female, and in the latter the bases do not
+touch. (14. Richardson, 'Fauna Bor. Americana,' p. 278.) In regard to
+ordinary cattle Mr. Blyth remarks: "In most of the wild bovine animals
+the horns are both longer and thicker in the bull than in the cow, and
+in the cow-banteng (Bos sondaicus) the horns are remarkably small, and
+inclined much backwards. In the domestic races of cattle, both of the
+humped and humpless types, the horns are short and thick in the bull,
+longer and more slender in the cow and ox; and in the Indian buffalo,
+they are shorter and thicker in the bull, longer and more slender in the
+cow. In the wild gaour (B. gaurus) the horns are mostly both longer and
+thicker in the bull than in the cow." (15. 'Land and Water,' 1867, p.
+346.) Dr. Forsyth Major also informs me that a fossil skull, believed to
+be that of the female Bos etruscus, has been found in Val d'Arno, which
+is wholly without horns. In the Rhinoceros simus, as I may add, the
+horns of the female are generally longer but less powerful than in
+the male; and in some other species of rhinoceros they are said to be
+shorter in the female. (16. Sir Andrew Smith, 'Zoology of S. Africa,'
+pl. xix. Owen, 'Anatomy of Vertebrates,' vol. iii. p. 624.) From these
+various facts we may infer as probable that horns of all kinds, even
+when they are equally developed in the two sexes, were primarily
+acquired by the male in order to conquer other males, and have been
+transferred more or less completely to the female.
+
+The effects of castration deserve notice, as throwing light on this
+same point. Stags after the operation never renew their horns. The male
+reindeer, however, must be excepted, as after castration he does renew
+them. This fact, as well as the possession of horns by both sexes, seems
+at first to prove that the horns in this species do not constitute
+a sexual character (17. This is the conclusion of Seidlitz, 'Die
+Darwinsche Theorie,' 1871, p. 47.); but as they are developed at a very
+early age, before the sexes differ in constitution, it is not surprising
+that they should be unaffected by castration, even if they were
+aboriginally acquired by the male. With sheep both sexes properly bear
+horns; and I am informed that with Welch sheep the horns of the males
+are considerably reduced by castration; but the degree depends much on
+the age at which the operation is performed, as is likewise the case
+with other animals. Merino rams have large horns, whilst the ewes
+"generally speaking are without horns"; and in this breed castration
+seems to produce a somewhat greater effect, so that if performed at an
+early age the horns "remain almost undeveloped." (18. I am much obliged
+to Prof. Victor Carus, for having made enquiries for me in Saxony on
+this subject. H. von Nathusius ('Viehzucht,' 1872, p. 64) says that the
+horns of sheep castrated at an early period, either altogether disappear
+or remain as mere rudiments; but I do not know whether he refers to
+merinos or to ordinary breeds.) On the Guinea coast there is a breed in
+which the females never bear horns, and, as Mr. Winwood Reade informs
+me, the rams after castration are quite destitute of them. With cattle,
+the horns of the males are much altered by castration; for instead of
+being short and thick, they become longer than those of the cow, but
+otherwise resemble them. The Antilope bezoartica offers a somewhat
+analogous case: the males have long straight spiral horns, nearly
+parallel to each other, and directed backwards; the females occasionally
+bear horns, but these when present are of a very different shape, for
+they are not spiral, and spreading widely, bend round with the points
+forwards. Now it
+
+is a remarkable fact that, in the castrated male, as Mr. Blyth informs
+me, the horns are of the same peculiar shape as in the female, but
+longer and thicker. If we may judge from analogy, the female probably
+shews us, in these two cases of cattle and the antelope, the former
+condition of the horns in some early progenitor of each species. But why
+castration should lead to the reappearance of an early condition of the
+horns cannot be explained with any certainty. Nevertheless, it
+seems probable, that in nearly the same manner as the constitutional
+disturbance in the offspring, caused by a cross between two distinct
+species or races, often leads to the reappearance of long-lost
+characters (19. I have given various experiments and other evidence
+proving that this is the case, in my 'Variation of Animals and
+Plants under Domestication,' vol. ii. 1868, pp. 39-47.); so here,
+the disturbance in the constitution of the individual, resulting from
+castration, produces the same effect.
+
+The tusks of the elephant, in the different species or races, differ
+according to sex, nearly as do the horns of ruminants. In India and
+Malacca the males alone are provided with well-developed tusks. The
+elephant of Ceylon is considered by most naturalists as a distinct race,
+but by some as a distinct species, and here "not one in a hundred is
+found with tusks, the few that possess them being exclusively males."
+(20. Sir J. Emerson Tennent, 'Ceylon,' 1859, vol. ii. p. 274. For
+Malacca, 'Journal of Indian Archipelago,' vol. iv. p. 357.) The
+African elephant is undoubtedly distinct, and the female has large
+well-developed tusks, though not so large as those of the male.
+
+These differences in the tusks of the several races and species of
+elephants--the great variability of the horns of deer, as notably in the
+wild reindeer--the occasional presence of horns in the female Antilope
+Bezoartica, and their frequent absence in the female of Antilocapra
+americana--the presence of two tusks in some few male narwhals--the
+complete absence of tusks in some female walruses--are all instances
+of the extreme variability of secondary sexual characters, and of their
+liability to differ in closely-allied forms.
+
+Although tusks and horns appear in all cases to have been primarily
+developed as sexual weapons, they often serve other purposes. The
+elephant uses his tusks in attacking the tiger; according to Bruce, he
+scores the trunks of trees until they can be thrown down easily, and
+he likewise thus extracts the farinaceous cores of palms; in Africa
+he often uses one tusk, always the same, to probe the ground and thus
+ascertain whether it will bear his weight. The common bull defends the
+herd with his horns; and the elk in Sweden has been known, according to
+Lloyd, to strike a wolf dead with a single blow of his great horns. Many
+similar facts could be given. One of the most curious secondary uses to
+which the horns of an animal may be occasionally put is that observed
+by Captain Hutton (21. 'Calcutta Journal of Natural History,' vol. ii,
+1843, p. 526.) with the wild goat (Capra aegagrus) of the Himalayas and,
+as it is also said with the ibex, namely that when the male accidentally
+falls from a height he bends inwards his head, and by alighting on his
+massive horns, breaks the shock. The female cannot thus use her horns,
+which are smaller, but from her more quiet disposition she does not need
+this strange kind of shield so much.
+
+Each male animal uses his weapons in his own peculiar fashion. The
+common ram makes a charge and butts with such force with the bases of
+his horns, that I have seen a powerful man knocked over like a child.
+Goats and certain species of sheep, for instance the Ovis cycloceros of
+Afghanistan (22. Mr. Blyth, in 'Land and Water,' March, 1867, p. 134,
+on the authority of Capt. Hutton and others. For the wild Pembrokeshire
+goats, see the 'Field,' 1869, p. 150.), rear on their hind legs, and
+then not only butt, but "make a cut down and a jerk up, with the ribbed
+front of their scimitar-shaped horn, as with a sabre. When the O.
+cycloceros attacked a large domestic ram, who was a noted bruiser,
+he conquered him by the sheer novelty of his mode of fighting, always
+closing at once with his adversary, and catching him across the face and
+nose with a sharp drawing jerk of the head, and then bounding out of the
+way before the blow could be returned." In Pembrokeshire a male goat,
+the master of a flock which during several generations had run wild, was
+known to have killed several males in single combat; this goat possessed
+enormous horns, measuring thirty-nine inches in a straight line from
+tip to tip. The common bull, as every one knows, gores and tosses his
+opponent; but the Italian buffalo is said never to use his horns: he
+gives a tremendous blow with his convex forehead, and then tramples on
+his fallen enemy with his knees--an instinct which the common bull does
+not possess. (23. M. E.M. Bailly, "Sur l'usage des cornes," etc.,
+.Annal des Sciences Nat.' tom. ii. 1824, p. 369.) Hence a dog who pins
+a buffalo by the nose is immediately crushed. We must, however, remember
+that the Italian buffalo has been long domesticated, and it is by no
+means certain that the wild parent-form had similar horns. Mr. Bartlett
+informs me that when a female Cape buffalo (Bubalus caffer) was turned
+into an enclosure with a bull of the same species, she attacked him, and
+he in return pushed her about with great violence. But it was manifest
+to Mr. Bartlett that, had not the bull shewn dignified forbearance, he
+could easily have killed her by a single lateral thrust with his immense
+horns. The giraffe uses his short, hair-covered horns, which are rather
+longer in the male than in the female, in a curious manner; for, with
+his long neck, he swings his head to either side, almost upside down,
+with such force that I have seen a hard plank deeply indented by a
+single blow.
+
+[Fig. 63. Oryx leucoryx, male (from the Knowsley Menagerie).]
+
+With antelopes it is sometimes difficult to imagine how they can
+possibly use their curiously-shaped horns; thus the springboc (Ant.
+euchore) has rather short upright horns, with the sharp points bent
+inwards almost at right angles, so as to face each other; Mr. Bartlett
+does not know how they are used, but suggests that they would inflict
+a fearful wound down each side of the face of an antagonist. The
+slightly-curved horns of the Oryx leucoryx (Fig. 63) are directed
+backwards, and are of such length that their points reach beyond the
+middle of the back, over which they extend in almost parallel lines.
+Thus they seem singularly ill-fitted for fighting; but Mr. Bartlett
+informs me that when two of these animals prepare for battle, they kneel
+down, with their heads between their fore legs, and in this attitude
+the horns stand nearly parallel and close to the ground, with the points
+directed forwards and a little upwards. The combatants then gradually
+approach each other, and each endeavours to get the upturned points
+under the body of the other; if one succeeds in doing this, he suddenly
+springs up, throwing up his head at the same time, and can thus wound or
+perhaps even transfix his antagonist. Both animals always kneel down,
+so as to guard as far as possible against this manoeuvre. It has been
+recorded that one of these antelopes has used his horn with effect even
+against a lion; yet from being forced to place his head between the
+forelegs in order to bring the points of the horns forward, he would
+generally be under a great disadvantage when attacked by any other
+animal. It is, therefore, not probable that the horns have been modified
+into their present great length and peculiar position, as a protection
+against beasts of prey. We can however see that, as soon as some ancient
+male progenitor of the Oryx acquired moderately long horns, directed
+a little backwards, he would be compelled, in his battles with rival
+males, to bend his head somewhat inwards or downwards, as is now done by
+certain stags; and it is not improbable that he might have acquired
+the habit of at first occasionally and afterwards of regularly kneeling
+down. In this case it is almost certain that the males which possessed
+the longest horns would have had a great advantage over others with
+shorter horns; and then the horns would gradually have been rendered
+longer and longer, through sexual selection, until they acquired their
+present extraordinary length and position.
+
+With stags of many kinds the branches of the horns offer a curious case
+of difficulty; for certainly a single straight point would inflict
+a much more serious wound than several diverging ones. In Sir Philip
+Egerton's museum there is a horn of the red-deer (Cervus elaphus),
+thirty inches in length, with "not fewer than fifteen snags or
+branches"; and at Moritzburg there is still preserved a pair of antlers
+of a red-deer, shot in 1699 by Frederick I., one of which bears the
+astonishing number of thirty-three branches and the other twenty-seven,
+making altogether sixty branches. Richardson figures a pair of antlers
+of the wild reindeer with twenty-nine points. (24. On the horns of
+red-deer, Owen, 'British Fossil Mammals,' 1846, p. 478; Richardson on
+the horns of the reindeer, 'Fauna Bor. Americana,' 1829, p. 240. I
+am indebted to Prof. Victor Carus, for the Moritzburg case.) From the
+manner in which the horns are branched, and more especially from
+deer being known occasionally to fight together by kicking with their
+fore-feet (25. Hon. J.D. Caton ('Ottawa Acad. of Nat. Science,' May
+1868, p. 9) says that the American deer fight with their fore-feet,
+after "the question of superiority has been once settled and
+acknowledged in the herd." Bailly, 'Sur l'Usage des cornes,' 'Annales
+des Sciences Nat.' tom. ii. 1824, p. 371.), M. Bailly actually comes to
+the conclusion that their horns are more injurious than useful to them.
+But this author overlooks the pitched battles between rival males. As
+I felt much perplexed about the use or advantage of the branches, I
+applied to Mr. McNeill of Colonsay, who has long and carefully observed
+the habits of red-deer, and he informs me that he has never seen some of
+the branches brought into use, but that the brow antlers, from inclining
+downwards, are a great protection to the forehead, and their points are
+likewise used in attack. Sir Philip Egerton also informs me both as to
+red-deer and fallow-deer that, in fighting, they suddenly dash together,
+and getting their horns fixed against each other's bodies, a desperate
+struggle ensues. When one is at last forced to yield and turn round, the
+victor endeavours to plunge his brow antlers into his defeated foe. It
+thus appears that the upper branches are used chiefly or exclusively for
+pushing and fencing. Nevertheless in some species the upper branches
+are used as weapons of offence; when a man was attacked by a wapiti deer
+(Cervus canadensis) in Judge Caton's park in Ottawa, and several men
+tried to rescue him, the stag "never raised his head from the ground;
+in fact he kept his face almost flat on the ground, with his nose nearly
+between his fore feet, except when he rolled his head to one side to
+take a new observation preparatory to a plunge." In this position the
+ends of the horns were directed against his adversaries. "In rolling his
+head he necessarily raised it somewhat, because his antlers were so long
+that he could not roll his head without raising them on one side, while,
+on the other side they touched the ground." The stag by this procedure
+gradually drove the party of rescuers backwards to a distance of 150 or
+200 feet; and the attacked man was killed. (26. See a most interesting
+account in the Appendix to Hon. J.D. Caton's paper, as above quoted.)
+
+[Fig. 64. Strepsiceros Kudu (from Sir Andrew Smith's 'Zoology of South
+Africa.']
+
+Although the horns of stags are efficient weapons, there can, I think,
+be no doubt that a single point would have been much more dangerous than
+a branched antler; and Judge Caton, who has had large experience with
+deer, fully concurs in this conclusion. Nor do the branching horns,
+though highly important as a means of defence against rival stags,
+appear perfectly well adapted for this purpose, as they are liable to
+become interlocked. The suspicion has therefore crossed my mind that
+they may serve in part as ornaments. That the branched antlers of stags
+as well as the elegant lyrated horns of certain antelopes, with their
+graceful double curvature (Fig. 64), are ornamental in our eyes, no one
+will dispute. If, then, the horns, like the splendid accoutrements of
+the knights of old, add to the noble appearance of stags and antelopes,
+they may have been modified partly for this purpose, though mainly
+for actual service in battle; but I have no evidence in favour of this
+belief.
+
+An interesting case has lately been published, from which it appears
+that the horns of a deer in one district in the United States are now
+being modified through sexual and natural selection. A writer in an
+excellent American Journal (27. The 'American Naturalist,' Dec. 1869,
+p. 552.) says, that he has hunted for the last twenty-one years in the
+Adirondacks, where the Cervus virginianus abounds. About fourteen years
+ago he first heard of SPIKE-HORN BUCKS. These became from year to year
+more common; about five years ago he shot one, and afterwards another,
+and now they are frequently killed. "The spike-horn differs greatly from
+the common antler of the C. virginianus. It consists of a single spike,
+more slender than the antler, and scarcely half so long, projecting
+forward from the brow, and terminating in a very sharp point. It gives
+a considerable advantage to its possessor over the common buck. Besides
+enabling him to run more swiftly through the thick woods and underbrush
+(every hunter knows that does and yearling bucks run much more rapidly
+than the large bucks when armed with their cumbrous antlers), the
+spike-horn is a more effective weapon than the common antler. With this
+advantage the spike-horn bucks are gaining upon the common bucks, and
+may, in time, entirely supersede them in the Adirondacks. Undoubtedly,
+the first spike-horn buck was merely an accidental freak of nature. But
+his spike-horns gave him an advantage, and enabled him to propagate his
+peculiarity. His descendants having a like advantage, have propagated
+the peculiarity in a constantly increasing ratio, till they are slowly
+crowding the antlered deer from the region they inhabit." A critic has
+well objected to this account by asking, why, if the simple horns are
+now so advantageous, were the branched antlers of the parent-form ever
+developed? To this I can only answer by remarking, that a new mode of
+attack with new weapons might be a great advantage, as shewn by the case
+of the Ovis cycloceros, who thus conquered a domestic ram famous for his
+fighting power. Though the branched antlers of a stag are well adapted
+for fighting with his rivals, and though it might be an advantage to the
+prong-horned variety slowly to acquire long and branched horns, if
+he had to fight only with others of the same kind, yet it by no means
+follows that branched horns would be the best fitted for conquering a
+foe differently armed. In the foregoing case of the Oryx leucoryx, it is
+almost certain that the victory would rest with an antelope having short
+horns, and who therefore did not need to kneel down, though an oryx
+might profit by having still longer horns, if he fought only with his
+proper rivals.
+
+Male quadrupeds, which are furnished with tusks, use them in various
+ways, as in the case of horns. The boar strikes laterally and upwards;
+the musk-deer downwards with serious effect. (28. Pallas, 'Spicilegia
+Zoologica,' fasc. xiii. 1779, p. 18.) The walrus, though having so short
+a neck and so unwieldy a body, "can strike either upwards, or downwards,
+or sideways, with equal dexterity." (29. Lamont, 'Seasons with the
+Sea-Horses,' 1861, p. 141.) I was informed by the late Dr. Falconer,
+that the Indian elephant fights in a different manner according to the
+position and curvature of his tusks. When they are directed forwards and
+upwards he is able to fling a tiger to a great distance--it is said to
+even thirty feet; when they are short and turned downwards he endeavours
+suddenly to pin the tiger to the ground and, in consequence, is
+dangerous to the rider, who is liable to be jerked off the howdah.
+(30. See also Corse ('Philosophical Transactions,' 1799, p. 212) on
+the manner in which the short-tusked Mooknah variety attacks other
+elephants.)
+
+Very few male quadrupeds possess weapons of two distinct kinds specially
+adapted for fighting with rival males. The male muntjac-deer (Cervulus),
+however, offers an exception, as he is provided with horns and exserted
+canine teeth. But we may infer from what follows that one form of weapon
+has often been replaced in the course of ages by another. With ruminants
+the development of horns generally stands in an inverse relation with
+that of even moderately developed canine teeth. Thus camels, guanacoes,
+chevrotains, and musk-deer, are hornless, and they have efficient
+canines; these teeth being "always of smaller size in the females than
+in the males." The Camelidae have, in addition to their true canines, a
+pair of canine-shaped incisors in their upper jaws. (31. Owen, 'Anatomy
+of Vertebrates,' vol. iii. p. 349.) Male deer and antelopes, on the
+other hand, possess horns, and they rarely have canine teeth; and these,
+when present, are always of small size, so that it is doubtful whether
+they are of any service in their battles. In Antilope montana they exist
+only as rudiments in the young male, disappearing as he grows old; and
+they are absent in the female at all ages; but the females of certain
+other antelopes and of certain deer have been known occasionally to
+exhibit rudiments of these teeth. (32. See Ruppell (in 'Proc. Zoolog.
+Soc.' Jan. 12, 1836, p. 3) on the canines in deer and antelopes, with
+a note by Mr. Martin on a female American deer. See also Falconer
+('Palaeont. Memoirs and Notes,' vol. i. 1868, p. 576) on canines in an
+adult female deer. In old males of the musk-deer the canines (Pallas,
+'Spic. Zoolog.' fasc. xiii. 1779, p. 18) sometimes grow to the length of
+three inches, whilst in old females a rudiment projects scarcely half
+an inch above the gums.) Stallions have small canine teeth, which are
+either quite absent or rudimentary in the mare; but they do not appear
+to be used in fighting, for stallions bite with their incisors, and do
+not open their mouths wide like camels and guanacoes. Whenever the adult
+male possesses canines, now inefficient, whilst the female has either
+none or mere rudiments, we may conclude that the early male progenitor
+of the species was provided with efficient canines, which have been
+partially transferred to the females. The reduction of these teeth in
+the males seems to have followed from some change in their manner of
+fighting, often (but not in the horse) caused by the development of new
+weapons.
+
+Tusks and horns are manifestly of high importance to their possessors,
+for their development consumes much organised matter. A single tusk
+of the Asiatic elephant--one of the extinct woolly species--and of the
+African elephant, have been known to weigh respectively 150, 160, and
+180 pounds; and even greater weights have been given by some authors.
+(33. Emerson Tennent, 'Ceylon,' 1859, vol. ii. p. 275; Owen, 'British
+Fossil Mammals,' 1846, p. 245.) With deer, in which the horns are
+periodically renewed, the drain on the constitution must be greater; the
+horns, for instance, of the moose weigh from fifty to sixty pounds, and
+those of the extinct Irish elk from sixty to seventy pounds--the skull
+of the latter weighing on an average only five pounds and a quarter.
+Although the horns are not periodically renewed in sheep, yet their
+development, in the opinion of many agriculturists, entails a sensible
+loss to the breeder. Stags, moreover, in escaping from beasts of prey
+are loaded with an additional weight for the race, and are greatly
+retarded in passing through a woody country. The moose, for instance,
+with horns extending five and a half feet from tip to tip, although so
+skilful in their use that he will not touch or break a twig when walking
+quietly, cannot act so dexterously whilst rushing away from a pack of
+wolves. "During his progress he holds his nose up, so as to lay the
+horns horizontally back; and in this attitude cannot see the ground
+distinctly." (34. Richardson, 'Fauna Bor. Americana,' on the moose,
+Alces palmata, pp. 236, 237; on the expanse of the horns, 'Land and
+Water,' 1869, p. 143. See also Owen, 'British Fossil Mammals,' on the
+Irish elk, pp. 447, 455.) The tips of the horns of the great Irish
+elk were actually eight feet apart! Whilst the horns are covered with
+velvet, which lasts with red-deer for about twelve weeks, they are
+extremely sensitive to a blow; so that in Germany the stags at this time
+somewhat change their habits, and avoiding dense forests, frequent young
+woods and low thickets. (35. 'Forest Creatures,' by C. Boner, 1861,
+p. 60.) These facts remind us that male birds have acquired ornamental
+plumes at the cost of retarded flight, and other ornaments at the cost
+of some loss of power in their battles with rival males.
+
+With mammals, when, as is often the case, the sexes differ in size, the
+males are almost always larger and stronger. I am informed by Mr.
+Gould that this holds good in a marked manner with the marsupials
+of Australia, the males of which appear to continue growing until an
+unusually late age. But the most extraordinary case is that of one of
+the seals (Callorhinus ursinus), a full-grown female weighing less than
+one-sixth of a full-grown male. (36. See the very interesting paper
+by Mr. J.A. Allen in 'Bull. Mus. Comp. Zoology of Cambridge, United
+States,' vol. ii. No. 1, p. 82. The weights were ascertained by a
+careful observer, Capt. Bryant. Dr. Gill in 'The American Naturalist,'
+January, 1871, Prof. Shaler on the relative size of the sexes of whales,
+'American Naturalist,' January, 1873.) Dr. Gill remarks that it is
+with the polygamous seals, the males of which are well known to fight
+savagely together, that the sexes differ much in size; the monogamous
+species differing but little. Whales also afford evidence of the
+relation existing between the pugnacity of the males and their large
+size compared with that of the female; the males of the right-whales do
+not fight together, and they are not larger, but rather smaller, than
+their females; on the other hand, male sperm-whales fight much together,
+and their bodies are "often found scarred with the imprint of their
+rival's teeth," and they are double the size of the females. The greater
+strength of the male, as Hunter long ago remarked (37. 'Animal Economy,'
+p. 45.), is invariably displayed in those parts of the body which are
+brought into action in fighting with rival males--for instance, in the
+massive neck of the bull. Male quadrupeds are also more courageous
+and pugnacious than the females. There can be little doubt that these
+characters have been gained, partly through sexual selection, owing to a
+long series of victories, by the stronger and more courageous males
+over the weaker, and partly through the inherited effects of use. It is
+probable that the successive variations in strength, size, and courage,
+whether due to mere variability or to the effects of use, by the
+accumulation of which male quadrupeds have acquired these characteristic
+qualities, occurred rather late in life, and were consequently to a
+large extent limited in their transmission to the same sex.
+
+From these considerations I was anxious to obtain information as to the
+Scotch deer-hound, the sexes of which differ more in size than those of
+any other breed (though blood-hounds differ considerably), or than
+in any wild canine species known to me. Accordingly, I applied to Mr.
+Cupples, well known for his success with this breed, who has weighed and
+measured many of his own dogs, and who has with great kindness collected
+for me the following facts from various sources. Fine male dogs,
+measured at the shoulder, range from 28 inches, which is low, to 33 or
+even 34 inches in height; and in weight from 80 pounds, which is light,
+to 120 pounds, or even more. The females range in height from 23 to 27,
+or even to 28 inches; and in weight from 50 to 70, or even 80 pounds.
+(38. See also Richardson's 'Manual on the Dog,' p. 59. Much valuable
+information on the Scottish deer-hound is given by Mr. McNeill, who
+first called attention to the inequality in size between the sexes, in
+Scrope's 'Art of Deer-Stalking.' I hope that Mr. Cupples will keep to
+his intention of publishing a full account and history of this famous
+breed.) Mr. Cupples concludes that from 95 to 100 pounds for the male,
+and 70 for the female, would be a safe average; but there is reason to
+believe that formerly both sexes attained a greater weight. Mr. Cupples
+has weighed puppies when a fortnight old; in one litter the average
+weight of four males exceeded that of two females by six and a half
+ounces; in another litter the average weight of four males exceeded that
+of one female by less than one ounce; the same males when three weeks
+old, exceeded the female by seven and a half ounces, and at the age of
+six weeks by nearly fourteen ounces. Mr. Wright of Yeldersley House,
+in a letter to Mr. Cupples, says: "I have taken notes on the sizes and
+weights of puppies of many litters, and as far as my experience goes,
+dog-puppies as a rule differ very little from bitches till they arrive
+at about five or six months old; and then the dogs begin to increase,
+gaining upon the bitches both in weight and size. At birth, and for
+several weeks afterwards, a bitch-puppy will occasionally be larger
+than any of the dogs, but they are invariably beaten by them later." Mr.
+McNeill, of Colonsay, concludes that "the males do not attain their full
+growth till over two years old, though the females attain it sooner."
+According to Mr. Cupples' experience, male dogs go on growing in stature
+till they are from twelve to eighteen months old, and in weight till
+from eighteen to twenty-four months old; whilst the females cease
+increasing in stature at the age of from nine to fourteen or fifteen
+months, and in weight at the age of from twelve to fifteen months. From
+these various statements it is clear that the full difference in size
+between the male and female Scotch deer-hound is not acquired until
+rather late in life. The males almost exclusively are used for coursing,
+for, as Mr. McNeill informs me, the females have not sufficient strength
+and weight to pull down a full-grown deer. From the names used in old
+legends, it appears, as I hear from Mr. Cupples, that, at a very ancient
+period, the males were the most celebrated, the females being mentioned
+only as the mothers of famous dogs. Hence, during many generations, it
+is the male which has been chiefly tested for strength, size, speed, and
+courage, and the best will have been bred from. As, however, the males
+do not attain their full dimensions until rather late in life, they will
+have tended, in accordance with the law often indicated, to transmit
+their characters to their male offspring alone; and thus the great
+inequality in size between the sexes of the Scotch deer-hound may
+probably be accounted for.
+
+[Fig. 65. Head of Common wild boar, in prime of life (from Brehm).]
+
+The males of some few quadrupeds possess organs or parts developed
+solely as a means of defence against the attacks of other males. Some
+kinds of deer use, as we have seen, the upper branches of their horns
+chiefly or exclusively for defending themselves; and the Oryx antelope,
+as I am informed by Mr. Bartlett, fences most skilfully with his long,
+gently curved horns; but these are likewise used as organs of offence.
+The same observer remarks that rhinoceroses in fighting, parry each
+other's sidelong blows with their horns, which clatter loudly together,
+as do the tusks of boars. Although wild boars fight desperately, they
+seldom, according to Brehm, receive fatal wounds, as the blows fall
+on each other's tusks, or on the layer of gristly skin covering the
+shoulder, called by the German hunters, the shield; and here we have
+a part specially modified for defence. With boars in the prime of life
+(Fig. 65) the tusks in the lower jaw are used for fighting, but they
+become in old age, as Brehm states, so much curved inwards and upwards
+over the snout that they can no longer be used in this way. They may,
+however, still serve, and even more effectively, as a means of defence.
+In compensation for the loss of the lower tusks as weapons of offence,
+those in the upper jaw, which always project a little laterally,
+increase in old age so much in length and curve so much upwards that
+they can be used for attack. Nevertheless, an old boar is not so
+dangerous to man as one at the age of six or seven years. (39. Brehm,
+'Thierleben,' B. ii. ss. 729-732.)
+
+[Fig. 66. Skull of the Babirusa Pig (from Wallace's 'Malay
+Archipelago').]
+
+In the full-grown male Babirusa pig of Celebes (Fig. 66), the lower
+tusks are formidable weapons, like those of the European boar in the
+prime of life, whilst the upper tusks are so long and have their points
+so much curled inwards, sometimes even touching the forehead, that they
+are utterly useless as weapons of attack. They more nearly resemble
+horns than teeth, and are so manifestly useless as teeth that the animal
+was formerly supposed to rest his head by hooking them on to a
+branch! Their convex surfaces, however, if the head were held a little
+laterally, would serve as an excellent guard; and hence, perhaps, it is
+that in old animals they "are generally broken off, as if by fighting."
+(40. See Mr. Wallace's interesting account of this animal, 'The Malay
+Archipelago,' 1869, vol. i. p. 435.) Here, then, we have the curious
+case of the upper tusks of the Babirusa regularly assuming during the
+prime of life a structure which apparently renders them fitted only for
+defence; whilst in the European boar the lower tusks assume in a less
+degree and only during old age nearly the same form, and then serve in
+like manner solely for defence.
+
+[Fig. 67. Head of female Aethiopian wart-hog, from 'Proc. Zool. Soc.'
+1869, shewing the same characters as the male, though on a reduced
+scale. N.B. When the engraving was first made, I was under the
+impression that it represented the male.]
+
+In the wart-hog (see Phacochoerus aethiopicus, Fig. 67) the tusks in the
+upper jaw of the male curve upwards during the prime of life, and from
+being pointed serve as formidable weapons. The tusks in the lower jaw
+are sharper than those in the upper, but from their shortness it seems
+hardly possible that they can be used as weapons of attack. They must,
+however, greatly strengthen those in the upper jaw, from being ground so
+as to fit closely against their bases. Neither the upper nor the lower
+tusks appear to have been specially modified to act as guards, though
+no doubt they are to a certain extent used for this purpose. But the
+wart-hog is not destitute of other special means of protection, for it
+has, on each side of the face, beneath the eyes, a rather stiff, yet
+flexible, cartilaginous, oblong pad (Fig. 67), which projects two or
+three inches outwards; and it appeared to Mr. Bartlett and myself, when
+viewing the living animal, that these pads, when struck from beneath
+by the tusks of an opponent, would be turned upwards, and would thus
+admirably protect the somewhat prominent eyes. I may add, on the
+authority of Mr. Bartlett, that these boars when fighting stand directly
+face to face.
+
+Lastly, the African river-hog (Potomochoerus penicillatus) has a hard
+cartilaginous knob on each side of the face beneath the eyes, which
+answers to the flexible pad of the wart-hog; it has also two bony
+prominences on the upper jaw above the nostrils. A boar of this species
+in the Zoological Gardens recently broke into the cage of the wart-hog.
+They fought all night long, and were found in the morning much
+exhausted, but not seriously wounded. It is a significant fact,
+as shewing the purposes of the above-described projections and
+excrescences, that these were covered with blood, and were scored and
+abraded in an extraordinary manner.
+
+Although the males of so many members of the pig family are provided
+with weapons, and as we have just seen with means of defence, these
+weapons seem to have been acquired within a rather late geological
+period. Dr. Forsyth Major specifies (41. 'Atti della Soc. Italiana di
+Sc. Nat.' 1873, vol. xv. fasc. iv.) several miocene species, in none of
+which do the tusks appear to have been largely developed in the males;
+and Professor Rutimeyer was formerly struck with this same fact.
+
+The mane of the lion forms a good defence against the attacks of rival
+lions, the one danger to which he is liable; for the males, as Sir A.
+Smith informs me, engage in terrible battles, and a young lion dares not
+approach an old one. In 1857 a tiger at Bromwich broke into the cage of
+a lion and a fearful scene ensued: "the lion's mane saved his neck and
+head from being much injured, but the tiger at last succeeded in ripping
+up his belly, and in a few minutes he was dead." (42. 'The Times,'
+Nov. 10, 1857. In regard to the Canada lynx, see Audubon and Bachman,
+'Quadrupeds of North America,' 1846, p. 139.) The broad ruff round the
+throat and chin of the Canadian lynx (Felis canadensis) is much longer
+in the male than in the female; but whether it serves as a defence I do
+not know. Male seals are well known to fight desperately together, and
+the males of certain kinds (Otaria jubata) (43. Dr. Murie, on Otaria,
+'Proc. Zoolog. Soc.' 1869, p. 109. Mr. J.A. Allen, in the paper above
+quoted (p. 75), doubts whether the hair, which is longer on the neck in
+the male than in the female, deserves to be called a mane.) have great
+manes, whilst the females have small ones or none. The male baboon of
+the Cape of Good Hope (Cynocephalus porcarius) has a much longer mane
+and larger canine teeth than the female; and the mane probably serves
+as a protection, for, on asking the keepers in the Zoological Gardens,
+without giving them any clue to my object, whether any of the monkeys
+especially attacked each other by the nape of the neck, I was answered
+that this was not the case, except with the above baboon. In the
+Hamadryas baboon, Ehrenberg compares the mane of the adult male to that
+of a young lion, whilst in the young of both sexes and in the female the
+mane is almost absent.
+
+It appeared to me probable that the immense woolly mane of the male
+American bison, which reaches almost to the ground, and is much more
+developed in the males than in the females, served as a protection to
+them in their terrible battles; but an experienced hunter told Judge
+Caton that he had never observed anything which favoured this belief.
+The stallion has a thicker and fuller mane than the mare; and I have
+made particular inquiries of two great trainers and breeders, who have
+had charge of many entire horses, and am assured that they "invariably
+endeavour to seize one another by the neck." It does not, however,
+follow from the foregoing statements, that when the hair on the neck
+serves as a defence, that it was originally developed for this purpose,
+though this is probable in some cases, as in that of the lion. I am
+informed by Mr. McNeill that the long hairs on the throat of the stag
+(Cervus elaphus) serve as a great protection to him when hunted, for
+the dogs generally endeavour to seize him by the throat; but it is not
+probable that these hairs were specially developed for this purpose;
+otherwise the young and the females would have been equally protected.
+
+CHOICE IN PAIRING BY EITHER SEX OF QUADRUPEDS.
+
+Before describing in the next chapter, the differences between the sexes
+in voice, odours emitted, and ornaments, it will be convenient here to
+consider whether the sexes exert any choice in their unions. Does the
+female prefer any particular male, either before or after the males
+may have fought together for supremacy; or does the male, when not a
+polygamist, select any particular female? The general impression amongst
+breeders seems to be that the male accepts any female; and this owing to
+his eagerness, is, in most cases, probably the truth. Whether the female
+as a general rule indifferently accepts any male is much more doubtful.
+In the fourteenth chapter, on Birds, a considerable body of direct and
+indirect evidence was advanced, shewing that the female selects her
+partner; and it would be a strange anomaly if female quadrupeds,
+which stand higher in the scale and have higher mental powers, did not
+generally, or at least often, exert some choice. The female could in
+most cases escape, if wooed by a male that did not please or excite her;
+and when pursued by several males, as commonly occurs, she would often
+have the opportunity, whilst they were fighting together, of escaping
+with some one male, or at least of temporarily pairing with him. This
+latter contingency has often been observed in Scotland with female
+red-deer, as I am informed by Sir Philip Egerton and others. (44. Mr.
+Boner, in his excellent description of the habits of the red-deer in
+Germany ('Forest Creatures,' 1861, p. 81) says, "while the stag is
+defending his rights against one intruder, another invades the sanctuary
+of his harem, and carries off trophy after trophy." Exactly the same
+thing occurs with seals; see Mr. J.A. Allen, ibid. p. 100.)
+
+It is scarcely possible that much should be known about female
+quadrupeds in a state of nature making any choice in their marriage
+unions. The following curious details on the courtship of one of the
+eared seals (Callorhinus ursinus) are given (45. Mr. J.A. Allen in
+'Bull. Mus. Comp. Zoolog. of Cambridge, United States,' vol. ii. No. 1,
+p. 99.) on the authority of Capt. Bryant, who had ample opportunities
+for observation. He says, "Many of the females on their arrival at the
+island where they breed appear desirous of returning to some particular
+male, and frequently climb the outlying rocks to overlook the rookeries,
+calling out and listening as if for a familiar voice. Then changing to
+another place they do the same again...As soon as a female reaches the
+shore, the nearest male goes down to meet her, making meanwhile a noise
+like the clucking of a hen to her chickens. He bows to her and coaxes
+her until he gets between her and the water so that she cannot escape
+him. Then his manner changes, and with a harsh growl he drives her to
+a place in his harem. This continues until the lower row of harems is
+nearly full. Then the males higher up select the time when their more
+fortunate neighbours are off their guard to steal their wives. This they
+do by taking them in their mouths and lifting them over the heads of the
+other females, and carefully placing them in their own harem, carrying
+them as cats do their kittens. Those still higher up pursue the same
+method until the whole space is occupied. Frequently a struggle ensues
+between two males for the possession of the same female, and both
+seizing her at once pull her in two or terribly lacerate her with
+their teeth. When the space is all filled, the old male walks around
+complacently reviewing his family, scolding those who crowd or disturb
+the others, and fiercely driving off all intruders. This surveillance
+always keeps him actively occupied."
+
+As so little is known about the courtship of animals in a state
+of nature, I have endeavoured to discover how far our domesticated
+quadrupeds evince any choice in their unions. Dogs offer the best
+opportunity for observation, as they are carefully attended to and well
+understood. Many breeders have expressed a strong opinion on this
+head. Thus, Mr. Mayhew remarks, "The females are able to bestow their
+affections; and tender recollections are as potent over them as they are
+known to be in other cases, where higher animals are concerned. Bitches
+are not always prudent in their loves, but are apt to fling themselves
+away on curs of low degree. If reared with a companion of vulgar
+appearance, there often springs up between the pair a devotion which no
+time can afterwards subdue. The passion, for such it really is, becomes
+of a more than romantic endurance." Mr. Mayhew, who attended chiefly to
+the smaller breeds, is convinced that the females are strongly attracted
+by males of a large size. (46. 'Dogs: their Management,' by E. Mayhew,
+M.R.C.V.S., 2nd ed., 1864, pp. 187-192.) The well-known veterinary
+Blaine states (47. Quoted by Alex. Walker, 'On Intermarriage,' 1838, p.
+276; see also p. 244.) that his own female pug dog became so attached to
+a spaniel, and a female setter to a cur, that in neither case would they
+pair with a dog of their own breed until several weeks had elapsed.
+Two similar and trustworthy accounts have been given me in regard to
+a female retriever and a spaniel, both of which became enamoured with
+terrier-dogs.
+
+Mr. Cupples informs me that he can personally vouch for the accuracy
+of the following more remarkable case, in which a valuable and
+wonderfully-intelligent female terrier loved a retriever belonging to a
+neighbour to such a degree, that she had often to be dragged away from
+him. After their permanent separation, although repeatedly shewing milk
+in her teats, she would never acknowledge the courtship of any other
+dog, and to the regret of her owner never bore puppies. Mr. Cupples also
+states, that in 1868, a female deerhound in his kennel thrice produced
+puppies, and on each occasion shewed a marked preference for one of
+the largest and handsomest, but not the most eager, of four deerhounds
+living with her, all in the prime of life. Mr. Cupples has observed
+that the female generally favours a dog whom she has associated with and
+knows; her shyness and timidity at first incline her against a strange
+dog. The male, on the contrary, seems rather inclined towards strange
+females. It appears to be rare when the male refuses any particular
+female, but Mr. Wright, of Yeldersley House, a great breeder of dogs,
+informs me that he has known some instances; he cites the case of one of
+his own deerhounds, who would not take any notice of a particular female
+mastiff, so that another deerhound had to be employed. It would be
+superfluous to give, as I could, other instances, and I will only add
+that Mr. Barr, who has carefully bred many bloodhounds, states that in
+almost every instance particular individuals of opposite sexes shew a
+decided preference for each other. Finally, Mr. Cupples, after attending
+to this subject for another year, has written to me, "I have had full
+confirmation of my former statement, that dogs in breeding form decided
+preferences for each other, being often influenced by size, bright
+colour, and individual characters, as well as by the degree of their
+previous familiarity."
+
+In regard to horses, Mr. Blenkiron, the greatest breeder of race-horses
+in the world, informs me that stallions are so frequently capricious in
+their choice, rejecting one mare and without any apparent cause taking
+to another, that various artifices have to be habitually used. The
+famous Monarque, for instance, would never consciously look at the dam
+of Gladiateur, and a trick had to be practised. We can partly see the
+reason why valuable race-horse stallions, which are in such demand as to
+be exhausted, should be so particular in their choice. Mr. Blenkiron has
+never known a mare reject a horse; but this has occurred in Mr. Wright's
+stable, so that the mare had to be cheated. Prosper Lucas (48. 'Trait�
+de l'H�r�d. Nat.' tom. ii. 1850, p. 296.) quotes various statements from
+French authorities, and remarks, "On voit des �talons qui s'eprennent
+d'une jument, et negligent toutes les autres." He gives, on the
+authority of Baelen, similar facts in regard to bulls; and Mr. H.
+Reeks assures me that a famous short-horn bull belonging to his father
+"invariably refused to be matched with a black cow." Hoffberg, in
+describing the domesticated reindeer of Lapland says, "Foeminae majores
+et fortiores mares prae caeteris admittunt, ad eos confugiunt, a
+junioribus agitatae, qui hos in fugam conjiciunt." (49. 'Amoenitates
+Acad.' vol. iv. 1788, p. 160.) A clergyman, who has bred many pigs,
+asserts that sows often reject one boar and immediately accept another.
+
+From these facts there can be no doubt that, with most of our
+domesticated quadrupeds, strong individual antipathies and preferences
+are frequently exhibited, and much more commonly by the female than
+by the male. This being the case, it is improbable that the unions of
+quadrupeds in a state of nature should be left to mere chance. It is
+much more probable that the females are allured or excited by particular
+males, who possess certain characters in a higher degree than other
+males; but what these characters are, we can seldom or never discover
+with certainty.
+
+
+CHAPTER XVIII.
+
+SECONDARY SEXUAL CHARACTERS OF MAMMALS--continued.
+
+Voice--Remarkable sexual peculiarities in seals--Odour--Development
+of the hair--Colour of the hair and skin--Anomalous case of the female
+being more ornamented than the male--Colour and ornaments due to sexual
+selection--Colour acquired for the sake of protection--Colour,
+though common to both sexes, often due to sexual selection--On the
+disappearance of spots and stripes in adult quadrupeds--On the colours
+and ornaments of the Quadrumana--Summary.
+
+Quadrupeds use their voices for various purposes, as a signal of danger,
+as a call from one member of a troop to another, or from the mother to
+her lost offspring, or from the latter for protection to their mother;
+but such uses need not here be considered. We are concerned only with
+the difference between the voices of the sexes, for instance between
+that of the lion and lioness, or of the bull and cow. Almost all male
+animals use their voices much more during the rutting-season than at any
+other time; and some, as the giraffe and porcupine (1. Owen, 'Anatomy
+of Vertebrates,' vol. iii. p. 585.), are said to be completely mute
+excepting at this season. As the throats (i.e. the larynx and thyroid
+bodies (2. Ibid. p. 595.)) of stags periodically become enlarged at
+the beginning of the breeding-season, it might be thought that their
+powerful voices must be somehow of high importance to them; but this
+is very doubtful. From information given to me by two experienced
+observers, Mr. McNeill and Sir P. Egerton, it seems that young stags
+under three years old do not roar or bellow; and that the old ones begin
+bellowing at the commencement of the breeding-season, at first only
+occasionally and moderately, whilst they restlessly wander about in
+search of the females. Their battles are prefaced by loud and prolonged
+bellowing, but during the actual conflict they are silent. Animals of
+all kinds which habitually use their voices utter various noises under
+any strong emotion, as when enraged and preparing to fight; but this may
+merely be the result of nervous excitement, which leads to the spasmodic
+contraction of almost all the muscles of the body, as when a man grinds
+his teeth and clenches his fists in rage or agony. No doubt stags
+challenge each other to mortal combat by bellowing; but those with
+the more powerful voices, unless at the same time the stronger,
+better-armed, and more courageous, would not gain any advantage over
+their rivals.
+
+It is possible that the roaring of the lion may be of some service to
+him by striking terror into his adversary; for when enraged he likewise
+erects his mane and thus instinctively tries to make himself appear as
+terrible as possible. But it can hardly be supposed that the bellowing
+of the stag, even if it be of service to him in this way, can have
+been important enough to have led to the periodical enlargement of the
+throat. Some writers suggest that the bellowing serves as a call to the
+female; but the experienced observers above quoted inform me that female
+deer do not search for the male, though the males search eagerly for the
+females, as indeed might be expected from what we know of the habits
+of other male quadrupeds. The voice of the female, on the other hand,
+quickly brings to her one or more stags (3. See, for instance, Major W.
+Ross King ('The Sportsman in Canada,' 1866, pp. 53, 131) on the habits
+of the moose and wild reindeer.), as is well known to the hunters who
+in wild countries imitate her cry. If we could believe that the male had
+the power to excite or allure the female by his voice, the periodical
+enlargement of his vocal organs would be intelligible on the principle
+of sexual selection, together with inheritance limited to the same sex
+and season; but we have no evidence in favour of this view. As the case
+stands, the loud voice of the stag during the breeding-season does not
+seem to be of any special service to him, either during his courtship or
+battles, or in any other way. But may we not believe that the frequent
+use of the voice, under the strong excitement of love, jealousy, and
+rage, continued during many generations, may at last have produced an
+inherited effect on the vocal organs of the stag, as well as of other
+male animals? This appears to me, in our present state of knowledge, the
+most probable view.
+
+The voice of the adult male gorilla is tremendous, and he is furnished
+with a laryngeal sack, as is the adult male orang. (4. Owen 'Anatomy of
+Vertebrates,' vol. iii. p. 600.) The gibbons rank among the noisiest
+of monkeys, and the Sumatra species (Hylobates syndactylus) is also
+furnished with an air sack; but Mr. Blyth, who has had opportunities for
+observation, does not believe that the male is noisier than the female.
+Hence, these latter monkeys probably use their voices as a mutual call;
+and this is certainly the case with some quadrupeds, for instance
+the beaver. (5. Mr. Green, in 'Journal of Linnean Society,' vol.
+x. 'Zoology,' 1869, note 362.) Another gibbon, the H. agilis, is
+remarkable, from having the power of giving a complete and correct
+octave of musical notes (6. C.L. Martin, 'General Introduction to
+the Natural History of Mamm. Animals,' 1841, p. 431.), which we may
+reasonably suspect serves as a sexual charm; but I shall have to recur
+to this subject in the next chapter. The vocal organs of the American
+Mycetes caraya are one-third larger in the male than in the female, and
+are wonderfully powerful. These monkeys in warm weather make the forests
+resound at morning and evening with their overwhelming voices. The males
+begin the dreadful concert, and often continue it during many hours,
+the females sometimes joining in with their less powerful voices. An
+excellent observer, Rengger (7. 'Naturgeschichte der S�ugethiere von
+Paraguay,' 1830, ss. 15, 21.), could not perceive that they were excited
+to begin by any special cause; he thinks that, like many birds, they
+delight in their own music, and try to excel each other. Whether most
+of the foregoing monkeys have acquired their powerful voices in order
+to beat their rivals and charm the females--or whether the vocal organs
+have been strengthened and enlarged through the inherited effects of
+long-continued use without any particular good being thus gained--I will
+not pretend to say; but the former view, at least in the case of the
+Hylobates agilis, seems the most probable.
+
+I may here mention two very curious sexual peculiarities occurring in
+seals, because they have been supposed by some writers to affect the
+voice. The nose of the male sea-elephant (Macrorhinus proboscideus)
+becomes greatly elongated during the breeding-season, and can then be
+erected. In this state it is sometimes a foot in length. The female is
+not thus provided at any period of life. The male makes a wild, hoarse,
+gurgling noise, which is audible at a great distance and is believed
+to be strengthened by the proboscis; the voice of the female being
+different. Lesson compares the erection of the proboscis, with the
+swelling of the wattles of male gallinaceous birds whilst courting the
+females. In another allied kind of seal, the bladder-nose (Cystophora
+cristata), the head is covered by a great hood or bladder. This is
+supported by the septum of the nose, which is produced far backwards and
+rises into an internal crest seven inches in height. The hood is clothed
+with short hair, and is muscular; can be inflated until it more than
+equals the whole head in size! The males when rutting, fight furiously
+on the ice, and their roaring "is said to be sometimes so loud as to be
+heard four miles off." When attacked they likewise roar or bellow; and
+whenever irritated the bladder is inflated and quivers. Some naturalists
+believe that the voice is thus strengthened, but various other uses have
+been assigned to this extraordinary structure. Mr. R. Brown thinks that
+it serves as a protection against accidents of all kinds; but this is
+not probable, for, as I am assured by Mr. Lamont who killed 600 of these
+animals, the hood is rudimentary in the females, and it is not developed
+in the males during youth. (8. On the sea-elephant, see an article
+by Lesson, in 'Dict. Class. Hist. Nat.' tom. xiii. p. 418. For the
+Cystophora, or Stemmatopus, see Dr. Dekay, 'Annals of Lyceum of Nat.
+Hist.' New York, vol. i. 1824, p. 94. Pennant has also collected
+information from the sealers on this animal. The fullest account is
+given by Mr. Brown, in 'Proc. Zoolog. Soc.' 1868, p. 435.)
+
+ODOUR.
+
+With some animals, as with the notorious skunk of America, the
+overwhelming odour which they emit appears to serve exclusively as
+a defence. With shrew-mice (Sorex) both sexes possess abdominal
+scent-glands, and there can be little doubt, from the rejection of
+their bodies by birds and beasts of prey, that the odour is protective;
+nevertheless, the glands become enlarged in the males during the
+breeding-season. In many other quadrupeds the glands are of the same
+size in both sexes (9. As with the castoreum of the beaver, see Mr. L.H.
+Morgan's most interesting work, 'The American Beaver,' 1868, p. 300.
+Pallas ('Spic. Zoolog.' fasc. viii. 1779, p. 23) has well discussed the
+odoriferous glands of mammals. Owen ('Anat. of Vertebrates,' vol. iii.
+p. 634) also gives an account of these glands, including those of the
+elephant, and (p. 763) those of shrew-mice. On bats, Mr. Dobson in
+'Proceedings of the Zoological Society' 1873, p. 241.), but their uses
+are not known. In other species the glands are confined to the males,
+or are more developed than in the females; and they almost always become
+more active during the rutting-season. At this period the glands on the
+sides of the face of the male elephant enlarge, and emit a secretion
+having a strong musky odour. The males, and rarely the females, of many
+kinds of bats have glands and protrudable sacks situated in various
+parts; and it is believed that these are odoriferous.
+
+The rank effluvium of the male goat is well known, and that of certain
+male deer is wonderfully strong and persistent. On the banks of the
+Plata I perceived the air tainted with the odour of the male
+Cervus campestris, at half a mile to leeward of a herd; and a silk
+handkerchief, in which I carried home a skin, though often used and
+washed, retained, when first unfolded, traces of the odour for one year
+and seven months. This animal does not emit its strong odour until more
+than a year old, and if castrated whilst young never emits it. (10.
+Rengger, 'Naturgeschichte der S�ugethiere von Paraguay,' 1830, s. 355.
+This observer also gives some curious particulars in regard to the
+odour.) Besides the general odour, permeating the whole body of certain
+ruminants (for instance, Bos moschatus) in the breeding-season, many
+deer, antelopes, sheep, and goats possess odoriferous glands in various
+situations, more especially on their faces. The so-called tear-sacks, or
+suborbital pits, come under this head. These glands secrete a semi-fluid
+fetid matter which is sometimes so copious as to stain the whole face,
+as I have myself seen in an antelope. They are "usually larger in
+the male than in the female, and their development is checked by
+castration." (11. Owen, 'Anatomy of Vertebrates,' vol. iii. p. 632.
+See also Dr. Murie's observations on those glands in the 'Proc.
+Zoolog. Soc.' 1870, p. 340. Desmarest, 'On the Antilope subgutturosa,
+'Mammalogie,' 1820, p. 455.) According to Desmarest they are altogether
+absent in the female of Antilope subgutturosa. Hence, there can be no
+doubt that they stand in close relation with the reproductive functions.
+They are also sometimes present, and sometimes absent, in nearly allied
+forms. In the adult male musk-deer (Moschus moschiferus), a naked space
+round the tail is bedewed with an odoriferous fluid, whilst in the adult
+female, and in the male until two years old, this space is covered with
+hair and is not odoriferous. The proper musk-sack of this deer is from
+its position necessarily confined to the male, and forms an additional
+scent-organ. It is a singular fact that the matter secreted by this
+latter gland, does not, according to Pallas, change in consistence,
+or increase in quantity, during the rutting-season; nevertheless this
+naturalist admits that its presence is in some way connected with
+the act of reproduction. He gives, however, only a conjectural and
+unsatisfactory explanation of its use. (12. Pallas, 'Spicilegia Zoolog.'
+fasc. xiii. 1799, p. 24; Desmoulins, 'Dict. Class. d'Hist. Nat.' tom.
+iii. p. 586.)
+
+In most cases, when only the male emits a strong odour during the
+breeding-season, it probably serves to excite or allure the female. We
+must not judge on this head by our own taste, for it is well known
+that rats are enticed by certain essential oils, and cats by valerian,
+substances far from agreeable to us; and that dogs, though they will
+not eat carrion, sniff and roll on it. From the reasons given when
+discussing the voice of the stag, we may reject the idea that the odour
+serves to bring the females from a distance to the males. Active and
+long-continued use cannot here have come into play, as in the case of
+the vocal organs. The odour emitted must be of considerable importance
+to the male, inasmuch as large and complex glands, furnished with
+muscles for everting the sack, and for closing or opening the orifice,
+have in some cases been developed. The development of these organs is
+intelligible through sexual selection, if the most odoriferous males are
+the most successful in winning the females, and in leaving offspring to
+inherit their gradually perfected glands and odours.
+
+DEVELOPMENT OF THE HAIR.
+
+We have seen that male quadrupeds often have the hair on their necks
+and shoulders much more developed than the females; and many additional
+instances could be given. This sometimes serves as a defence to the
+male during his battles; but whether the hair in most cases has been
+specially developed for this purpose, is very doubtful. We may feel
+almost certain that this is not the case, when only a thin and narrow
+crest runs along the back; for a crest of this kind would afford
+scarcely any protection, and the ridge of the back is not a place likely
+to be injured; nevertheless such crests are sometimes confined to the
+males, or are much more developed in them than in the females. Two
+antelopes, the Tragelaphus scriptus (13. Dr. Gray, 'Gleanings from the
+Menagerie at Knowsley,' pl. 28.) (Fig. 70) and Portax picta may be given
+as instances. When stags, and the males of the wild goat, are enraged
+or terrified, these crests stand erect (14. Judge Caton on the Wapiti,
+'Transact. Ottawa Acad. Nat. Sciences,' 1868, pp. 36, 40; Blyth, 'Land
+and Water,' on Capra aegagrus 1867, p. 37.); but it cannot be supposed
+that they have been developed merely for the sake of exciting fear in
+their enemies. One of the above-named antelopes, the Portax picta, has
+a large well-defined brush of black hair on the throat, and this is much
+larger in the male than in the female. In the Ammotragus tragelaphus
+of North Africa, a member of the sheep-family, the fore-legs are almost
+concealed by an extraordinary growth of hair, which depends from the
+neck and upper halves of the legs; but Mr. Bartlett does not believe
+that this mantle is of the least use to the male, in whom it is much
+more developed than in the female.
+
+[Fig. 68. Pithecia satanas, male (from Brehm).]
+
+Male quadrupeds of many kinds differ from the females in having more
+hair, or hair of a different character, on certain parts of their faces.
+Thus the bull alone has curled hair on the forehead. (15. Hunter's
+'Essays and Observations,' edited by Owen, 1861. vol. i. p. 236.) In
+three closely-allied sub-genera of the goat family, only the males
+possess beards, sometimes of large size; in two other sub-genera both
+sexes have a beard, but it disappears in some of the domestic breeds of
+the common goat; and neither sex of the Hemitragus has a beard. In the
+ibex the beard is not developed during the summer, and is so small
+at other times that it may be called rudimentary. (16. See Dr. Gray's
+'Catalogue of Mammalia in the British Museum,' part iii. 1852, p. 144.)
+With some monkeys the beard is confined to the male, as in the orang; or
+is much larger in the male than in the female, as in the Mycetes caraya
+and Pithecia satanas (Fig. 68). So it is with the whiskers of some
+species of Macacus (17. Rengger, 'S�ugethiere,' etc., s. 14; Desmarest,
+'Mammalogie,' p. 86.), and, as we have seen, with the manes of some
+species of baboons. But with most kinds of monkeys the various tufts of
+hair about the face and head are alike in both sexes.
+
+The males of various members of the ox family (Bovidae), and of certain
+antelopes, are furnished with a dewlap, or great fold of skin on the
+neck, which is much less developed in the female.
+
+Now, what must we conclude with respect to such sexual differences as
+these? No one will pretend that the beards of certain male goats, or the
+dewlaps of the bull, or the crests of hair along the backs of certain
+male antelopes, are of any use to them in their ordinary habits. It
+is possible that the immense beard of the male Pithecia, and the large
+beard of the male orang, may protect their throats when fighting; for
+the keepers in the Zoological Gardens inform me that many monkeys attack
+each other by the throat; but it is not probable that the beard has
+been developed for a distinct purpose from that served by the whiskers,
+moustache, and other tufts of hair on the face; and no one will suppose
+that these are useful as a protection. Must we attribute all these
+appendages of hair or skin to mere purposeless variability in the male?
+It cannot be denied that this is possible; for in many domesticated
+quadrupeds, certain characters, apparently not derived through reversion
+from any wild parent form, are confined to the males, or are more
+developed in them than in the females--for instance, the hump on the
+male zebu-cattle of India, the tail of fat-tailed rams, the arched
+outline of the forehead in the males of several breeds of sheep, and
+lastly, the mane, the long hairs on the hind legs, and the dewlap of the
+male of the Berbura goat. (18. See the chapters on these several animals
+in vol. i. of my 'Variation of Animals under Domestication;' also vol.
+ii. p. 73; also chap. xx. on the practice of selection by semi-civilised
+people. For the Berbura goat, see Dr. Gray, 'Catalogue,' ibid. p. 157.)
+The mane, which occurs only in the rams of an African breed of sheep,
+is a true secondary sexual character, for, as I hear from Mr. Winwood
+Reade, it is not developed if the animal be castrated. Although we
+ought to be extremely cautious, as shewn in my work on 'Variation under
+Domestication,' in concluding that any character, even with animals kept
+by semi-civilised people, has not been subjected to selection by man,
+and thus augmented, yet in the cases just specified this is improbable;
+more especially as the characters are confined to the males, or are more
+strongly developed in them than in the females. If it were positively
+known that the above African ram is a descendant of the same primitive
+stock as the other breeds of sheep, and if the Berbura male-goat with
+his mane, dewlap, etc., is descended from the same stock as other goats,
+then, assuming that selection has not been applied to these characters,
+they must be due to simple variability, together with sexually-limited
+inheritance.
+
+Hence it appears reasonable to extend this same view to all analogous
+cases with animals in a state of nature. Nevertheless I cannot persuade
+myself that it generally holds good, as in the case of the extraordinary
+development of hair on the throat and fore-legs of the male Ammotragus,
+or in that of the immense beard of the male Pithecia. Such study as I
+have been able to give to nature makes me believe that parts or organs
+which are highly developed, were acquired at some period for a
+special purpose. With those antelopes in which the adult male is more
+strongly-coloured than the female, and with those monkeys in which the
+hair on the face is elegantly arranged and coloured in a diversified
+manner, it seems probable that the crests and tufts of hair were gained
+as ornaments; and this I know is the opinion of some naturalists. If
+this be correct, there can be little doubt that they were gained or at
+least modified through sexual selection; but how far the same view may
+be extended to other mammals is doubtful.
+
+COLOUR OF THE HAIR AND OF THE NAKED SKIN.
+
+I will first give briefly all the cases known to me of male quadrupeds
+differing in colour from the females. With Marsupials, as I am informed
+by Mr. Gould, the sexes rarely differ in this respect; but the great
+red kangaroo offers a striking exception, "delicate blue being the
+prevailing tint in those parts of the female which in the male are red."
+(19. Osphranter rufus, Gould, 'Mammals of Australia,' 1863, vol. ii.
+On the Didelphis, Desmarest, 'Mammalogie,' p. 256.) In the Didelphis
+opossum of Cayenne the female is said to be a little more red than the
+male. Of the Rodents, Dr. Gray remarks: "African squirrels, especially
+those found in the tropical regions, have the fur much brighter and more
+vivid at some seasons of the year than at others, and the fur of the
+male is generally brighter than that of the female." (20. 'Annals and
+Magazine of Natural History,' Nov. 1867, p. 325. On the Mus minutus,
+Desmarest, 'Mammalogie,' p. 304.) Dr. Gray informs me that he specified
+the African squirrels, because, from their unusually bright colours,
+they best exhibit this difference. The female of the Mus minutus of
+Russia is of a paler and dirtier tint than the male. In a large number
+of bats the fur of the male is lighter than in the female. (21. J.A.
+Allen, in 'Bulletin of Mus. Comp. Zoolog. of Cambridge, United States,'
+1869, p. 207. Mr. Dobson on sexual characters in the Chiroptera,
+'Proceedings of the Zoological Society,' 1873, p. 241. Dr. Gray on
+Sloths, ibid. 1871, p. 436.) Mr. Dobson also remarks, with respect
+to these animals: "Differences, depending partly or entirely on
+the possession by the male of fur of a much more brilliant hue, or
+distinguished by different markings or by the greater length of certain
+portions, are met only, to any appreciable extent, in the frugivorous
+bats in which the sense of sight is well developed." This last remark
+deserves attention, as bearing on the question whether bright colours
+are serviceable to male animals from being ornamental. In one genus of
+sloths, it is now established, as Dr. Gray states, "that the males are
+ornamented differently from the females--that is to say, that they have
+a patch of soft short hair between the shoulders, which is generally
+of a more or less orange colour, and in one species pure white. The
+females, on the contrary, are destitute of this mark."
+
+The terrestrial Carnivora and Insectivora rarely exhibit sexual
+differences of any kind, including colour. The ocelot (Felis pardalis),
+however, is exceptional, for the colours of the female, compared with
+those of the male, are "moins apparentes, le fauve, �tant plus terne, le
+blanc moins pur, les raies ayant moins de largeur et les taches moins de
+diam�tre." (22. Desmarest, 'Mammalogie,' 1820, p. 220. On Felis mitis,
+Rengger, ibid. s. 194.) The sexes of the allied Felis mitis also differ,
+but in a less degree; the general hues of the female being rather paler
+than in the male, with the spots less black. The marine Carnivora or
+seals, on the other hand, sometimes differ considerably in colour,
+and they present, as we have already seen, other remarkable sexual
+differences. Thus the male of the Otaria nigrescens of the southern
+hemisphere is of a rich brown shade above; whilst the female, who
+acquires her adult tints earlier in life than the male, is dark-grey
+above, the young of both sexes being of a deep chocolate colour. The
+male of the northern Phoca groenlandica is tawny grey, with a curious
+saddle-shaped dark mark on the back; the female is much smaller, and
+has a very different appearance, being "dull white or yellowish
+straw-colour, with a tawny hue on the back"; the young at first are pure
+white, and can "hardly be distinguished among the icy hummocks and snow,
+their colour thus acting as a protection." (23. Dr. Murie on the Otaria,
+'Proceedings Zoological Society,' 1869, p. 108. Mr. R. Brown on the
+P. groenlandica, ibid. 1868, p. 417. See also on the colours of seals,
+Desmarest, ibid. pp. 243, 249.)
+
+With Ruminants sexual differences of colour occur more commonly than
+in any other order. A difference of this kind is general in the
+Strepsicerene antelopes; thus the male nilghau (Portax picta) is
+bluish-grey and much darker than the female, with the square white patch
+on the throat, the white marks on the fetlocks, and the black spots on
+the ears all much more distinct. We have seen that in this species the
+crests and tufts of hair are likewise more developed in the male than in
+the hornless female. I am informed by Mr. Blyth that the male,
+without shedding his hair, periodically becomes darker during the
+breeding-season. Young males cannot be distinguished from young females
+until about twelve months old; and if the male is emasculated before
+this period, he never, according to the same authority, changes colour.
+The importance of this latter fact, as evidence that the colouring of
+the Portax is of sexual origin, becomes obvious, when we hear (24. Judge
+Caton, in 'Transactions of the Ottawa Academy of Natural Sciences,'
+1868, p. 4.) that neither the red summer-coat nor the blue winter-coat
+of the Virginian deer is at all affected by emasculation. With most or
+all of the highly-ornamented species of Tragelaphus the males are darker
+than the hornless females, and their crests of hair are more fully
+developed. In the male of that magnificent antelope, the Derbyan eland,
+the body is redder, the whole neck much blacker, and the white band
+which separates these colours broader than in the female. In the Cape
+eland, also, the male is slightly darker than the female. (25. Dr. Gray,
+'Cat. of Mamm. in Brit. Mus.' part iii. 1852, pp. 134-142; also Dr.
+Gray, 'Gleanings from the Menagerie of Knowsley,' in which there is a
+splendid drawing of the Oreas derbianus: see the text on Tragelaphus.
+For the Cape eland (Oreas canna), see Andrew Smith, 'Zoology of S.
+Africa,' pl. 41 and 42. There are also many of these Antelopes in the
+Zoological Gardens.)
+
+In the Indian black-buck (A. bezoartica), which belongs to another tribe
+of antelopes, the male is very dark, almost black; whilst the hornless
+female is fawn-coloured. We meet in this species, as Mr. Blyth informs
+me, with an exactly similar series of facts, as in the Portax
+picta, namely, in the male periodically changing colour during the
+breeding-season, in the effects of emasculation on this change, and in
+the young of both sexes being indistinguishable from each other. In the
+Antilope niger the male is black, the female, as well as the young
+of both sexes, being brown; in A. sing-sing the male is much brighter
+coloured than the hornless female, and his chest and belly are blacker;
+in the male A. caama, the marks and lines which occur on various
+parts of the body are black, instead of brown as in the female; in the
+brindled gnu (A. gorgon) "the colours of the male are nearly the same
+as those of the female, only deeper and of a brighter hue." (26. On
+the Ant. niger, see 'Proc. Zool. Soc.' 1850, p. 133. With respect to an
+allied species, in which there is an equal sexual difference in colour,
+see Sir S. Baker, 'The Albert Nyanza,' 1866, vol. ii. p. 627. For the A.
+sing-sing, Gray, 'Cat. B. Mus.' p. 100. Desmarest, 'Mammalogie,' p.
+468, on the A. caama. Andrew Smith, 'Zoology of S. Africa,' on the Gnu.)
+Other analogous cases could be added.
+
+The Banteng bull (Bos sondaicus) of the Malayan Archipelago is almost
+black, with white legs and buttocks; the cow is of a bright dun, as are
+the young males until about the age of three years, when they rapidly
+change colour. The emasculated bull reverts to the colour of the
+female. The female Kemas goat is paler, and both it and the female Capra
+aegagrus are said to be more uniformly tinted than their males. Deer
+rarely present any sexual differences in colour. Judge Caton, however,
+informs me that in the males of the wapiti deer (Cervus canadensis) the
+neck, belly, and legs are much darker than in the female; but during the
+winter the darker tints gradually fade away and disappear. I may here
+mention that Judge Caton has in his park three races of the Virginian
+deer, which differ slightly in colour, but the differences are almost
+exclusively confined to the blue winter or breeding-coat; so that
+this case may be compared with those given in a previous chapter of
+closely-allied or representative species of birds, which differ from
+each other only in their breeding plumage. (27. 'Ottawa Academy of
+Sciences,' May 21, 1868, pp. 3, 5.) The females of Cervus paludosus of
+S. America, as well as the young of both sexes, do not possess the black
+stripes on the nose and the blackish-brown line on the breast, which
+are characteristic of the adult males. (28. S. Muller, on the Banteng,
+'Zoog. Indischen Archipel.' 1839-1844, tab. 35; see also Raffles, as
+quoted by Mr. Blyth, in 'Land and Water,' 1867, p. 476. On goats,
+Dr. Gray, 'Catalogue of the British Museum,' p. 146; Desmarest,
+'Mammalogie,' p. 482. On the Cervus paludosus, Rengger, ibid. s.
+345.) Lastly, as I am informed by Mr. Blyth, the mature male of the
+beautifully coloured and spotted axis deer is considerably darker than
+the female: and this hue the castrated male never acquires.
+
+The last Order which we need consider is that of the Primates. The male
+of the Lemur macaco is generally coal-black, whilst the female is brown.
+(29. Sclater, 'Proc. Zool. Soc.' 1866, p. i. The same fact has also
+been fully ascertained by MM. Pollen and van Dam. See, also, Dr. Gray
+in 'Annals and Magazine of Natural History,' May 1871, p. 340.) Of the
+Quadrumana of the New World, the females and young of Mycetes caraya are
+greyish-yellow and like each other; in the second year the young male
+becomes reddish-brown; in the third, black, excepting the stomach,
+which, however, becomes quite black in the fourth or fifth year. There
+is also a strongly-marked difference in colour between the sexes of
+Mycetes seniculus and Cebus capucinus; the young of the former, and I
+believe of the latter species, resembling the females. With Pithecia
+leucocephala the young likewise resemble the females, which are
+brownish-black above and light rusty-red beneath, the adult males being
+black. The ruff of hair round the face of Ateles marginatus is tinted
+yellow in the male and white in the female. Turning to the Old World,
+the males of Hylobates hoolock are always black, with the exception of
+a white band over the brows; the females vary from whity-brown to a
+dark tint mixed with black, but are never wholly black. (30. On Mycetes,
+Rengger, ibid. s. 14; and Brehm, 'Thierleben,' B. i. s. 96, 107. On
+Ateles Desmarest, 'Mammalogie,' p. 75. On Hylobates, Blyth, 'Land and
+Water,' 1867, p. 135. On the Semnopithecus, S. Muller, 'Zoog. Indischen
+Archipel.' tab. x.) In the beautiful Cercopithecus diana, the head of
+the adult male is of an intense black, whilst that of the female is
+dark grey; in the former the fur between the thighs is of an elegant
+fawn-colour, in the latter it is paler. In the beautiful and curious
+moustache monkey (Cercopithecus cephus) the only difference between the
+sexes is that the tail of the male is chestnut and that of the female
+grey; but Mr. Bartlett informs me that all the hues become more
+pronounced in the male when adult, whilst in the female they remain
+as they were during youth. According to the coloured figures given by
+Solomon Muller, the male of Semnopithecus chrysomelas is nearly
+black, the female being pale brown. In the Cercopithecus cynosurus and
+griseo-viridis one part of the body, which is confined to the male sex,
+is of the most brilliant blue or green, and contrasts strikingly with
+the naked skin on the hinder part of the body, which is vivid red.
+
+[Fig. 69. Head of male Mandrill (from Gervais, 'Hist. Nat. des
+Mammif�res').]
+
+Lastly, in the baboon family, the adult male of Cynocephalus hamadryas
+differs from the female not only by his immense mane, but slightly in
+the colour of the hair and of the naked callosities. In the drill (C.
+leucophaeus) the females and young are much paler-coloured, with less
+green, than the adult males. No other member in the whole class of
+mammals is coloured in so extraordinary a manner as the adult male
+mandrill (C. mormon). The face at this age becomes of a fine blue, with
+the ridge and tip of the nose of the most brilliant red. According
+to some authors, the face is also marked with whitish stripes, and is
+shaded in parts with black, but the colours appear to be variable. On
+the forehead there is a crest of hair, and on the chin a yellow beard.
+"Toutes les parties sup�rieures de leurs cuisses et le grand espace nu
+de leurs fesses sont �galement color�s du rouge le plus vif, avec un
+m�lange de bleu qui ne manque reellement pas d'�l�gance." (31. Gervais,
+'Hist. Nat. des Mammif�res,' 1854, p. 103. Figures are given of the
+skull of the male. Also Desmarest, 'Mammalogie,' p. 70. Geoffroy
+St.-Hilaire and F. Cuvier, 'Hist. Nat. des Mammif�res,' 1824, tom. i.)
+When the animal is excited all the naked parts become much more
+vividly tinted. Several authors have used the strongest expressions in
+describing these resplendent colours, which they compare with those of
+the most brilliant birds. Another remarkable peculiarity is that when
+the great canine teeth are fully developed, immense protuberances of
+bone are formed on each cheek, which are deeply furrowed longitudinally,
+and the naked skin over them is brilliantly-coloured, as just-described.
+(Fig. 69.) In the adult females and in the young of both sexes these
+protuberances are scarcely perceptible; and the naked parts are much
+less bright coloured, the face being almost black, tinged with blue. In
+the adult female, however, the nose at certain regular intervals of time
+becomes tinted with red.
+
+In all the cases hitherto given the male is more strongly or brighter
+coloured than the female, and differs from the young of both sexes. But
+as with some few birds it is the female which is brighter coloured than
+the male, so with the Rhesus monkey (Macacus rhesus), the female has a
+large surface of naked skin round the tail, of a brilliant carmine
+red, which, as I was assured by the keepers in the Zoological Gardens,
+periodically becomes even yet more vivid, and her face also is pale red.
+On the other hand, in the adult male and in the young of both sexes (as
+I saw in the Gardens), neither the naked skin at the posterior end of
+the body, nor the face, shew a trace of red. It appears, however, from
+some published accounts, that the male does occasionally, or during
+certain seasons, exhibit some traces of the red. Although he is thus
+less ornamented than the female, yet in the larger size of his
+body, larger canine teeth, more developed whiskers, more prominent
+superciliary ridges, he follows the common rule of the male excelling
+the female.
+
+I have now given all the cases known to me of a difference in colour
+between the sexes of mammals. Some of these may be the result of
+variations confined to one sex and transmitted to the same sex, without
+any good being gained, and therefore without the aid of selection. We
+have instances of this with our domesticated animals, as in the males
+of certain cats being rusty-red, whilst the females are tortoise-shell
+coloured. Analogous cases occur in nature: Mr. Bartlett has seen many
+black varieties of the jaguar, leopard, vulpine phalanger, and wombat;
+and he is certain that all, or nearly all these animals, were males. On
+the other hand, with wolves, foxes, and apparently American squirrels,
+both sexes are occasionally born black. Hence it is quite possible that
+with some mammals a difference in colour between the sexes, especially
+when this is congenital, may simply be the result, without the aid of
+selection, of the occurrence of one or more variations, which from the
+first were sexually limited in their transmission. Nevertheless it
+is improbable that the diversified, vivid, and contrasted colours of
+certain quadrupeds, for instance, of the above monkeys and antelopes,
+can thus be accounted for. We should bear in mind that these colours do
+not appear in the male at birth, but only at or near maturity; and that
+unlike ordinary variations, they are lost if the male be emasculated.
+It is on the whole probable that the strongly-marked colours and other
+ornamental characters of male quadrupeds are beneficial to them in their
+rivalry with other males, and have consequently been acquired through
+sexual selection. This view is strengthened by the differences in colour
+between the sexes occurring almost exclusively, as may be collected from
+the previous details, in those groups and sub-groups of mammals which
+present other and strongly-marked secondary sexual characters; these
+being likewise due to sexual selection.
+
+Quadrupeds manifestly take notice of colour. Sir S. Baker repeatedly
+observed that the African elephant and rhinoceros attacked white or grey
+horses with special fury. I have elsewhere shewn (32. The 'Variation of
+Animals and Plants under Domestication,' 1868, vol. ii. pp. 102, 103.)
+that half-wild horses apparently prefer to pair with those of the same
+colour, and that herds of fallow-deer of different colours, though
+living together, have long kept distinct. It is a more significant fact
+that a female zebra would not admit the addresses of a male ass until he
+was painted so as to resemble a zebra, and then, as John Hunter remarks,
+"she received him very readily. In this curious fact, we have instinct
+excited by mere colour, which had so strong an effect as to get the
+better of everything else. But the male did not require this, the female
+being an animal somewhat similar to himself, was sufficient to rouse
+him." (33. 'Essays and Observations,' by J. Hunter, edited by Owen,
+1861, vol. i. p. 194.)
+
+In an earlier chapter we have seen that the mental powers of the higher
+animals do not differ in kind, though greatly in degree, from the
+corresponding powers of man, especially of the lower and barbarous
+races; and it would appear that even their taste for the beautiful is
+not widely different from that of the Quadrumana. As the negro of Africa
+raises the flesh on his face into parallel ridges "or cicatrices, high
+above the natural surface, which unsightly deformities are considered
+great personal attractions" (34. Sir S. Baker, 'The Nile Tributaries of
+Abyssinia,' 1867.);--as negroes and savages in many parts of the world
+paint their faces with red, blue, white, or black bars,--so the male
+mandrill of Africa appears to have acquired his deeply-furrowed and
+gaudily-coloured face from having been thus rendered attractive to the
+female. No doubt it is to us a most grotesque notion that the posterior
+end of the body should be coloured for the sake of ornament even more
+brilliantly than the face; but this is not more strange than that the
+tails of many birds should be especially decorated.
+
+With mammals we do not at present possess any evidence that the males
+take pains to display their charms before the female; and the elaborate
+manner in which this is performed by male birds and other animals is the
+strongest argument in favour of the belief that the females admire, or
+are excited by, the ornaments and colours displayed before them. There
+is, however, a striking parallelism between mammals and birds in all
+their secondary sexual characters, namely in their weapons for fighting
+with rival males, in their ornamental appendages, and in their colours.
+In both classes, when the male differs from the female, the young of
+both sexes almost always resemble each other, and in a large majority
+of cases resemble the adult female. In both classes the male assumes the
+characters proper to his sex shortly before the age of reproduction;
+and if emasculated at an early period, loses them. In both classes the
+change of colour is sometimes seasonal, and the tints of the naked parts
+sometimes become more vivid during the act of courtship. In both classes
+the male is almost always more vividly or strongly coloured than the
+female, and is ornamented with larger crests of hair or feathers, or
+other such appendages. In a few exceptional cases the female in both
+classes is more highly ornamented than the male. With many mammals, and
+at least in the case of one bird, the male is more odoriferous than the
+female. In both classes the voice of the male is more powerful than that
+of the female. Considering this parallelism, there can be little doubt
+that the same cause, whatever it may be, has acted on mammals and birds;
+and the result, as far as ornamental characters are concerned, may be
+attributed, as it appears to me, to the long-continued preference of
+the individuals of one sex for certain individuals of the opposite sex,
+combined with their success in leaving a larger number of offspring to
+inherit their superior attractions.
+
+EQUAL TRANSMISSION OF ORNAMENTAL CHARACTERS TO BOTH SEXES.
+
+With many birds, ornaments, which analogy leads us to believe were
+primarily acquired by the males, have been transmitted equally, or
+almost equally, to both sexes; and we may now enquire how far this view
+applies to mammals. With a considerable number of species, especially
+of the smaller kinds, both sexes have been coloured, independently of
+sexual selection, for the sake of protection; but not, as far as I can
+judge, in so many cases, nor in so striking a manner, as in most of the
+lower classes. Audubon remarks that he often mistook the musk-rat
+(35. Fiber zibethicus, Audubon and Bachman, 'The Quadrupeds of North
+America,' 1846, p. 109.), whilst sitting on the banks of a muddy stream,
+for a clod of earth, so complete was the resemblance. The hare on her
+form is a familiar instance of concealment through colour; yet this
+principle partly fails in a closely-allied species, the rabbit, for when
+running to its burrow, it is made conspicuous to the sportsman, and no
+doubt to all beasts of prey, by its upturned white tail. No one doubts
+that the quadrupeds inhabiting snow-clad regions have been rendered
+white to protect them from their enemies, or to favour their stealing
+on their prey. In regions where snow never lies for long, a white coat
+would be injurious; consequently, species of this colour are extremely
+rare in the hotter parts of the world. It deserves notice that many
+quadrupeds inhabiting moderately cold regions, although they do not
+assume a white winter dress, become paler during this season; and this
+apparently is the direct result of the conditions to which they have
+long been exposed. Pallas (36. 'Novae species Quadrupedum e Glirium
+ordine,' 1778, p. 7. What I have called the roe is the Capreolus
+sibiricus subecaudatus of Pallas.) states that in Siberia a change of
+this nature occurs with the wolf, two species of Mustela, the domestic
+horse, the Equus hemionus, the domestic cow, two species of antelopes,
+the musk-deer, the roe, elk, and reindeer. The roe, for instance, has a
+red summer and a greyish-white winter coat; and the latter may perhaps
+serve as a protection to the animal whilst wandering through the
+leafless thickets, sprinkled with snow and hoar-frost. If the
+above-named animals were gradually to extend their range into regions
+perpetually covered with snow, their pale winter-coats would probably be
+rendered through natural selection, whiter and whiter, until they became
+as white as snow.
+
+Mr. Reeks has given me a curious instance of an animal profiting by
+being peculiarly coloured. He raised from fifty to sixty white and brown
+piebald rabbits in a large walled orchard; and he had at the same time
+some similarly coloured cats in his house. Such cats, as I have often
+noticed, are very conspicuous during day; but as they used to lie
+in watch during the dusk at the mouths of the burrows, the rabbits
+apparently did not distinguish them from their parti-coloured brethren.
+The result was that, within eighteen months, every one of these
+parti-coloured rabbits was destroyed; and there was evidence that this
+was effected by the cats. Colour seems to be advantageous to another
+animal, the skunk, in a manner of which we have had many instances in
+other classes. No animal will voluntarily attack one of these creatures
+on account of the dreadful odour which it emits when irritated; but
+during the dusk it would not easily be recognised and might be attacked
+by a beast of prey. Hence it is, as Mr. Belt believes (37. 'The
+Naturalist in Nicaragua,' p. 249.), that the skunk is provided with a
+great white bushy tail, which serves as a conspicuous warning.
+
+[Fig. 70. Tragelaphus scriptus, male (from the Knowsley Menagerie).
+
+Fig. 71. Damalis pygarga, male (from the Knowsley Menagerie).]
+
+Although we must admit that many quadrupeds have received their present
+tints either as a protection, or as an aid in procuring prey, yet with a
+host of species, the colours are far too conspicuous and too singularly
+arranged to allow us to suppose that they serve for these purposes. We
+may take as an illustration certain antelopes; when we see the square
+white patch on the throat, the white marks on the fetlocks, and the
+round black spots on the ears, all more distinct in the male of the
+Portax picta, than in the female;--when we see that the colours are more
+vivid, that the narrow white lines on the flank and the broad white bar
+on the shoulder are more distinct in the male Oreas derbyanus than in
+the female;--when we see a similar difference between the sexes of the
+curiously-ornamented Tragelaphus scriptus (Fig. 70),--we cannot believe
+that differences of this kind are of any service to either sex in their
+daily habits of life. It seems a much more probable conclusion that
+the various marks were first acquired by the males and their colours
+intensified through sexual selection, and then partially transferred to
+the females. If this view be admitted, there can be little doubt that
+the equally singular colours and marks of many other antelopes, though
+common to both sexes, have been gained and transmitted in a like manner.
+Both sexes, for instance, of the koodoo (Strepsiceros kudu) (Fig. 64)
+have narrow white vertical lines on their hind flanks, and an elegant
+angular white mark on their foreheads. Both sexes in the genus
+Damalis are very oddly coloured; in D. pygarga the back and neck are
+purplish-red, shading on the flanks into black; and these colours are
+abruptly separated from the white belly and from a large white space
+on the buttocks; the head is still more oddly coloured, a large oblong
+white mask, narrowly-edged with black, covers the face up to the eyes
+(Fig. 71); there are three white stripes on the forehead, and the ears
+are marked with white. The fawns of this species are of a uniform pale
+yellowish-brown. In Damalis albifrons the colouring of the head differs
+from that in the last species in a single white stripe replacing the
+three stripes, and in the ears being almost wholly white. (38. See the
+fine plates in A. Smith's 'Zoology of South Africa,' and Dr. Gray's
+'Gleanings from the Menagerie of Knowsley.') After having studied to the
+best of my ability the sexual differences of animals belonging to all
+classes, I cannot avoid the conclusion that the curiously-arranged
+colours of many antelopes, though common to both sexes, are the result
+of sexual selection primarily applied to the male.
+
+The same conclusion may perhaps be extended to the tiger, one of the
+most beautiful animals in the world, the sexes of which cannot be
+distinguished by colour, even by the dealers in wild beasts. Mr. Wallace
+believes (39. 'Westminster Review,' July 1, 1867, p. 5.) that the
+striped coat of the tiger "so assimilates with the vertical stems of
+the bamboo, as to assist greatly in concealing him from his approaching
+prey." But this view does not appear to me satisfactory. We have some
+slight evidence that his beauty may be due to sexual selection, for in
+two species of Felis the analogous marks and colours are rather brighter
+in the male than in the female. The zebra is conspicuously striped, and
+stripes cannot afford any protection in the open plains of South Africa.
+Burchell (40. 'Travels in South Africa,' 1824, vol. ii. p. 315.) in
+describing a herd says, "their sleek ribs glistened in the sun, and the
+brightness and regularity of their striped coats presented a picture of
+extraordinary beauty, in which probably they are not surpassed by any
+other quadruped." But as throughout the whole group of the Equidae
+the sexes are identical in colour, we have here no evidence of sexual
+selection. Nevertheless he who attributes the white and dark vertical
+stripes on the flanks of various antelopes to this process, will
+probably extend the same view to the Royal Tiger and beautiful Zebra.
+
+We have seen in a former chapter that when young animals belonging to
+any class follow nearly the same habits of life as their parents, and
+yet are coloured in a different manner, it may be inferred that they
+have retained the colouring of some ancient and extinct progenitor.
+In the family of pigs, and in the tapirs, the young are marked with
+longitudinal stripes, and thus differ from all the existing adult
+species in these two groups. With many kinds of deer the young are
+marked with elegant white spots, of which their parents exhibit not a
+trace. A graduated series can be followed from the axis deer, both sexes
+of which at all ages and during all seasons are beautifully spotted (the
+male being rather more strongly coloured than the female), to species in
+which neither the old nor the young are spotted. I will specify some of
+the steps in this series. The Mantchurian deer (Cervus mantchuricus)
+is spotted during the whole year, but, as I have seen in the Zoological
+Gardens, the spots are much plainer during the summer, when the general
+colour of the coat is lighter, than during the winter, when the general
+colour is darker and the horns are fully developed. In the hog-deer
+(Hyelaphus porcinus) the spots are extremely conspicuous during the
+summer when the coat is reddish-brown, but quite disappear during
+the winter when the coat is brown. (41. Dr. Gray, 'Gleanings from the
+Menagerie of Knowsley,' p. 64. Mr. Blyth, in speaking ('Land and Water,'
+1869, p. 42) of the hog-deer of Ceylon, says it is more brightly spotted
+with white than the common hog-deer, at the season when it renews its
+horns.) In both these species the young are spotted. In the Virginian
+deer the young are likewise spotted, and about five per cent. of the
+adult animals living in Judge Caton's park, as I am informed by him,
+temporarily exhibit at the period when the red summer coat is being
+replaced by the bluish winter coat, a row of spots on each flank, which
+are always the same in number, though very variable in distinctness.
+From this condition there is but a very small step to the complete
+absence of spots in the adults at all seasons; and, lastly, to their
+absence at all ages and seasons, as occurs with certain species. From
+the existence of this perfect series, and more especially from the fawns
+of so many species being spotted, we may conclude that the now living
+members of the deer family are the descendants of some ancient species
+which, like the axis deer, was spotted at all ages and seasons. A still
+more ancient progenitor probably somewhat resembled the Hyomoschus
+aquaticus--for this animal is spotted, and the hornless males have
+large exserted canine teeth, of which some few true deer still retain
+rudiments. Hyomoschus, also, offers one of those interesting cases of
+a form linking together two groups, for it is intermediate in certain
+osteological characters between the pachyderms and ruminants, which were
+formerly thought to be quite distinct. (42. Falconer and Cautley, 'Proc.
+Geolog. Soc.' 1843; and Falconer's 'Pal. Memoirs,' vol. i. p. 196.)
+
+A curious difficulty here arises. If we admit that coloured spots and
+stripes were first acquired as ornaments, how comes it that so many
+existing deer, the descendants of an aboriginally spotted animal, and
+all the species of pigs and tapirs, the descendants of an aboriginally
+striped animal, have lost in their adult state their former ornaments? I
+cannot satisfactorily answer this question. We may feel almost sure that
+the spots and stripes disappeared at or near maturity in the progenitors
+of our existing species, so that they were still retained by the
+young; and, owing to the law of inheritance at corresponding ages, were
+transmitted to the young of all succeeding generations. It may have been
+a great advantage to the lion and puma, from the open nature of their
+usual haunts, to have lost their stripes, and to have been thus rendered
+less conspicuous to their prey; and if the successive variations, by
+which this end was gained, occurred rather late in life, the young would
+have retained their stripes, as is now the case. As to deer, pigs, and
+tapirs, Fritz M�ller has suggested to me that these animals, by the
+removal of their spots or stripes through natural selection, would
+have been less easily seen by their enemies; and that they would have
+especially required this protection, as soon as the carnivora increased
+in size and number during the tertiary periods. This may be the true
+explanation, but it is rather strange that the young should not have
+been thus protected, and still more so that the adults of some species
+should have retained their spots, either partially or completely, during
+part of the year. We know that, when the domestic ass varies and becomes
+reddish-brown, grey, or black, the stripes on the shoulders and even on
+the spine frequently disappear, though we cannot explain the cause. Very
+few horses, except dun-coloured kinds, have stripes on any part of their
+bodies, yet we have good reason to believe that the aboriginal horse was
+striped on the legs and spine, and probably on the shoulders. (43. The
+'Variation of Animals and Plants under Domestication,' 1868, vol. i. pp.
+61-64.) Hence the disappearance of the spots and stripes in our adult
+existing deer, pigs, and tapirs, may be due to a change in the general
+colour of their coats; but whether this change was effected through
+sexual or natural selection, or was due to the direct action of the
+conditions of life, or to some other unknown cause, it is impossible
+to decide. An observation made by Mr. Sclater well illustrates our
+ignorance of the laws which regulate the appearance and disappearance of
+stripes; the species of Asinus which inhabit the Asiatic continent are
+destitute of stripes, not having even the cross shoulder-stripe, whilst
+those which inhabit Africa are conspicuously striped, with the partial
+exception of A. taeniopus, which has only the cross shoulder-stripe and
+generally some faint bars on the legs; and this species inhabits the
+almost intermediate region of Upper Egypt and Abyssinia. (44. 'Proc.
+Zool. Soc.' 1862, p. 164. See, also, Dr. Hartmann, 'Ann. d. Landw.' Bd.
+xliii. s. 222.)
+
+QUADRUMANA.
+
+[Fig. 72. Head of Semnopithecus rubicundus. This and the following
+figures (from Prof. Gervais) are given to shew the odd arrangement and
+development of the hair on the head.
+
+Fig. 73. Head of Semnopithecus comatus.
+
+Fig. 74. Head of Cebus capucinus.
+
+Fig. 75. Head of Ateles marginatus.
+
+Fig. 76. Head of Cebus vellerosus.]
+
+Before we conclude, it will be well to add a few remarks on the
+ornaments of monkeys. In most of the species the sexes resemble each
+other in colour, but in some, as we have seen, the males differ from the
+females, especially in the colour of the naked parts of the skin, in the
+development of the beard, whiskers, and mane. Many species are coloured
+either in so extraordinary or so beautiful a manner, and are furnished
+with such curious and elegant crests of hair, that we can hardly avoid
+looking at these characters as having been gained for the sake of
+ornament. The accompanying figures (Figs. 72 to 76) serve to shew the
+arrangement of the hair on the face and head in several species. It
+is scarcely conceivable that these crests of hair, and the strongly
+contrasted colours of the fur and skin, can be the result of mere
+variability without the aid of selection; and it is inconceivable that
+they can be of use in any ordinary way to these animals. If so, they
+have probably been gained through sexual selection, though transmitted
+equally, or almost equally, to both sexes. With many of the Quadrumana,
+we have additional evidence of the action of sexual selection in the
+greater size and strength of the males, and in the greater development
+of their canine teeth, in comparison with the females.
+
+[Fig. 77. Cercopithecus petaurista (from Brehm).]
+
+A few instances will suffice of the strange manner in which both sexes
+of some species are coloured, and of the beauty of others. The face of
+the Cercopithecus petaurista (Fig. 77) is black, the whiskers and beard
+being white, with a defined, round, white spot on the nose, covered with
+short white hair, which gives to the animal an almost ludicrous aspect.
+The Semnopithecus frontatus likewise has a blackish face with a long
+black beard, and a large naked spot on the forehead of a bluish-white
+colour. The face of Macacus lasiotus is dirty flesh-coloured, with a
+defined red spot on each cheek. The appearance of Cercocebus aethiops
+is grotesque, with its black face, white whiskers and collar, chestnut
+head, and a large naked white spot over each eyelid. In very many
+species, the beard, whiskers, and crests of hair round the face are of
+a different colour from the rest of the head, and when different, are
+always of a lighter tint (45. I observed this fact in the Zoological
+Gardens; and many cases may be seen in the coloured plates in Geoffroy
+St.-Hilaire and F. Cuvier, 'Histoire Nat. des Mammif�res,' tom. i.
+1824.), being often pure white, sometimes bright yellow, or reddish.
+The whole face of the South American Brachyurus calvus is of a "glowing
+scarlet hue"; but this colour does not appear until the animal is nearly
+mature. (46. Bates, 'The Naturalist on the Amazons,' 1863, vol. ii. p.
+310.) The naked skin of the face differs wonderfully in colour in the
+various species. It is often brown or flesh-colour, with parts perfectly
+white, and often as black as that of the most sooty negro. In the
+Brachyurus the scarlet tint is brighter than that of the most blushing
+Caucasian damsel. It is sometimes more distinctly orange than in any
+Mongolian, and in several species it is blue, passing into violet or
+grey. In all the species known to Mr. Bartlett, in which the adults of
+both sexes have strongly-coloured faces, the colours are dull or absent
+during early youth. This likewise holds good with the mandrill and
+Rhesus, in which the face and the posterior parts of the body are
+brilliantly coloured in one sex alone. In these latter cases we
+have reason to believe that the colours were acquired through sexual
+selection; and we are naturally led to extend the same view to the
+foregoing species, though both sexes when adult have their faces
+coloured in the same manner.
+
+[Fig. 78. Cercopithecus diana (from Brehm).]
+
+Although many kinds of monkeys are far from beautiful according to
+our taste, other species are universally admired for their elegant
+appearance and bright colours. The Semnopithecus nemaeus, though
+peculiarly coloured, is described as extremely pretty; the orange-tinted
+face is surrounded by long whiskers of glossy whiteness, with a line
+of chestnut-red over the eyebrows; the fur on the back is of a delicate
+grey, with a square patch on the loins, the tail and the fore-arms being
+of a pure white; a gorget of chestnut surmounts the chest; the thighs
+are black, with the legs chestnut-red. I will mention only two other
+monkeys for their beauty; and I have selected these as presenting slight
+sexual differences in colour, which renders it in some degree probable
+that both sexes owe their elegant appearance to sexual selection. In the
+moustache-monkey (Cercopithecus cephus) the general colour of the fur is
+mottled-greenish with the throat white; in the male the end of the tail
+is chestnut, but the face is the most ornamented part, the skin being
+chiefly bluish-grey, shading into a blackish tint beneath the eyes, with
+the upper lip of a delicate blue, clothed on the lower edge with a thin
+black moustache; the whiskers are orange-coloured, with the upper part
+black, forming a band which extends backwards to the ears, the latter
+being clothed with whitish hairs. In the Zoological Society's Gardens
+I have often overheard visitors admiring the beauty of another monkey,
+deservedly called Cercopithecus diana (Fig. 78); the general colour of
+the fur is grey; the chest and inner surface of the forelegs are white;
+a large triangular defined space on the hinder part of the back is rich
+chestnut; in the male the inner sides of the thighs and the abdomen are
+delicate fawn-coloured, and the top of the head is black; the face and
+ears are intensely black, contrasting finely with a white transverse
+crest over the eyebrows and a long white peaked beard, of which the
+basal portion is black. (47. I have seen most of the above monkeys in
+the Zoological Society's Gardens. The description of the Semnopithecus
+nemaeus is taken from Mr. W.C. Martin's 'Natural History of Mammalia,'
+1841, p. 460; see also pp. 475, 523.)
+
+In these and many other monkeys, the beauty and singular arrangement of
+their colours, and still more the diversified and elegant arrangement of
+the crests and tufts of hair on their heads, force the conviction on my
+mind that these characters have been acquired through sexual selection
+exclusively as ornaments.
+
+SUMMARY.
+
+The law of battle for the possession of the female appears to prevail
+throughout the whole great class of mammals. Most naturalists will admit
+that the greater size, strength, courage, and pugnacity of the male,
+his special weapons of offence, as well as his special means of defence,
+have been acquired or modified through that form of selection which
+I have called sexual. This does not depend on any superiority in the
+general struggle for life, but on certain individuals of one sex,
+generally the male, being successful in conquering other males, and
+leaving a larger number of offspring to inherit their superiority than
+do the less successful males.
+
+There is another and more peaceful kind of contest, in which the males
+endeavour to excite or allure the females by various charms. This is
+probably carried on in some cases by the powerful odours emitted by the
+males during the breeding-season; the odoriferous glands having been
+acquired through sexual selection. Whether the same view can be extended
+to the voice is doubtful, for the vocal organs of the males must have
+been strengthened by use during maturity, under the powerful excitements
+of love, jealousy or rage, and will consequently have been transmitted
+to the same sex. Various crests, tufts, and mantles of hair, which are
+either confined to the male, or are more developed in this sex than
+in the female, seem in most cases to be merely ornamental, though they
+sometimes serve as a defence against rival males. There is even reason
+to suspect that the branching horns of stags, and the elegant horns
+of certain antelopes, though properly serving as weapons of offence or
+defence, have been partly modified for ornament.
+
+When the male differs in colour from the female, he generally exhibits
+darker and more strongly-contrasted tints. We do not in this class meet
+with the splendid red, blue, yellow, and green tints, so common with
+male birds and many other animals. The naked parts, however, of certain
+Quadrumana must be excepted; for such parts, often oddly situated, are
+brilliantly coloured in some species. The colours of the male in other
+cases may be due to simple variation, without the aid of selection. But
+when the colours are diversified and strongly pronounced, when they
+are not developed until near maturity, and when they are lost after
+emasculation, we can hardly avoid the conclusion that they have been
+acquired through sexual selection for the sake of ornament, and have
+been transmitted exclusively, or almost exclusively, to the same sex.
+When both sexes are coloured in the same manner, and the colours are
+conspicuous or curiously arranged, without being of the least apparent
+use as a protection, and especially when they are associated with
+various other ornamental appendages, we are led by analogy to the
+same conclusion, namely, that they have been acquired through sexual
+selection, although transmitted to both sexes. That conspicuous and
+diversified colours, whether confined to the males or common to
+both sexes, are as a general rule associated in the same groups and
+sub-groups with other secondary sexual characters serving for war or
+for ornament, will be found to hold good, if we look back to the various
+cases given in this and the last chapter.
+
+The law of the equal transmission of characters to both sexes, as far
+as colour and other ornaments are concerned, has prevailed far more
+extensively with mammals than with birds; but weapons, such as horns
+and tusks, have often been transmitted either exclusively or much more
+perfectly to the males than to the females. This is surprising, for, as
+the males generally use their weapons for defence against enemies of all
+kinds, their weapons would have been of service to the females. As far
+as we can see, their absence in this sex can be accounted for only by
+the form of inheritance which has prevailed. Finally, with quadrupeds
+the contest between the individuals of the same sex, whether peaceful or
+bloody, has, with the rarest exceptions, been confined to the males; so
+that the latter have been modified through sexual selection, far more
+commonly than the females, either for fighting with each other or for
+alluring the opposite sex.
+
+
+PART III.
+
+SEXUAL SELECTION IN RELATION TO MAN, AND CONCLUSION.
+
+
+CHAPTER XIX.
+
+SECONDARY SEXUAL CHARACTERS OF MAN.
+
+Differences between man and woman--Causes of such differences and of
+certain characters common to both sexes--Law of battle--Differences in
+mental powers, and voice--On the influence of beauty in determining
+the marriages of mankind--Attention paid by savages to ornaments--Their
+ideas of beauty in woman--The tendency to exaggerate each natural
+peculiarity.
+
+With mankind the differences between the sexes are greater than in
+most of the Quadrumana, but not so great as in some, for instance,
+the mandrill. Man on an average is considerably taller, heavier, and
+stronger than woman, with squarer shoulders and more plainly-pronounced
+muscles. Owing to the relation which exists between muscular development
+and the projection of the brows (1. Schaaffhausen, translation
+in 'Anthropological Review,' Oct. 1868, pp. 419, 420, 427.), the
+superciliary ridge is generally more marked in man than in woman.
+His body, and especially his face, is more hairy, and his voice has a
+different and more powerful tone. In certain races the women are said
+to differ slightly in tint from the men. For instance, Schweinfurth,
+in speaking of a negress belonging to the Monbuttoos, who inhabit the
+interior of Africa a few degrees north of the equator, says, "Like all
+her race, she had a skin several shades lighter than her husband's,
+being something of the colour of half-roasted coffee." (2. 'The Heart
+of Africa,' English transl. 1873, vol i. p. 544.) As the women labour in
+the fields and are quite unclothed, it is not likely that they differ
+in colour from the men owing to less exposure to the weather. European
+women are perhaps the brighter coloured of the two sexes, as may be seen
+when both have been equally exposed.
+
+Man is more courageous, pugnacious and energetic than woman, and has a
+more inventive genius. His brain is absolutely larger, but whether or
+not proportionately to his larger body, has not, I believe, been fully
+ascertained. In woman the face is rounder; the jaws and the base of
+the skull smaller; the outlines of the body rounder, in parts more
+prominent; and her pelvis is broader than in man (3. Ecker, translation,
+in 'Anthropological Review,' Oct. 1868, pp. 351-356. The comparison of
+the form of the skull in men and women has been followed out with much
+care by Welcker.); but this latter character may perhaps be considered
+rather as a primary than a secondary sexual character. She comes to
+maturity at an earlier age than man.
+
+As with animals of all classes, so with man, the distinctive characters
+of the male sex are not fully developed until he is nearly mature;
+and if emasculated they never appear. The beard, for instance, is a
+secondary
+
+sexual character, and male children are beardless, though at an early
+age they have abundant hair on the head. It is probably due to the
+rather late appearance in life of the successive variations whereby man
+has acquired his masculine characters, that they are transmitted to the
+male sex alone. Male and female children resemble each other closely,
+like the young of so many other animals in which the adult sexes differ
+widely; they likewise resemble the mature female much more closely
+than the mature male. The female, however, ultimately assumes certain
+distinctive characters, and in the formation of her skull, is said to be
+intermediate between the child and the man. (4. Ecker and Welcker, ibid.
+pp. 352, 355; Vogt, 'Lectures on Man,' Eng. translat. p. 81.) Again, as
+the young of closely allied though distinct species do not differ nearly
+so much from each other as do the adults, so it is with the children
+of the different races of man. Some have even maintained that
+race-differences cannot be detected in the infantile skull. (5.
+Schaaffhausen, 'Anthropolog. Review,' ibid. p. 429.) In regard to
+colour, the new-born negro child is reddish nut-brown, which soon
+becomes slaty-grey; the black colour being fully developed within a year
+in the Soudan, but not until three years in Egypt. The eyes of the negro
+are at first blue, and the hair chestnut-brown rather than black, being
+curled only at the ends. The children of the Australians immediately
+after birth are yellowish-brown, and become dark at a later age. Those
+of the Guaranys of Paraguay are whitish-yellow, but they acquire in the
+course of a few weeks the yellowish-brown tint of their parents. Similar
+observations have been made in other parts of America. (6. Pruner-Bey,
+on negro infants as quoted by Vogt, 'Lectures on Man,' Eng. translat.
+1864, p. 189: for further facts on negro infants, as quoted from
+Winterbottom and Camper, see Lawrence, 'Lectures on Physiology,'
+etc. 1822, p. 451. For the infants of the Guaranys, see Rengger,
+'S�ugethiere,' etc. s. 3. See also Godron, 'De l'Esp�ce,' tom. ii. 1859,
+p. 253. For the Australians, Waitz, 'Introduction to Anthropology,' Eng.
+translat. 1863, p. 99.)
+
+I have specified the foregoing differences between the male and female
+sex in mankind, because they are curiously like those of the Quadrumana.
+With these animals the female is mature at an earlier age than the
+male; at least this is certainly the case in Cebus azarae. (7. Rengger,
+'S�ugethiere,' etc., 1830, s. 49.) The males of most species are larger
+and stronger than the females, of which fact the gorilla affords a
+well-known instance. Even in so trifling a character as the greater
+prominence of the superciliary ridge, the males of certain monkeys
+differ from the females (8. As in Macacus cynomolgus (Desmarest,
+'Mammalogie,' p. 65), and in Hylobates agilis (Geoffroy St.-Hilaire and
+F. Cuvier, 'Histoire Nat. des Mammif�res,' 1824, tom. i. p. 2)., and
+agree in this respect with mankind. In the gorilla and certain other
+monkeys, the cranium of the adult male presents a strongly-marked
+sagittal crest, which is absent in the female; and Ecker found a trace
+of a similar difference between the two sexes in the Australians. (9.
+'Anthropological Review,' Oct. 1868, p. 353.) With monkeys when there is
+any difference in the voice, that of the male is the more powerful. We
+have seen that certain male monkeys have a well-developed beard, which
+is quite deficient, or much less developed in the female. No instance
+is known of the beard, whiskers, or moustache being larger in the female
+than in the male monkey. Even in the colour of the beard there is a
+curious parallelism between man and the Quadrumana, for with man when
+the beard differs in colour from the hair of the head, as is commonly
+the case, it is, I believe, almost always of a lighter tint, being
+often reddish. I have repeatedly observed this fact in England; but two
+gentlemen have lately written to me, saying that they form an exception
+to the rule. One of these gentlemen accounts for the fact by the wide
+difference in colour of the hair on the paternal and maternal sides of
+his family. Both had been long aware of this peculiarity (one of them
+having often been accused of dyeing his beard), and had been thus led
+to observe other men, and were convinced that the exceptions were very
+rare. Dr. Hooker attended to this little point for me in Russia, and
+found no exception to the rule. In Calcutta, Mr. J. Scott, of the
+Botanic Gardens, was so kind as to observe the many races of men to be
+seen there, as well as in some other parts of India, namely, two races
+of Sikhim, the Bhoteas, Hindoos, Burmese, and Chinese, most of which
+races have very little hair on the face; and he always found that when
+there was any difference in colour between the hair of the head and
+the beard, the latter was invariably lighter. Now with monkeys, as has
+already been stated, the beard frequently differs strikingly in colour
+from the hair of the head, and in such cases it is always of a lighter
+hue, being often pure white, sometimes yellow or reddish. (10. Mr. Blyth
+informs me that he has only seen one instance of the beard, whiskers,
+etc., in a monkey becoming white with old age, as is so commonly the
+case with us. This, however, occurred in an aged Macacus cynomolgus,
+kept in confinement whose moustaches were "remarkably long and
+human-like." Altogether this old monkey presented a ludicrous
+resemblance to one of the reigning monarchs of Europe, after whom he
+was universally nick-named. In certain races of man the hair on the head
+hardly ever becomes grey; thus Mr. D. Forbes has never, as he informs
+me, seen an instance with the Aymaras and Quichuas of South America.)
+
+In regard to the general hairiness of the body, the women in all races
+are less hairy than the men; and in some few Quadrumana the under side
+of the body of the female is less hairy than that of the male. (11.
+This is the case with the females of several species of Hylobates; see
+Geoffroy St.-Hilaire and F. Cuvier, 'Hist. Nat. des Mamm.' tom. i. See
+also, on H. lar, 'Penny Cyclopedia,' vol. ii. pp. 149, 150.) Lastly,
+male monkeys, like men, are bolder and fiercer than the females. They
+lead the troop, and when there is danger, come to the front. We thus see
+how close is the parallelism between the sexual differences of man and
+the Quadrumana. With some few species, however, as with certain baboons,
+the orang and the gorilla, there is a considerably greater difference
+between the sexes, as in the size of the canine teeth, in the
+development and colour of the hair, and especially in the colour of the
+naked parts of the skin, than in mankind.
+
+All the secondary sexual characters of man are highly variable, even
+within the limits of the same race; and they differ much in the several
+races. These two rules hold good generally throughout the animal
+kingdom. In the excellent observations made on board the Novara (12. The
+results were deduced by Dr. Weisbach from the measurements made by Drs.
+K. Scherzer and Schwarz, see 'Reise der Novara: Anthropolog. Theil,'
+1867, ss. 216, 231, 234, 236, 239, 269.), the male Australians were
+found to exceed the females by only 65 millim. in height, whilst with
+the Javans the average excess was 218 millim.; so that in this latter
+race the difference in height between the sexes is more than thrice as
+great as with the Australians. Numerous measurements were carefully made
+of the stature, the circumference of the neck and chest, the length of
+the back-bone and of the arms, in various races; and nearly all these
+measurements shew that the males differ much more from one another than
+do the females. This fact indicates that, as far as these characters
+are concerned, it is the male which has been chiefly modified, since the
+several races diverged from their common stock.
+
+The development of the beard and the hairiness of the body differ
+remarkably in the men of distinct races, and even in different tribes or
+families of the same race. We Europeans see this amongst ourselves. In
+the Island of St. Kilda, according to Martin (13. 'Voyage to St. Kilda'
+(3rd ed. 1753), p. 37.), the men do not acquire beards until the age
+of thirty or upwards, and even then the beards are very thin. On the
+Europaeo-Asiatic continent, beards prevail until we pass beyond India;
+though with the natives of Ceylon they are often absent, as was noticed
+in ancient times by Diodorus. (14. Sir J.E. Tennent, 'Ceylon,' vol. ii.
+1859, p. 107.) Eastward of India beards disappear, as with the Siamese,
+Malays, Kalmucks, Chinese, and Japanese; nevertheless, the Ainos (15.
+Quatrefages, 'Revue des Cours Scientifiques,' Aug. 29, 1868, p.
+630; Vogt, 'Lectures on Man,' Eng. trans. p. 127.), who inhabit the
+northernmost islands of the Japan Archipelago, are the hairiest men in
+the world. With negroes the beard is scanty or wanting, and they rarely
+have whiskers; in both sexes the body is frequently almost destitute of
+fine down. (16. On the beards of negroes, Vogt, 'Lectures,' etc. p. 127;
+Waitz, 'Introduct. to Anthropology,' Engl. translat. 1863, vol. i.
+p. 96. It is remarkable that in the United States ('Investigations in
+Military and Anthropological Statistics of American Soldiers,' 1869, p.
+569) the pure negroes and their crossed offspring seem to have bodies
+almost as hairy as Europeans.) On the other hand, the Papuans of
+the Malay Archipelago, who are nearly as black as negroes, possess
+well-developed beards. (17. Wallace, 'The Malay Arch.' vol. ii. 1869, p.
+178.) In the Pacific Ocean the inhabitants of the Fiji Archipelago have
+large bushy beards, whilst those of the not distant archipelagoes of
+Tonga and Samoa are beardless; but these men belong to distinct races.
+In the Ellice group all the inhabitants belong to the same race; yet
+on one island alone, namely Nunemaya, "the men have splendid beards";
+whilst on the other islands "they have, as a rule, a dozen straggling
+hairs for a beard." (18. Dr. J. Barnard Davis on Oceanic Races, in
+'Anthropological Review,' April 1870, pp. 185, 191.)
+
+Throughout the great American continent the men may be said to be
+beardless; but in almost all the tribes a few short hairs are apt to
+appear on the face, especially in old age. With the tribes of North
+America, Catlin estimates that eighteen out of twenty men are completely
+destitute by nature of a beard; but occasionally there may be seen a
+man, who has neglected to pluck out the hairs at puberty, with a soft
+beard an inch or two in length. The Guaranys of Paraguay differ from all
+the surrounding tribes in having a small beard, and even some hair on
+the body, but no whiskers. (19. Catlin, 'North American Indians,' 3rd.
+ed. 1842, vol. ii. p. 227. On the Guaranys, see Azara, 'Voyages dans
+l'Am�rique Merid.' tom. ii. 1809, p. 85; also Rengger, 'S�ugethiere
+von Paraguay,' s. 3.) I am informed by Mr. D. Forbes, who particularly
+attended to this point, that the Aymaras and Quichuas of the Cordillera
+are remarkably hairless, yet in old age a few straggling hairs
+occasionally appear on the chin. The men of these two tribes have very
+little hair on the various parts of the body where hair grows abundantly
+in Europeans, and the women have none on the corresponding parts. The
+hair on the head, however, attains an extraordinary length in both
+sexes, often reaching almost to the ground; and this is likewise the
+case with some of the N. American tribes. In the amount of hair, and in
+the general shape of the body, the sexes of the American aborigines do
+not differ so much from each other, as in most other races. (20. Prof.
+and Mrs. Agassiz ('Journey in Brazil,' p. 530) remark that the sexes of
+the American Indians differ less than those of the negroes and of the
+higher races. See also Rengger, ibid. p. 3, on the Guaranys.) This fact
+is analogous with what occurs with some closely allied monkeys; thus the
+sexes of the chimpanzee are not as different as those of the orang or
+gorilla. (21. Rutimeyer, 'Die Grenzen der Thierwelt; eine Betrachtung zu
+Darwin's Lehre,' 1868, s. 54.)
+
+In the previous chapters we have seen that with mammals, birds, fishes,
+insects, etc., many characters, which there is every reason to believe
+were primarily gained through sexual selection by one sex, have
+been transferred to the other. As this same form of transmission has
+apparently prevailed much with mankind, it will save useless repetition
+if we discuss the origin of characters peculiar to the male sex together
+with certain other characters common to both sexes.
+
+LAW OF BATTLE.
+
+With savages, for instance, the Australians, the women are the constant
+cause of war both between members of the same tribe and between distinct
+tribes. So no doubt it was in ancient times; "nam fuit ante Helenam
+mulier teterrima belli causa." With some of the North American Indians,
+the contest is reduced to a system. That excellent observer, Hearne (22.
+'A Journey from Prince of Wales Fort,' 8vo. ed. Dublin, 1796, p. 104.
+Sir J. Lubbock ('Origin of Civilisation,' 1870, p. 69) gives other and
+similar cases in North America. For the Guanas of South America see
+Azara, 'Voyages,' etc. tom. ii. p. 94.), says:--"It has ever been the
+custom among these people for the men to wrestle for any woman to whom
+they are attached; and, of course, the strongest party always carries
+off the prize. A weak man, unless he be a good hunter, and well-beloved,
+is seldom permitted to keep a wife that a stronger man thinks worth his
+notice. This custom prevails throughout all the tribes, and causes a
+great spirit of emulation among their youth, who are upon all occasions,
+from their childhood, trying their strength and skill in wrestling."
+With the Guanas of South America, Azara states that the men rarely marry
+till twenty years old or more, as before that age they cannot conquer
+their rivals.
+
+Other similar facts could be given; but even if we had no evidence on
+this head, we might feel almost sure, from the analogy of the higher
+Quadrumana (23. On the fighting of the male gorillas, see Dr. Savage, in
+'Boston Journal of Natural History,' vol. v. 1847, p. 423. On Presbytis
+entellus, see the 'Indian Field,' 1859, p. 146.), that the law of battle
+had prevailed with man during the early stages of his development. The
+occasional appearance at the present day of canine teeth which project
+above the others, with traces of a diastema or open space for the
+reception of the opposite canines, is in all probability a case of
+reversion to a former state, when the progenitors of man were provided
+with these weapons, like so many existing male Quadrumana. It was
+remarked in a former chapter that as man gradually became erect, and
+continually used his hands and arms for fighting with sticks and stones,
+as well as for the other purposes of life, he would have used his jaws
+and teeth less and less. The jaws, together with their muscles, would
+then have been reduced through disuse, as would the teeth through the
+not well understood principles of correlation and economy of growth;
+for we everywhere see that parts, which are no longer of service, are
+reduced in size. By such steps the original inequality between the
+jaws and teeth in the two sexes of mankind would ultimately have
+been obliterated. The case is almost parallel with that of many
+male Ruminants, in which the canine teeth have been reduced to mere
+rudiments, or have disappeared, apparently in consequence of the
+development of horns. As the prodigious difference between the skulls of
+the two sexes in the orang and gorilla stands in close relation with the
+development of the immense canine teeth in the males, we may infer that
+the reduction of the jaws and teeth in the early male progenitors of
+man must have led to a most striking and favourable change in his
+appearance.
+
+There can be little doubt that the greater size and strength of man,
+in comparison with woman, together with his broader shoulders, more
+developed muscles, rugged outline of body, his greater courage and
+pugnacity, are all due in chief part to inheritance from his half-human
+male ancestors. These characters would, however, have been preserved or
+even augmented during the long ages of man's savagery, by the success of
+the strongest and boldest men, both in the general struggle for life and
+in their contests for wives; a success which would have ensured their
+leaving a more numerous progeny than their less favoured brethren. It
+is not probable that the greater strength of man was primarily acquired
+through the inherited effects of his having worked harder than woman
+for his own subsistence and that of his family; for the women in all
+barbarous nations are compelled to work at least as hard as the men.
+With civilised people the arbitrament of battle for the possession of
+the women has long ceased; on the other hand, the men, as a general
+rule, have to work harder than the women for their joint subsistence,
+and thus their greater strength will have been kept up.
+
+DIFFERENCE IN THE MENTAL POWERS OF THE TWO SEXES.
+
+With respect to differences of this nature between man and woman, it is
+probable that sexual selection has played a highly important part. I
+am aware that some writers doubt whether there is any such inherent
+difference; but this is at least probable from the analogy of the lower
+animals which present other secondary sexual characters. No one disputes
+that the bull differs in disposition from the cow, the wild-boar from
+the sow, the stallion from the mare, and, as is well known to the
+keepers of menageries, the males of the larger apes from the females.
+Woman seems to differ from man in mental disposition, chiefly in her
+greater tenderness and less selfishness; and this holds good even with
+savages, as shewn by a well-known passage in Mungo Park's Travels,
+and by statements made by many other travellers. Woman, owing to her
+maternal instincts, displays these qualities towards her infants in an
+eminent degree; therefore it is likely that she would often extend them
+towards her fellow-creatures. Man is the rival of other men; he delights
+in competition, and this leads to ambition which passes too easily
+into selfishness. These latter qualities seem to be his natural and
+unfortunate birthright. It is generally admitted that with woman the
+powers of intuition, of rapid perception, and perhaps of imitation, are
+more strongly marked than in man; but some, at least, of these faculties
+are characteristic of the lower races, and therefore of a past and lower
+state of civilisation.
+
+The chief distinction in the intellectual powers of the two sexes is
+shewn by man's attaining to a higher eminence, in whatever he takes up,
+than can woman--whether requiring deep thought, reason, or imagination,
+or merely the use of the senses and hands. If two lists were made of
+the most eminent men and women in poetry, painting, sculpture, music
+(inclusive both of composition and performance), history, science, and
+philosophy, with half-a-dozen names under each subject, the two lists
+would not bear comparison. We may also infer, from the law of the
+deviation from averages, so well illustrated by Mr. Galton, in his
+work on 'Hereditary Genius,' that if men are capable of a decided
+pre-eminence over women in many subjects, the average of mental power in
+man must be above that of woman.
+
+Amongst the half-human progenitors of man, and amongst savages, there
+have been struggles between the males during many generations for the
+possession of the females. But mere bodily strength and size would do
+little for victory, unless associated with courage, perseverance, and
+determined energy. With social animals, the young males have to pass
+through many a contest before they win a female, and the older males
+have to retain their females by renewed battles. They have, also, in the
+case of mankind, to defend their females, as well as their young, from
+enemies of all kinds, and to hunt for their joint subsistence. But to
+avoid enemies or to attack them with success, to capture wild animals,
+and to fashion weapons, requires the aid of the higher mental faculties,
+namely, observation, reason, invention, or imagination. These various
+faculties will thus have been continually put to the test and selected
+during manhood; they will, moreover, have been strengthened by use
+during this same period of life. Consequently in accordance with the
+principle often alluded to, we might expect that they would at
+least tend to be transmitted chiefly to the male offspring at the
+corresponding period of manhood.
+
+Now, when two men are put into competition, or a man with a woman, both
+possessed of every mental quality in equal perfection, save that one
+has higher energy, perseverance, and courage, the latter will generally
+become more eminent in every pursuit, and will gain the ascendancy. (24.
+J. Stuart Mill remarks ('The Subjection of Women,' 1869, p. 122), "The
+things in which man most excels woman are those which require most
+plodding, and long hammering at single thoughts." What is this but
+energy and perseverance?) He may be said to possess genius--for genius
+has been declared by a great authority to be patience; and patience, in
+this sense, means unflinching, undaunted perseverance. But this view
+of genius is perhaps deficient; for without the higher powers of
+the imagination and reason, no eminent success can be gained in many
+subjects. These latter faculties, as well as the former, will have been
+developed in man, partly through sexual selection,--that is, through the
+contest of rival males, and partly through natural selection, that is,
+from success in the general struggle for life; and as in both cases the
+struggle will have been during maturity, the characters gained will have
+been transmitted more fully to the male than to the female offspring.
+It accords in a striking manner with this view of the modification and
+re-inforcement of many of our mental faculties by sexual selection,
+that, firstly, they notoriously undergo a considerable change at puberty
+(25. Maudsley, 'Mind and Body,' p. 31.), and, secondly, that eunuchs
+remain throughout life inferior in these same qualities. Thus, man has
+ultimately become superior to woman. It is, indeed, fortunate that the
+law of the equal transmission of characters to both sexes prevails
+with mammals; otherwise, it is probable that man would have become as
+superior in mental endowment to woman, as the peacock is in ornamental
+plumage to the peahen.
+
+It must be borne in mind that the tendency in characters acquired by
+either sex late in life, to be transmitted to the same sex at the same
+age, and of early acquired characters to be transmitted to both sexes,
+are rules which, though general, do not always hold. If they always held
+good, we might conclude (but I here exceed my proper bounds) that the
+inherited effects of the early education of boys and girls would be
+transmitted equally to both sexes; so that the present inequality in
+mental power between the sexes would not be effaced by a similar course
+of early training; nor can it have been caused by their dissimilar early
+training. In order that woman should reach the same standard as man, she
+ought, when nearly adult, to be trained to energy and perseverance, and
+to have her reason and imagination exercised to the highest point; and
+then she would probably transmit these qualities chiefly to her adult
+daughters. All women, however, could not be thus raised, unless during
+many generations those who excelled in the above robust virtues were
+married, and produced offspring in larger numbers than other women. As
+before remarked of bodily strength, although men do not now fight for
+their wives, and this form of selection has passed away, yet during
+manhood, they generally undergo a severe struggle in order to maintain
+themselves and their families; and this will tend to keep up or even
+increase their mental powers, and, as a consequence, the present
+inequality between the sexes. (26. An observation by Vogt bears on this
+subject: he says, "It is a remarkable circumstance, that the difference
+between the sexes, as regards the cranial cavity, increases with the
+development of the race, so that the male European excels much more the
+female, than the negro the negress. Welcker confirms this statement
+of Huschke from his measurements of negro and German skulls." But
+Vogt admits ('Lectures on Man,' Eng. translat. 1864, p. 81) that more
+observations are requisite on this point.
+
+VOICE AND MUSICAL POWERS.
+
+In some species of Quadrumana there is a great difference between the
+adult sexes, in the power of their voices and in the development of the
+vocal organs; and man appears to have inherited this difference from his
+early progenitors. His vocal cords are about one-third longer than in
+woman, or than in boys; and emasculation produces the same effect on him
+as on the lower animals, for it "arrests that prominent growth of the
+thyroid, etc., which accompanies the elongation of the cords." (27.
+Owen, 'Anatomy of Vertebrates,' vol. iii. p. 603.) With respect to the
+cause of this difference between the sexes, I have nothing to add to
+the remarks in the last chapter on the probable effects of the
+long-continued use of the vocal organs by the male under the excitement
+of love, rage and jealousy. According to Sir Duncan Gibb (28. 'Journal
+of the Anthropological Society,' April 1869, p. lvii. and lxvi.),
+the voice and the form of the larynx differ in the different races of
+mankind; but with the Tartars, Chinese, etc., the voice of the male is
+said not to differ so much from that of the female, as in most other
+races.
+
+The capacity and love for singing or music, though not a sexual
+character in man, must not here be passed over. Although the sounds
+emitted by animals of all kinds serve many purposes, a strong case can
+be made out, that the vocal organs were primarily used and perfected in
+relation to the propagation of the species. Insects and some few spiders
+are the lowest animals which voluntarily produce any sound; and this is
+generally effected by the aid of beautifully constructed stridulating
+organs, which are often confined to the males. The sounds thus produced
+consist, I believe in all cases, of the same note, repeated rhythmically
+(29. Dr. Scudder, 'Notes on Stridulation,' in 'Proc. Boston Soc. of Nat.
+Hist.' vol. xi. April 1868.); and this is sometimes pleasing even to the
+ears of man. The chief and, in some cases, exclusive purpose appears to
+be either to call or charm the opposite sex.
+
+The sounds produced by fishes are said in some cases to be made only by
+the males during the breeding-season. All the air-breathing Vertebrata
+necessarily possess an apparatus for inhaling and expelling air, with a
+pipe capable of being closed at one end. Hence when the primeval
+members of this class were strongly excited and their muscles violently
+contracted, purposeless sounds would almost certainly have been
+produced; and these, if they proved in any way serviceable, might
+readily have been modified or intensified by the preservation of
+properly adapted variations. The lowest Vertebrates which breathe air
+are Amphibians; and of these, frogs and toads possess vocal organs,
+which are incessantly used during the breeding-season, and which are
+often more highly developed in the male than in the female. The male
+alone of the tortoise utters a noise, and this only during the season of
+love. Male alligators roar or bellow during the same season. Every one
+knows how much birds use their vocal organs as a means of courtship; and
+some species likewise perform what may be called instrumental music.
+
+In the class of Mammals, with which we are here more particularly
+concerned, the males of almost all the species use their voices during
+the breeding-season much more than at any other time; and some are
+absolutely mute excepting at this season. With other species both sexes,
+or only the females, use their voices as a love-call. Considering
+these facts, and that the vocal organs of some quadrupeds are much more
+largely developed in the male than in the female, either permanently or
+temporarily during the breeding-season; and considering that in most of
+the lower classes the sounds produced by the males, serve not only to
+call but to excite or allure the female, it is a surprising fact that
+we have not as yet any good evidence that these organs are used by male
+mammals to charm the females. The American Mycetes caraya perhaps forms
+an exception, as does the Hylobates agilis, an ape allied to man. This
+gibbon has an extremely loud but musical voice. Mr. Waterhouse states
+(30. Given in W.C.L. Martin's 'General Introduction to Natural History
+of Mamm. Animals,' 1841, p. 432; Owen, 'Anatomy of Vertebrates,' vol.
+iii, p. 600.), "It appeared to me that in ascending and descending the
+scale, the intervals were always exactly half-tones; and I am sure that
+the highest note was the exact octave to the lowest. The quality of the
+notes is very musical; and I do not doubt that a good violinist would
+be able to give a correct idea of the gibbon's composition, excepting
+as regards its loudness." Mr. Waterhouse then gives the notes. Professor
+Owen, who is a musician, confirms the foregoing statement, and remarks,
+though erroneously, that this gibbon "alone of brute mammals may be
+said to sing." It appears to be much excited after its performance.
+Unfortunately, its habits have never been closely observed in a state
+of nature; but from the analogy of other animals, it is probable that it
+uses its musical powers more especially during the season of courtship.
+
+This gibbon is not the only species in the genus which sings, for my
+son, Francis Darwin, attentively listened in the Zoological Gardens to
+H. leuciscus whilst singing a cadence of three notes, in true musical
+intervals and with a clear musical tone. It is a more surprising fact
+that certain rodents utter musical sounds. Singing mice have often been
+mentioned and exhibited, but imposture has commonly been suspected. We
+have, however, at last a clear account by a well-known observer, the
+Rev. S. Lockwood (31. The 'American Naturalist,' 1871, p. 761.), of
+the musical powers of an American species, the Hesperomys cognatus,
+belonging to a genus distinct from that of the English mouse. This
+little animal was kept in confinement, and the performance was
+repeatedly heard. In one of the two chief songs, "the last bar would
+frequently be prolonged to two or three; and she would sometimes change
+from C sharp and D, to C natural and D, then warble on these two
+notes awhile, and wind up with a quick chirp on C sharp and D.
+The distinctness between the semitones was very marked, and easily
+appreciable to a good ear." Mr. Lockwood gives both songs in musical
+notation; and adds that though this little mouse "had no ear for time,
+yet she would keep to the key of B (two flats) and strictly in a major
+key."..."Her soft clear voice falls an octave with all the precision
+possible; then at the wind up, it rises again into a very quick trill on
+C sharp and D."
+
+A critic has asked how the ears of man, and he ought to have added of
+other animals, could have been adapted by selection so as to distinguish
+musical notes. But this question shews some confusion on the subject; a
+noise is the sensation resulting from the co-existence of several aerial
+"simple vibrations" of various periods, each of which intermits so
+frequently that its separate existence cannot be perceived. It is only
+in the want of continuity of such vibrations, and in their want of
+harmony inter se, that a noise differs from a musical note. Thus an ear
+to be capable of discriminating noises--and the high importance of this
+power to all animals is admitted by every one--must be sensitive to
+musical notes. We have evidence of this capacity even low down in the
+animal scale: thus Crustaceans are provided with auditory hairs of
+different lengths, which have been seen to vibrate when the proper
+musical notes are struck. (32. Helmholtz, 'Theorie Phys. de la Musique,'
+1868, p. 187.) As stated in a previous chapter, similar observations
+have been made on the hairs of the antennae of gnats. It has been
+positively asserted by good observers that spiders are attracted by
+music. It is also well known that some dogs howl when hearing particular
+tones. (33. Several accounts have been published to this effect. Mr.
+Peach writes to me that an old dog of his howls when B flat is sounded
+on the flute, and to no other note. I may add another instance of a dog
+always whining, when one note on a concertina, which was out of tune,
+was played.) Seals apparently appreciate music, and their fondness for
+it "was well known to the ancients, and is often taken advantage of
+by the hunters at the present day." (34. Mr. R. Brown, in 'Proc. Zool.
+Soc.' 1868, p. 410.)
+
+Therefore, as far as the mere perception of musical notes is concerned,
+there seems no special difficulty in the case of man or of any other
+animal. Helmholtz has explained on physiological principles why concords
+are agreeable, and discords disagreeable to the human ear; but we are
+little concerned with these, as music in harmony is a late invention. We
+are more concerned with melody, and here again, according to Helmholtz,
+it is intelligible why the notes of our musical scale are used. The ear
+analyses all sounds into their component "simple vibrations," although
+we are not conscious of this analysis. In a musical note the lowest in
+pitch of these is generally predominant, and the others which are
+less marked are the octave, the twelfth, the second octave, etc., all
+harmonies of the fundamental predominant note; any two notes of our
+scale have many of these harmonic over-tones in common. It seems pretty
+clear then, that if an animal always wished to sing precisely the same
+song, he would guide himself by sounding those notes in succession,
+which possess many over-tones in common--that is, he would choose for
+his song, notes which belong to our musical scale.
+
+But if it be further asked why musical tones in a certain order and
+rhythm give man and other animals pleasure, we can no more give the
+reason than for the pleasantness of certain tastes and smells. That they
+do give pleasure of some kind to animals, we may infer from their
+being produced during the season of courtship by many insects, spiders,
+fishes, amphibians, and birds; for unless the females were able
+to appreciate such sounds and were excited or charmed by them, the
+persevering efforts of the males, and the complex structures often
+possessed by them alone, would be useless; and this it is impossible to
+believe.
+
+Human song is generally admitted to be the basis or origin of
+instrumental music. As neither the enjoyment nor the capacity of
+producing musical notes are faculties of the least use to man in
+reference to his daily habits of life, they must be ranked amongst the
+most mysterious with which he is endowed. They are present, though in a
+very rude condition, in men of all races, even the most savage; but so
+different is the taste of the several races, that our music gives no
+pleasure to savages, and their music is to us in most cases hideous and
+unmeaning. Dr. Seemann, in some interesting remarks on this subject (35.
+'Journal of Anthropological Society,' Oct. 1870, p. clv. See also the
+several later chapters in Sir John Lubbock's 'Prehistoric Times,' 2nd
+ed. 1869, which contain an admirable account of the habits of savages.),
+"doubts whether even amongst the nations of Western Europe, intimately
+connected as they are by close and frequent intercourse, the music of
+the one is interpreted in the same sense by the others. By travelling
+eastwards we find that there is certainly a different language of music.
+Songs of joy and dance-accompaniments are no longer, as with us, in
+the major keys, but always in the minor." Whether or not the half-human
+progenitors of man possessed, like the singing gibbons, the capacity
+of producing, and therefore no doubt of appreciating, musical notes,
+we know that man possessed these faculties at a very remote period. M.
+Lartet has described two flutes made out of the bones and horns of the
+reindeer, found in caves together with flint tools and the remains
+of extinct animals. The arts of singing and of dancing are also very
+ancient, and are now practised by all or nearly all the lowest races
+of man. Poetry, which may be considered as the offspring of song, is
+likewise so ancient, that many persons have felt astonished that it
+should have arisen during the earliest ages of which we have any record.
+
+We see that the musical faculties, which are not wholly deficient in
+any race, are capable of prompt and high development, for Hottentots
+and Negroes have become excellent musicians, although in their native
+countries they rarely practise anything that we should consider music.
+Schweinfurth, however, was pleased with some of the simple melodies
+which he heard in the interior of Africa. But there is nothing anomalous
+in the musical faculties lying dormant in man: some species of birds
+which never naturally sing, can without much difficulty be taught to do
+so; thus a house-sparrow has learnt the song of a linnet. As these two
+species are closely allied, and belong to the order of Insessores, which
+includes nearly all the singing-birds in the world, it is possible
+that a progenitor of the sparrow may have been a songster. It is
+more remarkable that parrots, belonging to a group distinct from the
+Insessores, and having differently constructed vocal organs, can be
+taught not only to speak, but to pipe or whistle tunes invented by man,
+so that they must have some musical capacity. Nevertheless it would be
+very rash to assume that parrots are descended from some ancient
+form which was a songster. Many cases could be advanced of organs and
+instincts originally adapted for one purpose, having been utilised for
+some distinct purpose. (36. Since this chapter was printed, I have seen
+a valuable article by Mr. Chauncey Wright ('North American Review,' Oct.
+1870, page 293), who, in discussing the above subject, remarks, "There
+are many consequences of the ultimate laws or uniformities of nature,
+through which the acquisition of one useful power will bring with it
+many resulting advantages as well as limiting disadvantages, actual or
+possible, which the principle of utility may not have comprehended in
+its action." As I have attempted to shew in an early chapter of this
+work, this principle has an important bearing on the acquisition by
+man of some of his mental characteristics.) Hence the capacity for high
+musical development which the savage races of man possess, may be due
+either to the practice by our semi-human progenitors of some rude form
+of music, or simply to their having acquired the proper vocal organs for
+a different purpose. But in this latter case we must assume, as in the
+above instance of parrots, and as seems to occur with many animals, that
+they already possessed some sense of melody.
+
+Music arouses in us various emotions, but not the more terrible ones of
+horror, fear, rage, etc. It awakens the gentler feelings of tenderness
+and love, which readily pass into devotion. In the Chinese annals it
+is said, "Music hath the power of making heaven descend upon earth." It
+likewise stirs up in us the sense of triumph and the glorious ardour for
+war. These powerful and mingled feelings may well give rise to the
+sense of sublimity. We can concentrate, as Dr. Seemann observes, greater
+intensity of feeling in a single musical note than in pages of writing.
+It is probable that nearly the same emotions, but much weaker and far
+less complex, are felt by birds when the male pours forth his full
+volume of song, in rivalry with other males, to captivate the female.
+Love is still the commonest theme of our songs. As Herbert Spencer
+remarks, "music arouses dormant sentiments of which we had not conceived
+the possibility, and do not know the meaning; or, as Richter says, tells
+us of things we have not seen and shall not see." Conversely, when vivid
+emotions are felt and expressed by the orator, or even in common speech,
+musical cadences and rhythm are instinctively used. The negro in Africa
+when excited often bursts forth in song; "another will reply in song,
+whilst the company, as if touched by a musical wave, murmur a chorus in
+perfect unison." (37. Winwood Reade, 'The Martyrdom of Man,' 1872, p.
+441, and 'African Sketch Book,' 1873, vol. ii. p. 313.) Even monkeys
+express strong feelings in different tones--anger and impatience by
+low,--fear and pain by high notes. (38. Rengger, 'S�ugethiere von
+Paraguay,' s. 49.) The sensations and ideas thus excited in us by music,
+or expressed by the cadences of oratory, appear from their vagueness,
+yet depth, like mental reversions to the emotions and thoughts of a
+long-past age.
+
+All these facts with respect to music and impassioned speech become
+intelligible to a certain extent, if we may assume that musical tones
+and rhythm were used by our half-human ancestors, during the season of
+courtship, when animals of all kinds are excited not only by love,
+but by the strong passions of jealousy, rivalry, and triumph. From the
+deeply-laid principle of inherited associations, musical tones in this
+case would be likely to call up vaguely and indefinitely the strong
+emotions of a long-past age. As we have every reason to suppose that
+articulate speech is one of the latest, as it certainly is the highest,
+of the arts acquired by man, and as the instinctive power of producing
+musical notes and rhythms is developed low down in the animal series, it
+would be altogether opposed to the principle of evolution, if we were to
+admit that man's musical capacity has been developed from the tones used
+in impassioned speech. We must suppose that the rhythms and cadences of
+oratory are derived from previously developed musical powers. (39. See
+the very interesting discussion on the 'Origin and Function of Music,'
+by Mr. Herbert Spencer, in his collected 'Essays,' 1858, p. 359. Mr.
+Spencer comes to an exactly opposite conclusion to that at which I have
+arrived. He concludes, as did Diderot formerly, that the cadences used
+in emotional speech afford the foundation from which music has been
+developed; whilst I conclude that musical notes and rhythm were first
+acquired by the male or female progenitors of mankind for the sake of
+charming the opposite sex. Thus musical tones became firmly associated
+with some of the strongest passions an animal is capable of feeling, and
+are consequently used instinctively, or through association when
+strong emotions are expressed in speech. Mr. Spencer does not offer any
+satisfactory explanation, nor can I, why high or deep notes should be
+expressive, both with man and the lower animals, of certain emotions.
+Mr. Spencer gives also an interesting discussion on the relations
+between poetry, recitative and song.) We can thus understand how it is
+that music, dancing, song, and poetry are such very ancient arts. We may
+go even further than this, and, as remarked in a former chapter, believe
+that musical sounds afforded one of the bases for the development of
+language. (40. I find in Lord Monboddo's 'Origin of Language,' vol.
+i. 1774, p. 469, that Dr. Blacklock likewise thought "that the first
+language among men was music, and that before our ideas were expressed
+by articulate sounds, they were communicated by tones varied according
+to different degrees of gravity and acuteness.")
+
+As the males of several quadrumanous animals have their vocal organs
+much more developed than in the females, and as a gibbon, one of the
+anthropomorphous apes, pours forth a whole octave of musical notes and
+may be said to sing, it appears probable that the progenitors of man,
+either the males or females or both sexes, before acquiring the power
+of expressing their mutual love in articulate language, endeavoured to
+charm each other with musical notes and rhythm. So little is known about
+the use of the voice by the Quadrumana during the season of love, that
+we have no means of judging whether the habit of singing was first
+acquired by our male or female ancestors. Women are generally thought to
+possess sweeter voices than men, and as far as this serves as any guide,
+we may infer that they first acquired musical powers in order to attract
+the other sex. (41. See an interesting discussion on this subject by
+Haeckel, 'Generelle Morphologie,' B. ii. 1866, s. 246.) But if so,
+this must have occurred long ago, before our ancestors had become
+sufficiently human to treat and value their women merely as useful
+slaves. The impassioned orator, bard, or musician, when with his varied
+tones and cadences he excites the strongest emotions in his hearers,
+little suspects that he uses the same means by which his half-human
+ancestors long ago aroused each other's ardent passions, during their
+courtship and rivalry.
+
+THE INFLUENCE OF BEAUTY IN DETERMINING THE MARRIAGES OF MANKIND.
+
+In civilised life man is largely, but by no means exclusively,
+influenced in the choice of his wife by external appearance; but we are
+chiefly concerned with primeval times, and our only means of forming
+a judgment on this subject is to study the habits of existing
+semi-civilised and savage nations. If it can be shewn that the men
+of different races prefer women having various characteristics, or
+conversely with the women, we have then to enquire whether such choice,
+continued during many generations, would produce any sensible effect on
+the race, either on one sex or both according to the form of inheritance
+which has prevailed.
+
+It will be well first to shew in some detail that savages pay the
+greatest attention to their personal appearance. (42. A full and
+excellent account of the manner in which savages in all parts of the
+world ornament themselves, is given by the Italian traveller, Professor
+Mantegazza, 'Rio de la Plata, Viaggi e Studi,' 1867, pp. 525-545; all
+the following statements, when other references are not given, are taken
+from this work. See, also, Waitz, 'Introduction to Anthropology,' Eng.
+translat. vol. i. 1863, p. 275, et passim. Lawrence also gives very full
+details in his 'Lectures on Physiology,' 1822. Since this chapter was
+written Sir J. Lubbock has published his 'Origin of Civilisation,' 1870,
+in which there is an interesting chapter on the present subject, and
+from which (pp. 42, 48) I have taken some facts about savages dyeing
+their teeth and hair, and piercing their teeth.) That they have a
+passion for ornament is notorious; and an English philosopher goes so
+far as to maintain, that clothes were first made for ornament and not
+for warmth. As Professor Waitz remarks, "however poor and miserable man
+is, he finds a pleasure in adorning himself." The extravagance of the
+naked Indians of South America in decorating themselves is shewn "by a
+man of large stature gaining with difficulty enough by the labour of a
+fortnight to procure in exchange the chica necessary to paint himself
+red." (43. Humboldt, 'Personal Narrative,' Eng. translat. vol. iv. p.
+515; on the imagination shewn in painting the body, p. 522; on modifying
+the form of the calf of the leg, p. 466.) The ancient barbarians of
+Europe during the Reindeer period brought to their caves any brilliant
+or singular objects which they happened to find. Savages at the
+present day everywhere deck themselves with plumes, necklaces, armlets,
+ear-rings, etc. They paint themselves in the most diversified manner.
+"If painted nations," as Humboldt observes, "had been examined with the
+same attention as clothed nations, it would have been perceived that the
+most fertile imagination and the most mutable caprice have created the
+fashions of painting, as well as those of garments."
+
+In one part of Africa the eyelids are coloured black; in another the
+nails are coloured yellow or purple. In many places the hair is dyed of
+various tints. In different countries the teeth are stained black, red,
+blue, etc., and in the Malay Archipelago it is thought shameful to have
+white teeth "like those of a dog." Not one great country can be named,
+from the polar regions in the north to New Zealand in the south,
+in which the aborigines do not tattoo themselves. This practice was
+followed by the Jews of old, and by the ancient Britons. In Africa some
+of the natives tattoo themselves, but it is a much more common practice
+to raise protuberances by rubbing salt into incisions made in various
+parts of the body; and these are considered by the inhabitants of
+Kordofan and Darfur "to be great personal attractions." In the Arab
+countries no beauty can be perfect until the cheeks "or temples have
+been gashed." (44. 'The Nile Tributaries,' 1867; 'The Albert N'yanza,'
+1866, vol. i. p. 218.) In South America, as Humboldt remarks, "a mother
+would be accused of culpable indifference towards her children, if she
+did not employ artificial means to shape the calf of the leg after the
+fashion of the country." In the Old and New Worlds the shape of the
+skull was formerly modified during infancy in the most extraordinary
+manner, as is still the case in many places, and such deformities are
+considered ornamental. For instance, the savages of Colombia (45. Quoted
+by Prichard, 'Physical History of Mankind,' 4th ed. vol. i. 1851, p.
+321.) deem a much flattened head "an essential point of beauty."
+
+The hair is treated with especial care in various countries; it is
+allowed to grow to full length, so as to reach to the ground, or is
+combed into "a compact frizzled mop, which is the Papuan's pride and
+glory." (46. On the Papuans, Wallace, 'The Malay Archipelago,' vol.
+ii. p. 445. On the coiffure of the Africans, Sir S. Baker, 'The Albert
+N'yanza,' vol. i. p. 210.) In northern Africa "a man requires a period
+of from eight to ten years to perfect his coiffure." With other nations
+the head is shaved, and in parts of South America and Africa even the
+eyebrows and eyelashes are eradicated. The natives of the Upper Nile
+knock out the four front teeth, saying that they do not wish to
+resemble brutes. Further south, the Batokas knock out only the two upper
+incisors, which, as Livingstone (47. 'Travels,' p. 533.) remarks, gives
+the face a hideous appearance, owing to the prominence of the lower jaw;
+but these people think the presence of the incisors most unsightly, and
+on beholding some Europeans, cried out, "Look at the great teeth!" The
+chief Sebituani tried in vain to alter this fashion. In various parts of
+Africa and in the Malay Archipelago the natives file the incisors into
+points like those of a saw, or pierce them with holes, into which they
+insert studs.
+
+As the face with us is chiefly admired for its beauty, so with savages
+it is the chief seat of mutilation. In all quarters of the world the
+septum, and more rarely the wings of the nose are pierced; rings,
+sticks, feathers, and other ornaments being inserted into the holes.
+The ears are everywhere pierced and similarly ornamented, and with the
+Botocudos and Lenguas of South America the hole is gradually so much
+enlarged that the lower edge touches the shoulder. In North and South
+America and in Africa either the upper or lower lip is pierced; and with
+the Botocudos the hole in the lower lip is so large that a disc of wood,
+four inches in diameter, is placed in it. Mantegazza gives a curious
+account of the shame felt by a South American native, and of the
+ridicule which he excited, when he sold his tembeta,--the large coloured
+piece of wood which is passed through the hole. In Central Africa
+the women perforate the lower lip and wear a crystal, which, from the
+movement of the tongue, has "a wriggling motion, indescribably ludicrous
+during conversation." The wife of the chief of Latooka told Sir S. Baker
+(49. 'The Albert N'yanza,' 1866, vol. i. p. 217.) that Lady Baker "would
+be much improved if she would extract her four front teeth from the
+lower jaw, and wear the long pointed polished crystal in her under lip."
+Further south with the Makalolo, the upper lip is perforated, and a
+large metal and bamboo ring, called a pelele, is worn in the hole. "This
+caused the lip in one case to project two inches beyond the tip of the
+nose; and when the lady smiled, the contraction of the muscles elevated
+it over the eyes. 'Why do the women wear these things?' the venerable
+chief, Chinsurdi, was asked. Evidently surprised at such a stupid
+question, he replied, 'For beauty! They are the only beautiful things
+women have; men have beards, women have none. What kind of a person
+would she be without the pelele? She would not be a woman at all with
+a mouth like a man, but no beard.'" (49. Livingstone, 'British
+Association,' 1860; report given in the 'Athenaeum,' July 7, 1860, p.
+29.)
+
+Hardly any part of the body, which can be unnaturally modified, has
+escaped. The amount of suffering thus caused must have been extreme, for
+many of the operations require several years for their completion, so
+that the idea of their necessity must be imperative. The motives are
+various; the men paint their bodies to make themselves appear terrible
+in battle; certain mutilations are connected with religious rites, or
+they mark the age of puberty, or the rank of the man, or they serve to
+distinguish the tribes. Amongst savages the same fashions prevail for
+long periods (50. Sir S. Baker (ibid. vol. i. p. 210) speaking of
+the natives of Central Africa says, "every tribe has a distinct and
+unchanging fashion for dressing the hair." See Agassiz ('Journey in
+Brazil,' 1868, p. 318) on invariability of the tattooing of Amazonian
+Indians.), and thus mutilations, from whatever cause first made, soon
+come to be valued as distinctive marks. But self-adornment, vanity, and
+the admiration of others, seem to be the commonest motives. In regard to
+tattooing, I was told by the missionaries in New Zealand that when they
+tried to persuade some girls to give up the practice, they answered, "We
+must just have a few lines on our lips; else when we grow old we shall
+be so very ugly." With the men of New Zealand, a most capable judge (51.
+Rev. R. Taylor, 'New Zealand and its Inhabitants,' 1855, p. 152.) says,
+"to have fine tattooed faces was the great ambition of the young, both
+to render themselves attractive to the ladies, and conspicuous in war."
+A star tattooed on the forehead and a spot on the chin are thought by
+the women in one part of Africa to be irresistible attractions. (52.
+Mantegazza, 'Viaggi e Studi,' p. 542.) In most, but not all parts of
+the world, the men are more ornamented than the women, and often in a
+different manner; sometimes, though rarely, the women are hardly at all
+ornamented. As the women are made by savages to perform the greatest
+share of the work, and as they are not allowed to eat the best kinds of
+food, so it accords with the characteristic selfishness of man that they
+should not be allowed to obtain, or use the finest ornaments. Lastly,
+it is a remarkable fact, as proved by the foregoing quotations, that
+the same fashions in modifying the shape of the head, in ornamenting the
+hair, in painting, tattooing, in perforating the nose, lips, or ears,
+in removing or filing the teeth, etc., now prevail, and have long
+prevailed, in the most distant quarters of the world. It is extremely
+improbable that these practices, followed by so many distinct nations,
+should be due to tradition from any common source. They indicate the
+close similarity of the mind of man, to whatever race he may belong,
+just as do the almost universal habits of dancing, masquerading, and
+making rude pictures.
+
+Having made these preliminary remarks on the admiration felt by savages
+for various ornaments, and for deformities most unsightly in our eyes,
+let us see how far the men are attracted by the appearance of their
+women, and what are their ideas of beauty. I have heard it maintained
+that savages are quite indifferent about the beauty of their women,
+valuing them solely as slaves; it may therefore be well to observe that
+this conclusion does not at all agree with the care which the women take
+in ornamenting themselves, or with their vanity. Burchell (53. 'Travels
+in South Africa,' 1824, vol. i. p. 414.) gives an amusing account of a
+Bush-woman who used as much grease, red ochre, and shining powder "as
+would have ruined any but a very rich husband." She displayed also "much
+vanity and too evident a consciousness of her superiority." Mr. Winwood
+Reade informs me that the negroes of the West Coast often discuss the
+beauty of their women. Some competent observers have attributed the
+fearfully common practice of infanticide partly to the desire felt by
+the women to retain their good looks. (54. See, for references, Gerland,
+'Ueber das Aussterben der Naturv�lker,' 1868, ss. 51, 53, 55; also
+Azara, 'Voyages,' etc., tom. ii. p. 116.) In several regions the women
+wear charms and use love-philters to gain the affections of the men; and
+Mr. Brown enumerates four plants used for this purpose by the women of
+North-Western America. (55. On the vegetable productions used by the
+North-Western American Indians, see 'Pharmaceutical Journal,' vol. x.)
+
+Hearne (56. 'A Journey from Prince of Wales Fort,' 8vo. ed. 1796, p.
+89.), an excellent observer, who lived many years with the American
+Indians, says, in speaking of the women, "Ask a Northern Indian what
+is beauty, and he will answer, a broad flat face, small eyes, high
+cheek-bones, three or four broad black lines across each cheek, a low
+forehead, a large broad chin, a clumsy hook nose, a tawny hide, and
+breasts hanging down to the belt." Pallas, who visited the northern
+parts of the Chinese empire, says, "those women are preferred who have
+the Mandschu form; that is to say, a broad face, high cheek-bones,
+very broad noses, and enormous ears"(57. Quoted by Prichard, 'Physical
+History of Mankind,' 3rd ed. vol. iv. 1844, p. 519; Vogt, 'Lectures
+on Man,' Eng. translat. p. 129. On the opinion of the Chinese on the
+Cingalese, E. Tennent, 'Ceylon,' 1859, vol. ii. p. 107.); and Vogt
+remarks that the obliquity of the eye, which is proper to the Chinese
+and Japanese, is exaggerated in their pictures for the purpose, as it
+"seems, of exhibiting its beauty, as contrasted with the eye of the
+red-haired barbarians." It is well known, as Huc repeatedly remarks,
+that the Chinese of the interior think Europeans hideous, with their
+white skins and prominent noses. The nose is far from being too
+prominent, according to our ideas, in the natives of Ceylon; yet "the
+Chinese in the seventh century, accustomed to the flat features of the
+Mongol races, were surprised at the prominent noses of the Cingalese;
+and Thsang described them as having 'the beak of a bird, with the body
+of a man.'"
+
+Finlayson, after minutely describing the people of Cochin China, says
+that their rounded heads and faces are their chief characteristics; and,
+he adds, "the roundness of the whole countenance is more striking in
+the women, who are reckoned beautiful in proportion as they display this
+form of face." The Siamese have small noses with divergent nostrils, a
+wide mouth, rather thick lips, a remarkably large face, with very high
+and broad cheek-bones. It is, therefore, not wonderful that "beauty,
+according to our notion, is a stranger to them. Yet they consider
+their own females to be much more beautiful than those of Europe."
+(58. Prichard, as taken from Crawfurd and Finlayson, 'Phys. Hist. of
+Mankind,' vol. iv. pp. 534, 535.)
+
+It is well known that with many Hottentot women the posterior part of
+the body projects in a wonderful manner; they are steatopygous; and Sir
+Andrew Smith is certain that this peculiarity is greatly admired by
+the men. (59. Idem illustrissimus viator dixit mihi praecinctorium vel
+tabulam foeminae, quod nobis teterrimum est, quondam permagno aestimari
+ab hominibus in hac gente. Nunc res mutata est, et censent talem
+conformationem minime optandam esse.) He once saw a woman who was
+considered a beauty, and she was so immensely developed behind, that
+when seated on level ground she could not rise, and had to push herself
+along until she came to a slope. Some of the women in various negro
+tribes have the same peculiarity; and, according to Burton, the Somal
+men are said to choose their wives by ranging them in a line, and by
+picking her out who projects farthest a tergo. Nothing can be more
+hateful to a negro than the opposite form." (60. The 'Anthropological
+Review,' November 1864, p. 237. For additional references, see Waitz,
+'Introduction to Anthropology,' Eng. translat., 1863, vol. i. p. 105.)
+
+With respect to colour, the negroes rallied Mungo Park on the whiteness
+of his skin and the prominence of his nose, both of which they
+considered as "unsightly and unnatural conformations." He in return
+praised the glossy jet of their skins and the lovely depression of their
+noses; this they said was "honeymouth," nevertheless they gave him food.
+The African Moors, also, "knitted their brows and seemed to shudder"
+at the whiteness of his skin. On the eastern coast, the negro boys when
+they saw Burton, cried out, "Look at the white man; does he not look
+like a white ape?" On the western coast, as Mr. Winwood Reade informs
+me, the negroes admire a very black skin more than one of a lighter
+tint. But their horror of whiteness may be attributed, according to this
+same traveller, partly to the belief held by most negroes that demons
+and spirits are white, and partly to their thinking it a sign of
+ill-health.
+
+The Banyai of the more southern part of the continent are negroes,
+but "a great many of them are of a light coffee-and-milk colour,
+and, indeed, this colour is considered handsome throughout the whole
+country"; so that here we have a different standard of taste. With
+the Kaffirs, who differ much from negroes, "the skin, except among the
+tribes near Delagoa Bay, is not usually black, the prevailing colour
+being a mixture of black and red, the most common shade being chocolate.
+Dark complexions, as being most common, are naturally held in the
+highest esteem. To be told that he is light-coloured, or like a white
+man, would be deemed a very poor compliment by a Kaffir. I have heard of
+one unfortunate man who was so very fair that no girl would marry him."
+One of the titles of the Zulu king is, "You who are black." (61. Mungo
+Park's 'Travels in Africa,' 4to. 1816, pp. 53, 131. Burton's statement
+is quoted by Schaaffhausen, 'Archiv. fur Anthropologie,' 1866, s. 163.
+On the Banyai, Livingstone, 'Travels,' p. 64. On the Kaffirs, the Rev.
+J. Shooter, 'The Kafirs of Natal and the Zulu Country,' 1857, p. 1.) Mr.
+Galton, in speaking to me about the natives of S. Africa, remarked that
+their ideas of beauty seem very different from ours; for in one tribe
+two slim, slight, and pretty girls were not admired by the natives.
+
+Turning to other quarters of the world; in Java, a yellow, not a white
+girl, is considered, according to Madame Pfeiffer, a beauty. A man of
+Cochin China "spoke with contempt of the wife of the English Ambassador,
+that she had white teeth like a dog, and a rosy colour like that of
+potato-flowers." We have seen that the Chinese dislike our white skin,
+and that the N. Americans admire "a tawny hide." In S. America,
+the Yuracaras, who inhabit the wooded, damp slopes of the eastern
+Cordillera, are remarkably pale-coloured, as their name in their own
+language expresses; nevertheless they consider European women as very
+inferior to their own. (62. For the Javans and Cochin-Chinese, see
+Waitz, 'Introduct. to Anthropology,' Eng. translat. vol. i. p. 305. On
+the Yuracaras, A. d'Orbigny, as quoted in Prichard, 'Physical History of
+Mankind,' vol. v. 3rd ed. p. 476.)
+
+In several of the tribes of North America the hair on the head grows to
+a wonderful length; and Catlin gives a curious proof how much this is
+esteemed, for the chief of the Crows was elected to this office from
+having the longest hair of any man in the tribe, namely ten feet and
+seven inches. The Aymaras and Quichuas of S. America, likewise have very
+long hair; and this, as Mr. D. Forbes informs me, is so much valued as
+a beauty, that cutting it off was the severest punishment which he
+could inflict on them. In both the Northern and Southern halves of the
+continent the natives sometimes increase the apparent length of their
+hair by weaving into it fibrous substances. Although the hair on the
+head is thus cherished, that on the face is considered by the North
+American Indians "as very vulgar," and every hair is carefully
+eradicated. This practice prevails throughout the American continent
+from Vancouver's Island in the north to Tierra del Fuego in the south.
+When York Minster, a Fuegian on board the "Beagle," was taken back to
+his country, the natives told him he ought to pull out the few short
+hairs on his face. They also threatened a young missionary, who was left
+for a time with them, to strip him naked, and pluck the hair from his
+face and body, yet he was far from being a hairy man. This fashion is
+carried so far that the Indians of Paraguay eradicate their eyebrows and
+eyelashes, saying that they do not wish to be like horses. (63. 'North
+American Indians,' by G. Catlin, 3rd ed., 1842, vol. i. p. 49; vol. ii,
+p. 227. On the natives of Vancouver's Island, see Sproat, 'Scenes and
+Studies of Savage Life,' 1868, p. 25. On the Indians of Paraguay, Azara,
+'Voyages,' tom. ii. p. 105.)
+
+It is remarkable that throughout the world the races which are almost
+completely destitute of a beard dislike hairs on the face and body, and
+take pains to eradicate them. The Kalmucks are beardless, and they are
+well known, like the Americans, to pluck out all straggling hairs; and
+so it is with the Polynesians, some of the Malays, and the Siamese. Mr.
+Veitch states that the Japanese ladies "all objected to our whiskers,
+considering them very ugly, and told us to cut them off, and be like
+Japanese men." The New Zealanders have short, curled beards; yet they
+formerly plucked out the hairs on the face. They had a saying that
+"there is no woman for a hairy man;" but it would appear that the
+fashion has changed in New Zealand, perhaps owing to the presence of
+Europeans, and I am assured that beards are now admired by the Maories.
+(64. On the Siamese, Prichard, ibid. vol. iv. p. 533. On the Japanese,
+Veitch in 'Gardeners' Chronicle,' 1860, p. 1104. On the New Zealanders,
+Mantegazza, 'Viaggi e Studi,' 1867, p. 526. For the other nations
+mentioned, see references in Lawrence, 'Lectures on Physiology,' etc.,
+1822, p. 272.)
+
+On the other hand, bearded races admire and greatly value their beards;
+among the Anglo-Saxons every part of the body had a recognised value;
+"the loss of the beard being estimated at twenty shillings, while the
+breaking of a thigh was fixed at only twelve." (65. Lubbock, 'Origin of
+Civilisation,' 1870, p. 321.) In the East men swear solemnly by their
+beards. We have seen that Chinsurdi, the chief of the Makalolo in
+Africa, thought that beards were a great ornament. In the Pacific the
+Fijian's beard is "profuse and bushy, and is his greatest pride"; whilst
+the inhabitants of the adjacent archipelagoes of Tonga and Samoa are
+"beardless, and abhor a rough chin." In one island alone of the Ellice
+group "the men are heavily bearded, and not a little proud thereof."
+(66. Dr. Barnard Davis quotes Mr. Prichard and others for these facts
+in regard to the Polynesians, in 'Anthropolog. Review,' April 1870, pp.
+185, 191.)
+
+We thus see how widely the different races of man differ in their taste
+for the beautiful. In every nation sufficiently advanced to have made
+effigies of their gods or of their deified rulers, the sculptors no
+doubt have endeavoured to express their highest ideal of beauty and
+grandeur. (67. Ch. Comte has remarks to this effect in his 'Trait� de
+L�gislation,' 3rd ed. 1837, p. 136.) Under this point of view it is
+well to compare in our mind the Jupiter or Apollo of the Greeks with the
+Egyptian or Assyrian statues; and these with the hideous bas-reliefs on
+the ruined buildings of Central America.
+
+I have met with very few statements opposed to this conclusion. Mr.
+Winwood Reade, however, who has had ample opportunities for observation,
+not only with the negroes of the West Coast of Africa, but with those of
+the interior who have never associated with Europeans, is convinced that
+their ideas of beauty are ON THE WHOLE the same as ours; and Dr. Rohlfs
+writes to me to the same effect with respect to Bornu and the countries
+inhabited by the Pullo tribes. Mr. Reade found that he agreed with the
+negroes in their estimation of the beauty of the native girls; and that
+their appreciation of the beauty of European women corresponded with
+ours. They admire long hair, and use artificial means to make it appear
+abundant; they admire also a beard, though themselves very scantily
+provided. Mr. Reade feels doubtful what kind of nose is most
+appreciated; a girl has been heard to say, "I do not want to marry
+him, he has got no nose"; and this shews that a very flat nose is not
+admired. We should, however, bear in mind that the depressed, broad
+noses and projecting jaws of the negroes of the West Coast are
+exceptional types with the inhabitants of Africa. Notwithstanding the
+foregoing statements, Mr. Reade admits that negroes "do not like the
+colour of our skin; they look on blue eyes with aversion, and they think
+our noses too long and our lips too thin." He does not think it probable
+that negroes would ever prefer the most beautiful European woman, on the
+mere grounds of physical admiration, to a good-looking negress. (68. The
+'African Sketch Book,' vol. ii. 1873, pp. 253, 394, 521. The Fuegians,
+as I have been informed by a missionary who long resided with them,
+consider European women as extremely beautiful; but from what we have
+seen of the judgment of the other aborigines of America, I cannot but
+think that this must be a mistake, unless indeed the statement refers
+to the few Fuegians who have lived for some time with Europeans, and
+who must consider us as superior beings. I should add that a most
+experienced observer, Capt. Burton, believes that a woman whom we
+consider beautiful is admired throughout the world. 'Anthropological
+Review,' March, 1864, p. 245.)
+
+The general truth of the principle, long ago insisted on by Humboldt
+(69. 'Personal Narrative,' Eng. translat. vol. iv. p. 518, and
+elsewhere. Mantegazza, in his 'Viaggi e Studi,' strongly insists on
+this same principle.), that man admires and often tries to exaggerate
+whatever characters nature may have given him, is shewn in many ways.
+The practice of beardless races extirpating every trace of a beard, and
+often all the hairs on the body affords one illustration. The skull has
+been greatly modified during ancient and modern times by many nations;
+and there can be little doubt that this has been practised, especially
+in N. and S. America, in order to exaggerate some natural and admired
+peculiarity. Many American Indians are known to admire a head so
+extremely flattened as to appear to us idiotic. The natives on the
+north-western coast compress the head into a pointed cone; and it is
+their constant practice to gather the hair into a knot on the top of the
+head, for the sake, as Dr. Wilson remarks, "of increasing the apparent
+elevation of the favourite conoid form." The inhabitants of Arakhan
+admire a broad, smooth forehead, and in order to produce it, they fasten
+a plate of lead on the heads of the new-born children. On the other
+hand, "a broad, well-rounded occiput is considered a great beauty" by
+the natives of the Fiji Islands. (70. On the skulls of the American
+tribes, see Nott and Gliddon, 'Types of Mankind,' 1854, p. 440;
+Prichard, 'Physical History of Mankind,' vol. i. 3rd ed. p. 321; on the
+natives of Arakhan, ibid. vol. iv. p. 537. Wilson, 'Physical Ethnology,'
+Smithsonian Institution, 1863, p. 288; on the Fijians, p. 290. Sir J.
+Lubbock ('Prehistoric Times,' 2nd ed. 1869, p. 506) gives an excellent
+resume on this subject.)
+
+As with the skull, so with the nose; the ancient Huns during the age
+of Attila were accustomed to flatten the noses of their infants with
+bandages, "for the sake of exaggerating a natural conformation." With
+the Tahitians, to be called LONG-NOSE is considered as an insult, and
+they compress the noses and foreheads of their children for the sake
+of beauty. The same holds with the Malays of Sumatra, the Hottentots,
+certain Negroes, and the natives of Brazil. (71. On the Huns, Godron,
+'De l'Esp�ce,' tom. ii. 1859, p. 300. On the Tahitians, Waitz,
+'Anthropology,' Eng. translat. vol. i. p. 305. Marsden, quoted by
+Prichard, 'Phys. Hist. of Mankind,' 3rd edit. vol. v. p. 67. Lawrence,
+'Lectures on Physiology,' p. 337.) The Chinese have by nature unusually
+small feet (72. This fact was ascertained in the 'Reise der Novara:
+Anthropolog. Theil.' Dr. Weisbach, 1867, s. 265.); and it is well known
+that the women of the upper classes distort their feet to make them
+still smaller. Lastly, Humboldt thinks that the American Indians prefer
+colouring their bodies with red paint in order to exaggerate their
+natural tint; and until recently European women added to their naturally
+bright colours by rouge and white cosmetics; but it may be doubted
+whether barbarous nations have generally had any such intention in
+painting themselves.
+
+In the fashions of our own dress we see exactly the same principle and
+the same desire to carry every point to an extreme; we exhibit, also,
+the same spirit of emulation. But the fashions of savages are far
+more permanent than ours; and whenever their bodies are artificially
+modified, this is necessarily the case. The Arab women of the Upper Nile
+occupy about three days in dressing their hair; they never imitate other
+tribes, "but simply vie with each other in the superlativeness of their
+own style." Dr. Wilson, in speaking of the compressed skulls of various
+American races, adds, "such usages are among the least eradicable, and
+long survive the shock of revolutions that change dynasties and efface
+more important national peculiarities." (73. 'Smithsonian Institution,'
+1863, p. 289. On the fashions of Arab women, Sir S. Baker, 'The Nile
+Tributaries,' 1867, p. 121.) The same principle comes into play in
+the art of breeding; and we can thus understand, as I have
+elsewhere explained (74. The 'Variation of Animals and Plants under
+Domestication,' vol. i. p. 214; vol. ii. p. 240.), the wonderful
+development of the many races of animals and plants, which have been
+kept merely for ornament. Fanciers always wish each character to be
+somewhat increased; they do not admire a medium standard; they certainly
+do not desire any great and abrupt change in the character of their
+breeds; they admire solely what they are accustomed to, but they
+ardently desire to see each characteristic feature a little more
+developed.
+
+The senses of man and of the lower animals seem to be so constituted
+that brilliant colours and certain forms, as well as harmonious and
+rhythmical sounds, give pleasure and are called beautiful; but why this
+should be so we know not. It is certainly not true that there is in the
+mind of man any universal standard of beauty with respect to the human
+body. It is, however, possible that certain tastes may in the course
+of time become inherited, though there is no evidence in favour of this
+belief: and if so, each race would possess its own innate ideal
+standard of beauty. It has been argued (75. Schaaffhausen, 'Archiv. f�r
+Anthropologie,' 1866, s. 164.) that ugliness consists in an approach
+to the structure of the lower animals, and no doubt this is partly
+true with the more civilised nations, in which intellect is highly
+appreciated; but this explanation will hardly apply to all forms of
+ugliness. The men of each race prefer what they are accustomed to; they
+cannot endure any great change; but they like variety, and admire
+each characteristic carried to a moderate extreme. (76. Mr. Bain has
+collected ('Mental and Moral Science,' 1868, pp. 304-314) about a dozen
+more or less different theories of the idea of beauty; but none is quite
+the same as that here given.) Men accustomed to a nearly oval face,
+to straight and regular features, and to bright colours, admire, as we
+Europeans know, these points when strongly developed. On the other hand,
+men accustomed to a broad face, with high cheek-bones, a depressed nose,
+and a black skin, admire these peculiarities when strongly marked. No
+doubt characters of all kinds may be too much developed for beauty.
+Hence a perfect beauty, which implies many characters modified in
+a particular manner, will be in every race a prodigy. As the great
+anatomist Bichat long ago said, if every one were cast in the same
+mould, there would be no such thing as beauty. If all our women were
+to become as beautiful as the Venus de' Medici, we should for a time
+be charmed; but we should soon wish for variety; and as soon as we had
+obtained variety, we should wish to see certain characters a little
+exaggerated beyond the then existing common standard.
+
+
+CHAPTER XX.
+
+SECONDARY SEXUAL CHARACTERS OF MAN--continued.
+
+On the effects of the continued selection of women according to a
+different standard of beauty in each race--On the causes which interfere
+with sexual selection in civilised and savage nations--Conditions
+favourable to sexual selection during primeval times--On the manner of
+action of sexual selection with mankind--On the women in savage tribes
+having some power to choose their husbands--Absence of hair on the body,
+and development of the beard--Colour of the skin--Summary.
+
+We have seen in the last chapter that with all barbarous races
+ornaments, dress, and external appearance are highly valued; and
+that the men judge of the beauty of their women by widely different
+standards. We must next inquire whether this preference and the
+consequent selection during many generations of those women, which
+appear to the men of each race the most attractive, has altered the
+character either of the females alone, or of both sexes. With mammals
+the general rule appears to be that characters of all kinds are
+inherited equally by the males and females; we might therefore expect
+that with mankind any characters gained by the females or by the males
+through sexual selection would commonly be transferred to the offspring
+of both sexes. If any change has thus been effected, it is almost
+certain that the different races would be differently modified, as each
+has its own standard of beauty.
+
+With mankind, especially with savages, many causes interfere with the
+action of sexual selection as far as the bodily frame is concerned.
+Civilised men are largely attracted by the mental charms of women, by
+their wealth, and especially by their social position; for men rarely
+marry into a much lower rank. The men who succeed in obtaining the more
+beautiful women will not have a better chance of leaving a long line of
+descendants than other men with plainer wives, save the few who bequeath
+their fortunes according to primogeniture. With respect to the opposite
+form of selection, namely, of the more attractive men by the women,
+although in civilised nations women have free or almost free choice,
+which is not the case with barbarous races, yet their choice is largely
+influenced by the social position and wealth of the men; and the success
+of the latter in life depends much on their intellectual powers and
+energy, or on the fruits of these same powers in their forefathers. No
+excuse is needed for treating this subject in some detail; for, as the
+German philosopher Schopenhauer remarks, "the final aim of all love
+intrigues, be they comic or tragic, is really of more importance than
+all other ends in human life. What it all turns upon is nothing less
+than the composition of the next generation...It is not the weal or woe
+of any one individual, but that of the human race to come, which is
+here at stake." (1. 'Schopenhauer and Darwinism,' in 'Journal of
+Anthropology,' Jan. 1871, p. 323.
+
+There is, however, reason to believe that in certain civilised and
+semi-civilised nations sexual selection has effected something in
+modifying the bodily frame of some of the members. Many persons are
+convinced, as it appears to me with justice, that our aristocracy,
+including under this term all wealthy families in which primogeniture
+has long prevailed, from having chosen during many generations from all
+classes the more beautiful women as their wives, have become handsomer,
+according to the European standard, than the middle classes; yet the
+middle classes are placed under equally favourable conditions of
+life for the perfect development of the body. Cook remarks that the
+superiority in personal appearance "which is observable in the erees
+or nobles in all the other islands (of the Pacific) is found in the
+Sandwich Islands"; but this may be chiefly due to their better food and
+manner of life.
+
+The old traveller Chardin, in describing the Persians, says their "blood
+is now highly refined by frequent intermixtures with the Georgians and
+Circassians, two nations which surpass all the world in personal beauty.
+There is hardly a man of rank in Persia who is not born of a Georgian
+or Circassian mother." He adds that they inherit their beauty, "not
+from their ancestors, for without the above mixture, the men of rank in
+Persia, who are descendants of the Tartars, would be extremely ugly."
+(2. These quotations are taken from Lawrence ('Lectures on Physiology,'
+etc., 1822, p. 393), who attributes the beauty of the upper classes in
+England to the men having long selected the more beautiful women.) Here
+is a more curious case; the priestesses who attended the temple of Venus
+Erycina at San-Giuliano in Sicily, were selected for their beauty out of
+the whole of Greece; they were not vestal virgins, and Quatrefages (3.
+'Anthropologie,' 'Revue des Cours Scientifiques,' Oct. 1868, p. 721.),
+who states the foregoing fact, says that the women of San-Giuliano
+are now famous as the most beautiful in the island, and are sought by
+artists as models. But it is obvious that the evidence in all the above
+cases is doubtful.
+
+The following case, though relating to savages, is well worth giving for
+its curiosity. Mr. Winwood Reade informs me that the Jollofs, a tribe of
+negroes on the west coast of Africa, "are remarkable for their uniformly
+fine appearance." A friend of his asked one of these men, "How is it
+that every one whom I meet is so fine looking, not only your men but
+your women?" The Jollof answered, "It is very easily explained: it has
+always been our custom to pick out our worst-looking slaves and to sell
+them." It need hardly be added that with all savages, female slaves
+serve as concubines. That this negro should have attributed,
+whether rightly or wrongly, the fine appearance of his tribe to the
+long-continued elimination of the ugly women is not so surprising as
+it may at first appear; for I have elsewhere shewn (4. 'Variation of
+Animals and Plants under Domestication,' vol. i. p. 207.) that negroes
+fully appreciate the importance of selection in the breeding of their
+domestic animals, and I could give from Mr. Reade additional evidence on
+this head.
+
+THE CAUSES WHICH PREVENT OR CHECK THE ACTION OF SEXUAL SELECTION WITH
+SAVAGES.
+
+The chief causes are, first, so-called communal marriages or promiscuous
+intercourse; secondly, the consequences of female infanticide; thirdly,
+early betrothals; and lastly, the low estimation in which women are
+held, as mere slaves. These four points must be considered in some
+detail.
+
+It is obvious that as long as the pairing of man, or of any other
+animal, is left to mere chance, with no choice exerted by either sex,
+there can be no sexual selection; and no effect will be produced on the
+offspring by certain individuals having had an advantage over others in
+their courtship. Now it is asserted that there exist at the present day
+tribes which practise what Sir J. Lubbock by courtesy calls communal
+marriages; that is, all the men and women in the tribe are husbands and
+wives to one another. The licentiousness of many savages is no doubt
+astonishing, but it seems to me that more evidence is requisite, before
+we fully admit that their intercourse is in any case promiscuous.
+Nevertheless all those who have most closely studied the subject (5. Sir
+J. Lubbock, 'The Origin of Civilisation,' 1870, chap. iii. especially
+pp. 60-67. Mr. M'Lennan, in his extremely valuable work on 'Primitive
+Marriage,' 1865, p. 163, speaks of the union of the sexes "in the
+earliest times as loose, transitory, and in some degree promiscuous."
+Mr. M'Lennan and Sir J. Lubbock have collected much evidence on the
+extreme licentiousness of savages at the present time. Mr. L.H. Morgan,
+in his interesting memoir of the classificatory system of relationship.
+('Proceedings of the American Academy of Sciences,' vol. vii. Feb.
+1868, p. 475), concludes that polygamy and all forms of marriage during
+primeval times were essentially unknown. It appears also, from Sir
+J. Lubbock's work, that Bachofen likewise believes that communal
+intercourse originally prevailed.), and whose judgment is worth much
+more than mine, believe that communal marriage (this expression being
+variously guarded) was the original and universal form throughout the
+world, including therein the intermarriage of brothers and sisters. The
+late Sir A. Smith, who had travelled widely in S. Africa, and knew much
+about the habits of savages there and elsewhere, expressed to me the
+strongest opinion that no race exists in which woman is considered as
+the property of the community. I believe that his judgment was largely
+determined by what is implied by the term marriage. Throughout
+the following discussion I use the term in the same sense as when
+naturalists speak of animals as monogamous, meaning thereby that the
+male is accepted by or chooses a single female, and lives with her
+either during the breeding-season or for the whole year, keeping
+possession of her by the law of might; or, as when they speak of a
+polygamous species, meaning that the male lives with several females.
+This kind of marriage is all that concerns us here, as it suffices for
+the work of sexual selection. But I know that some of the writers above
+referred to imply by the term marriage a recognised right protected by
+the tribe.
+
+The indirect evidence in favour of the belief of the former prevalence
+of communal marriages is strong, and rests chiefly on the terms of
+relationship which are employed between the members of the same tribe,
+implying a connection with the tribe, and not with either parent. But
+the subject is too large and complex for even an abstract to be here
+given, and I will confine myself to a few remarks. It is evident in the
+case of such marriages, or where the marriage tie is very loose, that
+the relationship of the child to its father cannot be known. But it
+seems almost incredible that the relationship of the child to its mother
+should ever be completely ignored, especially as the women in most
+savage tribes nurse their infants for a long time. Accordingly, in many
+cases the lines of descent are traced through the mother alone, to the
+exclusion of the father. But in other cases the terms employed express a
+connection with the tribe alone, to the exclusion even of the mother.
+It seems possible that the connection between the related members of the
+same barbarous tribe, exposed to all sorts of danger, might be so much
+more important, owing to the need of mutual protection and aid, than
+that between the mother and her child, as to lead to the sole use
+of terms expressive of the former relationships; but Mr. Morgan is
+convinced that this view is by no means sufficient.
+
+The terms of relationship used in different parts of the world may be
+divided, according to the author just quoted, into two great classes,
+the classificatory and descriptive, the latter being employed by us. It
+is the classificatory system which so strongly leads to the belief that
+communal and other extremely loose forms of marriage were originally
+universal. But as far as I can see, there is no necessity on this ground
+for believing in absolutely promiscuous intercourse; and I am glad to
+find that this is Sir J. Lubbock's view. Men and women, like many of the
+lower animals, might formerly have entered into strict though temporary
+unions for each birth, and in this case nearly as much confusion would
+have arisen in the terms of relationship as in the case of promiscuous
+intercourse. As far as sexual selection is concerned, all that is
+required is that choice should be exerted before the parents unite,
+and it signifies little whether the unions last for life or only for a
+season.
+
+Besides the evidence derived from the terms of relationship, other lines
+of reasoning indicate the former wide prevalence of communal marriage.
+Sir J. Lubbock accounts for the strange and widely-extended habit of
+exogamy--that is, the men of one tribe taking wives from a distinct
+tribe,--by communism having been the original form of intercourse; so
+that a man never obtained a wife for himself unless he captured her
+from a neighbouring and hostile tribe, and then she would naturally have
+become his sole and valuable property. Thus the practice of capturing
+wives might have arisen; and from the honour so gained it might
+ultimately have become the universal habit. According to Sir J.
+Lubbock (6. 'Address to British Association On the Social and Religious
+Condition of the Lower Races of Man,' 1870, p. 20.), we can also thus
+understand "the necessity of expiation for marriage as an infringement
+of tribal rites, since according to old ideas, a man had no right to
+appropriate to himself that which belonged to the whole tribe." Sir J.
+Lubbock further gives a curious body of facts shewing that in old times
+high honour was bestowed on women who were utterly licentious; and
+this, as he explains, is intelligible, if we admit that promiscuous
+intercourse was the aboriginal, and therefore long revered custom of the
+tribe. (7. 'Origin of Civilisation,' 1870, p. 86. In the several works
+above quoted, there will be found copious evidence on relationship
+through the females alone, or with the tribe alone.)
+
+Although the manner of development of the marriage tie is an obscure
+subject, as we may infer from the divergent opinions on several points
+between the three authors who have studied it most closely, namely, Mr.
+Morgan, Mr. M'Lennan, and Sir J. Lubbock, yet from the foregoing and
+several other lines of evidence it seems probable (8. Mr. C. Staniland
+Wake argues strongly ('Anthropologia,' March, 1874, p. 197) against the
+views held by these three writers on the former prevalence of almost
+promiscuous intercourse; and he thinks that the classificatory system of
+relationship can be otherwise explained.) that the habit of marriage,
+in any strict sense of the word, has been gradually developed; and that
+almost promiscuous or very loose intercourse was once extremely common
+throughout the world. Nevertheless, from the strength of the feeling of
+jealousy all through the animal kingdom, as well as from the analogy of
+the lower animals, more particularly of those which come nearest to man,
+I cannot believe that absolutely promiscuous intercourse prevailed
+in times past, shortly before man attained to his present rank in
+the zoological scale. Man, as I have attempted to shew, is certainly
+descended from some ape-like creature. With the existing Quadrumana, as
+far as their habits are known, the males of some species are monogamous,
+but live during only a part of the year with the females: of this the
+orang seems to afford an instance. Several kinds, for example some of
+the Indian and American monkeys, are strictly monogamous, and associate
+all the year round with their wives. Others are polygamous, for
+example the gorilla and several American species, and each family
+lives separate. Even when this occurs, the families inhabiting the same
+district are probably somewhat social; the chimpanzee, for instance,
+is occasionally met with in large bands. Again, other species are
+polygamous, but several males, each with his own females, live
+associated in a body, as with several species of baboons. (9. Brehm
+('Thierleben,' B. i. p. 77) says Cynocephalus hamadryas lives in great
+troops containing twice as many adult females as adult males.
+See Rengger on American polygamous species, and Owen ('Anatomy of
+Vertebrates,' vol. iii. p. 746) on American monogamous species. Other
+references might be added.) We may indeed conclude from what we know of
+the jealousy of all male quadrupeds, armed, as many of them are,
+with special weapons for battling with their rivals, that promiscuous
+intercourse in a state of nature is extremely improbable. The pairing
+may not last for life, but only for each birth; yet if the males which
+are the strongest and best able to defend or otherwise assist their
+females and young, were to select the more attractive females, this
+would suffice for sexual selection.
+
+Therefore, looking far enough back in the stream of time, and judging
+from the social habits of man as he now exists, the most probable view
+is that he aboriginally lived in small communities, each with a single
+wife, or if powerful with several, whom he jealously guarded against all
+other men. Or he may not have been a social animal, and yet have lived
+with several wives, like the gorilla; for all the natives "agree that
+but one adult male is seen in a band; when the young male grows up,
+a contest takes place for mastery, and the strongest, by killing
+and driving out the others, establishes himself as the head of the
+community." (10. Dr. Savage, in 'Boston Journal of Natural History,'
+vol. v. 1845-47, p. 423.) The younger males, being thus expelled and
+wandering about, would, when at last successful in finding a partner,
+prevent too close interbreeding within the limits of the same family.
+
+Although savages are now extremely licentious, and although communal
+marriages may formerly have largely prevailed, yet many tribes practise
+some form of marriage, but of a far more lax nature than that of
+civilised nations. Polygamy, as just stated, is almost universally
+followed by the leading men in every tribe. Nevertheless there are
+tribes, standing almost at the bottom of the scale, which are strictly
+monogamous. This is the case with the Veddahs of Ceylon: they have a
+saying, according to Sir J. Lubbock (11. 'Prehistoric Times,' 1869, p.
+424.), "that death alone can separate husband and wife." An intelligent
+Kandyan chief, of course a polygamist, "was perfectly scandalised at the
+utter barbarism of living with only one wife, and never parting until
+separated by death." It was, he said, "just like the Wanderoo monkeys."
+Whether savages who now enter into some form of marriage, either
+polygamous or monogamous, have retained this habit from primeval times,
+or whether they have returned to some form of marriage, after passing
+through a stage of promiscuous intercourse, I will not pretend to
+conjecture.
+
+INFANTICIDE.
+
+This practice is now very common throughout the world, and there is
+reason to believe that it prevailed much more extensively during former
+times. (12. Mr. M'Lennan, 'Primitive Marriage,' 1865. See especially
+on exogamy and infanticide, pp. 130, 138, 165.) Barbarians find it
+difficult to support themselves and their children, and it is a simple
+plan to kill their infants. In South America some tribes, according to
+Azara, formerly destroyed so many infants of both sexes that they were
+on the point of extinction. In the Polynesian Islands women have been
+known to kill from four or five, to even ten of their children; and
+Ellis could not find a single woman who had not killed at least one. In
+a village on the eastern frontier of India Colonel MacCulloch found not
+a single female child. Wherever infanticide (13. Dr. Gerland ('Ueber
+das Aussterben der Naturv�lker,' 1868) has collected much information on
+infanticide, see especially ss. 27, 51, 54. Azara ('Voyages,' etc.,
+tom. ii. pp. 94, 116) enters in detail on the motives. See also M'Lennan
+(ibid. p. 139) for cases in India. In the former reprints of the
+2nd edition of this book an incorrect quotation from Sir G. Grey was
+unfortunately given in the above passage and has now been removed from
+the text.) prevails the struggle for existence will be in so far less
+severe, and all the members of the tribe will have an almost equally
+good chance of rearing their few surviving children. In most cases a
+larger number of female than of male infants are destroyed, for it is
+obvious that the latter are of more value to the tribe, as they will,
+when grown up, aid in defending it, and can support themselves. But the
+trouble experienced by the women in rearing children, their consequent
+loss of beauty, the higher estimation set on them when few, and their
+happier fate, are assigned by the women themselves, and by various
+observers, as additional motives for infanticide.
+
+When, owing to female infanticide, the women of a tribe were few, the
+habit of capturing wives from neighbouring tribes would naturally arise.
+Sir J. Lubbock, however, as we have seen, attributes the practice in
+chief part to the former existence of communal marriage, and to the men
+having consequently captured women from other tribes to hold as
+their sole property. Additional causes might be assigned, such as the
+communities being very small, in which case, marriageable women would
+often be deficient. That the habit was most extensively practised during
+former times, even by the ancestors of civilised nations, is clearly
+shewn by the preservation of many curious customs and ceremonies,
+of which Mr. M'Lennan has given an interesting account. In our own
+marriages the "best man" seems originally to have been the chief abettor
+of the bridegroom in the act of capture. Now as long as men habitually
+procured their wives through violence and craft, they would have
+been glad to seize on any woman, and would not have selected the more
+attractive ones. But as soon as the practice of procuring wives from
+a distinct tribe was effected through barter, as now occurs in many
+places, the more attractive women would generally have been purchased.
+The incessant crossing, however, between tribe and tribe, which
+necessarily follows from any form of this habit, would tend to keep all
+the people inhabiting the same country nearly uniform in character;
+and this would interfere with the power of sexual selection in
+differentiating the tribes.
+
+The scarcity of women, consequent on female infanticide, leads, also,
+to another practice, that of polyandry, still common in several parts
+of the world, and which formerly, as Mr. M'Lennan believes, prevailed
+almost universally: but this latter conclusion is doubted by Mr. Morgan
+and Sir J. Lubbock. (14. 'Primitive Marriage,' p. 208; Sir J. Lubbock,
+'Origin of Civilisation,' p. 100. See also Mr. Morgan, loc. cit., on the
+former prevalence of polyandry.) Whenever two or more men are compelled
+to marry one woman, it is certain that all the women of the tribe will
+get married, and there will be no selection by the men of the more
+attractive women. But under these circumstances the women no doubt
+will have the power of choice, and will prefer the more attractive men.
+Azara, for instance, describes how carefully a Guana woman bargains for
+all sorts of privileges, before accepting some one or more husbands; and
+the men in consequence take unusual care of their personal appearance.
+So amongst the Todas of India, who practise polyandry, the girls can
+accept or refuse any man. (15. Azara, 'Voyages,' etc., tom. ii. pp.
+92-95; Colonel Marshall, 'Amongst the Todas,' p. 212.) A very ugly man
+in these cases would perhaps altogether fail in getting a wife, or get
+one later in life; but the handsomer men, although more successful in
+obtaining wives, would not, as far as we can see, leave more offspring
+to inherit their beauty than the less handsome husbands of the same
+women.
+
+EARLY BETROTHALS AND SLAVERY OF WOMEN.
+
+With many savages it is the custom to betroth the females whilst mere
+infants; and this would effectually prevent preference being exerted on
+either side according to personal appearance. But it would not prevent
+the more attractive women from being afterwards stolen or taken by force
+from their husbands by the more powerful men; and this often happens in
+Australia, America, and elsewhere. The same consequences with reference
+to sexual selection would to a certain extent follow, when women are
+valued almost solely as slaves or beasts of burden, as is the case with
+many savages. The men, however, at all times would prefer the handsomest
+slaves according to their standard of beauty.
+
+We thus see that several customs prevail with savages which must greatly
+interfere with, or completely stop, the action of sexual selection. On
+the other hand, the conditions of life to which savages are exposed,
+and some of their habits, are favourable to natural selection; and this
+comes into play at the same time with sexual selection. Savages are
+known to suffer severely from recurrent famines; they do not increase
+their food by artificial means; they rarely refrain from marriage (16.
+Burchell says ('Travels in S. Africa,' vol. ii. 1824, p. 58), that among
+the wild nations of Southern Africa, neither men nor women ever pass
+their lives in a state of celibacy. Azara ('Voyages dans l'Am�rique
+Merid.' tom. ii. 1809, p. 21) makes precisely the same remark in regard
+to the wild Indians of South America.), and generally marry whilst
+young. Consequently they must be subjected to occasional hard struggles
+for existence, and the favoured individuals will alone survive.
+
+At a very early period, before man attained to his present rank in the
+scale, many of his conditions would be different from what now obtains
+amongst savages. Judging from the analogy of the lower animals, he would
+then either live with a single female, or be a polygamist. The most
+powerful and able males would succeed best in obtaining attractive
+females. They would also succeed best in the general struggle for life,
+and in defending their females, as well as their offspring, from enemies
+of all kinds. At this early period the ancestors of man would not
+be sufficiently advanced in intellect to look forward to distant
+contingencies; they would not foresee that the rearing of all their
+children, especially their female children, would make the struggle
+for life severer for the tribe. They would be governed more by their
+instincts and less by their reason than are savages at the present day.
+They would not at that period have partially lost one of the strongest
+of all instincts, common to all the lower animals, namely the love of
+their young offspring; and consequently they would not have practised
+female infanticide. Women would not have been thus rendered scarce, and
+polyandry would not have been practised; for hardly any other cause,
+except the scarcity of women seems sufficient to break down the natural
+and widely prevalent feeling of jealousy, and the desire of each male
+to possess a female for himself. Polyandry would be a natural
+stepping-stone to communal marriages or almost promiscuous intercourse;
+though the best authorities believe that this latter habit preceded
+polyandry. During primordial times there would be no early betrothals,
+for this implies foresight. Nor would women be valued merely as useful
+slaves or beasts of burthen. Both sexes, if the females as well as the
+males were permitted to exert any choice, would choose their partners
+not for mental charms, or property, or social position, but almost
+solely from external appearance. All the adults would marry or pair, and
+all the offspring, as far as that was possible, would be reared; so that
+the struggle for existence would be periodically excessively severe.
+Thus during these times all the conditions for sexual selection would
+have been more favourable than at a later period, when man had advanced
+in his intellectual powers but had retrograded in his instincts.
+Therefore, whatever influence sexual selection may have had in producing
+the differences between the races of man, and between man and the higher
+Quadrumana, this influence would have been more powerful at a remote
+period than at the present day, though probably not yet wholly lost.
+
+THE MANNER OF ACTION OF SEXUAL SELECTION WITH MANKIND.
+
+With primeval man under the favourable conditions just stated, and
+with those savages who at the present time enter into any marriage tie,
+sexual selection has probably acted in the following manner, subject to
+greater or less interference from female infanticide, early betrothals,
+etc. The strongest and most vigorous men--those who could best defend
+and hunt for their families, who were provided with the best weapons
+and possessed the most property, such as a large number of dogs or other
+animals,--would succeed in rearing a greater average number of offspring
+than the weaker and poorer members of the same tribes. There can, also,
+be no doubt that such men would generally be able to select the more
+attractive women. At present the chiefs of nearly every tribe throughout
+the world succeed in obtaining more than one wife. I hear from Mr.
+Mantell that, until recently, almost every girl in New Zealand who
+was pretty, or promised to be pretty, was tapu to some chief. With the
+Kafirs, as Mr. C. Hamilton states (17. 'Anthropological Review,' Jan.
+1870, p. xvi.), "the chiefs generally have the pick of the women for
+many miles round, and are most persevering in establishing or confirming
+their privilege." We have seen that each race has its own style
+of beauty, and we know that it is natural to man to admire each
+characteristic point in his domestic animals, dress, ornaments, and
+personal appearance, when carried a little beyond the average. If then
+the several foregoing propositions be admitted, and I cannot see that
+they are doubtful, it would be an inexplicable circumstance if the
+selection of the more attractive women by the more powerful men of each
+tribe, who would rear on an average a greater number of children, did
+not after the lapse of many generations somewhat modify the character of
+the tribe.
+
+When a foreign breed of our domestic animals is introduced into a new
+country, or when a native breed is long and carefully attended to,
+either for use or ornament, it is found after several generations to
+have undergone a greater or less amount of change whenever the means of
+comparison exist. This follows from unconscious selection during a long
+series of generations--that is, the preservation of the most approved
+individuals--without any wish or expectation of such a result on the
+part of the breeder. So again, if during many years two careful breeders
+rear animals of the same family, and do not compare them together or
+with a common standard, the animals are found to have become, to the
+surprise of their owners, slightly different. (18. The 'Variation of
+Animals and Plants under Domestication,' vol. ii. pp. 210-217.) Each
+breeder has impressed, as von Nathusius well expresses it, the character
+of his own mind--his own taste and judgment--on his animals. What
+reason, then, can be assigned why similar results should not follow from
+the long-continued selection of the most admired women by those men of
+each tribe who were able to rear the greatest number of children?
+This would be unconscious selection, for an effect would be produced,
+independently of any wish or expectation on the part of the men who
+preferred certain women to others.
+
+Let us suppose the members of a tribe, practising some form of marriage,
+to spread over an unoccupied continent, they would soon split up into
+distinct hordes, separated from each other by various barriers, and
+still more effectually by the incessant wars between all barbarous
+nations. The hordes would thus be exposed to slightly different
+conditions and habits of life, and would sooner or later come to differ
+in some small degree. As soon as this occurred, each isolated tribe
+would form for itself a slightly different standard of beauty (19. An
+ingenious writer argues, from a comparison of the pictures of Raphael,
+Rubens, and modern French artists, that the idea of beauty is not
+absolutely the same even throughout Europe: see the 'Lives of Haydn and
+Mozart,' by Bombet (otherwise M. Beyle), English translation, p. 278.);
+and then unconscious selection would come into action through the more
+powerful and leading men preferring certain women to others. Thus the
+differences between the tribes, at first very slight, would gradually
+and inevitably be more or less increased.
+
+With animals in a state of nature, many characters proper to the males,
+such as size, strength, special weapons, courage and pugnacity, have
+been acquired through the law of battle. The semi-human progenitors of
+man, like their allies the Quadrumana, will almost certainly have been
+thus modified; and, as savages still fight for the possession of their
+women, a similar process of selection has probably gone on in a greater
+or less degree to the present day. Other characters proper to the males
+of the lower animals, such as bright colours and various ornaments, have
+been acquired by the more attractive males having been preferred by the
+females. There are, however, exceptional cases in which the males are
+the selectors, instead of having been the selected. We recognise such
+cases by the females being more highly ornamented than the males,--their
+ornamental characters having been transmitted exclusively or chiefly to
+their female offspring. One such case has been described in the order to
+which man belongs, that of the Rhesus monkey.
+
+Man is more powerful in body and mind than woman, and in the savage
+state he keeps her in a far more abject state of bondage than does the
+male of any other animal; therefore it is not surprising that he should
+have gained the power of selection. Women are everywhere conscious of
+the value of their own beauty; and when they have the means, they take
+more delight in decorating themselves with all sorts of ornaments than
+do men. They borrow the plumes of male birds, with which nature has
+decked this sex, in order to charm the females. As women have long been
+selected for beauty, it is not surprising that some of their successive
+variations should have been transmitted exclusively to the same sex;
+consequently that they should have transmitted beauty in a somewhat
+higher degree to their female than to their male offspring, and thus
+have become more beautiful, according to general opinion, than men.
+Women, however, certainly transmit most of their characters, including
+some beauty, to their offspring of both sexes; so that the continued
+preference by the men of each race for the more attractive women,
+according to their standard of taste, will have tended to modify in the
+same manner all the individuals of both sexes belonging to the race.
+
+With respect to the other form of sexual selection (which with the
+lower animals is much the more common), namely, when the females are the
+selectors, and accept only those males which excite or charm them most,
+we have reason to believe that it formerly acted on our progenitors. Man
+in all probability owes his beard, and perhaps some other characters,
+to inheritance from an ancient progenitor who thus gained his ornaments.
+But this form of selection may have occasionally acted during later
+times; for in utterly barbarous tribes the women have more power
+in choosing, rejecting, and tempting their lovers, or of afterwards
+changing their husbands, than might have been expected. As this is a
+point of some importance, I will give in detail such evidence as I have
+been able to collect.
+
+Hearne describes how a woman in one of the tribes of Arctic America
+repeatedly ran away from her husband and joined her lover; and with the
+Charruas of S. America, according to Azara, divorce is quite optional.
+Amongst the Abipones, a man on choosing a wife bargains with the parents
+about the price. But "it frequently happens that the girl rescinds what
+has been agreed upon between the parents and the bridegroom, obstinately
+rejecting the very mention of marriage." She often runs away, hides
+herself, and thus eludes the bridegroom. Captain Musters who lived
+with the Patagonians, says that their marriages are always settled by
+inclination; "if the parents make a match contrary to the daughter's
+will, she refuses and is never compelled to comply." In Tierra del Fuego
+a young man first obtains the consent of the parents by doing them some
+service, and then he attempts to carry off the girl; "but if she is
+unwilling, she hides herself in the woods until her admirer is heartily
+tired of looking for her, and gives up the pursuit; but this seldom
+happens." In the Fiji Islands the man seizes on the woman whom he wishes
+for his wife by actual or pretended force; but "on reaching the home of
+her abductor, should she not approve of the match, she runs to some
+one who can protect her; if, however, she is satisfied, the matter is
+settled forthwith." With the Kalmucks there is a regular race between
+the bride and bridegroom, the former having a fair start; and Clarke
+"was assured that no instance occurs of a girl being caught, unless she
+has a partiality to the pursuer." Amongst the wild tribes of the
+Malay Archipelago there is also a racing match; and it appears from M.
+Bourien's account, as Sir J. Lubbock remarks, that "the race, 'is not to
+the swift, nor the battle to the strong,' but to the young man who has
+the good fortune to please his intended bride." A similar custom, with
+the same result, prevails with the Koraks of North-Eastern Asia.
+
+Turning to Africa: the Kafirs buy their wives, and girls are severely
+beaten by their fathers if they will not accept a chosen husband; but
+it is manifest from many facts given by the Rev. Mr. Shooter, that they
+have considerable power of choice. Thus very ugly, though rich men, have
+been known to fail in getting wives. The girls, before consenting to be
+betrothed, compel the men to shew themselves off first in front and then
+behind, and "exhibit their paces." They have been known to propose to a
+man, and they not rarely run away with a favoured lover. So again, Mr.
+Leslie, who was intimately acquainted with the Kafirs, says, "it is a
+mistake to imagine that a girl is sold by her father in the same manner,
+and with the same authority, with which he would dispose of a cow."
+Amongst the degraded Bushmen of S. Africa, "when a girl has grown up to
+womanhood without having been betrothed, which, however, does not often
+happen, her lover must gain her approbation, as well as that of the
+parents." (20. Azara, 'Voyages,' etc., tom. ii. p. 23. Dobrizhoffer,
+'An Account of the Abipones,' vol. ii. 1822, p. 207. Capt. Musters,
+in 'Proc. R. Geograph. Soc.' vol. xv. p. 47. Williams on the Fiji
+Islanders, as quoted by Lubbock, 'Origin of Civilisation,' 1870, p.
+79. On the Fuegians, King and Fitzroy, 'Voyages of the "Adventure" and
+"Beagle,"' vol. ii. 1839, p. 182. On the Kalmucks, quoted by M'Lennan,
+'Primitive Marriage,' 1865, p. 32. On the Malays, Lubbock, ibid. p. 76.
+The Rev. J. Shooter, 'On the Kafirs of Natal,' 1857, pp. 52-60. Mr.
+D. Leslie, 'Kafir Character and Customs,' 1871, p. 4. On the Bush-men,
+Burchell, 'Travels in S. Africa,' ii. 1824, p. 59. On the Koraks by
+McKennan, as quoted by Mr. Wake, in 'Anthropologia,' Oct. 1873, p. 75.)
+Mr. Winwood Reade made inquiries for me with respect to the negroes of
+Western Africa, and he informs me that "the women, at least among
+the more intelligent Pagan tribes, have no difficulty in getting the
+husbands whom they may desire, although it is considered unwomanly to
+ask a man to marry them. They are quite capable of falling in love, and
+of forming tender, passionate, and faithful attachments." Additional
+cases could be given.
+
+We thus see that with savages the women are not in quite so abject a
+state in relation to marriage as has often been supposed. They can
+tempt the men whom they prefer, and can sometimes reject those whom they
+dislike, either before or after marriage. Preference on the part of the
+women, steadily acting in any one direction, would ultimately affect the
+character of the tribe; for the women would generally choose not merely
+the handsomest men, according to their standard of taste, but those
+who were at the same time best able to defend and support them. Such
+well-endowed pairs would commonly rear a larger number of offspring than
+the less favoured. The same result would obviously follow in a still
+more marked manner if there was selection on both sides; that is, if the
+more attractive, and at the same time more powerful men were to prefer,
+and were preferred by, the more attractive women. And this double form
+of selection seems actually to have occurred, especially during the
+earlier periods of our long history.
+
+We will now examine a little more closely some of the characters which
+distinguish the several races of man from one another and from the lower
+animals, namely, the greater or less deficiency of hair on the body, and
+the colour of the skin. We need say nothing about the great diversity in
+the shape of the features and of the skull between the different races,
+as we have seen in the last chapter how different is the standard of
+beauty in these respects. These characters will therefore probably have
+been acted on through sexual selection; but we have no means of judging
+whether they have been acted on chiefly from the male or female side.
+The musical faculties of man have likewise been already discussed.
+
+ABSENCE OF HAIR ON THE BODY, AND ITS DEVELOPMENT ON THE FACE AND HEAD.
+
+From the presence of the woolly hair or lanugo on the human foetus, and
+of rudimentary hairs scattered over the body during maturity, we may
+infer that man is descended from some animal which was born hairy
+and remained so during life. The loss of hair is an inconvenience and
+probably an injury to man, even in a hot climate, for he is thus exposed
+to the scorching of the sun, and to sudden chills, especially during wet
+weather. As Mr. Wallace remarks, the natives in all countries are glad
+to protect their naked backs and shoulders with some slight covering. No
+one supposes that the nakedness of the skin is any direct advantage
+to man; his body therefore cannot have been divested of hair through
+natural selection. (21. 'Contributions to the Theory of Natural
+Selection,' 1870, p. 346. Mr. Wallace believes (p. 350) "that some
+intelligent power has guided or determined the development of man"; and
+he considers the hairless condition of the skin as coming under this
+head. The Rev. T.R. Stebbing, in commenting on this view ('Transactions
+of Devonshire Association for Science,' 1870) remarks, that had Mr.
+Wallace "employed his usual ingenuity on the question of man's hairless
+skin, he might have seen the possibility of its selection through its
+superior beauty or the health attaching to superior cleanliness.") Nor,
+as shewn in a former chapter, have we any evidence that this can be due
+to the direct action of climate, or that it is the result of correlated
+development.
+
+The absence of hair on the body is to a certain extent a secondary
+sexual character; for in all parts of the world women are less hairy
+than men. Therefore we may reasonably suspect that this character has
+been gained through sexual selection. We know that the faces of several
+species of monkeys, and large surfaces at the posterior end of the body
+of other species, have been denuded of hair; and this we may safely
+attribute to sexual selection, for these surfaces are not only vividly
+coloured, but sometimes, as with the male mandrill and female rhesus,
+much more vividly in the one sex than in the other, especially during
+the breeding-season. I am informed by Mr. Bartlett that, as these
+animals gradually reach maturity, the naked surfaces grow larger
+compared with the size of their bodies. The hair, however, appears to
+have been removed, not for the sake of nudity, but that the colour
+of the skin may be more fully displayed. So again with many birds, it
+appears as if the head and neck had been divested of feathers through
+sexual selection, to exhibit the brightly-coloured skin.
+
+As the body in woman is less hairy than in man, and as this character is
+common to all races, we may conclude that it was our female semi-human
+ancestors who were first divested of hair, and that this occurred at
+an extremely remote period before the several races had diverged from a
+common stock. Whilst our female ancestors were gradually acquiring this
+new character of nudity, they must have transmitted it almost equally to
+their offspring of both sexes whilst young; so that its transmission,
+as with the ornaments of many mammals and birds, has not been limited
+either by sex or age. There is nothing surprising in a partial loss of
+hair having been esteemed as an ornament by our ape-like progenitors,
+for we have seen that innumerable strange characters have been thus
+esteemed by animals of all kinds, and have consequently been gained
+through sexual selection. Nor is it surprising that a slightly injurious
+character should have been thus acquired; for we know that this is the
+case with the plumes of certain birds, and with the horns of certain
+stags.
+
+The females of some of the anthropoid apes, as stated in a former
+chapter, are somewhat less hairy on the under surface than the males;
+and here we have what might have afforded a commencement for the process
+of denudation. With respect to the completion of the process through
+sexual selection, it is well to bear in mind the New Zealand proverb,
+"There is no woman for a hairy man." All who have seen photographs
+of the Siamese hairy family will admit how ludicrously hideous is the
+opposite extreme of excessive hairiness. And the king of Siam had
+to bribe a man to marry the first hairy woman in the family; and she
+transmitted this character to her young offspring of both sexes. (22.
+The 'Variation of Animals and Plants under Domestication,' vol. ii.
+1868, p. 237.)
+
+Some races are much more hairy than others, especially the males; but
+it must not be assumed that the more hairy races, such as the European,
+have retained their primordial condition more completely than the naked
+races, such as the Kalmucks or Americans. It is more probable that the
+hairiness of the former is due to partial reversion; for characters
+which have been at some former period long inherited are always apt to
+return. We have seen that idiots are often very hairy, and they are apt
+to revert in other characters to a lower animal type. It does not appear
+that a cold climate has been influential in leading to this kind of
+reversion; excepting perhaps with the negroes, who have been reared
+during several generations in the United States (23. 'Investigations
+into Military and Anthropological Statistics of American Soldiers,'
+by B.A. Gould, 1869, p. 568:--Observations were carefully made on the
+hairiness of 2129 black and coloured soldiers, whilst they were bathing;
+and by looking to the published table, "it is manifest at a glance that
+there is but little, if any, difference between the white and the black
+races in this respect." It is, however, certain that negroes in their
+native and much hotter land of Africa, have remarkably smooth bodies.
+It should be particularly observed, that both pure blacks and mulattoes
+were included in the above enumeration; and this is an unfortunate
+circumstance, as in accordance with a principle, the truth of which I
+have elsewhere proved, crossed races of man would be eminently liable
+to revert to the primordial hairy character of their early ape-like
+progenitors.), and possibly with the Ainos, who inhabit the northern
+islands of the Japan archipelago. But the laws of inheritance are so
+complex that we can seldom understand their action. If the greater
+hairiness of certain races be the result of reversion, unchecked by any
+form of selection, its extreme variability, even within the limits of
+the same race, ceases to be remarkable. (24. Hardly any view advanced
+in this work has met with so much disfavour (see for instance,
+Sprengel, 'Die Fortschritte des Darwinismus,' 1874, p. 80) as the above
+explanation of the loss of hair in mankind through sexual selection; but
+none of the opposed arguments seem to me of much weight, in comparison
+with the facts shewing that the nudity of the skin is to a certain
+extent a secondary sexual character in man and in some of the
+Quadrumana.)
+
+With respect to the beard in man, if we turn to our best guide, the
+Quadrumana, we find beards equally developed in both sexes of many
+species, but in some, either confined to the males, or more developed
+in them than in the females. From this fact and from the curious
+arrangement, as well as the bright colours of the hair about the heads
+of many monkeys, it is highly probable, as before explained, that
+the males first acquired their beards through sexual selection as an
+ornament, transmitting them in most cases, equally or nearly so, to
+their offspring of both sexes. We know from Eschricht (25. 'Ueber die
+Richtung der Haare am Menschlichen K�rper,' in M�ller's 'Archiv. f�r
+Anat. und Phys.' 1837, s. 40.) that with mankind the female as well
+as the male foetus is furnished with much hair on the face, especially
+round the mouth; and this indicates that we are descended from
+progenitors of whom both sexes were bearded. It appears therefore at
+first sight probable that man has retained his beard from a very early
+period, whilst woman lost her beard at the same time that her body
+became almost completely divested of hair. Even the colour of our beards
+seems to have been inherited from an ape-like progenitor; for when there
+is any difference in tint between the hair of the head and the beard,
+the latter is lighter coloured in all monkeys and in man. In those
+Quadrumana in which the male has a larger beard than that of the female,
+it is fully developed only at maturity, just as with mankind; and it is
+possible that only the later stages of development have been retained
+by man. In opposition to this view of the retention of the beard from
+an early period is the fact of its great variability in different races,
+and even within the same race; for this indicates reversion,--long lost
+characters being very apt to vary on re-appearance.
+
+Nor must we overlook the part which sexual selection may have played
+in later times; for we know that with savages the men of the beardless
+races take infinite pains in eradicating every hair from their faces as
+something odious, whilst the men of the bearded races feel the greatest
+pride in their beards. The women, no doubt, participate in these
+feelings, and if so sexual selection can hardly have failed to have
+effected something in the course of later times. It is also possible
+that the long-continued habit of eradicating the hair may have produced
+an inherited effect. Dr. Brown-Sequard has shewn that if certain animals
+are operated on in a particular manner, their offspring are affected.
+Further evidence could be given of the inheritance of the effects of
+mutilations; but a fact lately ascertained by Mr. Salvin (26. On the
+tail-feathers of Motmots, 'Proceedings of the Zoological Society,' 1873,
+p. 429.) has a more direct bearing on the present question; for he has
+shewn that the motmots, which are known habitually to bite off the
+barbs of the two central tail-feathers, have the barbs of these feathers
+naturally somewhat reduced. (27. Mr. Sproat has suggested ('Scenes and
+Studies of Savage Life,' 1868, p. 25) this same view. Some distinguished
+ethnologists, amongst others M. Gosse of Geneva, believe that artificial
+modifications of the skull tend to be inherited.) Nevertheless, with
+mankind the habit of eradicating the beard and the hairs on the body
+would probably not have arisen until these had already become by some
+means reduced.
+
+It is difficult to form any judgment as to how the hair on the head
+became developed to its present great length in many races. Eschricht
+(28. 'Ueber die Richtung,' ibid. s. 40.) states that in the human foetus
+the hair on the face during the fifth month is longer than that on
+the head; and this indicates that our semi-human progenitors were not
+furnished with long tresses, which must therefore have been a late
+acquisition. This is likewise indicated by the extraordinary difference
+in the length of the hair in the different races; in the negro the hair
+forms a mere curly mat; with us it is of great length, and with the
+American natives it not rarely reaches to the ground. Some species of
+Semnopithecus have their heads covered with moderately long hair, and
+this probably serves as an ornament and was acquired through sexual
+selection. The same view may perhaps be extended to mankind, for we
+know that long tresses are now and were formerly much admired, as may be
+observed in the works of almost every poet; St. Paul says, "if a woman
+have long hair, it is a glory to her;" and we have seen that in North
+America a chief was elected solely from the length of his hair.
+
+COLOUR OF THE SKIN.
+
+The best kind of evidence that in man the colour of the skin has been
+modified through sexual selection is scanty; for in most races the sexes
+do not differ in this respect, and only slightly, as we have seen, in
+others. We know, however, from the many facts already given that the
+colour of the skin is regarded by the men of all races as a highly
+important element in their beauty; so that it is a character which would
+be likely to have been modified through selection, as has occurred in
+innumerable instances with the lower animals. It seems at first sight
+a monstrous supposition that the jet-blackness of the negro should have
+been gained through sexual selection; but this view is supported by
+various analogies, and we know that negroes admire their own colour.
+With mammals, when the sexes differ in colour, the male is often black
+or much darker than the female; and it depends merely on the form of
+inheritance whether this or any other tint is transmitted to both sexes
+or to one alone. The resemblance to a negro in miniature of Pithecia
+satanas with his jet black skin, white rolling eyeballs, and hair parted
+on the top of the head, is almost ludicrous.
+
+The colour of the face differs much more widely in the various kinds
+of monkeys than it does in the races of man; and we have some reason
+to believe that the red, blue, orange, almost white and black tints
+of their skin, even when common to both sexes, as well as the bright
+colours of their fur, and the ornamental tufts about the head, have
+all been acquired through sexual selection. As the order of development
+during growth, generally indicates the order in which the characters of
+a species have been developed and modified during previous generations;
+and as the newly-born infants of the various races of man do not differ
+nearly as much in colour as do the adults, although their bodies are
+as completely destitute of hair, we have some slight evidence that the
+tints of the different races were acquired at a period subsequent to the
+removal of the hair, which must have occurred at a very early period in
+the history of man.
+
+SUMMARY.
+
+We may conclude that the greater size, strength, courage, pugnacity, and
+energy of man, in comparison with woman, were acquired during primeval
+times, and have subsequently been augmented, chiefly through the
+contests of rival males for the possession of the females. The greater
+intellectual vigour and power of invention in man is probably due to
+natural selection, combined with the inherited effects of habit, for the
+most able men will have succeeded best in defending and providing for
+themselves and for their wives and offspring. As far as the extreme
+intricacy of the subject permits us to judge, it appears that our male
+ape-like progenitors acquired their beards as an ornament to charm
+or excite the opposite sex, and transmitted them only to their male
+offspring. The females apparently first had their bodies denuded of
+hair, also as a sexual ornament; but they transmitted this character
+almost equally to both sexes. It is not improbable that the females were
+modified in other respects for the same purpose and by the same means;
+so that women have acquired sweeter voices and become more beautiful
+than men.
+
+It deserves attention that with mankind the conditions were in many
+respects much more favourable for sexual selection, during a very early
+period, when man had only just attained to the rank of manhood, than
+during later times. For he would then, as we may safely conclude, have
+been guided more by his instinctive passions, and less by foresight or
+reason. He would have jealously guarded his wife or wives. He would
+not have practised infanticide; nor valued his wives merely as useful
+slaves; nor have been betrothed to them during infancy. Hence we may
+infer that the races of men were differentiated, as far as sexual
+selection is concerned, in chief part at a very remote epoch; and this
+conclusion throws light on the remarkable fact that at the most ancient
+period, of which we have not as yet any record, the races of man had
+already come to differ nearly or quite as much as they do at the present
+day.
+
+The views here advanced, on the part which sexual selection has played
+in the history of man, want scientific precision. He who does not admit
+this agency in the case of the lower animals, will disregard all that I
+have written in the later chapters on man. We cannot positively say that
+this character, but not that, has been thus modified; it has, however,
+been shewn that the races of man differ from each other and from their
+nearest allies, in certain characters which are of no service to them
+in their daily habits of life, and which it is extremely probable would
+have been modified through sexual selection. We have seen that with the
+lowest savages the people of each tribe admire their own characteristic
+qualities,--the shape of the head and face, the squareness of the
+cheek-bones, the prominence or depression of the nose, the colour of
+the skin, the length of the hair on the head, the absence of hair on
+the face and body, or the presence of a great beard, and so forth. Hence
+these and other such points could hardly fail to be slowly and gradually
+exaggerated, from the more powerful and able men in each tribe, who
+would succeed in rearing the largest number of offspring, having
+selected during many generations for their wives the most strongly
+characterised and therefore most attractive women. For my own part I
+conclude that of all the causes which have led to the differences in
+external appearance between the races of man, and to a certain extent
+between man and the lower animals, sexual selection has been the most
+efficient.
+
+
+CHAPTER XXI.
+
+GENERAL SUMMARY AND CONCLUSION.
+
+Main conclusion that man is descended from some lower form--Manner of
+development--Genealogy of man--Intellectual and moral faculties--Sexual
+Selection--Concluding remarks.
+
+A brief summary will be sufficient to recall to the reader's mind the
+more salient points in this work. Many of the views which have been
+advanced are highly speculative, and some no doubt will prove erroneous;
+but I have in every case given the reasons which have led me to one
+view rather than to another. It seemed worth while to try how far the
+principle of evolution would throw light on some of the more complex
+problems in the natural history of man. False facts are highly injurious
+to the progress of science, for they often endure long; but false views,
+if supported by some evidence, do little harm, for every one takes a
+salutary pleasure in proving their falseness: and when this is done, one
+path towards error is closed and the road to truth is often at the same
+time opened.
+
+The main conclusion here arrived at, and now held by many naturalists
+who are well competent to form a sound judgment, is that man is
+descended from some less highly organised form. The grounds upon which
+this conclusion rests will never be shaken, for the close similarity
+between man and the lower animals in embryonic development, as well as
+in innumerable points of structure and constitution, both of high and of
+the most trifling importance,--the rudiments which he retains, and the
+abnormal reversions to which he is occasionally liable,--are facts which
+cannot be disputed. They have long been known, but until recently they
+told us nothing with respect to the origin of man. Now when viewed by
+the light of our knowledge of the whole organic world, their meaning is
+unmistakable. The great principle of evolution stands up clear and firm,
+when these groups or facts are considered in connection with others,
+such as the mutual affinities of the members of the same group,
+their geographical distribution in past and present times, and their
+geological succession. It is incredible that all these facts should
+speak falsely. He who is not content to look, like a savage, at the
+phenomena of nature as disconnected, cannot any longer believe that man
+is the work of a separate act of creation. He will be forced to admit
+that the close resemblance of the embryo of man to that, for instance,
+of a dog--the construction of his skull, limbs and whole frame on the
+same plan with that of other mammals, independently of the uses to
+which the parts may be put--the occasional re-appearance of various
+structures, for instance of several muscles, which man does not
+normally possess, but which are common to the Quadrumana--and a crowd of
+analogous facts--all point in the plainest manner to the conclusion that
+man is the co-descendant with other mammals of a common progenitor.
+
+We have seen that man incessantly presents individual differences in
+all parts of his body and in his mental faculties. These differences or
+variations seem to be induced by the same general causes, and to obey
+the same laws as with the lower animals. In both cases similar laws of
+inheritance prevail. Man tends to increase at a greater rate than his
+means of subsistence; consequently he is occasionally subjected to a
+severe struggle for existence, and natural selection will have effected
+whatever lies within its scope. A succession of strongly-marked
+variations of a similar nature is by no means requisite; slight
+fluctuating differences in the individual suffice for the work of
+natural selection; not that we have any reason to suppose that in the
+same species, all parts of the organisation tend to vary to the
+same degree. We may feel assured that the inherited effects of the
+long-continued use or disuse of parts will have done much in the same
+direction with natural selection. Modifications formerly of importance,
+though no longer of any special use, are long-inherited. When one part
+is modified, other parts change through the principle of correlation,
+of which we have instances in many curious cases of correlated
+monstrosities. Something may be attributed to the direct and definite
+action of the surrounding conditions of life, such as abundant food,
+heat or moisture; and lastly, many characters of slight physiological
+importance, some indeed of considerable importance, have been gained
+through sexual selection.
+
+No doubt man, as well as every other animal, presents structures, which
+seem to our limited knowledge, not to be now of any service to him, nor
+to have been so formerly, either for the general conditions of life,
+or in the relations of one sex to the other. Such structures cannot be
+accounted for by any form of selection, or by the inherited effects of
+the use and disuse of parts. We know, however, that many strange and
+strongly-marked peculiarities of structure occasionally appear in our
+domesticated productions, and if their unknown causes were to act more
+uniformly, they would probably become common to all the individuals of
+the species. We may hope hereafter to understand something about the
+causes of such occasional modifications, especially through the study of
+monstrosities: hence the labours of experimentalists, such as those of
+M. Camille Dareste, are full of promise for the future. In general
+we can only say that the cause of each slight variation and of each
+monstrosity lies much more in the constitution of the organism, than
+in the nature of the surrounding conditions; though new and changed
+conditions certainly play an important part in exciting organic changes
+of many kinds.
+
+Through the means just specified, aided perhaps by others as yet
+undiscovered, man has been raised to his present state. But since he
+attained to the rank of manhood, he has diverged into distinct races,
+or as they may be more fitly called, sub-species. Some of these, such
+as the Negro and European, are so distinct that, if specimens had been
+brought to a naturalist without any further information, they would
+undoubtedly have been considered by him as good and true species.
+Nevertheless all the races agree in so many unimportant details
+of structure and in so many mental peculiarities that these can be
+accounted for only by inheritance from a common progenitor; and a
+progenitor thus characterised would probably deserve to rank as man.
+
+It must not be supposed that the divergence of each race from the other
+races, and of all from a common stock, can be traced back to any one
+pair of progenitors. On the contrary, at every stage in the process of
+modification, all the individuals which were in any way better fitted
+for their conditions of life, though in different degrees, would have
+survived in greater numbers than the less well-fitted. The process would
+have been like that followed by man, when he does not intentionally
+select particular individuals, but breeds from all the superior
+individuals, and neglects the inferior. He thus slowly but surely
+modifies his stock, and unconsciously forms a new strain. So with
+respect to modifications acquired independently of selection, and due to
+variations arising from the nature of the organism and the action of the
+surrounding conditions, or from changed habits of life, no single pair
+will have been modified much more than the other pairs inhabiting the
+same country, for all will have been continually blended through free
+intercrossing.
+
+By considering the embryological structure of man,--the homologies
+which he presents with the lower animals,--the rudiments which he
+retains,--and the reversions to which he is liable, we can partly recall
+in imagination the former condition of our early progenitors; and can
+approximately place them in their proper place in the zoological series.
+We thus learn that man is descended from a hairy, tailed quadruped,
+probably arboreal in its habits, and an inhabitant of the Old World.
+This creature, if its whole structure had been examined by a naturalist,
+would have been classed amongst the Quadrumana, as surely as the still
+more ancient progenitor of the Old and New World monkeys. The Quadrumana
+and all the higher mammals are probably derived from an ancient
+marsupial animal, and this through a long line of diversified forms,
+from some amphibian-like creature, and this again from some fish-like
+animal. In the dim obscurity of the past we can see that the early
+progenitor of all the Vertebrata must have been an aquatic animal,
+provided with branchiae, with the two sexes united in the same
+individual, and with the most important organs of the body (such as the
+brain and heart) imperfectly or not at all developed. This animal seems
+to have been more like the larvae of the existing marine Ascidians than
+any other known form.
+
+The high standard of our intellectual powers and moral disposition is
+the greatest difficulty which presents itself, after we have been driven
+to this conclusion on the origin of man. But every one who admits the
+principle of evolution, must see that the mental powers of the higher
+animals, which are the same in kind with those of man, though so
+different in degree, are capable of advancement. Thus the interval
+between the mental powers of one of the higher apes and of a fish,
+or between those of an ant and scale-insect, is immense; yet their
+development does not offer any special difficulty; for with our
+domesticated animals, the mental faculties are certainly variable, and
+the variations are inherited. No one doubts that they are of the utmost
+importance to animals in a state of nature. Therefore the conditions
+are favourable for their development through natural selection. The
+same conclusion may be extended to man; the intellect must have been
+all-important to him, even at a very remote period, as enabling him to
+invent and use language, to make weapons, tools, traps, etc., whereby
+with the aid of his social habits, he long ago became the most dominant
+of all living creatures.
+
+A great stride in the development of the intellect will have followed,
+as soon as the half-art and half-instinct of language came into use;
+for the continued use of language will have reacted on the brain and
+produced an inherited effect; and this again will have reacted on the
+improvement of language. As Mr. Chauncey Wright (1. 'On the Limits of
+Natural Selection,' in the 'North American Review,' Oct. 1870, p. 295.)
+has well remarked, the largeness of the brain in man relatively to his
+body, compared with the lower animals, may be attributed in chief part
+to the early use of some simple form of language,--that wonderful engine
+which affixes signs to all sorts of objects and qualities, and excites
+trains of thought which would never arise from the mere impression of
+the senses, or if they did arise could not be followed out. The higher
+intellectual powers of man, such as those of ratiocination, abstraction,
+self-consciousness, etc., probably follow from the continued improvement
+and exercise of the other mental faculties.
+
+The development of the moral qualities is a more interesting problem.
+The foundation lies in the social instincts, including under this term
+the family ties. These instincts are highly complex, and in the case
+of the lower animals give special tendencies towards certain definite
+actions; but the more important elements are love, and the distinct
+emotion of sympathy. Animals endowed with the social instincts take
+pleasure in one another's company, warn one another of danger, defend
+and aid one another in many ways. These instincts do not extend to all
+the individuals of the species, but only to those of the same community.
+As they are highly beneficial to the species, they have in all
+probability been acquired through natural selection.
+
+A moral being is one who is capable of reflecting on his past actions
+and their motives--of approving of some and disapproving of others;
+and the fact that man is the one being who certainly deserves this
+designation, is the greatest of all distinctions between him and the
+lower animals. But in the fourth chapter I have endeavoured to shew that
+the moral sense follows, firstly, from the enduring and ever-present
+nature of the social instincts; secondly, from man's appreciation of
+the approbation and disapprobation of his fellows; and thirdly, from the
+high activity of his mental faculties, with past impressions extremely
+vivid; and in these latter respects he differs from the lower animals.
+Owing to this condition of mind, man cannot avoid looking both backwards
+and forwards, and comparing past impressions. Hence after some temporary
+desire or passion has mastered his social instincts, he reflects and
+compares the now weakened impression of such past impulses with
+the ever-present social instincts; and he then feels that sense of
+dissatisfaction which all unsatisfied instincts leave behind them,
+he therefore resolves to act differently for the future,--and this is
+conscience. Any instinct, permanently stronger or more enduring than
+another, gives rise to a feeling which we express by saying that it
+ought to be obeyed. A pointer dog, if able to reflect on his past
+conduct, would say to himself, I ought (as indeed we say of him) to have
+pointed at that hare and not have yielded to the passing temptation of
+hunting it.
+
+Social animals are impelled partly by a wish to aid the members of their
+community in a general manner, but more commonly to perform certain
+definite actions. Man is impelled by the same general wish to aid his
+fellows; but has few or no special instincts. He differs also from the
+lower animals in the power of expressing his desires by words, which
+thus become a guide to the aid required and bestowed. The motive to give
+aid is likewise much modified in man: it no longer consists solely of a
+blind instinctive impulse, but is much influenced by the praise or blame
+of his fellows. The appreciation and the bestowal of praise and blame
+both rest on sympathy; and this emotion, as we have seen, is one of the
+most important elements of the social instincts. Sympathy, though gained
+as an instinct, is also much strengthened by exercise or habit. As all
+men desire their own happiness, praise or blame is bestowed on actions
+and motives, according as they lead to this end; and as happiness is an
+essential part of the general good, the greatest-happiness principle
+indirectly serves as a nearly safe standard of right and wrong. As the
+reasoning powers advance and experience is gained, the remoter effects
+of certain lines of conduct on the character of the individual, and on
+the general good, are perceived; and then the self-regarding virtues
+come within the scope of public opinion, and receive praise, and their
+opposites blame. But with the less civilised nations reason often errs,
+and many bad customs and base superstitions come within the same scope,
+and are then esteemed as high virtues, and their breach as heavy crimes.
+
+The moral faculties are generally and justly esteemed as of higher
+value than the intellectual powers. But we should bear in mind that the
+activity of the mind in vividly recalling past impressions is one of
+the fundamental though secondary bases of conscience. This affords the
+strongest argument for educating and stimulating in all possible ways
+the intellectual faculties of every human being. No doubt a man with a
+torpid mind, if his social affections and sympathies are well developed,
+will be led to good actions, and may have a fairly sensitive conscience.
+But whatever renders the imagination more vivid and strengthens the
+habit of recalling and comparing past impressions, will make the
+conscience more sensitive, and may even somewhat compensate for weak
+social affections and sympathies.
+
+The moral nature of man has reached its present standard, partly through
+the advancement of his reasoning powers and consequently of a just
+public opinion, but especially from his sympathies having been rendered
+more tender and widely diffused through the effects of habit, example,
+instruction, and reflection. It is not improbable that after long
+practice virtuous tendencies may be inherited. With the more civilised
+races, the conviction of the existence of an all-seeing Deity has had
+a potent influence on the advance of morality. Ultimately man does not
+accept the praise or blame of his fellows as his sole guide, though
+few escape this influence, but his habitual convictions, controlled
+by reason, afford him the safest rule. His conscience then becomes the
+supreme judge and monitor. Nevertheless the first foundation or origin
+of the moral sense lies in the social instincts, including sympathy; and
+these instincts no doubt were primarily gained, as in the case of the
+lower animals, through natural selection.
+
+The belief in God has often been advanced as not only the greatest,
+but the most complete of all the distinctions between man and the lower
+animals. It is however impossible, as we have seen, to maintain that
+this belief is innate or instinctive in man. On the other hand a
+belief in all-pervading spiritual agencies seems to be universal; and
+apparently follows from a considerable advance in man's reason, and from
+a still greater advance in his faculties of imagination, curiosity and
+wonder. I am aware that the assumed instinctive belief in God has been
+used by many persons as an argument for His existence. But this is
+a rash argument, as we should thus be compelled to believe in the
+existence of many cruel and malignant spirits, only a little more
+powerful than man; for the belief in them is far more general than in
+a beneficent Deity. The idea of a universal and beneficent Creator does
+not seem to arise in the mind of man, until he has been elevated by
+long-continued culture.
+
+He who believes in the advancement of man from some low organised form,
+will naturally ask how does this bear on the belief in the immortality
+of the soul. The barbarous races of man, as Sir J. Lubbock has shewn,
+possess no clear belief of this kind; but arguments derived from the
+primeval beliefs of savages are, as we have just seen, of little or
+no avail. Few persons feel any anxiety from the impossibility of
+determining at what precise period in the development of the individual,
+from the first trace of a minute germinal vesicle, man becomes an
+immortal being; and there is no greater cause for anxiety because the
+period cannot possibly be determined in the gradually ascending organic
+scale. (2. The Rev. J.A. Picton gives a discussion to this effect in his
+'New Theories and the Old Faith,' 1870.)
+
+I am aware that the conclusions arrived at in this work will be
+denounced by some as highly irreligious; but he who denounces them is
+bound to shew why it is more irreligious to explain the origin of man as
+a distinct species by descent from some lower form, through the laws
+of variation and natural selection, than to explain the birth of the
+individual through the laws of ordinary reproduction. The birth both
+of the species and of the individual are equally parts of that grand
+sequence of events, which our minds refuse to accept as the result of
+blind chance. The understanding revolts at such a conclusion, whether
+or not we are able to believe that every slight variation of
+structure,--the union of each pair in marriage, the dissemination of
+each seed,--and other such events, have all been ordained for some
+special purpose.
+
+Sexual selection has been treated at great length in this work; for, as
+I have attempted to shew, it has played an important part in the history
+of the organic world. I am aware that much remains doubtful, but I
+have endeavoured to give a fair view of the whole case. In the lower
+divisions of the animal kingdom, sexual selection seems to have done
+nothing: such animals are often affixed for life to the same spot, or
+have the sexes combined in the same individual, or what is still
+more important, their perceptive and intellectual faculties are not
+sufficiently advanced to allow of the feelings of love and jealousy, or
+of the exertion of choice. When, however, we come to the Arthropoda and
+Vertebrata, even to the lowest classes in these two great Sub-Kingdoms,
+sexual selection has effected much.
+
+In the several great classes of the animal kingdom,--in mammals, birds,
+reptiles, fishes, insects, and even crustaceans,--the differences
+between the sexes follow nearly the same rules. The males are almost
+always the wooers; and they alone are armed with special weapons for
+fighting with their rivals. They are generally stronger and larger than
+the females, and are endowed with the requisite qualities of courage
+and pugnacity. They are provided, either exclusively or in a much higher
+degree than the females, with organs for vocal or instrumental music,
+and with odoriferous glands. They are ornamented with infinitely
+diversified appendages, and with the most brilliant or conspicuous
+colours, often arranged in elegant patterns, whilst the females are
+unadorned. When the sexes differ in more important structures, it is
+the male which is provided with special sense-organs for discovering
+the female, with locomotive organs for reaching her, and often with
+prehensile organs for holding her. These various structures for charming
+or securing the female are often developed in the male during only part
+of the year, namely the breeding-season. They have in many cases been
+more or less transferred to the females; and in the latter case they
+often appear in her as mere rudiments. They are lost or never gained by
+the males after emasculation. Generally they are not developed in the
+male during early youth, but appear a short time before the age for
+reproduction. Hence in most cases the young of both sexes resemble each
+other; and the female somewhat resembles her young offspring throughout
+life. In almost every great class a few anomalous cases occur, where
+there has been an almost complete transposition of the characters proper
+to the two sexes; the females assuming characters which properly belong
+to the males. This surprising uniformity in the laws regulating the
+differences between the sexes in so many and such widely separated
+classes, is intelligible if we admit the action of one common cause,
+namely sexual selection.
+
+Sexual selection depends on the success of certain individuals over
+others of the same sex, in relation to the propagation of the species;
+whilst natural selection depends on the success of both sexes, at all
+ages, in relation to the general conditions of life. The sexual struggle
+is of two kinds; in the one it is between individuals of the same sex,
+generally the males, in order to drive away or kill their rivals, the
+females remaining passive; whilst in the other, the struggle is likewise
+between the individuals of the same sex, in order to excite or charm
+those of the opposite sex, generally the females, which no longer remain
+passive, but select the more agreeable partners. This latter kind of
+selection is closely analogous to that which man unintentionally, yet
+effectually, brings to bear on his domesticated productions, when he
+preserves during a long period the most pleasing or useful individuals,
+without any wish to modify the breed.
+
+The laws of inheritance determine whether characters gained through
+sexual selection by either sex shall be transmitted to the same sex, or
+to both; as well as the age at which they shall be developed. It appears
+that variations arising late in life are commonly transmitted to one
+and the same sex. Variability is the necessary basis for the action of
+selection, and is wholly independent of it. It follows from this, that
+variations of the same general nature have often been taken advantage of
+and accumulated through sexual selection in relation to the propagation
+of the species, as well as through natural selection in relation to
+the general purposes of life. Hence secondary sexual characters, when
+equally transmitted to both sexes can be distinguished from ordinary
+specific characters only by the light of analogy. The modifications
+acquired through sexual selection are often so strongly pronounced that
+the two sexes have frequently been ranked as distinct species, or even
+as distinct genera. Such strongly-marked differences must be in some
+manner highly important; and we know that they have been acquired in
+some instances at the cost not only of inconvenience, but of exposure to
+actual danger.
+
+The belief in the power of sexual selection rests chiefly on the
+following considerations. Certain characters are confined to one sex;
+and this alone renders it probable that in most cases they are connected
+with the act of reproduction. In innumerable instances these characters
+are fully developed only at maturity, and often during only a part of
+the year, which is always the breeding-season. The males (passing over
+a few exceptional cases) are the more active in courtship; they are the
+better armed, and are rendered the more attractive in various ways. It
+is to be especially observed that the males display their attractions
+with elaborate care in the presence of the females; and that they
+rarely or never display them excepting during the season of love. It is
+incredible that all this should be purposeless. Lastly we have distinct
+evidence with some quadrupeds and birds, that the individuals of one
+sex are capable of feeling a strong antipathy or preference for certain
+individuals of the other sex.
+
+Bearing in mind these facts, and the marked results of man's unconscious
+selection, when applied to domesticated animals and cultivated plants,
+it seems to me almost certain that if the individuals of one sex were
+during a long series of generations to prefer pairing with certain
+individuals of the other sex, characterised in some peculiar manner, the
+offspring would slowly but surely become modified in this same manner.
+I have not attempted to conceal that, excepting when the males are more
+numerous than the females, or when polygamy prevails, it is doubtful how
+the more attractive males succeed in leaving a large number of offspring
+to inherit their superiority in ornaments or other charms than the less
+attractive males; but I have shewn that this would probably follow from
+the females,--especially the more vigorous ones, which would be the
+first to breed,--preferring not only the more attractive but at the same
+time the more vigorous and victorious males.
+
+Although we have some positive evidence that birds appreciate bright and
+beautiful objects, as with the bower-birds of Australia, and although
+they certainly appreciate the power of song, yet I fully admit that it
+is astonishing that the females of many birds and some mammals should
+be endowed with sufficient taste to appreciate ornaments, which we
+have reason to attribute to sexual selection; and this is even more
+astonishing in the case of reptiles, fish, and insects. But we really
+know little about the minds of the lower animals. It cannot be supposed,
+for instance, that male birds of paradise or peacocks should take such
+pains in erecting, spreading, and vibrating their beautiful plumes
+before the females for no purpose. We should remember the fact given
+on excellent authority in a former chapter, that several peahens, when
+debarred from an admired male, remained widows during a whole season
+rather than pair with another bird.
+
+Nevertheless I know of no fact in natural history more wonderful than
+that the female Argus pheasant should appreciate the exquisite shading
+of the ball-and-socket ornaments and the elegant patterns on the
+wing-feather of the male. He who thinks that the male was created as
+he now exists must admit that the great plumes, which prevent the wings
+from being used for flight, and which are displayed during courtship and
+at no other time in a manner quite peculiar to this one species, were
+given to him as an ornament. If so, he must likewise admit that the
+female was created and endowed with the capacity of appreciating such
+ornaments. I differ only in the conviction that the male Argus pheasant
+acquired his beauty gradually, through the preference of the females
+during many generations for the more highly ornamented males; the
+aesthetic capacity of the females having been advanced through exercise
+or habit, just as our own taste is gradually improved. In the male
+through the fortunate chance of a few feathers being left unchanged, we
+can distinctly trace how simple spots with a little fulvous shading
+on one side may have been developed by small steps into the wonderful
+ball-and-socket ornaments; and it is probable that they were actually
+thus developed.
+
+Everyone who admits the principle of evolution, and yet feels great
+difficulty in admitting that female mammals, birds, reptiles, and fish,
+could have acquired the high taste implied by the beauty of the males,
+and which generally coincides with our own standard, should reflect that
+the nerve-cells of the brain in the highest as well as in the lowest
+members of the Vertebrate series, are derived from those of the common
+progenitor of this great Kingdom. For we can thus see how it has come
+to pass that certain mental faculties, in various and widely distinct
+groups of animals, have been developed in nearly the same manner and to
+nearly the same degree.
+
+The reader who has taken the trouble to go through the several
+chapters devoted to sexual selection, will be able to judge how far
+the conclusions at which I have arrived are supported by sufficient
+evidence. If he accepts these conclusions he may, I think, safely extend
+them to mankind; but it would be superfluous here to repeat what I have
+so lately said on the manner in which sexual selection apparently has
+acted on man, both on the male and female side, causing the two sexes to
+differ in body and mind, and the several races to differ from each other
+in various characters, as well as from their ancient and lowly-organised
+progenitors.
+
+He who admits the principle of sexual selection will be led to the
+remarkable conclusion that the nervous system not only regulates most
+of the existing functions of the body, but has indirectly influenced
+the progressive development of various bodily structures and of certain
+mental qualities. Courage, pugnacity, perseverance, strength and size of
+body, weapons of all kinds, musical organs, both vocal and instrumental,
+bright colours and ornamental appendages, have all been indirectly
+gained by the one sex or the other, through the exertion of choice, the
+influence of love and jealousy, and the appreciation of the beautiful in
+sound, colour or form; and these powers of the mind manifestly depend on
+the development of the brain.
+
+Man scans with scrupulous care the character and pedigree of his horses,
+cattle, and dogs before he matches them; but when he comes to his own
+marriage he rarely, or never, takes any such care. He is impelled by
+nearly the same motives as the lower animals, when they are left to
+their own free choice, though he is in so far superior to them that
+he highly values mental charms and virtues. On the other hand he is
+strongly attracted by mere wealth or rank. Yet he might by selection
+do something not only for the bodily constitution and frame of his
+offspring, but for their intellectual and moral qualities. Both sexes
+ought to refrain from marriage if they are in any marked degree inferior
+in body or mind; but such hopes are Utopian and will never be even
+partially realised until the laws of inheritance are thoroughly
+known. Everyone does good service, who aids towards this end. When the
+principles of breeding and inheritance are better understood, we shall
+not hear ignorant members of our legislature rejecting with scorn a plan
+for ascertaining whether or not consanguineous marriages are injurious
+to man.
+
+The advancement of the welfare of mankind is a most intricate problem:
+all ought to refrain from marriage who cannot avoid abject poverty for
+their children; for poverty is not only a great evil, but tends to its
+own increase by leading to recklessness in marriage. On the other hand,
+as Mr. Galton has remarked, if the prudent avoid marriage, whilst the
+reckless marry, the inferior members tend to supplant the better members
+of society. Man, like every other animal, has no doubt advanced to his
+present high condition through a struggle for existence consequent on
+his rapid multiplication; and if he is to advance still higher, it is to
+be feared that he must remain subject to a severe struggle. Otherwise
+he would sink into indolence, and the more gifted men would not be more
+successful in the battle of life than the less gifted. Hence our natural
+rate of increase, though leading to many and obvious evils, must not be
+greatly diminished by any means. There should be open competition for
+all men; and the most able should not be prevented by laws or customs
+from succeeding best and rearing the largest number of offspring.
+Important as the struggle for existence has been and even still is, yet
+as far as the highest part of man's nature is concerned there are other
+agencies more important. For the moral qualities are advanced, either
+directly or indirectly, much more through the effects of habit, the
+reasoning powers, instruction, religion, etc., than through natural
+selection; though to this latter agency may be safely attributed the
+social instincts, which afforded the basis for the development of the
+moral sense.
+
+The main conclusion arrived at in this work, namely, that man is
+descended from some lowly organised form, will, I regret to think, be
+highly distasteful to many. But there can hardly be a doubt that we are
+descended from barbarians. The astonishment which I felt on first seeing
+a party of Fuegians on a wild and broken shore will never be forgotten
+by me, for the reflection at once rushed into my mind--such were our
+ancestors. These men were absolutely naked and bedaubed with paint,
+their long hair was tangled, their mouths frothed with excitement, and
+their expression was wild, startled, and distrustful. They possessed
+hardly any arts, and like wild animals lived on what they could catch;
+they had no government, and were merciless to every one not of their own
+small tribe. He who has seen a savage in his native land will not feel
+much shame, if forced to acknowledge that the blood of some more
+humble creature flows in his veins. For my own part I would as soon be
+descended from that heroic little monkey, who braved his dreaded enemy
+in order to save the life of his keeper, or from that old baboon, who
+descending from the mountains, carried away in triumph his young comrade
+from a crowd of astonished dogs--as from a savage who delights to
+torture his enemies, offers up bloody sacrifices, practices infanticide
+without remorse, treats his wives like slaves, knows no decency, and is
+haunted by the grossest superstitions.
+
+Man may be excused for feeling some pride at having risen, though not
+through his own exertions, to the very summit of the organic scale; and
+the fact of his having thus risen, instead of having been aboriginally
+placed there, may give him hope for a still higher destiny in the
+distant future. But we are not here concerned with hopes or fears, only
+with the truth as far as our reason permits us to discover it; and I
+have given the evidence to the best of my ability. We must, however,
+acknowledge, as it seems to me, that man with all his noble qualities,
+with sympathy which feels for the most debased, with benevolence which
+extends not only to other men but to the humblest living creature,
+with his god-like intellect which has penetrated into the movements and
+constitution of the solar system--with all these exalted powers--Man
+still bears in his bodily frame the indelible stamp of his lowly origin.
+
+
+SUPPLEMENTAL NOTE.
+
+ON SEXUAL SELECTION IN RELATION TO MONKEYS.
+
+Reprinted from NATURE, November 2, 1876, p. 18.
+
+In the discussion on Sexual Selection in my 'Descent of Man,' no case
+interested and perplexed me so much as the brightly-coloured hinder ends
+and adjoining parts of certain monkeys. As these parts are more brightly
+coloured in one sex than the other, and as they become more brilliant
+during the season of love, I concluded that the colours had been gained
+as a sexual attraction. I was well aware that I thus laid myself open to
+ridicule; though in fact it is not more surprising that a monkey should
+display his bright-red hinder end than that a peacock should display his
+magnificent tail. I had, however, at that time no evidence of monkeys
+exhibiting this part of their bodies during their courtship; and
+such display in the case of birds affords the best evidence that the
+ornaments of the males are of service to them by attracting or exciting
+the females. I have lately read an article by Joh. von Fischer, of
+Gotha, published in 'Der Zoologische Garten,' April 1876, on the
+expression of monkeys under various emotions, which is well worthy of
+study by any one interested in the subject, and which shews that the
+author is a careful and acute observer. In this article there is an
+account of the behaviour of a young male mandrill when he first beheld
+himself in a looking-glass, and it is added, that after a time he turned
+round and presented his red hinder end to the glass. Accordingly I wrote
+to Herr J. von Fischer to ask what he supposed was the meaning of this
+strange action, and he has sent me two long letters full of new and
+curious details, which will, I hope, be hereafter published. He says
+that he was himself at first perplexed by the above action, and was thus
+led carefully to observe several individuals of various other species of
+monkeys, which he has long kept in his house. He finds that not only the
+mandrill (Cynocephalus mormon) but the drill (C. leucophaeus) and
+three other kinds of baboons (C. hamadryas, sphinx, and babouin), also
+Cynopithecus niger, and Macacus rhesus and nemestrinus, turn this part
+of their bodies, which in all these species is more or less brightly
+coloured, to him when they are pleased, and to other persons as a sort
+of greeting. He took pains to cure a Macacus rhesus, which he had kept
+for five years, of this indecorous habit, and at last succeeded. These
+monkeys are particularly apt to act in this manner, grinning at the same
+time, when first introduced to a new monkey, but often also to their
+old monkey friends; and after this mutual display they begin to play
+together. The young mandrill ceased spontaneously after a time to act
+in this manner towards his master, von Fischer, but continued to do
+so towards persons who were strangers and to new monkeys. A young
+Cynopithecus niger never acted, excepting on one occasion, in this way
+towards his master, but frequently towards strangers, and continues to
+do so up to the present time. From these facts Von Fischer concludes
+that the monkeys which behaved in this manner before a looking-glass
+(viz., the mandrill, drill, Cynopithecus niger, Macacus rhesus and
+nemestrinus) acted as if their reflection were a new acquaintance. The
+mandrill and drill, which have their hinder ends especially ornamented,
+display it even whilst quite young, more frequently and more
+ostentatiously than do the other kinds. Next in order comes Cynocephalus
+hamadryas, whilst the other species act in this manner seldomer. The
+individuals, however, of the same species vary in this respect, and
+some which were very shy never displayed their hinder ends. It deserves
+especial attention that Von Fischer has never seen any species purposely
+exhibit the hinder part of its body, if not at all coloured. This
+remark applies to many individuals of Macacus cynomolgus and Cercocebus
+radiatus (which is closely allied to M. rhesus), to three species of
+Cercopithecus and several American monkeys. The habit of turning the
+hinder ends as a greeting to an old friend or new acquaintance, which
+seems to us so odd, is not really more so than the habits of many
+savages, for instance that of rubbing their bellies with their hands, or
+rubbing noses together. The habit with the mandrill and drill seems to
+be instinctive or inherited, as it was followed by very young animals;
+but it is modified or guided, like so many other instincts, by
+observation, for Von Fischer says that they take pains to make their
+display fully; and if made before two observers, they turn to him who
+seems to pay the most attention.
+
+With respect to the origin of the habit, Von Fischer remarks that his
+monkeys like to have their naked hinder ends patted or stroked, and that
+they then grunt with pleasure. They often also turn this part of their
+bodies to other monkeys to have bits of dirt picked off, and so no doubt
+it would be with respect to thorns. But the habit with adult animals
+is connected to a certain extent with sexual feelings, for Von Fischer
+watched through a glass door a female Cynopithecus niger, and she during
+several days, "umdrehte und dem M�nnchen mit gurgelnden T�nen die stark
+ger�thete Sitzflache zeigte, was ich fr�her nie an diesem Thier bemerkt
+hatte. Beim Anblick dieses Gegenstandes erregte sich das M�nnchen
+sichtlich, denn es polterte heftig an den St�ben, ebenfalls gurgelnde
+Laute ausstossend." As all the monkeys which have the hinder parts
+of their bodies more or less brightly coloured live, according to Von
+Fischer, in open rocky places, he thinks that these colours serve to
+render one sex conspicuous at a distance to the other; but, as monkeys
+are such gregarious animals, I should have thought that there was no
+need for the sexes to recognise each other at a distance. It seems to
+me more probable that the bright colours, whether on the face or hinder
+end, or, as in the mandrill, on both, serve as a sexual ornament and
+attraction. Anyhow, as we now know that monkeys have the habit of
+turning their hinder ends towards other monkeys, it ceases to be at all
+surprising that it should have been this part of their bodies which has
+been more or less decorated. The fact that it is only the monkeys thus
+characterised which, as far as at present known, act in this manner as a
+greeting towards other monkeys renders it doubtful whether the habit
+was first acquired from some independent cause, and that afterwards the
+parts in question were coloured as a sexual ornament; or whether the
+colouring and the habit of turning round were first acquired through
+variation and sexual selection, and that afterwards the habit was
+retained as a sign of pleasure or as a greeting, through the principle
+of inherited association. This principle apparently comes into play on
+many occasions: thus it is generally admitted that the songs of birds
+serve mainly as an attraction during the season of love, and that the
+leks, or great congregations of the black-grouse, are connected with
+their courtship; but the habit of singing has been retained by some
+birds when they feel happy, for instance by the common robin, and the
+habit of congregating has been retained by the black-grouse during other
+seasons of the year.
+
+I beg leave to refer to one other point in relation to sexual selection.
+It has been objected that this form of selection, as far as the
+ornaments of the males are concerned, implies that all females within
+the same district must possess and exercise exactly the same taste.
+It should, however, be observed, in the first place, that although the
+range of variation of a species may be very large, it is by no means
+indefinite. I have elsewhere given a good instance of this fact in the
+pigeon, of which there are at least a hundred varieties differing
+widely in their colours, and at least a score of varieties of the fowl
+differing in the same kind of way; but the range of colour in these two
+species is extremely distinct. Therefore the females of natural species
+cannot have an unlimited scope for their taste. In the second place, I
+presume that no supporter of the principle of sexual selection believes
+that the females select particular points of beauty in the males; they
+are merely excited or attracted in a greater degree by one male than
+by another, and this seems often to depend, especially with birds, on
+brilliant colouring. Even man, excepting perhaps an artist, does not
+analyse the slight differences in the features of the woman whom he may
+admire, on which her beauty depends. The male mandrill has not only the
+hinder end of his body, but his face gorgeously coloured and marked with
+oblique ridges, a yellow beard, and other ornaments. We may infer from
+what we see of the variation of animals under domestication, that the
+above several ornaments of the mandrill were gradually acquired by
+one individual varying a little in one way, and another individual in
+another way. The males which were the handsomest or the most attractive
+in any manner to the females would pair oftenest, and would leave rather
+more offspring than other males. The offspring of the former, although
+variously intercrossed, would either inherit the peculiarities of their
+fathers or transmit an increased tendency to vary in the same manner.
+Consequently the whole body of males inhabiting the same country would
+tend from the effects of constant intercrossing to become modified
+almost uniformly, but sometimes a little more in one character and
+sometimes in another, though at an extremely slow rate; all ultimately
+being thus rendered more attractive to the females. The process is like
+that which I have called unconscious selection by man, and of which I
+have given several instances. In one country the inhabitants value a
+fleet or light dog or horse, and in another country a heavier and more
+powerful one; in neither country is there any selection of individual
+animals with lighter or stronger bodies and limbs; nevertheless after
+a considerable lapse of time the individuals are found to have been
+modified in the desired manner almost uniformly, though differently in
+each country. In two absolutely distinct countries inhabited by the
+same species, the individuals of which can never during long ages have
+intermigrated and intercrossed, and where, moreover, the variations
+will probably not have been identically the same, sexual selection might
+cause the males to differ. Nor does the belief appear to me altogether
+fanciful that two sets of females, surrounded by a very different
+environment, would be apt to acquire somewhat different tastes with
+respect to form, sound, or colour. However this may be, I have given
+in my 'Descent of Man' instances of closely-allied birds inhabiting
+distinct countries, of which the young and the females cannot be
+distinguished, whilst the adult males differ considerably, and this may
+be attributed with much probability to the action of sexual selection.
+
+
+
+INDEX.
+
+Abbot, C., on the battles of seals.
+
+Abductor of the fifth metatarsal, presence of, in man.
+
+Abercrombie, Dr., on disease of the brain affecting speech.
+
+Abipones, marriage customs of the.
+
+Abortion, prevalence of the practice of.
+
+Abou-Simbel, caves of.
+
+Abramis brama.
+
+Abstraction, power of, in animals.
+
+Acalles, stridulation of.
+
+Acanthodactylus capensis, sexual differences of colour in.
+
+Accentor Modularis.
+
+Acclimatisation, difference of, in different races of men.
+
+Achetidae, stridulation of the; rudimentary stridulating organs in
+female.
+
+Acilius sulcatus, elytra of the female.
+
+Acomus, development of spurs in the female of.
+
+Acridiidae, stridulation of the; rudimentary stridulating organs in
+female.
+
+Acromio-basilar muscle, and quadrupedal gait.
+
+Acting.
+
+Actiniae, bright colours of.
+
+Adams, Mr., migration of birds; intelligence of nut-hatch; on the
+Bombycilla carolinensis.
+
+Admiral butterfly.
+
+Adoption of the young of other animals by female monkeys.
+
+Advancement in the organic scale, Von Baer's definition of.
+
+Aeby, on the difference between the skulls of man and the quadrumana.
+
+Aesthetic faculty, not highly developed in savages.
+
+Affection, maternal; manifestation of, by animals; parental and filial,
+partly the result of natural selection; mutual, of birds; shewn by birds
+in confinement, for certain persons.
+
+Africa, probably the birthplace of man; South, crossed population of;
+South, retention of colour by the Dutch in; South, proportion of the
+sexes in the butterflies of; tattooing practised in; Northern, coiffure
+of natives of.
+
+Agassiz, L., on conscience in dogs; on the coincidence of the races of
+man with zoological provinces; on the number of species of man; on the
+courtship of the land-snails; on the brightness of the colours of male
+fishes during the breeding season; on the frontal protuberance of the
+males of Geophagus and Cichla; male fishes hatching ova in their
+mouths; sexual differences in colour of chromids; on the slight sexual
+differences of the South Americans; on the tattooing of the Amazonian
+Indians.
+
+Age, in relation to the transmission of characters in birds; variation
+in accordance with, in birds.
+
+Agelaeus phoeniceus.
+
+Ageronia feronia, noise produced by.
+
+Agrion, dimorphism in.
+
+Agrion Ramburii, sexes of.
+
+Agrionidae, difference in the sexes of.
+
+Agrotis exclamationis.
+
+Ague, tertian, dog suffering from.
+
+Ainos, hairiness of the.
+
+Aitchison, Mr., on sheep.
+
+Aithurus polytmus, young of.
+
+Albino birds.
+
+Alca torda, young of.
+
+Alces palmata.
+
+Alder and Hancock, MM., on the nudi-branch mollusca.
+
+Allen, J.A., vigour of birds earliest hatched; effect of difference of
+temperature, light, etc., on birds; colours of birds; on the relative
+size of the sexes of Callorhinus ursinus; on the name of Otaria jubata;
+on the pairing of seals; on sexual differences in the colour of bats.
+
+Allen, S., on the habits of Hoplopterus; on the plumes of herons; on the
+vernal moult of Herodius bubulcus.
+
+Alligator, courtship of the male; roaring of the male.
+
+Amadavat, pugnacity of male.
+
+Amadina Lathami, display of plumage by the male.
+
+Amadina castanotis, display of plumage by the male.
+
+Amazons, butterflies of the; fishes of the.
+
+America, variation in the skulls of aborigines of; wide range of
+aborigines of; lice of the natives of; general beardlessness of the
+natives of.
+
+America, North, butterflies of; Indians of, women a cause of strife
+among the; Indians of, their notions of female beauty.
+
+America, South, character of the natives of; population of parts of;
+piles of stones in; extinction of the fossil horse of; desert-birds of;
+slight sexual difference of the aborigines of; prevalence of infanticide
+in.
+
+American languages, often highly artificial.
+
+Americans, wide geographical range of; native, variability of; and
+negroes, difference of; aversion of, to hair on the face.
+
+Ammophila, on the jaws of.
+
+Ammotragus tragelaphus, hairy forelegs of.
+
+Amphibia, affinity of, to the ganoid fishes; vocal organs of the.
+
+Amphibians, breeding whilst immature.
+
+Amphioxus.
+
+Amphipoda, males sexually mature while young.
+
+Amunoph III., negro character of, features of.
+
+Anal appendages of insects.
+
+Analogous variation in the plumage of birds.
+
+Anas.
+
+Anas acuta, male plumage of.
+
+Anas boschas, male plumage of.
+
+Anas histrionica.
+
+Anas punctata.
+
+Anastomus oscitans, sexes and young of; white nuptial plumage of.
+
+Anatidae, voices of.
+
+Anax junius, differences in the sexes of.
+
+Andaman islanders, susceptible to change of climate.
+
+Anderson, Dr., on the tail of Macacus brunneus; the Bufo sikimmensis;
+sounds of Echis carinata.
+
+Andreana fulva.
+
+Anglo-Saxons, estimation of the beard among the.
+
+Animals, domesticated, more fertile than wild; cruelty of savages to;
+characters common to man and; domestic, change of breeds of.
+
+Annelida, colours of.
+
+Anobium tessellatum, sounds produced by.
+
+Anolis cristatellus, male, crest of; pugnacity of the male; throat-pouch
+of.
+
+Anser canadensis.
+
+Anset cygnoides; knob at the base of the beak of.
+
+Anser hyperboreus, whiteness of.
+
+Antelope, prong-horned, horns of.
+
+Antelopes, generally polygamous; horns of; canine teeth of some male;
+use of horns of; dorsal crests in; dewlaps of; winter change of two
+species of; peculiar markings of.
+
+Antennae, furnished with cushions in the male of Penthe.
+
+Anthidium manicatum, large male of.
+
+Anthocharis cardamines; sexual difference of colour in.
+
+Anthocharis genutia.
+
+Anthocharis sara.
+
+Anthophora acervorum, large male of.
+
+Anthophora retusa, difference of the sexes in.
+
+Anthropidae.
+
+Anthus, moulting of.
+
+Antics of birds.
+
+Antigua, Dr. Nicholson's observations on yellow fever in.
+
+Antilocapra americana, horns of.
+
+Antilope bezoartica, horned females of; sexual difference in the colour
+of.
+
+Antilope Dorcas and euchore.
+
+Antilope euchore, horns of.
+
+Antilope montana, rudimentary canines in the young male of.
+
+Antilope niger, sing-sing, caama, and gorgon, sexual differences in the
+colours of.
+
+Antilope oreas, horns of.
+
+Antilope saiga, polygamous habits of.
+
+Antilope strepsiceros, horns of.
+
+Antilope subgutturosa, absence of suborbital pits in.
+
+Antipathy, shewn by birds in confinement, to certain persons.
+
+Ants, large size of the cerebral ganglia in; soldier, large jaws of;
+playing together; memory in; intercommunication of, by means of the
+antennae; habits of; difference of the sexes in; recognition of each
+other by, after separation.
+
+Ants White, habits of.
+
+Anura.
+
+Apatania muliebris, male unknown.
+
+Apathus, difference of the sexes in.
+
+Apatura Iris.
+
+Apes, difference of the young, from the adult; semi-erect attitude
+of some; mastoid processes of; influences of the jaw-muscles on the
+physiognomy of; female, destitute of large canines; building platforms;
+imitative faculties of; anthropomorphous; probable speedy extermination
+of the; Gratiolet on the evolution of; canine teeth of male; females of
+some, less hairy beneath than the males.
+
+Apes, long-armed, their mode of progression.
+
+Aphasia, Dr. Bateman on.
+
+Apis mellifica, large male of.
+
+Apollo, Greek statues of.
+
+Apoplexy in Cebus Azarae.
+
+Appendages, anal, of insects.
+
+Approbation, influence of the love of.
+
+Aprosmictus scapulatus.
+
+Apus, proportion of sexes.
+
+Aquatic birds, frequency of white plumage in.
+
+Aquila chrysaetos.
+
+Arab women, elaborate and peculiar coiffure of.
+
+Arabs, fertility of crosses with other races; gashing of cheeks and
+temples among the.
+
+Arachnida.
+
+Arakhan, artificial widening of the forehead by the natives of.
+
+Arboricola, young of.
+
+Archeopteryx.
+
+Arctiidae, coloration of the.
+
+Ardea asha, rufescens, and coerulea, change of colour in.
+
+Ardea coerulea, breeding in immature plumage.
+
+Ardea gularis, change of plumage in.
+
+Ardea herodias, love-gestures of the male.
+
+Ardea ludoviciana, age of mature plumage in; continued growth of crest
+and plumes in the male of.
+
+Ardea nycticorax, cries of.
+
+Ardeola, young of.
+
+Ardetta, changes of plumage in.
+
+Argenteuil.
+
+Argus pheasant, display of plumage by the male; ocellated spots of the;
+gradation of characters in the.
+
+Argyll, Duke of, on the physical weakness of man; the fashioning of
+implements peculiar to man; on the contest in man between right and
+wrong; on the primitive civilisation of man; on the plumage of the male
+Argus pheasant; on Urosticte Benjamini; on the nests of birds.
+
+Argynnis, colouring of the lower surface of.
+
+Aricoris epitus, sexual differences in the wings of.
+
+Aristocracy, increased beauty of the.
+
+Arms, proportions of, in soldiers and sailors; direction of the hair on
+the.
+
+Arms and hands, free use of, indirectly correlated with diminution of
+canines.
+
+Arrest of development.
+
+Arrow-heads, stone, general resemblance of.
+
+Arrows, use of.
+
+Arteries, variations in the course of the.
+
+Artery, effect of tying, upon the lateral channels.
+
+Arthropoda.
+
+Arts practised by savages.
+
+Ascension, coloured incrustation on the rocks of.
+
+Ascidia, affinity of the lancelet to; tad-pole like larvae of.
+
+Ascidians, bright colours of some.
+
+Asinus, Asiatic and African species of.
+
+Asinus taeniopus.
+
+Ass, colour-variations of the.
+
+Ateles, effects of brandy on an; absence of the thumb in.
+
+Ateles beelzebuth, ears of.
+
+Ateles marginatus, colour of the ruff of; hair on the head of.
+
+Ateuchus cicatricosus, habits of.
+
+Ateuchus, stridulation of.
+
+Athalia, proportions of the sexes in.
+
+Atropus pulsatorius.
+
+Attention, manifestations of, in animals.
+
+Audouin, V., on a hymenopterous parasite with a sedentary male.
+
+Audubon, J.J., on the pinioned goose; on the speculum of Mergus
+cucullatus; on the pugnacity of male birds; on courtship of Caprimulgus;
+on Tetrao cupido; on Ardea nycticorax; on Sturnella ludoviciana; on
+the vocal organs of Tetra cupido; on the drumming of the male Tetrao
+umbellus; on sounds produced by the nightjar; on Ardea herodias and
+Cathartes jota; on Mimus polyglottus; on display in male birds; on
+the spring change of colour in some finches; on migration of mocking
+thrushes; recognition of a dog by a turkey; selection of mate by female
+birds; on the turkey; on variation in the male scarlet tanager; on the
+musk-rat; on the habits of Pyranga aestiva; on local differences in the
+nests of the same species of birds; on the habits of woodpeckers; on
+Bombycilla carolinensis; on young females of Pyranga aestiva acquiring
+male characters; on the immature plumage of thrushes; on the immature
+plumage of birds; on birds breeding in immature plumage; on the growth
+of the crest and plume in the male Ardea ludoviciana; on the change of
+colour in some species of Ardea.
+
+Audobon and Bachman, MM., on squirrels fighting; on the Canadian lynx.
+
+Aughey, Prof., on rattlesnakes.
+
+Austen, N.L., on Anolis cristatellus.
+
+Australia, not the birthplace of man; half-castes killed by the natives
+of; lice of the natives of.
+
+Australia, South, variation in the skulls of aborigines of.
+
+Australians, colour of new-born children of; relative height of the
+sexes of; women a cause of war among the.
+
+Axis deer, sexual difference in the colour of the.
+
+Aymaras, measurements of the; no grey hair among the; hairlessness of
+the face in the; long hair of the.
+
+Azara, on the proportion of men and women among the Guaranys; on
+Palamedea cornuta; on the beards of the Guaranys; on strife for women
+among the Guanas; on infanticide; on the eradication of the eyebrows
+and eyelashes by the Indians of Paraguay; on polyandry among the Guanas;
+celibacy unknown among the savages of South America; on the freedom of
+divorce among the Charruas.
+
+Babbage C., on the greater proportion of illegitimate female births.
+
+Babirusa, tusks of the.
+
+Baboon, revenge in a; rage excited in, by reading; manifestation of
+memory by a; employing a mat for shelter against the sun; protected from
+punishment by its companions.
+
+Baboon, Cape, mane of the male; Hamadryas, mane of the male.
+
+Baboon, effects of intoxicating liquors on; ears of; diversity of the
+mental faculties in; hands of; habits of; variability of the tail in;
+manifestation of maternal affection by; using stones and sticks as
+weapons; co-operation of; silence of, on plundering expeditions;
+apparent polygamy of; polygamous and social habits of.
+
+Baboons, courtship of.
+
+Bachman, Dr., on the fertility of mulattoes.
+
+Baer, K.E. von, on embryonic development; definition of advancement in
+the organic scale.
+
+Bagehot, W., on the social virtues among primitive men; slavery formerly
+beneficial; on the value of obedience; on human progress; on the
+persistence of savage tribes in classical times.
+
+Bailly, E.M., on the mode of fighting of the Italian buffalo; on the
+fighting of stags.
+
+Bain, A., on the sense of duty; aid springing from sympathy; on the
+basis of sympathy; on the love of approbation etc.; on the idea of
+beauty.
+
+Baird, W., on a difference in colour between the males and females of
+some Entozoa.
+
+Baker, Mr., observation on the proportion of the sexes in
+pheasant-chicks.
+
+Baker, Sir S., on the fondness of the Arabs for discordant music; on
+sexual difference in the colours of an antelope; on the elephant
+and rhinoceros attacking white or grey horses; on the disfigurements
+practised by the negroes; on the gashing of the cheeks and temples
+practised in Arab countries; on the coiffure of the North Africans;
+on the perforation of the lower lip by the women of Latooka; on the
+distinctive characters of the coiffure of central African tribes; on the
+coiffure of Arab women.
+
+"Balz" of the Black-cock.
+
+Bantam, Sebright.
+
+Banteng, horns of; sexual differences in the colours of the.
+
+Banyai, colour of the.
+
+Barbarism, primitive, of civilised nations.
+
+Barbs, filamentous, of the feathers, in certain birds.
+
+Barr, Mr., on sexual preference in dogs.
+
+Barrago, F., on the Simian resemblances of man.
+
+Barrington, Daines, on the language of birds; on the clucking of the
+hen; on the object of the song of birds; on the singing of female birds;
+on birds acquiring the songs of other birds; on the muscles of the
+larynx in song-birds; on the want of the power of song by female birds.
+
+Barrow, on the widow-bird.
+
+Bartels, Dr., supernumerary mammae in men.
+
+Bartlett, A.D., period of hatching of bird's eggs; on the tragopan; on
+the development of the spurs in Crossoptilon auritum; on the fighting
+of the males of Plectopterus gambensis; on the Knot; on display in
+male birds; on the display of plumage by the male Polyplectron;
+on Crossoptilon auritum and Phasianus Wallichii; on the habits of
+Lophophorus; on the colour of the mouth in Buceros bicornis; on the
+incubation of the cassowary; on the Cape Buffalo; on the use of the
+horns of antelopes; on the fighting of male wart-hogs; on Ammotragus
+tragelaphus; on the colours of Cercopithecus cephus; on the colours of
+the faces of monkeys; on the naked surfaces of monkeys.
+
+Bartlett, on courting of Argus pheasant.
+
+Bartram, on the courtship of the male alligator.
+
+Basque language, highly artificial.
+
+Bate, C.S., on the superior activity of male crustacea; on the
+proportions of the sexes in crabs; on the chelae of crustacea; on the
+relative size of the sexes in crustacea; on the colours of crustacea.
+
+Bateman, Dr., tendency to imitation in certain diseased states; on
+Aphasia.
+
+Bates, H.W., on variation in the form of the head of Amazonian Indians;
+on the proportion of the sexes among Amazonian butterflies; on sexual
+differences in the wings of butterflies; on the field-cricket; on
+Pyrodes pulcherrimus; on the horns of Lamellicorn beetles; on the
+colours of Epicaliae, etc.; on the coloration of tropical butterflies;
+on the variability of Papilio Sesostris and Childrenae; on male and
+female butterflies inhabiting different stations; on mimicry; on the
+caterpillar of a Sphinx; on the vocal organs of the umbrella-bird; on
+the toucans; on Brackyurus calvus.
+
+Batokas, knocking out two upper incisors.
+
+Batrachia, eagerness of male.
+
+Bats, scent-glands; sexual differences in the colour of; fur of male
+frugivorous.
+
+Battle, law of; among beetles; among birds; among mammals; in man.
+
+Beak, sexual difference in the forms of the; in the colour of the.
+
+Beaks, of birds, bright colours of.
+
+Beard, development of, in man; analogy of the, in man and the
+quadrumana; variation of the development of the, in different races of
+men; estimation of, among bearded nations; probable origin of the.
+
+Beard, in monkeys; of mammals.
+
+Beautiful, taste for the, in birds; in the quadrumana.
+
+Beauty, sense of, in animals; appreciation of, by birds; influence of;
+variability of the standard of.
+
+Beauty, sense of, sufficiently permanent for action of sexual selection.
+
+Beaven, Lieut., on the development of the horns in Cervus Eldi.
+
+Beaver, instinct and intelligence of the; voice of the; castoreum of
+the.
+
+Beavers, battles of male.
+
+Bechstein, on female birds choosing the best singers among the males;
+on rivalry in song-birds; on the singing of female birds; on birds
+acquiring the songs of other birds; on pairing the canary and siskin; on
+a sub-variety of the monk pigeon; on spurred hens.
+
+Beddoe, Dr., on causes of difference in stature.
+
+Bee-eater.
+
+Bees, pollen-baskets and stings of; destruction of drones and queens by;
+female, secondary sexual characters of; proportion of sexes; difference
+of the sexes in colour and sexual selection.
+
+Beetle, luminous larva of a.
+
+Beetles, size of the cerebral ganglia in; dilatation of the foretarsi in
+male; blind; stridulation of.
+
+Belgium, ancient inhabitants of.
+
+Bell, Sir C., on emotional muscles in man; "snarling muscles;" on the
+hand.
+
+Bell, T., on the numerical proportion of the sexes in moles; on the
+newts; on the croaking of the frog; on the difference in the coloration
+of the sexes in Zootoca vivipara; on moles fighting.
+
+Bell-bird, sexual difference in the colour of the.
+
+Bell-birds, colours of.
+
+Belt, Mr., on the nakedness of tropical mankind; on a spider-monkey
+and eagle; habits of ants; Lampridae distasteful to mammals; mimicry of
+Leptalides; colours of Nicaraguan frogs; display of humming-birds; on
+the toucans; protective colouring of skunk.
+
+Benevolence, manifested by birds.
+
+Bennett, A.W., attachment of mated birds; on the habits of Dromaeus
+irroratus.
+
+Bennett, Dr., on birds of paradise.
+
+Berbers, fertility of crosses with other races.
+
+Bernicla antarctica, colours of.
+
+Bernicle gander pairing with a Canada goose.
+
+Bert, M., crustaceans distinguish colours.
+
+Bettoni, E., on local differences in the nests of Italian birds.
+
+Beyle, M., see Bombet.
+
+Bhoteas, colour of the beard in.
+
+Bhringa, disc-formed tail-feathers of.
+
+Bianconi, Prof., on structures as explained through mechanical
+principles.
+
+Bibio, sexual differences in the genus.
+
+Bichat, on beauty.
+
+Bickes, proportion of sexes in man.
+
+Bile, coloured, in many animals.
+
+Bimana.
+
+Birds, imitations of the songs of other birds by; dreaming; killed
+by telegraph wires; language of; sense of beauty in; pleasure of, in
+incubation; male, incubation by; and reptiles, alliance of; sexual
+differences in the beak of some; migratory, arrival of the male before
+the female; apparent relation between polygamy and marked sexual
+differences in; monogamous, becoming polygamous under domestication;
+eagerness of male in pursuit of the female; wild, numerical proportion
+of the sexes in; secondary sexual characters of; difference of size in
+the sexes of; fights of male, witnessed by females; display of male,
+to captivate the females; close attention of, to the songs of others;
+acquiring the song of their foster-parents; brilliant, rarely good
+songsters; love-antics and dances of; coloration of; moulting of;
+unpaired; male, singing out of season; mutual affection of; in
+confinement, distinguish persons; hybrid, production of; Albino;
+European, number of species of; variability of; geographical
+distribution of colouring; gradation of secondary sexual characters in;
+obscurely coloured, building concealed nests; young female, acquiring
+male characters; breeding in immature plumage; moulting of; aquatic,
+frequency of white plumage in; vocal courtship of; naked skin of the
+head and neck in.
+
+Birgus latro, habits of.
+
+Birkbeck, Mr., on the finding of new mates by golden eagles.
+
+Birthplace of man.
+
+Births, numerical proportions of the sexes in, in animals and man; male
+and female, numerical proportion of, in England.
+
+Bischoff, Prof., on the agreement between the brains of man and of the
+orang; figure of the embryo of the dog; on the convolutions of the brain
+in the human foetus; on the difference between the skulls of man and the
+quadrumana; resemblance between the ape's and man's.
+
+Bishop, J., on the vocal organs of frogs; on the vocal organs of cervine
+birds; on the trachea of the Merganser.
+
+Bison, American, co-operation of; mane of the male.
+
+Bitterns, dwarf, coloration of the sexes of.
+
+Biziura lobata, musky odour of the male; large size of male.
+
+Blackbird, sexual differences in the; proportion of the sexes in the;
+acquisition of a song by; colour of the beak in the sexes of the;
+pairing with a thrush; colours and nidification of the; young of the;
+sexual difference in coloration of the.
+
+Black-buck, Indian, sexual difference in the colour of the.
+
+Blackcap, arrival of the male, before the female; young of the.
+
+Black-cock, polygamous; proportion of the sexes in the; pugnacity
+and love-dance of the; call of the; moulting of the; duration of
+the courtship of the; and pheasant, hybrids of; sexual difference in
+coloration of the; crimson eye-cere of the.
+
+Black-grouse, characters of young.
+
+Blacklock, Dr., on music.
+
+Blackwall, J., on the speaking of the magpie; on the desertion of their
+young by swallows; on the superior activity of male spiders; on the
+proportion of the sexes in spiders; on sexual variation of colour in
+spiders; on male spiders.
+
+Bladder-nose Seal, hood of the.
+
+Blaine, on the affections of dogs.
+
+Blair, Dr., on the relative liability of Europeans to yellow fever.
+
+Blake, C.C., on the jaw from La Naulette.
+
+Blakiston, Captain, on the American snipe; on the dances of Tetrao
+phasianellus.
+
+Blasius, Dr., on the species of European birds.
+
+Bledius taurus, hornlike processes of male.
+
+Bleeding, tendency to profuse.
+
+Blenkiron, Mr., on sexual preference in horses.
+
+Blennies, crest developed on the head of male, during the breeding
+season.
+
+Blethisa multipunctata, stridulation of.
+
+Bloch, on the proportions of the sexes in fishes.
+
+Blood, arterial, red colour of.
+
+Blood pheasant, number of spurs in.
+
+Blow-fly, sounds made by.
+
+Bluebreast, red-throated, sexual differences of the.
+
+Blumenbach, on Man; on the large size of the nasal cavities in American
+aborigines; on the position of man; on the number of species of man.
+
+Blyth, E., on the structure of the hand in the species of Hylobates;
+observations on Indian crows; on the development of the horns in the
+Koodoo and Eland antelopes; on the pugnacity of the males of
+Gallicrex cristatus; on the presence of spurs in the female Euplocamus
+erythrophthalmus; on the pugnacity of the amadavat; on the spoonbill; on
+the moulting of Anthus; on the moulting of bustards, plovers, and Gallus
+bankiva; on the Indian honey-buzzard; on sexual differences in
+the colour of the eyes of hornbills; on Oriolus melanocephalus; on
+Palaeornis javanicus; on the genus Ardetta; on the peregrine falcon; on
+young female birds acquiring male characters; on the immature plumage
+of birds; on representative species of birds; on the young of Turnix; on
+anomalous young of Lanius rufus and Colymbus glacialis; on the sexes
+and young of the sparrows; on dimorphism in some herons; on the
+ascertainment of the sex of nestling bullfinches by pulling out
+breast-feathers; on orioles breeding in immature plumage; on the sexes
+and young of Buphus and Anastomus; on the young of the blackcap and
+blackbird; on the young of the stonechat; on the white plumage of
+Anastomus; on the horns of Bovine animals; on the horns of Antilope
+bezoartica; on the mode of fighting of Ovis cycloceros; on the voice
+of the Gibbons; on the crest of the male wild goat; on the colours of
+Portax picta; on the colours of Antilope bezoartica; on the colour of
+the Axis deer; on sexual difference of colour in Hylobates hoolock; on
+the hog-deer; on the beard and whiskers in a monkey, becoming white with
+age.
+
+Boar, wild, polygamous in India; use of the tusks by the; fighting of.
+
+Boardman, Mr., Albino birds in U.S.
+
+Boitard and Corbie, MM., on the transmission of sexual peculiarities in
+pigeons; on the antipathy shewn by some female pigeons to certain males.
+
+Bold, Mr., on the singing of a sterile hybrid canary.
+
+Bombet, on the variability of the standard of beauty in Europe.
+
+Bombus, difference of the sexes in.
+
+Bombycidae, coloration of; pairing of the; colours of.
+
+Bombycilla carolinensis, red appendages of.
+
+Bombyx cynthia, proportion of the sexes in; pairing of.
+
+Bombyx mori, difference of size of the male and female cocoons of;
+pairing of.
+
+Bombyx Pernyi, proportion of sexes of.
+
+Bombyx Yamamai, M. Personnat on; proportion of sexes of.
+
+Bonaparte, C.L., on the call-notes of the wild turkey.
+
+Bond, F., on the finding of new mates by crows.
+
+Bone, implements of, skill displayed in making.
+
+Boner, C., on the transfer of male characters to an old female chamois;
+on the habits of stags; on the pairing of red deer.
+
+Bones, increase of, in length and thickness, when carrying a greater
+weight.
+
+Bonizzi, P., difference of colour in sexes of pigeons.
+
+Bonnet monkey.
+
+Bonwick, J., extinction of Tasmanians.
+
+Boomerang.
+
+Boreus hyemalis, scarcity of the male.
+
+Bory St. Vincent, on the number of species of man; on the colours of
+Labrus pavo.
+
+Bos etruscus.
+
+Bos gaurus, horns of.
+
+Bos moschatus.
+
+Bos primigenius.
+
+Bos sondaicus, horns of, colours of.
+
+Botocudos, mode of life of; disfigurement of the ears and lower lip of
+the.
+
+Boucher de Perthes, J.C. de, on the antiquity of man.
+
+Bourbon, proportion of the sexes in a species of Papilio from.
+
+Bourien on the marriage-customs of the savages of the Malay Archipelago.
+
+Bovidae, dewlaps of.
+
+Bower-birds, habits of the; ornamented playing-places of.
+
+Bows, use of.
+
+Brachycephalic structure, possible explanation of.
+
+Brachyura.
+
+Brachyurus calvus, scarlet face of.
+
+Bradley, Mr., abductor ossis metatarsi quinti in man.
+
+Brain, of man, agreement of the, with that of lower animals;
+convolutions of, in the human foetus; influence of development of mental
+faculties upon the size of the; influence of the development of on the
+spinal column and skull; larger in some existing mammals than in their
+tertiary prototypes; relation of the development of the, to the progress
+of language; disease of the, affecting speech; difference in the
+convolutions of, in different races of men; supplement on, by Prof.
+Huxley; development of the gyri and sulci.
+
+Brakenridge, Dr., on the influence of climate.
+
+Brandt, A., on hairy men.
+
+Braubach, Prof., on the quasi-religious feeling of a dog towards his
+master; on the self-restraint of dogs.
+
+Brauer, F., on dimorphism in Neurothemis.
+
+Brazil, skulls found in caves of; population of; compression of the nose
+by the natives of.
+
+Break between man and the apes.
+
+Bream, proportion of the sexes in the.
+
+Breeding, age of, in birds.
+
+Breeding season, sexual characters making their appearance in the, in
+birds.
+
+Brehm, on the effects of intoxicating liquors on monkeys; on the
+recognition of women by male Cynocephali; on the diversity of the mental
+faculties of monkeys; on the habits of baboons; on revenge taken by
+monkeys; on manifestations of maternal affection by monkeys and baboons;
+on the instinctive dread of monkeys for serpents; on the use of stones
+as missiles by baboons; on a baboon using a mat for shelter from the
+sun; on the signal-cries of monkeys; on sentinels posted by monkeys; on
+co-operation of animals; on an eagle attacking a young Cercopithecus; on
+baboons in confinement protecting one of their number from punishment;
+on the habits of baboons when plundering; on polygamy in Cynocephalus
+and Cebus; on the numerical proportion of the sexes in birds; on the
+love-dance of the blackcock; Palamedea cornuta; on the habits of the
+Black-grouse; on sounds produced by birds of paradise; on assemblages
+of grouse; on the finding of new mates by birds; on the fighting of wild
+boars; on sexual differences in Mycetes; on the habits of Cynocephalus
+hamadryas.
+
+Brent, Mr., on the courtship of fowls.
+
+Breslau, numerical proportion of male and female births in.
+
+Bridgeman, Laura.
+
+Brimstone butterfly, sexual difference of colour in the.
+
+British, ancient, tattooing practised by.
+
+Broca, Prof., on the occurrence of the supra-condyloid foramen in the
+human humerus; anthropomorphous apes more bipedal than quadrupedal;
+on the capacity of Parisian skulls at different periods; comparison of
+modern and mediaeval skulls; on tails of quadrupeds; on the influence
+of natural selection; on hybridity in man; on human remains from Les
+Eyzies; on the cause of the difference between Europeans and Hindoos.
+
+Brodie, Sir B., on the origin of the moral sense in man.
+
+Bronn, H.G., on the copulation of insects of distinct species.
+
+Bronze period, men of, in Europe.
+
+Brown, R., sentinels of seals generally females; on the battles of
+seals; on the narwhal; on the occasional absence of the tusks in the
+female walrus; on the bladder-nose seal; on the colours of the sexes
+in Phoca Groenlandica; on the appreciation of music by seals; on plants
+used as love-philters, by North American women.
+
+Browne, Dr. Crichton, injury to infants during parturition.
+
+Brown-Sequard, Dr., on the inheritance of the effects of operations by
+guinea-pig.
+
+Bruce, on the use of the elephant's tusks.
+
+Brulerie, P. de la, on the habits of Ateuchus cicatricosus; on the
+stridulation of Ateuchus.
+
+Brunnich, on the pied ravens of the Feroe islands.
+
+Bryant, Dr., preference of tame pigeon for wild mate.
+
+Bryant, Captain, on the courtship of Callorhinus ursinus.
+
+Bubas bison, thoracic projection of.
+
+Bubalus caffer, use of horns.
+
+Bucephalus capensis, difference of the sexes of, in colour.
+
+Buceros, nidification and incubation of.
+
+Buceros bicornis, sexual differences in the colouring of the casque,
+beak, and mouth in.
+
+Buceros corrugatus, sexual differences in the beak of.
+
+Buchner, L., on the origin of man; on the use of the human foot as a
+prehensile organ; on the mode of progression of the apes; on want of
+self-consciousness, etc., in savages.
+
+Bucholz, Dr., quarrels of chamaeleons.
+
+Buckinghamshire, numerical proportion of male and female births in.
+
+Buckland, F., on the numerical proportion of the sexes in rats; on the
+proportion of the sexes in the trout; on Chimaera monstrosa.
+
+Buckland, W., on the complexity of crinoids.
+
+Buckler, W., proportion of sexes of Lepidoptera reared by.
+
+Bucorax abyssinicus, inflation of the neck-wattle of the male during
+courtship.
+
+Budytes Raii.
+
+Buffalo, Cape.
+
+Buffalo, Indian, horns of the.
+
+Buffalo, Italian, mode of fighting of the.
+
+Buffon, on the number of species of man.
+
+Bufo sikimmensis.
+
+Bugs.
+
+Buist, R., on the proportion of the sexes in salmon; on the pugnacity of
+the male salmon.
+
+Bulbul, pugnacity of the male; display of under tail-coverts by the
+male.
+
+Bull, mode of fighting of the; curled frontal hair of the.
+
+Buller, Dr., on the Huia; the attachment of birds.
+
+Bullfinch, sexual differences in the; piping; female, singing of the;
+courtship of the; widowed, finding a new mate; attacking a reed-bunting;
+nestling, sex ascertained by pulling out breast feathers.
+
+Bullfinches, distinguishing persons; rivalry of female.
+
+Bulls, two young, attacking an old one; wild, battles of.
+
+Bull-trout, male, colouring of, during the breeding season.
+
+Bunting, reed, head feathers of the male; attacked by a bullfinch.
+
+Buntings, characters of young.
+
+Buphus coromandus, sexes and young of; change of colour in.
+
+Burchell, Dr., on the zebra; on the extravagance of a Bushwoman in
+adorning herself; celibacy unknown among the savages of South Africa; on
+the marriage-customs of the Bushwomen.
+
+Burke, on the number of species of man.
+
+Burmese, colour of the beard in.
+
+Burton, Captain, on negro ideas of female beauty; on a universal ideal
+of beauty.
+
+Bushmen, marriage among.
+
+Bushwoman, extravagant ornamentation of a.
+
+Bushwomen, hair of; marriage-customs of.
+
+Bustard, throat-pouch of the male; humming noise produced by a male;
+Indian, ear-tufts of.
+
+Bustards, occurrence of sexual differences and of polygamy among the;
+love-gestures of the male; double moult in.
+
+Butler, A.G., on sexual differences in the wings of Aricoris epitus;
+courtship of butterflies; on the colouring of the sexes in species
+of Thecla; on the resemblance of Iphias glaucippe to a leaf; on the
+rejection of certain moths and caterpillars by lizards and frogs.
+
+Butterfly, noise produced by a; Emperor; meadow brown, instability of
+the ocellated spots of.
+
+Butterflies, proportion of the sexes in; forelegs atrophied in some
+males; sexual difference in the neuration of the wings of; pugnacity of
+male; protective resemblances of the lower surface of; display of the
+wings by; white, alighting upon bits of paper; attracted by a dead
+specimen of the same species; courtship of; male and female, inhabiting
+different stations.
+
+Buxton, C., observations on macaws; on an instance of benevolence in a
+parrot.
+
+Buzzard, Indian honey-; variation in the crest of.
+
+Cabbage butterflies.
+
+Cachalot, large head of the male.
+
+Cadences, musical, perception of, by animals.
+
+Caecum, large, in the early progenitors of man.
+
+Cairina moschata, pugnacity of the male.
+
+Californian Indians, decrease of.
+
+Callianassa, chelae of, figured.
+
+Callidryas, colours of sexes.
+
+Callionymus lyra, characters of the male.
+
+Callorhinus ursinus, relative size of the sexes of; courtship of.
+
+Calotes maria.
+
+Calotes nigrilabris, sexual difference in the colour of.
+
+Cambridge, O. Pickard, on the sexes of spiders; on the size of male
+Nephila.
+
+Camel, canine teeth of male.
+
+Campbell, J., on the Indian elephant; on the proportion of male and
+female births in the harems of Siam.
+
+Campylopterus hemileucurus.
+
+Canaries distinguishing persons.
+
+Canary, polygamy of the; change of plumage in, after moulting; female,
+selecting the best singing male; sterile hybrid, singing of a; female,
+singing of the; selecting a greenfinch; and siskin, pairing of.
+
+Cancer pagurus.
+
+Canestrini, G., on rudimentary characters and the origin of man; on
+rudimentary characters; on the movement of the ear in man; of the
+variability of the vermiform appendage in man; on the abnormal division
+of the malar bone in man; on abnormal conditions of the human uterus; on
+the persistence of the frontal suture in man; on the proportion of the
+sexes in silk-moths; secondary sexual characters of spiders.
+
+Canfield, Dr., on the horns of the Antilocapra.
+
+Canine teeth in man, diminution of, in man; diminution of, in horses;
+disappearance of, in male ruminants; large in the early progenitors of
+man.
+
+Canines, and horns, inverse development of.
+
+Canoes, use of.
+
+Cantharis, difference of colour in the sexes of a species of.
+
+Cantharus lineatus.
+
+Capercailzie, polygamous; proportion of the sexes in the; pugnacity of
+the male; pairing of the; autumn meetings of the; call of the; duration
+of the courtship of; behaviour of the female; inconvenience of black
+colour to the female; sexual difference in the coloration of the;
+crimson eye-cere of the male.
+
+Capitonidae, colours and nidification of the.
+
+Capra aegagrus, crest of the male; sexual difference in the colour of.
+
+Capreolus Sibiricus subecaudatus.
+
+Caprice, common to man and animals.
+
+Caprimulgus, noise made by the males of some species of, with their
+wings.
+
+Caprimulgus virginianus, pairing of.
+
+Carabidae.
+
+Carbonnier, on the natural history of the pike; on the relative size of
+the sexes in fishes; courtship of Chinese Macropus.
+
+Carcineutes, sexual difference of colour in.
+
+Carcinus moenas.
+
+Cardinalis virginianus.
+
+Carduelis elegans, sexual differences of the beak in.
+
+Carnivora, marine, polygamous habits of; sexual differences in the
+colours of.
+
+Carp, numerical proportion of the sexes in the.
+
+Carr, R., on the peewit.
+
+Carrier pigeon, late development of the wattle in the.
+
+Carrion beetles, stridulation of.
+
+Carrion-hawk, bright coloured female of.
+
+Carus, Prof. V., on the development of the horns in merino sheep; on
+antlers of red deer.
+
+Cassowary, sexes and incubation of the.
+
+Castnia, mode of holding wings.
+
+Castoreum.
+
+Castration, effects of.
+
+Casuarius galeatus.
+
+Cat, convoluted body in the extremity of the tail of a; sick, sympathy
+of a dog with a.
+
+Cataract in Cebus Azarae.
+
+Catarrh, liability of Cebus Azarae to.
+
+Catarrhine monkeys.
+
+Caterpillars, bright colours of.
+
+Cathartes aura.
+
+Cathartes jota, love-gestures of the male.
+
+Catlin, G., correlation of colour and texture of hair in the Mandans;
+on the development of the beard among the North American Indians; on the
+great length of the hair in some North American tribes.
+
+Caton, J.D., on the development of the horns in Cervus virginianus and
+strongyloceros; on the wild turkey; on the presence of traces of horns
+in the female wapiti; on the fighting of deer; on the crest of the male
+wapiti; on the colours of the Virginian deer; on sexual differences of
+colour in the wapiti; on the spots of the Virginian deer.
+
+Cats, dreaming; tortoise-shell; enticed by valerian; colours of.
+
+Cattle, rapid increase of, in South America; domestic, lighter in winter
+in Siberia; horns of; domestic, sexual differences of, late developed;
+numerical proportion of the sexes in.
+
+Caudal vertebrae, number of, in macaques and baboons; basal, of monkeys,
+imbedded in the body.
+
+Cavolini, observations on Serranus.
+
+Cebus, maternal affection in a; gradation of species of.
+
+Cebus Apella.
+
+Cebus Azarae, liability of, to the same diseases as man; distinct sounds
+produced by; early maturity of the female.
+
+Cebus capucinus, polygamous; sexual differences of colour in; hair on
+the head of.
+
+Cebus vellerosus, hair on the head of.
+
+Cecidomyiidae, proportions of the sexes in.
+
+Celibacy, unknown among the savages of South Africa and South America.
+
+Centipedes.
+
+Cephalopoda, absence of secondary sexual characters in.
+
+Cephalopterus ornatus.
+
+Cephalopterus penduliger.
+
+Cerambyx heros, stridulant organ of.
+
+Ceratodus, paddle of.
+
+Ceratophora aspera, nasal appendages of.
+
+Ceratophora Stoddartii, nasal horn of.
+
+Cerceris, habits of.
+
+Cercocebus aethiops, whiskers, etc., of.
+
+Cercopithecus, young, seized by an eagle and rescued by the troop;
+definition of species of.
+
+Cercopithecus cephus, sexual difference of colour in.
+
+Cercopithecus cynosurus and griseo-viridis, colour of the scrotum in.
+
+Cercopithecus Diana, sexual differences of colour in.
+
+Cercopithecus griseo-viridis.
+
+Cercopithecus petaurista, whiskers, etc., of.
+
+Ceres, of birds, bright colours of.
+
+Ceriornis Temminckii, swelling of the wattles of the male during
+courtship.
+
+Cervulus, weapons of.
+
+Cervulus moschatus, rudimentary horns of the female.
+
+Cervus alces.
+
+Cervus campestris, odour of.
+
+Cervus canadensis, traces of horns in the female; attacking a man;
+sexual difference in the colour of.
+
+Cervus elaphus, battles of male; horns of, with numerous points; long
+hairs on the throat of.
+
+Cervus Eldi.
+
+Cervus mantchuricus.
+
+Cervus paludosus, colours of.
+
+Cervus strongyloceros.
+
+Cervus virginianus, horns of, in course of modification.
+
+Ceryle, male black-belted in some species of.
+
+Cetacea, nakedness of.
+
+Ceylon, frequent absence of beard in the natives of.
+
+Chaffinch, proportion of the sexes in the; courtship of the.
+
+Chaffinches, new mates found by.
+
+Chalcophaps indicus, characters of young.
+
+Chalcosoma atlas, sexual differences of.
+
+Chamaeleo, sexual differences in the genus; combats of.
+
+Chamaeleo bifurcus.
+
+Chamaeleo Owenii.
+
+Chamaeleo pumilus.
+
+Chamaepetes unicolor, modified wing-feather in the male.
+
+Chameleons.
+
+Chamois, danger-signals of; transfer of male characters to an old
+female.
+
+Champneys, Mr., acromio-basilar muscle and quadrupedal gait.
+
+Chapman, Dr., on stridulation in Scolytus.
+
+Chapuis, Dr., on the transmission of sexual peculiarities in pigeons; on
+streaked Belgian pigeons.
+
+Char, male, colouring of, during the breeding season.
+
+Characters, male, developed in females; secondary sexual, transmitted
+through both sexes; natural, artificial, exaggeration of, by man.
+
+Charadrus hiaticula and pluvialis, sexes and young of.
+
+Chardin on the Persians.
+
+Charms, worn by women.
+
+Charruas, freedom of divorce among the.
+
+Chasmorhynchus, difference of colour in the sexes of; colours of.
+
+Chasmorhynchus niveus.
+
+Chasmorhynchus nudicollis.
+
+Chasmorhynchus tricarunculatus.
+
+Chastity, early estimation of.
+
+Chatterers, sexual differences in.
+
+Cheever, Rev. H.T., census of the Sandwich Islands.
+
+Cheiroptera, absence of secondary sexual characters in.
+
+Chelae of crustacea.
+
+Chelonia, sexual differences in.
+
+Chenalopex aegyptiacus, wing-knobs of.
+
+Chera progne.
+
+Chest, proportions of, in soldiers and sailors; large, of the Quechua
+and Aymara Indians.
+
+Chevrotains, canine teeth of.
+
+Chiasognathus, stridulation of.
+
+Chiasognathus Grantii, mandibles of.
+
+Children, legitimate and illegitimate, proportion of the sexes in.
+
+Chiloe, lice of the natives of; population of.
+
+Chimaera monstrosa, bony process on the head of the male.
+
+Chimaeroid fishes, prehensile organs of male.
+
+Chimpanzee, ears of the; representatives of the eyebrows in the; hands
+of the; absence of mastoid processes in the; platforms built by the;
+cracking nuts with a stone; direction of the hair on the arms of the;
+supposed evolution of the; polygamous and social habits of the.
+
+China, North, idea of female beauty in.
+
+China, Southern, inhabitants of.
+
+Chinese, use of flint tools by the; difficulty of distinguishing the
+races of the; colour of the beard in; general beardlessness of
+the; opinions of the, on the appearance of Europeans and Cingalese;
+compression of the feet of.
+
+Chinsurdi, his opinion of beards.
+
+Chlamydera maculata.
+
+Chloeon, pedunculated eyes of the male of.
+
+Chloephaga, coloration of the sexes in.
+
+Chlorocoelus Tanana.
+
+Chorda dorsalis.
+
+Chough, red beak of the.
+
+Chromidae, frontal protuberance in male; sexual differences in colour
+of.
+
+Chrysemys picta, long claws of the male.
+
+Chrysococcyx, characters of young of.
+
+Chrysomelidae, stridulation of.
+
+Cicada pruinosa.
+
+Cicada septendecim.
+
+Cicadae, songs of the; rudimentary sound-organs in females of.
+
+Cicatrix of a burn, causing modification of the facial bones.
+
+Cichla, frontal protuberance of male.
+
+Cimetiere du Sud, Paris.
+
+Cincloramphus cruralis, large size of male.
+
+Cinclus aquaticus.
+
+Cingalese, Chinese opinion of the appearance of the.
+
+Cirripedes, complemental males of.
+
+Civilisation, effects of, upon natural selection; influence of, in the
+competition of nations.
+
+Clanging of geese, etc.
+
+Claparede, E., on natural selection applied to man.
+
+Clarke, on the marriage-customs of Kalmucks.
+
+Classification.
+
+Claus, C., on the sexes of Saphirina.
+
+Cleft-palate, inherited.
+
+Climacteris erythrops, sexes of.
+
+Climate, cool, favourable to human progress; power of supporting
+extremes of, by man; want of connexion of, with colour; direct action
+of, on colours of birds.
+
+Cloaca, existence of a, in the early progenitors of man.
+
+Cloacal passage existing in the human embryo.
+
+Clubs, used as weapons before dispersion of mankind.
+
+Clucking of fowls.
+
+Clythra 4-punctata, stridulation of.
+
+Coan, Mr., Sandwich-islanders.
+
+Cobbe, Miss, on morality in hypothetical bee-community.
+
+Cobra, ingenuity of a.
+
+Coccus.
+
+Coccyx, in the human embryo; convoluted body at the extremity of the;
+imbedded in the body.
+
+Cochin-China, notions of beauty of the inhabitants of.
+
+Cock, blind, fed by its companion; game, killing a kite; comb and
+wattles of the; preference shewn by the, for young hens; game,
+transparent zone in the hackles of a.
+
+Cock of the rock.
+
+Cockatoos, nestling; black, immature plumage of.
+
+Coelenterata, absence of secondary sexual characters in.
+
+Coffee, fondness of monkeys for.
+
+Cold, supposed effects of; power of supporting, by man.
+
+Coleoptera, stridulation of; stridulant organs of, discussed.
+
+Colias edusa and hyale.
+
+Collingwood, C., on the pugnacity of the butterflies of Borneo; on
+butterflies being attracted by a dead specimen of the same species.
+
+Colobus, absence of the thumb.
+
+Colombia, flattened heads of savages of.
+
+Colonists, success of the English as.
+
+Coloration, protective, in birds.
+
+Colour, supposed to be dependent on light and heat; correlation of, with
+immunity from certain poisons and parasites; purpose of, in lepidoptera;
+relation of, to sexual functions, in fishes; difference of, in the
+sexes of snakes; sexual differences of, in lizards; influence of, in
+the pairing of birds of different species; relation of, to nidification;
+sexual differences of, in mammals; recognition of, by quadrupeds; of
+children, in different races of man; of the skin in man.
+
+Colours, admired alike by man and animals; bright, due to sexual
+selection; bright, among the lower animals; bright, protective to
+butterflies and moths; bright, in male fishes; transmission of, in
+birds.
+
+Colquhoun, example of reasoning in a retriever.
+
+Columba passerina, young of.
+
+Colymbus glacialis, anomalous young of.
+
+Comb, development of, in fowls.
+
+Combs and wattles in male birds.
+
+Community, preservation of variations useful to the, by natural
+selection.
+
+Complexion, different in men and women, in an African tribe.
+
+Compositae, gradation of species among the.
+
+Comte, C., on the expression of the ideal of beauty by sculpture.
+
+Conditions of life, action of changed, upon man; influence of, on
+plumage of birds.
+
+Condor, eyes and comb of the.
+
+Conjugations, origin of.
+
+Conscience, absence of, in some criminals.
+
+Constitution, difference of, in different races of men.
+
+Consumption, liability of Cebus Azarae to; connection between complexion
+and.
+
+Convergence of characters.
+
+Cooing of pigeons and doves.
+
+Cook, Captain, on the nobles of the Sandwich Islands.
+
+Cope, E.D., on the Dinosauria.
+
+Cophotis ceylanica, sexual differences of.
+
+Copris.
+
+Copris Isidis, sexual differences of.
+
+Copris lunaris, stridulation of.
+
+Corals, bright colours of.
+
+Coral-snakes.
+
+Cordylus, sexual difference of colour in a species of.
+
+Corfu, habits of the Chaffinch in.
+
+Cornelius, on the proportions of the sexes in Lucanus Cervus.
+
+Corpora Wolffiana, agreement of, with the kidneys of fishes.
+
+Correlated variation.
+
+Correlation, influence of, in the production of races.
+
+Corse, on the mode of fighting of the elephant.
+
+Corvus corone.
+
+Corvus graculus, red beak of.
+
+Corvus pica, nuptial assembly of.
+
+Corydalis cornutus, large jaws of the male.
+
+Cosmetornis.
+
+Cosmetornis vexillarius, elongation of wing-feathers in.
+
+Cotingidae, sexual differences in; coloration of the sexes of;
+resemblance of the females of distinct species of.
+
+Cottus scorpius, sexual differences in.
+
+Coulter, Dr., on the Californian Indians.
+
+Counting, origin of; limited power of, in primeval man.
+
+Courage, variability of, in the same species; universal high
+appreciation of; importance of; characteristic of men.
+
+Courtship, greater eagerness of males in; of fishes; of birds.
+
+Cow, winter change of colour.
+
+Crab, devil.
+
+Crab, shore, habits of.
+
+Crabro cribrarius, dilated tibiae of the male.
+
+Crabs, proportions of the sexes in.
+
+Cranz, on the inheritance of dexterity in seal-catching.
+
+Crawfurd, on the number of species of man.
+
+Crenilabrus massa and C. melops, nests, built by.
+
+Crest, origin of, in Polish fowls.
+
+Crests, of birds, difference of, in the sexes; dorsal hairy, of mammals.
+
+Cricket, field-, stridulation of the; pugnacity of male.
+
+Cricket, house-, stridulation of the.
+
+Crickets, sexual differences in.
+
+Crinoids, complexity of.
+
+Crioceridae, stridulation of the.
+
+Croaking of frogs.
+
+Crocodiles, musky odour of, during the breeding season.
+
+Crocodilia.
+
+Crossbills, characters of young.
+
+Crosses in man.
+
+Crossing of races, effects of the.
+
+Crossoptilon auritum, adornment of both sexes of; sexes alike in.
+
+Crotch, G.R., on the stridulation of beetles; on the stridulation of
+Heliopathes; on the stridulation of Acalles; habit of female deer at
+breeding time.
+
+Crow, Indians, long hair of the.
+
+Crow, young of the.
+
+Crows, vocal organs of the; living in triplets.
+
+Crows, carrion, new mates found by.
+
+Crows, Indian, feeding their blind companions.
+
+Cruelty of savages to animals.
+
+Crustacea, parasitic, loss of limbs by female; prehensile feet and
+antennae of; male, more active than female; parthenogenesis in;
+secondary sexual characters of; amphipod, males sexually mature while
+young; auditory hairs of.
+
+Crystal worn in the lower lip by some Central African women.
+
+Cuckoo fowls.
+
+Culicidae, attracted by each other's humming.
+
+Cullen, Dr., on the throat-pouch of the male bustard.
+
+Cultivation of plants, probable origin of.
+
+Cupples, Mr., on the numerical proportion of the sexes in dogs, sheep,
+and cattle; on the Scotch deerhound; on sexual preference in dogs.
+
+Curculionidae, sexual difference in length of snout in some; hornlike
+processes in male; musical.
+
+Curiosity, manifestations of, by animals.
+
+Curlews, double moult in.
+
+Cursores, comparative absence of sexual differences among the.
+
+Curtis, J., on the proportion of the sexes in Athalia.
+
+Cuvier, F., on the recognition of women by male quadrumana.
+
+Cuvier, G., on the number of caudal vertebrae in the mandrill; on
+instinct and intelligence; views of, as to the position of man; on the
+position of the seals; on Hectocotyle.
+
+Cyanalcyon, sexual difference in colours of; immature plumage of.
+
+Cyanecula suecica, sexual differences of.
+
+Cychrus, sounds produced by.
+
+Cycnia mendica, sexual difference of, in colour.
+
+Cygnus ferus, trachea of.
+
+Cygnus immutabilis.
+
+Cygnus olor, white young of.
+
+Cyllo Leda, instability of the ocellated spots of.
+
+Cynanthus, variation in the genus.
+
+Cynipidae, proportion of the sexes in.
+
+Cynocephalus, difference of the young from the adult; male, recognition
+of women by; polygamous habits of species of.
+
+Cynocephalus babouin.
+
+Cynocephalus chacma.
+
+Cynocephalus gelada.
+
+Cynocephalus hamadryas, sexual difference of colour in.
+
+Cynocephalus leucophaeus, colours of the sexes of.
+
+Cynocephalus mormon, colours of the male.
+
+Cynocephalus porcarius, mane of the male.
+
+Cynocephalus sphinx.
+
+Cynopithecus niger, ear of.
+
+Cypridina, proportions of the sexes in.
+
+Cyprinidae, proportion of the sexes in the.
+
+Cyprinidae, Indian.
+
+Cyprinodontidae, sexual differences in the.
+
+Cyprinus auratus.
+
+Cypris, relation of the sexes in.
+
+Cyrtodactylus rubidus.
+
+Cystophora cristata, hood of.
+
+Dacelo, sexual difference of colour in.
+
+Dacelo Gaudichaudi, young male of.
+
+Dal-ripa, a kind of ptarmigan.
+
+Damalis albifrons, peculiar markings of.
+
+Damalis pygarga, peculiar markings of.
+
+Dampness of climate, supposed influence of, on the colour of the skin.
+
+Danaidae.
+
+Dances of birds.
+
+Dancing, universality of.
+
+Danger-signals of animals.
+
+Daniell, Dr., his experience of residence in West Africa.
+
+Darfur, protuberances artificially produced by natives of.
+
+Darwin, F., on the stridulation of Dermestes murinus.
+
+Dasychira pudibunda, sexual difference of colour in.
+
+Davis, A.H., on the pugnacity of the male stag-beetle.
+
+Davis, J.B., on the capacity of the skull in various races of men; on
+the beards of the Polynesians.
+
+Death's Head Sphinx.
+
+Death-rate higher in towns than in rural districts.
+
+Death-tick.
+
+De Candolle, Alph., on a case of inherited power of moving the scalp.
+
+Declensions, origin of.
+
+Decoration in birds.
+
+Decticus.
+
+Deer, development of the horns in; spots of young; horns of; use of
+horns of; horns of a, in course of modification; size of the horns of;
+female, pairing with one male whilst others are fighting for her; male,
+attracted by the voice of the female; male, odour emitted by.
+
+Deer, Axis, sexual difference in the colour of the.
+
+Deer, fallow, different coloured herds of.
+
+Deer, Mantchurian.
+
+Deer, Virginian, colour of the, not affected by castration; colours of.
+
+Deerhound, Scotch, greater size of the male.
+
+Defensive orders of mammals.
+
+De Geer, C., on a female spider destroying a male.
+
+Dekay, Dr., on the bladder-nose seal.
+
+Delorenzi, G., division of malar bone.
+
+Demerara, yellow fever in.
+
+Dendrocygna.
+
+Dendrophila frontalis, young of.
+
+Denison, Sir W., manner of ridding themselves of vermin among the
+Australians; extinction of Tasmanians.
+
+Denny, H., on the lice of domestic animals.
+
+Dermestes murinus, stridulation of.
+
+Descent traced through the mother alone.
+
+Deserts, protective colouring of animals inhabiting.
+
+Desmarest, on the absence of suborbital pits in Antilope subgutturosa;
+on the whiskers of Macacus; on the colour of the opossum; on the colours
+of the sexes of Mus minutus; on the colouring of the ocelot; on the
+colours of seals; on Antilope caama; on the colours of goats; on sexual
+difference of colour in Ateles marginatus; on the mandrill; on Macacus
+cynomolgus.
+
+Desmoulins, on the number of species of man; on the muskdeer.
+
+Desor, on the imitation of man by monkeys.
+
+Despine, P., on criminals destitute of conscience.
+
+Development, embryonic of man; correlated.
+
+Devil, not believed in by the Fuegians.
+
+Devil-crab.
+
+Devonian, fossil-insect from the.
+
+Dewlaps, of Cattle and antelopes.
+
+Diadema, sexual differences of colouring in the species of.
+
+Diamond-beetles, bright colours of.
+
+Diastema, occurrence of, in man.
+
+Diastylidae, proportion of the sexes in.
+
+Dicrurus, racket-shaped feathers in; nidification of.
+
+Dicrurus macrocercus, change of plumage in.
+
+Didelphis opossum, sexual difference in the colour of.
+
+Differences, comparative, between different species of birds of the same
+sex.
+
+Digits, supernumerary, more frequent in men than in women;
+supernumerary, inheritance of; supernumerary, early development of.
+
+Dimorphism, in females of water-beetles; in Neurothemis and Agrion.
+
+Diodorus, on the absence of beard in the natives of Ceylon.
+
+Dipelicus Cantori, sexual differences of.
+
+Diplopoda, prehensile limbs of the male.
+
+Dipsas cynodon, sexual difference in the colour of.
+
+Diptera.
+
+Disease, generated by the contact of distinct peoples.
+
+Diseases, common to man and the lower animals; difference of liability
+to, in different races of men; new, effects of, upon savages; sexually
+limited.
+
+Display, coloration of Lepidoptera for; of plumage by male birds.
+
+Distribution, wide, of man; geographical, as evidence of specific
+distinctness in man.
+
+Disuse, effects of, in producing rudimentary organs; and use of parts,
+effects of; of parts, influence of, on the races of men.
+
+Divorce, freedom of, among the Charruas.
+
+Dixon, E.S., on the pairing of different species of geese; on the
+courtship of peafowl.
+
+Dobrizhoffer, on the marriage-customs of the Abipones.
+
+Dobson, Dr., on the Cheiroptera; scent-glands of bats; frugivorous bats.
+
+Dogs, suffering from tertian ague; memory of; dreaming; diverging when
+drawing sledges over thin ice; exercise of reasoning faculties by;
+domestic, progress of, in moral qualities; distinct tones uttered by;
+parallelism between his affection for his master and religious feeling;
+sociability of the; sympathy of, with a sick cat; sympathy of, with his
+master; their possession of conscience; possible use of the hair on the
+fore-legs of the; races of the; numerical proportion of male and female
+births in; sexual affection between individuals of; howling at certain
+notes; rolling in carrion.
+
+Dolichocephalic structure, possible cause of.
+
+Dolphins, nakedness of.
+
+Domestic animals, races of; change of breeds of.
+
+Domestication, influence of, in removing the sterility of hybrids.
+
+D'Orbigny, A., on the influence of dampness and dryness on the colour of
+the skin; on the Yuracaras.
+
+Dotterel.
+
+Doubleday, E., on sexual differences in the wings of butterflies.
+
+Doubleday, H., on the proportion of the sexes in the smaller moths;
+males of Lasiocampa quercus and on the attraction of the Saturnia
+carpini by the female; on the proportion of the sexes in the
+Lepidoptera; on the ticking of Anobium tesselatum; on the structure of
+Ageronia feronia; on white butterflies alighting upon paper.
+
+Douglas, J.W., on the sexual differences of the Hemiptera; colours of
+British Homoptera.
+
+Down, of birds.
+
+Draco, gular appendages of.
+
+Dragonet, Gemmeous.
+
+Dragon-flies, caudal appendages of male; relative size of the sexes of;
+difference in the sexes of; want of pugnacity by the male.
+
+Drake, breeding plumage of the.
+
+Dreams, possible source of the belief in spiritual agencies.
+
+Drill, sexual difference of colour in the.
+
+Dromaeus irroratus.
+
+Dromolaea, Saharan species of.
+
+Drongo shrike.
+
+Drongos, racket-shaped feathers in the tails of.
+
+Dryness of climate, supposed influence of, on the colour of the skin.
+
+Dryopithecus.
+
+Duck, harlequin, age of mature plumage in the; breeding in immature
+plumage.
+
+Duck, long-tailed, preference of male, for certain females.
+
+Duck, pintail, pairing with a widgeon.
+
+Duck, voice of the; pairing with a shield-drake; immature plumage of
+the.
+
+Duck, wild, sexual differences in the; speculum and male characters of;
+pairing with a pin-tail drake.
+
+Ducks, wild, becoming polygamous under partial domestication; dogs and
+cats recognised by.
+
+Dufosse, Dr., sounds produced by fish.
+
+Dugong, nakedness of; tusks of.
+
+Dujardin, on the relative size of the cerebral ganglia, in insects.
+
+Duncan, Dr., on the fertility of early marriages; comparative health of
+married and single.
+
+Dupont, M., on the occurrence of the supra-condyloid foramen in the
+humerus of man.
+
+Durand, J.P., on causes of variation.
+
+Dureau de la Malle, on the songs of birds; on the acquisition of an air
+by blackbirds.
+
+Dutch, retention of their colour by the, in South Africa.
+
+Duty, sense of.
+
+Duvaucel, female Hylobates washing her young.
+
+Dyaks, pride of, in mere homicide.
+
+Dynastes, large size of males of.
+
+Dynastini, stridulation of.
+
+Dytiscus, dimorphism of females of; grooved elytra of the female.
+
+Eagle, young Cercopithecus rescued from, by the troop.
+
+Eagle, white-headed, breeding in immature plumage.
+
+Eagles, golden, new mates found by.
+
+Ear, motion of the; external shell of the, useless in man; rudimentary
+point of the, in man.
+
+Ears, more variable in men than women; piercing and ornamentation of
+the.
+
+Earwigs, parental feeling in.
+
+Echidna.
+
+Echini, bright colours of some.
+
+Echinodermata, absence of secondary sexual characters in.
+
+Echis carinata.
+
+Ecker, figure of the human embryo; on the development of the gyri and
+sulci of the brain; on the sexual differences in the pelvis in man; on
+the presence of a sagittal crest in Australians.
+
+Edentata, former wide range of, in America; absence of secondary sexual
+characters in.
+
+Edolius, racket-shaped feathers in.
+
+Edwards, Mr., on the proportion of the sexes in North American species
+of Papilio.
+
+Eels, hermaphroditism of.
+
+Egerton, Sir P., on the use of the antlers of deer; on the pairing of
+red deer; on the bellowing of stags.
+
+Eggs, hatched by male fishes.
+
+Egret, Indian, sexes and young of.
+
+Egrets, breeding plumage of; white.
+
+Ehrenberg, on the mane of the male Hamadryas baboon.
+
+Ekstrom, M., on Harelda glacialis.
+
+Elachista rufocinerea, habits of male.
+
+Eland, development of the horns of the.
+
+Elands, sexual differences of colour in.
+
+Elaphomyia, sexual differences in.
+
+Elaphrus uliginosus, stridulation of.
+
+Elaps.
+
+Elateridae, proportion of the sexes in.
+
+Elaters, luminous.
+
+Elephant, rate of increase of the; nakedness of the; using a fan;
+Indian, forbearance to his keeper; polygamous habits of the; pugnacity
+of the male; tusks of; Indian, mode of fighting of the; male, odour
+emitted by the; attacking white or grey horses.
+
+Elevation of abode, modifying influence of.
+
+Elimination of inferior individuals.
+
+Elk, winter change of the.
+
+Elk, Irish, horns of the.
+
+Ellice Islands, beards of the natives.
+
+Elliot, D.G., on Pelecanus erythrorhynchus.
+
+Elliot, R., on the numerical proportion of the sexes in young rats; on
+the proportion of the sexes in sheep.
+
+Elliot, Sir W., on the polygamous habits of the Indian wild boar.
+
+Ellis, on the prevalence of infanticide in Polynesia.
+
+Elphinstone, Mr., on local difference of stature among the Hindoos; on
+the difficulty of distinguishing the native races of India.
+
+Elytra, of the females of Dytiscus Acilius, Hydroporus.
+
+Emberiza, characters of young.
+
+Emberiza miliaria.
+
+Emberiza schoeniclus, head-feathers of the male.
+
+Embryo of man; of the dog.
+
+Embryos of mammals, resemblance of the.
+
+Emigration.
+
+Emotions experienced by the lower animals in common with man; manifested
+by animals.
+
+Emperor butterfly.
+
+Emperor moth.
+
+Emu, sexes and incubation of.
+
+Emulation of singing birds.
+
+Endurance, estimation of.
+
+Energy, a characteristic of men.
+
+England, numerical proportion of male and female births in.
+
+Engleheart, Mr., on the finding of new mates by starlings.
+
+English, success of, as colonists.
+
+Engravers, short-sighted.
+
+Entomostraca.
+
+Entozoa, difference of colour between the males and females of some.
+
+Environment, direct action of the, in causing differences between the
+sexes.
+
+Envy, persistence of.
+
+Eocene period, possible divergence of men during the.
+
+Eolidae, colours of, produced by the biliary glands.
+
+Epeira nigra, small size of the male of.
+
+Ephemerae.
+
+Ephemeridae.
+
+Ephippiger vitium, stridulating organs of.
+
+Epicalia, sexual differences of colouring in the species of.
+
+Equus hemionus, winter change of.
+
+Erateina, coloration of.
+
+Ercolani, Prof., hermaphroditism in eels.
+
+Erect attitude of man.
+
+Eristalis, courting of.
+
+Eschricht, on the development of hair in man; on a languinous moustache
+in a female foetus; on the want of definition between the scalp and the
+forehead in some children; on the arrangement of the hair in the human
+foetus; on the hairiness of the face in the human foetus of both sexes.
+
+Esmeralda, difference of colour in the sexes of.
+
+Esox lucius.
+
+Esox reticulatus.
+
+Esquimaux, their belief in the inheritance of dexterity in
+seal-catching; mode of life of.
+
+Estrelda amandava, pugnacity of the male.
+
+Eubagis, sexual differences of colouring in the species of.
+
+Euchirus longimanus, sound produced by.
+
+Eudromias morinellus.
+
+Eulampis jugularis, colours of the female.
+
+Euler, on the rate of increase in the United States.
+
+Eunomota superciliaris, racket-shaped feathers in the tail of.
+
+Eupetomena macroura, colours of the female.
+
+Euphema splendida.
+
+Euplocamus erythrophthalmus, possession of spurs by the female.
+
+Europe, ancient inhabitants of.
+
+Europeans, difference of, from Hindoos; hairiness of, probably due to
+reversion.
+
+Eurostopodus, sexes of.
+
+Eurygnathus, different proportions of the head in the sexes of.
+
+Eustephanus, sexual differences of species of; young of.
+
+Exaggeration of natural characters by man.
+
+Exogamy.
+
+Experience, acquisition of, by animals.
+
+Expression, resemblances in, between man and the apes.
+
+Extinction of races, causes of.
+
+Eye, destruction of the; change of position in; obliquity of, regarded
+as a beauty by the Chinese and Japanese.
+
+Eyebrows, elevation of; development of long hairs in; in monkeys;
+eradicated in parts of South America and Africa; eradication of, by the
+Indians of Paraguay.
+
+Eyelashes, eradication of, by the Indians of Paraguay.
+
+Eyelids, coloured black, in part of Africa.
+
+Eyes, pillared, of the male of Chloeon; difference in the colour of, in
+the sexes of birds.
+
+Eyton, T.C., observations on the development of the horns in the fallow
+deer.
+
+Eyzies, Les, human remains from.
+
+Fabre, M., on the habits of Cerceris.
+
+Facial bones, causes of modification of the.
+
+Faculties, diversity of, in the same race of men; inheritance of;
+diversity of, in animals of the same species; mental variation of, in
+the same species; of birds.
+
+Fakirs, Indian, tortures undergone by.
+
+Falco leucocephalus.
+
+Falco peregrinus.
+
+Falco tinnunclus.
+
+Falcon, peregrine, new mate found by.
+
+Falconer, H., on the mode of fighting of the Indian elephant; on canines
+in a female deer; on Hyomoschus aquaticus.
+
+Falkland Islands, horses of.
+
+Fallow-deer, different coloured herds of.
+
+Famines, frequency of, among savages.
+
+Farr, Dr., on the effects of profligacy; on the influence of marriage on
+mortality.
+
+Farrar, F.W., on the origin of language; on the crossing or blending of
+languages; on the absence of the idea of God in certain races of men; on
+early marriages of the poor; on the middle ages.
+
+Farre, Dr., on the structure of the uterus.
+
+Fashions, long prevalence of, among savages.
+
+Faye, Prof., on the numerical proportion of male and female births in
+Norway and Russia; on the greater mortality of male children at and
+before birth.
+
+Feathers, modified, producing sounds; elongated, in male birds;
+racket-shaped; barbless and with filamentous barbs in certain birds;
+shedding of margins of.
+
+Feeding, high, probable influence of, in the pairing of birds of
+different species.
+
+Feet, thickening of the skin on the soles of the; modification of, in
+man.
+
+Felis canadensis, throat-ruff of.
+
+Felis pardalis and F. mitis, sexual difference in the colouring of.
+
+Female, behaviour of the, during courtship.
+
+Female birds, differences of.
+
+Females, presence of rudimentary male organs in; preference of, for
+certain males; pursuit of, by males; occurrence of secondary sexual
+characters in; development of male character by.
+
+Females and males, comparative numbers of; comparative mortality of,
+while young.
+
+Femur and tibia, proportions of, in the Aymara Indians.
+
+Fenton, Mr., decrease of Maories; infanticide amongst the Maories.
+
+Ferguson, Mr., on the courtship of fowls.
+
+Fertilisation, phenomena of, in plants; in the lower animals.
+
+Fertility lessened under changed conditions.
+
+Fevers, immunity of Negroes and Mulattoes from.
+
+Fiber zibethicus, protective colouring of it.
+
+Fick, H., effect of conscription for military service.
+
+Fidelity, in the elephant; of savages to one another; importance of.
+
+Field-slaves, difference of, from house-slaves.
+
+Fiji Archipelago, population of the.
+
+Fiji Islands, beards of the natives; marriage-customs of the.
+
+Fijians, burying their old and sick parents alive; estimation of the
+beard among the; admiration of, for a broad occiput.
+
+Filial affection, partly the result of natural selection.
+
+Filum terminale.
+
+Finch, racket-shaped feathers in the tail of a.
+
+Finches, spring change of colour in; British, females of the.
+
+Fingers, partially coherent, in species of Hylobates.
+
+Finlayson, on the Cochin Chinese.
+
+Fire, use of.
+
+Fischer, on the pugnacity of the male of Lethrus cephalotes.
+
+Fischer, F. Von, on display of brightly coloured parts by monkeys in
+courtship.
+
+Fish, eagerness of male; proportion of the sexes in; sounds produced by.
+
+Fishes, kidneys of, represented by Corpora Wolffiana in the human
+embryo; male, hatching ova in their mouths; receptacles for ova
+possessed by; relative size of the sexes in; fresh-water, of the
+tropics; protective resemblances in; change of colour in; nest-building;
+spawning of; sounds produced by; continued growth of.
+
+Flamingo, age of mature plumage.
+
+Flexor pollicis longus, similar variation of, in man.
+
+Flies, humming of.
+
+Flint tools.
+
+Flints, difficulty of chipping into form.
+
+Florida, Quiscalus major in.
+
+Florisuga mellivora.
+
+Flounder, coloration of the.
+
+Flower, W.H., on the abductor of the fifth metatarsal in apes; on the
+position of the Seals; on the Pithecia monachu; on the throat-pouch of
+the male bustard.
+
+Fly-catchers, colours and nidification of.
+
+Foetus, human, woolly covering of the; arrangement of the hair on.
+
+Food, influence of, upon stature.
+
+Foot, prehensile power of the, retained in some savages; prehensile, in
+the early progenitors of man.
+
+Foramen, supra-condyloid, exceptional occurrence of in the humerus of
+man; in the early progenitors of man.
+
+Forbes, D., on the Aymara Indians; on local variation of colour in the
+Quichuas; on the hairlessness of the Aymaras and Quichuas; on the long
+hair of the Aymaras and Quichaus.
+
+Forel, F., on white young swans.
+
+Forester, Hon. O.W., on an orphan hawk.
+
+Formica rufa, size of the cerebral ganglia in.
+
+Fossils, absence of, connecting man with the apes.
+
+Fowl, occurrence of spurs in the female; game, early pugnacity of;
+Polish, early development of cranial peculiarities of; variations in
+plumage of; examples of correlated development in the; domestic, breeds
+and sub-breeds of.
+
+Fowls, spangled Hamburg; inheritance of changes of plumage by; sexual
+peculiarities in, transmitted only to the same sex; loss of secondary
+sexual characters by male; Polish, origin of the crest in; period of
+inheritance of characters by; cuckoo-; development of the comb in;
+numerical proportion of the sexes in; courtship of; mongrel, between a
+black Spanish cock and different hens; pencilled Hamburg, difference of
+the sexes in; Spanish, sexual differences of the comb in; spurred, in
+both sexes.
+
+Fox, W.D., on some half-tamed wild ducks becoming polygamous, and on
+polygamy in the guinea-fowl and canary-bird; on the proportion of the
+sexes in cattle; on the pugnacity of the peacock; on a nuptial assembly
+of magpies; on the finding of new mates by crows; on partridges living
+in triplets; on the pairing of a goose with a Chinese gander.
+
+Foxes, wariness of young, in hunting districts; black.
+
+Fraser, C., on the different colours of the sexes in a species of
+Squilla.
+
+Fraser, G., colours of Thecla.
+
+Frere, Hookham, quoting Theognis on selection in mankind.
+
+Fringilla cannabina.
+
+Fringilla ciris, age of mature plumage in.
+
+Fringilla cyanea, age of mature plumage in.
+
+Fringilla leucophrys, young of.
+
+Fringilla spinus.
+
+Fringilla tristis, change of colour in, in spring; young of.
+
+Fringillidae, resemblance of the females of distinct species of.
+
+Frog, bright coloured and distasteful to birds.
+
+Frogs, male; temporary receptacles for ova possessed by; ready to breed
+before the females; fighting of; vocal organs of.
+
+Frontal bone, persistence of the suture in.
+
+Fruits, poisonous, avoided by animals.
+
+Fuegians, difference of stature among the; power of sight in the; skill
+of, in stone-throwing; resistance of the, to their severe climate;
+mental capacity of the; quasi-religious sentiments of the; resemblance
+of, in mental characters, to Europeans; mode of life of the; aversion
+of, to hair on the face; said to admire European women.
+
+Fulgoridae, songs of the.
+
+Fur, whiteness of, in Arctic animals in winter.
+
+Fur-bearing animals, acquired sagacity of.
+
+Gallicrex, sexual difference in the colour of the irides in.
+
+Gallicrex cristatus, pugnacity of male; red carbuncle occurring in the
+male during the breeding-season.
+
+Gallinaceae, frequency of polygamous habits and of sexual differences
+in the; love-gestures of; decomposed feathers in; stripes of young;
+comparative sexual differences between the species of; plumage of.
+
+Gallinaceous birds, weapons of the male; racket-shaped feathers on the
+heads of.
+
+Gallinula chloropus, pugnacity of the male.
+
+Galloperdix, spurs of; development of spurs in the female.
+
+Gallophasis, young of.
+
+Galls.
+
+Gallus bankiva, neck-hackles of.
+
+Gallus Stanleyi, pugnacity of the male.
+
+Galton, Mr., on hereditary genius; gregariousness and independence in
+animals; on the struggle between the social and personal impulses; on
+the effects of natural selection on civilised nations; on the sterility
+of sole daughters; on the degree of fertility of people of genius; on
+the early marriages of the poor; on the ancient Greeks; on the Middle
+Ages; on the progress of the United States; on South African notions of
+beauty.
+
+Gammarus, use of the chelae of.
+
+Gammarus marinus.
+
+Gannets, white only when mature.
+
+Ganoid fishes.
+
+Gaour, horns of the.
+
+Gap between man and the apes.
+
+Gaper, sexes and young of.
+
+Gardner, on an example of rationality in a Gelasimus.
+
+Garrulus glandarius.
+
+Gartner, on sterility of hybrid plants.
+
+Gasteropoda, pulmoniferous, courtship of.
+
+Gasterosteus, nidification of.
+
+Gasterosteus leiurus.
+
+Gasterosteus trachurus.
+
+Gastrophora, wings of, brightly coloured beneath.
+
+Gauchos, want of humanity among the.
+
+Gaudry, M., on a fossil monkey.
+
+Gavia, seasonal change of plumage in.
+
+Geese, clanging noise made by; pairing of different species of; Canada,
+selection of mates by.
+
+Gegenbaur, C., on the number of digits in the Ichthyopterygia; on the
+hermaphroditism of the remote progenitors of the vertebrata; two types
+of nipple in mammals.
+
+Gelasimus, proportions of the sexes in a species of; use of the enlarged
+chelae of the male; pugnacity of males of; rational actions of a;
+difference of colour in the sexes of a species of.
+
+Gemmules, dormant in one sex.
+
+Genius, hereditary.
+
+Genius, fertility of men and women of.
+
+Geoffroy St.-Hilaire, Isid., on the recognition of women by male
+quadrumana; on monstrosities; coincidences of arrested development with
+polydactylism; on animal-like anomalies in the human structure; on the
+correlation of monstrosities; on the distribution of hair in man and
+monkeys; on the caudal vertebrae of monkeys; on correlated variability;
+on the classification of man; on the long hair on the heads of species
+of Semnopithecus; on the hair in monkeys; on the development of horns in
+female deer; and F. Cuvier, on the mandrill; on Hylobates.
+
+Geographical distribution, as evidence of specific distinctions in man.
+
+Geometrae, brightly coloured beneath.
+
+Geophagus, frontal protuberance of, male; eggs hatched by the male, in
+the mouth or branchial cavity.
+
+Georgia, change of colour in Germans settled in.
+
+Geotrupes, stridulation of.
+
+Gerbe, M., on the nest-building of Crenilabus massa and C. Melops.
+
+Gerland, Dr., on the prevalence of infanticide; on the extinction of
+races.
+
+Gervais, P., on the hairiness of the gorilla; on the mandrill.
+
+Gesture-language.
+
+Ghost-moth, sexual difference of colour in the.
+
+Giard, M., disputes descent of vertebrates from Ascidians; colour of
+sponges and Ascidians; musky odour of Sphinx.
+
+Gibbon, voice of.
+
+Gibbon, Hoolock, nose of.
+
+Gibbs, Sir D., on differences of the voice in different races of men.
+
+Gill, Dr., male seals larger than females; sexual differences in seals.
+
+Giraffe, its mode of using the horns; mute, except in the rutting
+season.
+
+Giraud-Teulon, on the cause of short sight.
+
+Glanders, communicable to man from the lower animals.
+
+Glands, odoriferous, in mammals.
+
+Glareola, double moult in.
+
+Glomeris limbata, difference of colour in the sexes of.
+
+Glow-worm, female, apterous; luminosity of the.
+
+Gnats, dances of; auditory powers of.
+
+Gnu, skeletons of, found locked together; sexual differences in colour
+of the.
+
+Goat, male, wild, falling on his horns; male, odour emitted by; male,
+wild, crest of the; Berbura, mane, dewlap, etc., of the male; Kemas,
+sexual difference in the colour of the.
+
+Goats, sexual differences in the horns of; horns of; mode of fighting
+of; domestic, sexual differences of, late developed; beards of.
+
+Goatsucker, Virginian, pairing of the.
+
+Gobies, nidification of.
+
+God, want of the idea of, in some races of men.
+
+Godron, M., on variability; on difference of stature; on the want of
+connexion between climate and the colour of the skin; on the colour of
+the skin; on the colour of infants.
+
+Goldfinch, proportion of the sexes in the; sexual differences of the
+beak in the; courtship of the.
+
+Goldfinch, North American, young of.
+
+Goldfish.
+
+Gomphus, proportions of the sexes in; difference in the sexes of.
+
+Gonepteryx Rhamni, sexual difference of colour in.
+
+Goodsir, Prof., on the affinity of the lancelet to the ascidians.
+
+Goosander, young of.
+
+Goose, Antarctic, colours of the.
+
+Goose, Canada, pairing with a Bernicle gander.
+
+Goose, Chinese, knob on the beak of the.
+
+Goose, Egyptian.
+
+Goose, Sebastopol, plumage of.
+
+Goose, Snow-, whiteness of the.
+
+Goose, Spur-winged.
+
+Gorilla, semi-erect attitude of the; mastoid processes of the;
+protecting himself from rain with his hands; manner of sitting; supposed
+to be a kind of mandrill; polygamy of the; voice of the; cranium of;
+fighting of male.
+
+Gosse, P.H., on the pugnacity of the male Humming-bird.
+
+Gosse, M., on the inheritance of artificial modifications of the skull.
+
+Gould, B.A., on variation in the length of the legs in man; measurements
+of American soldiers; on the proportions of the body and capacity of the
+lungs in different races of men; on the inferior vitality of mulattoes.
+
+Gould, J., on migration of swifts; on the arrival of male snipes before
+the females; on the numerical proportion of the sexes in birds; on
+Neomorpha Grypus; on the species of Eustephanus; on the Australian
+musk-duck; on the relative size of the sexes in Briziura lobata and
+Cincloramphus cruralis; on Lobivanellus lobatus; on habits of Menura
+Alberti; on the rarity of song in brilliant birds; on Selasphorus
+platycerus; on the Bower-birds; on the ornamental plumage of the
+Humming-birds; on the moulting of the ptarmigan; on the display of
+plumage by the male Humming-birds; on the shyness of adorned male birds;
+on the decoration of the bowers of Bower-birds; on the decoration of
+their nest by Humming-birds; on variation in the genus Cynanthus; on the
+colour of the thighs in a male parrakeet; on Urosticte Benjamini; on
+the nidification of the Orioles; on obscurely-coloured birds building
+concealed nests; on trogons and king-fishers; on Australian parrots; on
+Australian pigeons; on the moulting of the ptarmigan; on the immature
+plumage of birds; on the Australian species of Turnix; on the young
+of Aithurus polytmus; on the colours of the bills of toucans; on the
+relative size of the sexes in the marsupials of Australia; on the
+colours of the Marsupials.
+
+Goureaux, on the stridulation of Mutilla europaea.
+
+Gout, sexually transmitted.
+
+Graba, on the Pied Ravens of the Feroe Islands; variety of the
+Guillemot.
+
+Gradation of secondary sexual characters in birds.
+
+Grallatores, absence of secondary sexual characters in; double moult in
+some.
+
+Grallina, nidification of.
+
+Grasshoppers, stridulation of the.
+
+Gratiolet, Prof., on the anthropomorphous apes; on the evolution of
+the anthropomorphous apes; on the difference in the development of the
+brains of apes and of man.
+
+Gray, Asa, on the gradation of species among the Compositae.
+
+Gray, J.E., on the caudal vertebrae of monkeys; on the presence of
+rudiments of horns in the female of Cervulus moschatus; on the horns of
+goats and sheep; on crests of male antelopes; on the beard of the ibex;
+on the Berbura goat; on sexual differences in the coloration of Rodents;
+ornaments of male sloth; on the colours of the Elands; on the Sing-sing
+antelope; on the colours of goats; on Lemur Macaco; on the hog-deer.
+
+"Greatest happiness principle."
+
+Greeks, ancient.
+
+Green, A.H., on beavers fighting; on the voice of the beaver.
+
+Greenfinch, selected by a female canary.
+
+Greg, W.R., on the effects of natural selection on civilised nations; on
+the early marriages of the poor; on the Ancient Greeks.
+
+Grenadiers, Prussian.
+
+Greyhounds, numerical proportion of the sexes in; numerical proportion
+of male and female births in.
+
+Grouse, red, monogamous; pugnacity of young male; producing a sound
+by beating their wings together; duration of courtship of; colours and
+nidification of.
+
+Gruber, Dr., on the occurrence of the supra-condyloid foramen in the
+humerus of man; on division of malar bone; stridulation of locust; on
+ephippiger.
+
+Grus americanus, age of mature plumage in; breeding in immature plumage.
+
+Grus virgo, trachea of.
+
+Gryllus campestris, pugnacity of male.
+
+Gryllus domesticus.
+
+Grypus, sexual differences in the beak in.
+
+Guanacoes, battles of; canine teeth of.
+
+Guanas, strife for women among the; polyandry among the.
+
+Guanche skeletons, occurrence of the supra-condyloid foramen in the
+humerus of.
+
+Guaranys, proportion of men and women among; colour of new-born children
+of the; beards of the.
+
+Guenee, A., on the sexes of Hyperythra.
+
+Guilding, L., on the stridulation of the Locustidae.
+
+Guillemot, variety of the.
+
+Guinea, sheep of, with males only horned.
+
+Guinea-fowl, monogamous; occasional polygamy of the; markings of the.
+
+Guinea-pigs, inheritance of the effects of operations by.
+
+Gulls, seasonal change of plumage in; white.
+
+Gunther, Dr., on paddle of Ceradotus; on hermaphroditism in Serranus; on
+male fishes hatching ova in their mouths; on mistaking infertile female
+fishes for males; on the prehensile organs of male Plagiostomous fishes;
+spines and brushes on fishes; on the pugnacity of the male salmon
+and trout; on the relative size of the sexes in fishes; on sexual
+differences in fishes; on the genus Callionymus; on a protective
+resemblance of a pipe-fish; on the genus Solenostoma; on the coloration
+of frogs and toads; combat of Testudo elegans; on the sexual differences
+in the Ophidia; on differences of the sexes of lizards.
+
+Gynanisa Isis, ocellated spots of.
+
+Gypsies, uniformity of, in various parts of the world.
+
+Habits, bad, facilitated by familiarity; variability of the force of.
+
+Haeckel, E., on the origin of man; on rudimentary characters; on death
+caused by inflammation of the vermiform appendage; on the canine teeth
+in man; on the steps by which man became a biped; on man as a member of
+the Catarrhine group; on the position of the Lemuridae; on the genealogy
+of the Mammalia; on the lancelet; on the transparency of pelagic
+animals; on the musical powers of women.
+
+Hagen, H., and Walsh, B.D., on American Neuroptera.
+
+Hair, development of, in man; character of, supposed to be determined by
+light and heat; distribution of, in man; possibly removed for ornamental
+purposes; arrangement and direction of; of the early progenitors of man;
+different texture of, in distinct races; and skin, correlation of colour
+of; development of, in mammals; management of, among different peoples;
+great length of, in some North American tribes; elongation of the, on
+the human head; possible inherited effect of plucking out.
+
+Hairiness, difference of, in the sexes in man; variation of, in races of
+men.
+
+Hairs and excretory pores, numerical relation of, in sheep.
+
+Hairy family, Siamese.
+
+Halbertsma, Prof., hermaphroditism in Serranus.
+
+Hamadryas baboon, turning over stones; mane of the male.
+
+Hamilton, C., on the cruelty of the Kaffirs to animals; on the
+engrossment of the women by the Kaffir chiefs.
+
+Hammering, difficulty of.
+
+Hancock, A., on the colours of the nudibranch Mollusca.
+
+Hands, larger at birth, in the children of labourers; structure of,
+in the quadrumana; and arms, freedom of, indirectly correlated with
+diminution of canines.
+
+Handwriting, inherited.
+
+Handyside, Dr., supernumerary mammae in men.
+
+Harcourt, E. Vernon, on Fringilla cannabina.
+
+Hare, protective colouring of the.
+
+Harelda glacialis.
+
+Hares, battles of male.
+
+Harlan, Dr., on the difference between field-and house-slaves.
+
+Harris, J.M., on the relation of complexion to climate.
+
+Harris, T.W., on the Katy-did locust; on the stridulation of the
+grasshoppers; on Oecanthus nivalis; on the colouring of Lepidoptera; on
+the colouring of Saturnia Io.
+
+Harting, spur of the Ornithorhynchus.
+
+Hartman, Dr., on the singing of Cicada septendecim.
+
+Hatred, persistence of.
+
+Haughton, S., on a variation of the flexor pollicis longus in man.
+
+Hawks, feeding orphan nestling.
+
+Hayes, Dr., on the diverging of sledge-dogs on thin ice.
+
+Haymond, R., on the drumming of the male Tetrao umbellus; on the
+drumming of birds.
+
+Head, altered position of, to suit the erect attitude of man; hairiness
+of, in man; processes of, in male beetles; artificial alterations of the
+form of the.
+
+Hearne, on strife for women among the North American Indians; on the
+North American Indians' notion of female beauty; repeated elopements of
+a North American woman.
+
+Heart, in the human embryo.
+
+Heat, supposed effects of.
+
+Hectocotyle.
+
+Hedge-warbler, young of the.
+
+Heel, small projection of, in the Aymara Indians.
+
+Hegt, M., on the development of the spurs in peacocks.
+
+Heliconidae, mimicry of, by other butterflies.
+
+Heliopathes, stridulation peculiar to the male.
+
+Heliothrix auriculata, young of.
+
+Helix pomatia, example of individual attachment in.
+
+Hellins, J., proportions of sexes of Lepidoptera reared by.
+
+Helmholtz, on pleasure derived from harmonies; on the human eye; on the
+vibration of the auditory hairs of crustacea; the physiology of harmony.
+
+Hemiptera.
+
+Hemitragus, beardless in both sexes.
+
+Hemsbach, M. von, on medial mamma in man.
+
+Hen, clucking of.
+
+Hepburn, Mr., on the autumn song of the water-ouzel.
+
+Hepialus humuli, sexual difference of colour in the.
+
+Herbs, poisonous, avoided by animals.
+
+Hermaphroditism, of embryos; in fishes.
+
+Herodias bubulcus, vernal moult of.
+
+Heron, Sir R., on the habits of peafowl.
+
+Herons, love-gestures of; decomposed feathers in; breeding plumage of;
+young of the; sometimes dimorphic; continued growth of crest and plumes
+in the males of some; change of colour in some.
+
+Hesperomys cognatus.
+
+Hetaerina, proportion of the sexes in; difference in the sexes of.
+
+Heterocerus, stridulation of.
+
+Hewitt, Mr., on a game-cock killing a kite; on the recognition of dogs
+and cats by ducks; on the pairing of a wild duck with a pintail drake;
+on the courtship of fowls; on the coupling of pheasants with common
+hens.
+
+Hilgendorf, sounds produced by crustaceans.
+
+Hindoo, his horror of breaking his caste.
+
+Hindoos, local difference of stature among; difference of, from
+Europeans; colour of the beard in.
+
+Hipparchia Janira, instability of the ocellated spots of.
+
+Hippocampus, development of; marsupial receptacles of the male.
+
+Hippocampus minor.
+
+Hippopotamus, nakedness of.
+
+Hips, proportions of, in soldiers and sailors.
+
+Hodgson, S., on the sense of duty.
+
+Hoffberg, on the horns of the reindeer; on sexual preferences shewn by
+reindeer.
+
+Hoffman, Prof., protective colours; fighting of frogs.
+
+Hog, wart-; river-.
+
+Hog-deer.
+
+Holland, Sir H., on the effects of new diseases.
+
+Homologous structures, correlated variation of.
+
+Homoptera, stridulation of the, and Orthoptera, discussed.
+
+Honduras, Quiscalus major in.
+
+Honey-buzzard of India, variation in the crest of.
+
+Honey-sucker, females and young of.
+
+Honey-suckers, moulting of the; Australian, nidification of.
+
+Honour, law of.
+
+Hooker, Dr., forbearance of elephant to his keeper; on the colour of the
+beard in man.
+
+Hookham, Mr., on mental concepts in animals.
+
+Hoolock Gibbon, nose of.
+
+Hoopoe, sounds produced by male.
+
+Hoplopterus armatus, wing-spurs of.
+
+Hornbill, African, inflation of the neck-wattle of the male during
+courtship.
+
+Hornbills, sexual difference in the colour of the eyes in; nidification
+and incubation of.
+
+Horne, C., on the rejection of a brightly-coloured locust by lizards and
+birds.
+
+Horns, sexual differences of, in sheep and goats; loss of, in female
+merino sheep; development of, in deer; development in antelopes; from
+the head and thorax, in male beetles; of deer; originally a masculine
+character in sheep; and canine teeth, inverse development of.
+
+Horse, fossil, extinction of the, in South America; polygamous; canine
+teeth of male; winter change of colour.
+
+Horses, rapid increase of, in South America; diminution of canine teeth
+in; dreaming; of the Falkland Islands and Pampas; numerical proportion
+of the sexes, in; lighter in winter in Siberia; sexual preferences in;
+pairing preferently with those of the same colour; numerical proportion
+of male and female births in; formerly striped.
+
+Hottentot women, peculiarities of.
+
+Hottentots, lice of; readily become musicians; notions of female beauty
+of the; compression of nose by.
+
+Hough, Dr. S., men's temperature more variable than women's; proportion
+of sexes in man.
+
+House-slaves, difference of, from field-slaves.
+
+Houzeau, on the baying of the dog; on reason in dogs; birds killed by
+telegraph wires; on the cries of domestic fowls and parrots; animals
+feel no pity; suicide in the Aleutian Islands.
+
+Howorth, H.H., extinction of savages.
+
+Huber, P., on ants playing together; on memory in ants; on the
+intercommunication of ants; on the recognition of each other by ants
+after separation.
+
+Huc, on Chinese opinions of the appearance of Europeans.
+
+Huia, the, of New Zealand.
+
+Human, man, classed alone in a kingdom.
+
+Human sacrifices.
+
+Humanity, unknown among some savages; deficiency of, among savages.
+
+Humboldt, A. von, on the rationality of mules; on a parrot preserving
+the language of a lost tribe; on the cosmetic arts of savages; on
+the exaggeration of natural characters by man; on the red painting of
+American Indians.
+
+Hume, D., on sympathetic feelings.
+
+Humming-bird, racket-shaped feathers in the tail of a; display of
+plumage by the male.
+
+Humming-birds, ornament their nests; polygamous; proportion of the sexes
+in; sexual differences in; pugnacity of male; modified primaries of
+male; coloration of the sexes of; display by; nidification of the;
+colours of female; young of.
+
+Humour, sense of, in dogs.
+
+Humphreys, H.N., on the habits of the stickleback.
+
+Hunger, instinct of.
+
+Huns, ancient, flattening of the nose by the.
+
+Hunter, J., on the number of species of man; on secondary sexual
+characters; on the general behaviour of female animals during courtship;
+on the muscles of the larynx in song-birds; on strength of males; on the
+curled frontal hair of the bull; on the rejection of an ass by a female
+zebra.
+
+Hunter, W.W., on the recent rapid increase of the Santali; on the
+Santali.
+
+Huss, Dr. Max, on mammary glands.
+
+Hussey, Mr., on a partridge distinguishing persons.
+
+Hutchinson, Col., example of reasoning in a retriever.
+
+Hutton, Captain, on the male wild goat falling on his horns.
+
+Huxley, T.H., on the structural agreement of man with the apes; on the
+agreement of the brain in man with that of lower animals; on the adult
+age of the orang; on the embryonic development of man; on the origin
+of man; on variation in the skulls of the natives of Australia; on the
+abductor of the fifth metatarsal in apes; on the nature of the reasoning
+power; on the position of man; on the suborders of primates; on the
+Lemuridae; on the Dinosauria; on the amphibian affinities of the
+Ichthyosaurians; on variability of the skull in certain races of man; on
+the races of man; Supplement on the brain.
+
+Hybrid birds, production of.
+
+Hydrophobia, communicable between man and the lower animals.
+
+Hydroporus, dimorphism of females of.
+
+Hyelaphus porcinus.
+
+Hygrogonus.
+
+Hyla, singing species of.
+
+Hylobates, absence of the thumb in; upright progression of some species
+of; maternal affection in a; direction of the hair on the arms of
+species of; females of, less hairy below than males.
+
+Hylobates agilis, hair on the arms of; musical voice of the;
+superciliary ridge of; voice of.
+
+Hylobates hoolock, sexual difference of colour in.
+
+Hylobates lar, hair on the arms of; female less hairy.
+
+Hylobates leuciscus, song of.
+
+Hylobates syndactylus, laryngeal sac of.
+
+Hylophila prasinana.
+
+Hymenoptera, large size of the cerebral ganglia in; classification of;
+sexual differences in the wings of; aculeate, relative size of the sexes
+of.
+
+Hymenopteron, parasitic, with a sedentary male.
+
+Hyomoschus aquaticus.
+
+Hyperythra, proportion of the sexes in.
+
+Hypogymna dispar, sexual difference of colour in.
+
+Hypopyra, coloration of.
+
+Ibex, male, falling on his horns; beard of the.
+
+Ibis, white, change of colour of naked skin in, during the breeding
+season; scarlet, young of the.
+
+Ibis tantalus, age of mature plumage in; breeding in immature plumage.
+
+Ibises, decomposed feathers in; white; and black.
+
+Ichneumonidae, difference of the sexes in.
+
+Ichthyopterygia.
+
+Ichthyosaurians.
+
+Idiots, microcephalous, their characters and habits; hairiness and
+animal nature of their actions; microcephalous, imitative faculties of.
+
+Iguana tuberculata.
+
+Iguanas.
+
+Illegitimate and legitimate children, proportion of the sexes in.
+
+Imagination, existence of, in animals.
+
+Imitation, of man by monkeys; tendency to, in monkeys, microcephalous
+idiots and savages; influence of.
+
+Immature plumage of birds.
+
+Implacentata.
+
+Implements, employed by monkeys; fashioning of, peculiar to man.
+
+Impregnation, period of, influence of, upon sex.
+
+Improvement, progressive, man alone supposed to be capable of.
+
+Incisor teeth, knocked out or filed by some savages.
+
+Increase, rate of; necessity of checks in.
+
+Indecency, hatred of, a modern virtue.
+
+India, difficulty of distinguishing the native races of; Cyprinidae of;
+colour of the beard in races of men of.
+
+Indian, North American, honoured for scalping a man of another tribe.
+
+Individuality, in animals.
+
+Indolence of man, when free from a struggle for existence.
+
+Indopicus carlotta, colours of the sexes of.
+
+Infanticide, prevalence of; supposed cause of; prevalence and causes of.
+
+Inferiority, supposed physical, of man.
+
+Inflammation of the bowels, occurrence of, in Cebus Azarae.
+
+Inheritance, of long and short sight; of effects of use of vocal and
+mental organs; of moral tendencies; laws of; sexual; sexually limited.
+
+Inquisition, influence of the.
+
+Insanity, hereditary.
+
+insect, fossil, from the Devonian.
+
+Insectivora, absence of secondary sexual characters in.
+
+Insects, relative size of the cerebral ganglia in; male, appearance
+of, before the females; pursuit of female, by the males; period of
+development of sexual characters in; secondary sexual characters of;
+kept in cages; stridulation.
+
+Insessores, vocal organs of.
+
+Instep, depth of, in soldiers and sailors.
+
+Instinct and intelligence.
+
+Instinct, migratory, vanquishing the maternal.
+
+Instinctive actions, the result of inheritance.
+
+Instinctive impulses, difference of the force; and moral impulses,
+alliance of.
+
+Instincts, complex origin of, through natural selection; possible origin
+of some; acquired, of domestic animals; variability of the force of;
+difference of force between the social and other; utilised for new
+purposes.
+
+Instrumental music of birds.
+
+Intellect, influence of, in natural selection in civilised society.
+
+Intellectual faculties, their influence on natural selection in man;
+probably perfected through natural selection.
+
+Intelligence, Mr. H. Spencer on the dawn of.
+
+Intemperance, no reproach among savages; its destructiveness.
+
+Intoxication in monkeys.
+
+Iphias glaucippe.
+
+Iris, sexual difference in the colour of the, in birds.
+
+Ischio-pubic muscle.
+
+Ithaginis cruentus, number of spurs in.
+
+Iulus, tarsal suckers of the males of.
+
+Jackals learning from dogs to bark.
+
+Jack-snipe, coloration of the.
+
+Jacquinot, on the number of species of man.
+
+Jaeger, Dr., length of bones increased from carrying weights; on the
+difficulty of approaching herds of wild animals; male Silver-pheasant,
+rejected when his plumage was spoilt.
+
+Jaguars, black.
+
+Janson, E.W., on the proportions of the sexes in Tomicus villosus; on
+stridulant beetles.
+
+Japan, encouragement of licentiousness in.
+
+Japanese, general beardlessness of the; aversion of the, to whiskers.
+
+Jardine, Sir W., on the Argus pheasant.
+
+Jarrold, Dr., on modifications of the skull induced by unnatural
+position.
+
+Jarves, Mr., on infanticide in the Sandwich Islands.
+
+Javans, relative height of the sexes of; notions of female beauty.
+
+Jaw, influence of the muscles of the, upon the physiognomy of the apes.
+
+Jaws, smaller proportionately to the extremities; influence of food upon
+the size of; diminution of, in man; in man, reduced by correlation.
+
+Jay, young of the; Canada, young of the.
+
+Jays, new mates found by; distinguishing persons.
+
+Jeffreys, J. Gwyn, on the form of the shell in the sexes of the
+Gasteropoda; on the influence of light upon the colours of shells.
+
+Jelly-fish, bright colours of some.
+
+Jenner, Dr., on the voice of the rook; on the finding of new mates by
+magpies; on retardation of the generative functions in birds.
+
+Jenyns, L., on the desertion of their young by swallows; on male birds
+singing after the proper season.
+
+Jerdon, Dr., on birds dreaming; on the pugnacity of the male bulbul;
+on the pugnacity of the male Ortygornis gularis; on the spurs of
+Galloperdix; on the habits of Lobivanellus; on the spoonbill; on the
+drumming of the Kalij-pheasant; on Indian bustards; on Otis bengalensis;
+on the ear-tufts of Sypheotides auritus; on the double moults of certain
+birds; on the moulting of the honeysuckers; on the moulting of bustards,
+plovers, and drongos; on the spring change of colour in some finches; on
+display in male birds; on the display of the under-tail coverts by the
+male bulbul; on the Indian honey-buzzard; on sexual differences in
+the colour of the eyes of hornbills; on the markings of the Tragopan
+pheasant; on the nidification of the Orioles; on the nidification of
+the hornbills; on the Sultan yellow-tit; on Palaeornis javanicus; on the
+immature plumage of birds; on representative species of birds; on the
+habits of Turnix; on the continued increase of beauty of the peacock; on
+coloration in the genus Palaeornis.
+
+Jevons, W.S., on the migrations of man.
+
+Jews, ancient use of flint tools by the; uniformity of, in various parts
+of the world; numerical proportion of male and female births among the;
+ancient, tattooing practised by.
+
+Johnstone, Lieut., on the Indian elephant.
+
+Jollofs, fine appearance of the.
+
+Jones, Albert, proportion of sexes of Lepidoptera, reared by.
+
+Juan Fernandez, humming-birds of.
+
+Junonia, sexual differences of colouring in species of.
+
+Jupiter, comparison with Assyrian effigies.
+
+Kaffir skull, occurrence of the diastema in a.
+
+Kaffirs, their cruelty to animals; lice of the; colour of
+the; engrossment of the handsomest women by the chiefs of the;
+marriage-customs of the.
+
+Kalij-pheasant, drumming of the male; young of.
+
+Kallima, resemblance of, to a withered leaf.
+
+Kulmucks, general beardlessness of; aversion of, to hairs on the face;
+marriage-customs of the.
+
+Kangaroo, great red, sexual difference in the colour of.
+
+Kant, Imm., on duty; on self-restraint; on the number of species of man.
+
+Katy-did, stridulation of the.
+
+Keen, Dr., on the mental powers of snakes.
+
+Keller, Dr., on the difficulty of fashioning stone implements.
+
+Kent, W.S., elongation of dorsal fin of Callionymus lyra; courtship of
+Labrus mixtus; colours and courtship of Cantharus lineatus.
+
+Kestrels, new mates found by.
+
+Kidney, one, doing double work in disease.
+
+King, W.R., on the vocal organs of Tetrao cupido; on the drumming of
+grouse; on the reindeer; on the attraction of male deer by the voice of
+the female.
+
+King and Fitzroy, on the marriage-customs of the Fuegians.
+
+King-crows, nidification of.
+
+Kingfisher, racket-shaped feathers in the tail of a.
+
+Kingfishers, colours and nidification of the; immature plumage of the;
+young of the.
+
+King Lory, immature plumage of the.
+
+Kingsley, C., on the sounds produced by the Umbrina.
+
+Kirby and Spence, on sexual differences in the length of the snout in
+Curculionidae; on the courtship of insects; on the elytra of Dytiscus;
+on peculiarities in the legs of male insects; on the relative size of
+the sexes in insects; on the Fulgoridae; on the habits of the Termites;
+on difference of colour in the sexes of beetles; on the horns of the
+male lamellicorn beetles; on hornlike processes in male Curculionidae;
+on the pugnacity of the male stag-beetle.
+
+Kite, killed by a game-cock.
+
+Knot, retention of winter plumage by the.
+
+Knox, R., on the semilunar fold; on the occurrence of the
+supra-condyloid foramen in the humerus of man; on the features of the
+young Memmon.
+
+Koala, length of the caecum in.
+
+Kobus ellipsiprymnus, proportion of the sexes in.
+
+Kolreuter, on the sterility of hybrid plants.
+
+Koodoo, development of the horns of the; markings of the.
+
+Koppen, F.T., on the migratory locust.
+
+Koraks, marriage customs of.
+
+Kordofan, protuberances artificially produced by natives of.
+
+Korte, on the proportion of sexes in locusts; Russian locusts.
+
+Kovalevsky, A., on the affinity of the Ascidia to the Vertebrata.
+
+Kovalevsky, W., on the pugnacity of the male capercailzie; on the
+pairing of the capercailzie.
+
+Krause, on a convoluted body at the extremity of the tail in a Macacus
+and a cat.
+
+Kupffer, Prof., on the affinity of the Ascidia to the Vertebrata.
+
+Labidocera Darwinii, prehensile organs of the male.
+
+Labrus, splendid colours of the species of.
+
+Labrus mixtus, sexual differences in.
+
+Labrus pavo.
+
+Lacertilia, sexual differences of.
+
+Lafresnaye, M. de, on birds of paradise.
+
+Lamarck, on the origin of man.
+
+Lamellibranchiata.
+
+Lamellicorn beetles, horn-like processes from the head and thorax of;
+influence of sexual selection on.
+
+Lamellicornia, stridulation of.
+
+Lamont, Mr., on the tusks of the walrus; on the use of its tusks by the
+walrus; on the bladder-nose seal.
+
+Lampornis porphyrurus, colours of the female.
+
+Lampyridae, distasteful to mammals.
+
+Lancelet.
+
+Landois, H., gnats attracted by sound; on the production of sound by the
+Cicadae; on the stridulating organ of the crickets; on Decticus; on
+the stridulating organs of the Acridiidae; stridulating apparatus, in
+Orthoptera; on the stridulation of Necrophorus; on the stridulant
+organ of Cerambyx heros; on the stridulant organ of Geotrupes; on the
+stridulating organs in the Coleoptera; on the ticking of Anobium.
+
+Landor, Dr., on remorse for not obeying tribal custom.
+
+Language, an art; articulate, origin of; relation of the progress of, to
+the development of the brain; effects of inheritance in production of;
+complex structure of, among barbarous nations; natural selection in;
+gesture; primeval; of a lost tribe preserved by a parrot.
+
+Languages, presence of rudiments in; classification of; variability of;
+crossing or blending of; complexity of, no test of perfection or proof
+of special creation; resemblance of, evidence of community of origin.
+
+Languages and species, identity of evidence of their gradual
+development.
+
+Lanius, characters of young.
+
+Lanius rufus, anomalous young of.
+
+Lankester, E.R., on comparative longevity; on the destructive effects of
+intemperance.
+
+Lanugo of the human foetus.
+
+Lapponian language, highly artificial.
+
+Lark, proportion of the sexes in the; female, singing of the.
+
+Larks, attracted by a mirror.
+
+Lartet, E., comparison of cranial capacities of skulls of recent and
+tertiary mammals; on the size of the brain in mammals; on Dryopithecus;
+on pre-historic flutes.
+
+Larus, seasonal change of plumage in.
+
+Larva, luminous, of a Brazilian beetle.
+
+Larynx, muscles of the, in songbirds.
+
+Lasiocampa quercus, attraction of males by the female; sexual difference
+of colour in.
+
+Latham, R.G., on the migrations of man.
+
+Latooka, perforation of the lower lip by the women of.
+
+Laurillard, on the abnormal division of the malar bone in man.
+
+Lawrence, W., on the superiority of savages to Europeans in power of
+sight; on the colour of negro infants; on the fondness of savages for
+ornaments; on beardless races; on the beauty of the English aristocracy.
+
+Layard, E.L., on the instance of rationality in a cobra; on the
+pugnacity of Gallus Stanleyi.
+
+Laycock, Dr., on vital periodicity; theroid nature of idiots.
+
+Leaves, autumn, tints useless.
+
+Lecky, Mr., on the sense of duty; on suicide; on the practice of
+celibacy; his view of the crimes of savages; on the gradual rise of
+morality.
+
+Leconte, J.L., on the stridulant organ in the Coprini and Dynastini.
+
+Lee, H., on the numerical proportion of the sexes in the trout.
+
+Leg, calf of the, artificially modified.
+
+Legitimate and illegitimate children, proportion of the sexes in.
+
+Legs, variation of the length of the, in man; proportions of, in
+soldiers and sailors; front, atrophied in some male butterflies;
+peculiarities of, in male insects.
+
+Leguay, on the occurrence of the supra-condyloid foramen in the humerus
+of man.
+
+Lek of the black-cock and capercailzie.
+
+Lemoine, Albert, on the origin of language.
+
+Lemur macaco, sexual difference of colour in.
+
+Lemuridae, ears of the; variability of the muscles in the; position and
+derivation of the; their origin.
+
+Lemurs, uterus in the.
+
+Lenguas, disfigurement of the ears of the.
+
+Leopards, black.
+
+Lepidoptera, numerical proportions of the sexes in the; colouring of;
+ocellated spots of.
+
+Lepidosiren.
+
+Leptalides, mimicry of.
+
+Leptorhynchus angustatus, pugnacity of male.
+
+Leptura testacea, difference of colour in the sexes.
+
+Leroy, on the wariness of young foxes in hunting-districts; on the
+desertion of their young by swallows.
+
+Leslie, D., marriage customs of Kaffirs.
+
+Lesse, valley of the.
+
+Lesson, on the birds of paradise; on the sea-elephant.
+
+Lessona, M., observations on Serranus.
+
+Lethrus cephalotes, pugnacity of the males of.
+
+Leuciscus phoxinus.
+
+Leuckart, R., on the vesicula prostatica; on the influence of the age of
+parents on the sex of offspring.
+
+Levator claviculae muscle.
+
+Libellula depressa, colour of the male.
+
+Libellulidae, relative size of the sexes of; difference in the sexes of.
+
+Lice of domestic animals and man.
+
+Licentiousness a check upon population; prevalence of, among savages.
+
+Lichtenstein, on Chera progne.
+
+Life, inheritance at corresponding periods of.
+
+Light, effects on complexion; influence of, upon the colours of shells.
+
+Lilford, Lord, the ruff attracted by bright objects.
+
+Limosa lapponica.
+
+Linaria.
+
+Linaria montana.
+
+Lindsay, Dr. W.L., diseases communicated from animals to man; madness in
+animals; the dog considers his master his God.
+
+Linnaeus, views of, as to the position of man.
+
+Linnet, numerical proportion of the sexes in the; crimson forehead and
+breast of the; courtship of the.
+
+Lion, polygamous; mane of the, defensive; roaring of the.
+
+Lions, stripes of young.
+
+Lips, piercing of the, by savages.
+
+Lithobius, prehensile appendages of the female.
+
+Lithosia, coloration in.
+
+Littorina littorea.
+
+Livingstone, Dr., manner of sitting of gorilla; on the influence of
+dampness and dryness on the colour of the skin; on the liability of
+negroes to tropical fevers after residence in a cold climate; on the
+spur-winged goose; on weaverbirds; on an African night-jar; on the
+battle-scars of South African male mammals; on the removal of the upper
+incisors by the Batokas; on the perforation of the upper lip by the
+Makalolo; on the Banyai.
+
+Livonia, numerical proportion of male and female births in.
+
+Lizards, relative size of the sexes of; gular pouches of.
+
+Lloyd, L., on the polygamy of the capercailzie and bustard; on the
+numerical proportion of the sexes in the capercailzie and blackcock; on
+the salmon; on the colours of the sea-scorpion; on the pugnacity of
+male grouse; on the capercailzie and blackcock; on the call of the
+capercailzie; on assemblages of grouse and snipes; on the pairing of a
+shield-drake with a common duck; on the battles of seals; on the elk.
+
+Lobivanellus, wing-spurs in.
+
+Local influences, effect of, upon stature.
+
+Lockwood, Mr., on the development of Hippocampus.
+
+Lockwood, Rev. S., musical mouse.
+
+Locust, bright-coloured, rejected by lizards and birds.
+
+Locust, migratory; selection by female.
+
+Locustidae, stridulation of the; descent of the.
+
+Locusts, proportion of sexes in; stridulation of.
+
+Longicorn beetles, difference of the sexes of, in colour; stridulation
+of.
+
+Lonsdale, Mr., on an example of personal attachment in Helix pomatia.
+
+Lophobranchii, marsupial receptacles of the male.
+
+Lophophorus, habits of.
+
+Lophorina atra, sexual difference in coloration of.
+
+Lophornis ornatus.
+
+Lord, J.K., on Salmo lycaodon.
+
+Lory, King; immature plumage of the.
+
+Lory, King, constancy of.
+
+Love-antics and dances of birds.
+
+Lowne, B.T., on Musca vomitoria.
+
+Loxia, characters of young of.
+
+Lubbock, Sir J., on the antiquity of man; on the origin of man; on
+the mental capacity of savages; on the origin of implements; on the
+simplification of languages; on the absence of the idea of God among
+certain races of men; on the origin of the belief in spiritual agencies;
+on superstitions; on the sense of duty; on the practice of burying the
+old and sick among the Fijians; on the immorality of savages; on Mr.
+Wallace's claim to the origination of the idea of natural selection; on
+the former barbarism of civilised nations; on improvements in the arts
+among savages; on resemblances of the mental characters in different
+races of men; on the arts practised by savages; on the power of counting
+in primeval man; on the prehensile organs of the male Labidocera
+Darwinii; on Chloeon; on Smynthurus luteus; finding of new mates by
+jays; on strife for women among the North American Indians; on music;
+on the ornamental practices of savages; on the estimation of the beard
+among the Anglo-Saxons; on artificial deformation of the skull; on
+"communal marriages;" on exogamy; on the Veddahs; on polyandry.
+
+Lucanidae, variability of the mandibles in the male.
+
+Lucanus, large size of males of.
+
+Lucanus cervus, numerical proportion of sexes of; weapons of the male.
+
+Lucanus elaphus, use of mandibles of; large jaws of male.
+
+Lucas, Prosper, on pigeons; on sexual preference in horses and bulls.
+
+Luminosity in insects.
+
+Lunar periods.
+
+Lund, Dr., on skulls found in Brazilian caves.
+
+Lungs, enlargement of, in the Quichua and Aymara Indians; a modified
+swim-bladder; different capacity of, in races of man.
+
+Luschka, Prof., on the termination of the coccyx.
+
+Luxury, expectation of life uninfluenced by.
+
+Lycaena, sexual differences of colour in species of.
+
+Lycaenae, colours of.
+
+Lyell, Sir C., on the antiquity of man; on the origin of man; on
+the parallelism of the development of species and languages; on the
+extinction of languages; on the Inquisition; on the fossil remains of
+vertebrata; on the fertility of mulattoes.
+
+Lynx, Canadian throat-ruff of the.
+
+Lyre-bird, assemblies of.
+
+Macacus, ears of; convoluted body in the extremity of the tail of;
+variability of the tail in species of; whiskers of species of.
+
+Macacus brunneus.
+
+Macacus cynomolgus, superciliary ridge of; beard and whiskers of;
+becoming white with age.
+
+Macacus ecaudatus.
+
+Macacus lasiotus, facial spots of.
+
+Macacus nemestrinus.
+
+Macacus radiatus.
+
+Macacus rhesus, sexual difference in the colour of.
+
+Macalister, Prof., on variations of the palmaris accessorius muscle; on
+muscular abnormalities in man; on the greater variability of the muscles
+in men than in women.
+
+Macaws, Mr. Buxton's observations on.
+
+McCann, J., on mental individuality.
+
+McClelland, J., on the Indian Cyprinidae.
+
+Macculloch, Col., on an Indian village without any female children.
+
+Macculloch, Dr., on tertian ague in a dog.
+
+Macgillivray, W., on the vocal organs of birds; on the Egyptian goose;
+on the habits of woodpeckers; on the habits of the snipe; on the
+whitethroat; on the moulting of the snipes; on the moulting of the
+Anatidae; on the finding of new mates by magpies; on the pairing of a
+blackbird and thrush; on pied ravens; on the guillemots; on the colours
+of the tits; on the immature plumage of birds.
+
+Machetes, sexes and young of.
+
+Machetes pugnax, supposed to be polygamous; numerical proportion of the
+sexes in; pugnacity of the male; double moult in.
+
+McIntosh, Dr., colours of the Nemertians.
+
+McKennan, marriage customs of Koraks.
+
+Mackintosh, on the moral sense.
+
+MacLachlan, R., on Apatania muliebris and Boreus hyemalis; on the
+anal appendages of male insects; on the pairing of dragon-flies; on
+dragon-flies; on dimorphism in Agrion; on the want of pugnacity in male
+dragon-flies; colour of ghost-moth in the Shetland Islands.
+
+M'Lennan, Mr., on infanticide; on the origin of the belief in spiritual
+agencies; on the prevalence of licentiousness among savages; on the
+primitive barbarism of civilised nations; on traces of the custom of the
+forcible capture of wives; on polyandry.
+
+Macnamara, Mr., susceptibility of Andaman islanders and Nepalese to
+change.
+
+M'Neill, Mr., on the use of the antlers of deer; on the Scotch
+deerhound; on the long hairs on the throat of the stag; on the bellowing
+of stags.
+
+Macropus, courtship of.
+
+Macrorhinus proboscideus, structure of the nose of.
+
+Magpie, power of speech of; vocal organs of the; nuptial assemblies of;
+new mates found by; stealing bright objects; young of the; coloration of
+the.
+
+Maillard, M., on the proportion of the sexes in a species of Papilio
+from Bourbon.
+
+Maine, Sir Henry, on the absorption of one tribe by another; a desire
+for improvement not general.
+
+Major, Dr. C. Forsyth, on fossil Italian apes; skull of Bos etruscus;
+tusks of miocene pigs.
+
+Makalolo, perforation of the upper lip by the.
+
+Malar bone, abnormal division of, in man.
+
+Malay Archipelago, marriage-customs of the savages of the.
+
+Malays, line of separation between the Papuans and the; general
+beardlessness of the; staining of the teeth among; aversion of some, to
+hairs on the face.
+
+Malays and Papuans, contrasted characters of.
+
+Male animals, struggles of, for the possession of the females; eagerness
+of, in courtship; generally more modified than female; differ in the
+same way from females and young.
+
+Male characters, developed in females; transfer of, to female birds.
+
+Male, sedentary, of a hymenopterous parasite.
+
+Malefactors.
+
+Males, presence of rudimentary female organs in.
+
+Males and females, comparative numbers of; comparative mortality of,
+while young.
+
+Malherbe, on the woodpeckers.
+
+Mallotus Peronii.
+
+Mallotus villosus.
+
+Malthus, T., on the rate of increase of population.
+
+Maluridae, nidification of the.
+
+Malurus, young of.
+
+Mammae, rudimentary, in male mammals; supernumerary, in women; of male
+human subject.
+
+Mammalia, Prof. Owen's classification of; genealogy of the.
+
+Mammals, recent and tertiary, comparison of cranial capacity of; nipples
+of; pursuit of female, by the males; secondary sexual characters of;
+weapons of; relative size of the sexes of; parallelism of, with birds
+in secondary sexual characters; voices of, used especially during the
+breeding season.
+
+Man, variability of; erroneously regarded as more domesticated than
+other animals; migrations of; wide distribution of; causes of the
+nakedness of; supposed physical inferiority of; a member of the
+Catarrhine group; early progenitors of; transition from ape indefinite;
+numerical proportions of the sexes in; difference between the sexes;
+proportion of sexes amongst the illegitimate; different complexion
+of male and female negroes; secondary sexual characters of; primeval
+condition of.
+
+Mandans, correlation of colour and texture of hair in the.
+
+Mandible, left, enlarged in the male of Taphroderes distortus.
+
+Mandibles, use of the, in Ammophila; large, of Corydalis cornutus;
+large, of male Lucanus elaphus.
+
+Mandrill, number of caudal vertebrae in the; colours of the male.
+
+Mantegazza, Prof., on last molar teeth of man; bright colours in male
+animals; on the ornaments of savages; on the beardlessness of the New
+Zealanders; on the exaggeration of natural characters by man.
+
+Mantell, W., on the engrossment of pretty girls by the New Zealand
+chiefs.
+
+Mantis, pugnacity of species of.
+
+Maories, mortality of; infanticide and proportion of sexes; distaste for
+hairiness amongst men.
+
+Marcus Aurelius, on the origin of the moral sense; on the influence of
+habitual thoughts.
+
+Mareca penelope.
+
+Marks, retained throughout groups of birds.
+
+Marriage, restraints upon, among savages; influence of, upon morals;
+influence of, on mortality; development of.
+
+Marriages, early; communal.
+
+Marshall, Dr. W., protuberances on birds' heads; on the moulting of
+birds; advantage to older birds of paradise.
+
+Marshall, Col., interbreeding amongst Todas; infanticide and proportion
+of sexes with Todas; choice of husband amongst Todas.
+
+Marshall, Mr., on the brain of a Bushwoman.
+
+Marsupials, development of the nictitating membrane in; uterus of;
+possession of nipples by; their origin from Monotremata; abdominal sacs
+of; relative size of the sexes of; colours of.
+
+Marsupium, rudimentary in male marsupials.
+
+Martin, W.C.L., on alarm manifested by an orang at the sight of a
+turtle; on the hair in Hylobates; on a female American deer; on the
+voice of Hylobates agilis; on Semnopithecus nemaeus.
+
+Martin, on the beards of the inhabitants of St. Kilda.
+
+Martins deserting their young.
+
+Martins, C., on death caused by inflammation of the vermiform appendage.
+
+Mastoid processes in man and apes.
+
+Maudsley, Dr., on the influence of the sense of smell in man; on idiots
+smelling their food; on Laura Bridgman; on the development of the vocal
+organs; moral sense failing in incipient madness; change of mental
+faculties at puberty in man.
+
+Mayers, W.F., on the domestication of the goldfish in China.
+
+Mayhew, E., on the affection between individuals of different sexes in
+the dog.
+
+Maynard, C.J., on the sexes of Chrysemys picta.
+
+Meckel, on correlated variation of the muscles of the arm and leg.
+
+Medicines, effect produced by, the same in man and in monkeys.
+
+Medusae, bright colours of some.
+
+Megalithic structures, prevalence of.
+
+Megapicus validus, sexual difference of colour in.
+
+Megasoma, large size of males of.
+
+Meigs, Dr. A., on variation in the skulls of the natives of America.
+
+Meinecke, on the numerical proportion of the sexes in butterflies.
+
+Melanesians, decrease of.
+
+Meldola, Mr., colours and marriage flight of Colias and Pieris.
+
+Meliphagidae, Australian, nidification of.
+
+Melita, secondary sexual characters of.
+
+Meloe, difference of colour in the sexes of a species of.
+
+Memnon, young.
+
+Memory, manifestations of, in animals.
+
+Mental characters, difference of, in different races of men.
+
+Mental faculties, diversity of, in the same race of men; inheritance of;
+variation of, in the same species; similarity of the, in different races
+of man; of birds.
+
+Mental powers, difference of, in the two sexes in man.
+
+Menura Alberti, song of.
+
+Menura superba, long tails of both sexes of.
+
+Merganser, trachea of the male.
+
+Merganser serrator, male plumage of.
+
+Mergus cucullatus, speculum of.
+
+Mergus merganser, young of.
+
+Metallura, splendid tail-feathers of.
+
+Methoca ichneumonides, large male of.
+
+Meves, M., on the drumming of the snipe.
+
+Mexicans, civilisation of the, not foreign.
+
+Meyer, on a convoluted body at the extremity of the tail in a Macacus
+and a cat.
+
+Meyer, Dr. A., on the copulation of Phryganidae of distinct species.
+
+Meyer, Prof. L., on development of helix of ear; men's ears more
+variable than women's; antennae serving as ears.
+
+Migrations of man, effects of.
+
+Migratory instinct of birds; vanquishing the maternal.
+
+Mill, J.S., on the origin of the moral sense; on the "greatest happiness
+principle;" on the difference of the mental powers in the sexes of man.
+
+Millipedes.
+
+Milne-Edwards, H., on the use of enlarged chelae of the male Gelasimus.
+
+Milvago leucurus, sexes and young of.
+
+Mimicry.
+
+Mimus polyglottus.
+
+Mind, difference of, in man and the highest animals; similarity of the,
+in different races.
+
+Minnow, proportion of the sexes in the.
+
+Mirror, behaviour of monkeys before.
+
+Mirrors, larks attracted by.
+
+Mitchell, Dr., interbreeding in the Hebrides.
+
+Mitford, selection of children in Sparta.
+
+Mivart, St. George, on the reduction of organs; on the ears of the
+lemuroidea; on variability of the muscles in lemuroidea; on the caudal
+vertebrae of monkeys; on the classification of the primates; on the
+orang and on man; on differences in the lemuroidea; on the crest of the
+male newt.
+
+Mobius, Prof., on reasoning powers in a pike.
+
+Mocking-thrush, partial migration of; young of the.
+
+Modifications, unserviceable.
+
+Moggridge, J.T., on habits of spiders; on habits of ants.
+
+Moles, numerical proportion of the sexes in; battles of male.
+
+Mollienesia petenensis, sexual difference in.
+
+Mollusca, beautiful colours and shapes of; absence of secondary sexual
+characters in the.
+
+Molluscoida.
+
+Monacanthus scopas and M. Peronii.
+
+Monboddo, Lord, on music.
+
+Mongolians, perfection of the senses in.
+
+Monkey, protecting his keeper from a baboon; bonnet-; rhesus-, sexual
+difference in colour of the; moustache-, colours of the.
+
+Monkeys, liability of, to the same diseases as man; male, recognition
+of women by; diversity of the mental faculties in; breaking hard fruits
+with stones; hands of the; basal caudal vertebrae of, imbedded in
+the body; revenge taken by; maternal affection in; variability of the
+faculty of attention in; American, manifestation of reason in; using
+stones and sticks; imitative faculties of; signal-cries of; mutual
+kindnesses of; sentinels posted by; human characters of; American,
+direction of the hair on the arms of some; gradation of species of;
+beards of; ornamental characters of; analogy of sexual differences of,
+with those of man; different degrees of difference in the sexes of;
+expression of emotions by; generally monogamous habits of; polygamous
+habits of some; naked surfaces of; courtship of.
+
+Monogamy, not primitive.
+
+Monogenists.
+
+Mononychus pseudacori, stridulation of.
+
+Monotremata, development of the nictitating membrane in; lactiferous
+glands of; connecting mammals with reptiles.
+
+Monstrosities, analogous, in man and lower animals; caused by arrest of
+development; correlation of; transmission of.
+
+Montagu, G., on the habits of the black and red grouse; on the pugnacity
+of the ruff; on the singing of birds; on the double moult of the male
+pintail.
+
+Monteiro, Mr., on Bucorax abyssinicus.
+
+Montes de Oca, M., on the pugnacity of male Humming-birds.
+
+Monticola cyanea.
+
+Monuments, as traces of extinct tribes.
+
+Moose, battles of; horns of the, an incumbrance.
+
+Moral and instinctive impulses, alliance of.
+
+Moral faculties, their influence on natural selection in man.
+
+Moral rules, distinction between the higher and lower.
+
+Moral sense, so-called, derived from the social instincts; origin of
+the.
+
+Moral tendencies, inheritance of.
+
+Morality, supposed to be founded in selfishness; test of, the general
+welfare of the community; gradual rise of; influence of a high standard
+of.
+
+Morgan, L.H., on the beaver; on the reasoning powers of the beaver; on
+the forcible capture of wives; on the castoreum of the beaver; marriage
+unknown in primeval times; on polyandry.
+
+Morley, J., on the appreciation of praise and fear of blame.
+
+Morris, F.O., on hawks feeding an orphan nestling.
+
+Morse, Dr., colours of mollusca.
+
+Morselli, E., division of the malar bone.
+
+Mortality, comparative, of female and male.
+
+Morton on the number of species of man.
+
+Moschkau, Dr. A., on a speaking starling.
+
+Moschus moschiferus, odoriferous organs of.
+
+Motacillae, Indian, young of.
+
+Moth, odoriferous.
+
+Moths, absence of mouth in some males; apterous female; male, prehensile
+use of the tarsi by; male, attracted by females; sound produced by;
+coloration of; sexual differences of colour in.
+
+Motmot, inheritance of mutilation of tail feathers; racket-shaped
+feathers in the tail of a.
+
+Moult, double; double annual, in birds.
+
+Moulting of birds.
+
+Moults, partial.
+
+Mouse, song of.
+
+Moustache-monkey, colours of the.
+
+Moustaches, in monkeys.
+
+Mud-turtle, long claws of the male.
+
+Mulattoes, persistent fertility of; immunity of, from yellow fever.
+
+Mule, sterility and strong vitality of the.
+
+Mules, rational.
+
+Muller, Ferd., on the Mexicans and Peruvians.
+
+Muller, Fritz, on astomatous males of Tanais; on the disappearance of
+spots and stripes in adult mammals; on the proportions of the sexes in
+some Crustacea; on secondary sexual characters in various Crustaceans;
+musical contest between male Cicadae; mode of holding wings in Castina;
+on birds shewing a preference for certain colours; on the sexual
+maturity of young amphipod Crustacea.
+
+Muller, Hermann, emergence of bees, from pupa; pollen-gathering of bees;
+proportion of sexes in bees; courting of Eristalis; colour and sexual
+selection with bees.
+
+Muller, J., on the nictitating membrane and semilunar fold.
+
+Muller, Max, on the origin of language; language implies power of
+general conception; struggle for life among the words, etc., of
+languages.
+
+Muller, S., on the banteng; on the colours of Semnopithecus chrysomelas.
+
+Muntjac-deer, weapons of the.
+
+Murie, J., on the reduction of organs; on the ears of the Lemuroidea; on
+variability of the muscles in the Lemuroidea; basal caudal vertebrae
+of Macacus brunneus imbedded in the body; on the manner of sitting in
+short-tailed apes; on differences in the Lemuroidea; on the throat-pouch
+of the male bustard; on the mane of Otaria jubata; on the sub-orbital
+pits of Ruminants; on the colours of the sexes in Otaria nigrescens.
+
+Murray, A., on the Pediculi of different races of men.
+
+Murray, T.A., on the fertility of Australian women with white men.
+
+Mus coninga.
+
+Mus minutus, sexual difference in the colour of.
+
+Musca vomitoria.
+
+Muscicapa grisola.
+
+Muscicapa luctuosa.
+
+Muscicapa ruticilla, breeding in immature plumage.
+
+Muscle, ischio-pubic.
+
+Muscles, rudimentary, occurrence of, in man; variability of the; effects
+of use and disuse upon; animal-like abnormalities of, in man; correlated
+variation of, in the arm and leg; variability of, in the hands and feet;
+of the jaws, influence of, on the physiognomy of the Apes; habitual
+spasms of, causing modifications of the facial bones, of the early
+progenitors of man; greater variability of the, in men than in women.
+
+Musculus sternalis, Prof. Turner on the.
+
+Music, of birds; discordant, love of savages for; reason of power of
+perception of notes in animals; power of distinguishing notes; its
+connection with primeval speech; different appreciation of, by different
+peoples; origin of; effects of.
+
+Musical cadences, perception of, by animals; powers of man.
+
+Musk-deer, canine teeth of male; male, odoriferous organs of the; winter
+change of the.
+
+Musk-duck, Australian; large size of male; of Guiana, pugnacity of the
+male.
+
+Musk-ox, horns of.
+
+Musk-rat, protective resemblance of the, to a clod of earth.
+
+Musophagae, colours and nidification of the; both sexes of, equally
+brilliant.
+
+Mussels opened by monkeys.
+
+Mustela, winter change of two species of.
+
+Musters, Captain, on Rhea Darwinii; marriages amongst Patagonians.
+
+Mutilations, healing of; inheritance of.
+
+Mutilla europaea, stridulation of.
+
+Mutillidae, absence of ocelli in female.
+
+Mycetes caraya, polygamous; vocal organs of; beard of; sexual
+differences of colour in; voice of.
+
+Mycetes seniculus, sexual differences of colour in.
+
+Myriapoda.
+
+Nageli, on the influence of natural selection on plants; on the
+gradation of species of plants.
+
+Nails, coloured yellow or purple in part of Africa.
+
+Narwhal, tusks of the.
+
+Nasal cavities, large size of, in American aborigines.
+
+Nascent organs.
+
+Nathusius, H. von, on the improved breeds of pigs; male domesticated
+animals more variable than females; horns of castrated sheep; on the
+breeding of domestic animals.
+
+Natural selection, its effects on the early progenitors of man;
+influence of, on man; limitation of the principle; influence of, on
+social animals; Mr. Wallace on the limitation of, by the influence of
+the mental faculties in man; influence of, in the progress of the United
+States; in relation to sex.
+
+Natural and sexual selection contrasted.
+
+Naulette, jaw from, large size of the canines in.
+
+Neanderthal skull, capacity of the.
+
+Neck, proportion of, in soldiers and sailors.
+
+Necrophorus, stridulation of.
+
+Nectarinia, young of.
+
+Nectariniae, moulting of the; nidification of.
+
+Negro, resemblance of a, to Europeans in mental characters.
+
+Negro-women, their kindness to Mungo Park.
+
+Negroes, Caucasian features in; character of; lice of; fertility of,
+when crossed with other races; blackness of; variability of; immunity
+of, from yellow fever; difference of, from Americans; disfigurements
+of the; colour of new-born children of; comparative beardlessness of;
+readily become musicians; appreciation of beauty of their women by; idea
+of beauty among; compression of the nose by some.
+
+Nemertians, colours of.
+
+Neolithic period.
+
+Neomorpha, sexual difference of the beak in.
+
+Nephila, size of male.
+
+Nests, made by fishes; decoration of, by Humming-birds.
+
+Neumeister, on a change of colour in pigeons after several moultings.
+
+Neuration, difference of, in the two sexes of some butterflies and
+hymenoptera.
+
+Neuroptera.
+
+Neurothemis, dimorphism in.
+
+New Zealand, expectation by the natives of, of their extinction;
+practice of tattooing in; aversion of natives of, to hairs on the face;
+pretty girls engrossed by the chiefs in.
+
+Newton, A., on the throat-pouch of the male bustard; on the differences
+between the females of two species of Oxynotus; on the habits of the
+Phalarope, dotterel, and godwit.
+
+Newts.
+
+Nicholson, Dr., on the non-immunity of dark Europeans from yellow fever.
+
+Nictitating membrane.
+
+Nidification of fishes; relation of, to colour; of British birds.
+
+Night-heron, cries of the.
+
+Nightingale, arrival of the male before the female; object of the song
+of the.
+
+Nightingales, new mates found by.
+
+Nightjar, selection of a mate by the female; Australian, sexes of;
+coloration of the.
+
+Nightjars, noise made by some male, with their wings; elongated feathers
+in.
+
+Nilghau, sexual differences of colour in the.
+
+Nilsson, Prof., on the resemblance of stone arrow-heads from various
+places; on the development of the horns of the reindeer.
+
+Nipples, absence of, in Monotremata.
+
+Nitsche, Dr., ear of foetal orang.
+
+Nitzsch, C.L., on the down of birds.
+
+Noctuae, brightly-coloured beneath.
+
+Noctuidae, coloration of.
+
+Nomadic habits, unfavourable to human progress.
+
+Nordmann, A., on Tetrao urogalloides.
+
+Norfolk Island, half-breeds on.
+
+Norway, numerical proportion of male and female births in.
+
+Nose, resemblance of, in man and the apes; piercing and ornamentation of
+the; very flat, not admired in negroes; flattening of the.
+
+Nott and Gliddon, on the features of Rameses II.; on the features of
+Amunoph III.; on skulls from Brazilian caves; on the immunity of negroes
+and mulattoes from yellow fever; on the deformation of the skull among
+American tribes.
+
+Novara, voyage of the, suicide in New Zealand.
+
+Nudibranch Mollusca, bright colours of.
+
+Numerals, Roman.
+
+Nunemaya, natives of, bearded.
+
+Nuthatch, of Japan, intelligence of; Indian.
+
+Obedience, value of.
+
+Observation, powers of, possessed by birds.
+
+Occupations, sometimes a cause of diminished stature; effect of, upon
+the proportions of the body.
+
+Ocelli, absence of, in female Mutilidae.
+
+Ocelli of birds, formation and variability of the.
+
+Ocelot, sexual differences in the colouring of the.
+
+Ocyhaps lophotes.
+
+Odonata.
+
+Odonestis potatoria, sexual difference of colour in.
+
+Odour, correlation of, with colour of skin; of moths; emitted by snakes
+in the breeding season; of mammals.
+
+Oecanthus nivalis, difference of colour in the sexes of.
+
+Oecanthus pellucidus.
+
+Ogle, Dr. W., relation between colour and power of smell.
+
+Oidemia.
+
+Oliver, on sounds produced by Pimelia striata.
+
+Omaloplia brunnea, stridulation of.
+
+Onitis furcifer, processes of anterior femora of the male, and on the
+head and thorax of the female.
+
+Onthophagus.
+
+Onthophagus rangifer, sexual differences of; variations in the horns of
+the male.
+
+Ophidia, sexual differences of.
+
+Ophidium.
+
+Opossum, wide range of, in America.
+
+Optic nerve, atrophy of the, caused by destruction of the eye.
+
+Orang-Outan, Bischoff on the agreement of the brain of the, with that
+of man; adult age of the; ears of the; vermiform appendage of; hands
+of the; absence of mastoid processes in the; platforms built by the;
+alarmed at the sight of a turtle; using a stick as a lever; using
+missiles; using the leaves of the Pandanus as a night covering;
+direction of the hair on the arms of the; its aberrant characters;
+supposed evolution of the; voice of the; monogamous habits of the; male,
+beard of the.
+
+Oranges, treatment of, by monkeys.
+
+Orange-tip butterfly.
+
+Orchestia Darwinii, dimorphism of males of.
+
+Orchestia Tucuratinga, limbs of.
+
+Ordeal, trial by.
+
+Oreas canna, colours of.
+
+Oreas Derbianus, colours of.
+
+Organs, prehensile; utilised for new purposes.
+
+Organic scale, von Baer's definition of progress in.
+
+Orioles, nidification of.
+
+Oriolus, species of, breeding in immature plumage.
+
+Oriolus melanocephalus, coloration of the sexes in.
+
+Ornaments, prevalence of similar; of male birds; fondness of savages
+for.
+
+Ornamental characters, equal transmission of, to both sexes, in mammals;
+of monkeys.
+
+Ornithoptera croesus.
+
+Ornithorhynchus, reptilian tendency of; spur of the male.
+
+Orocetes erythrogastra, young of.
+
+Orrony, Grotto of.
+
+Orsodacna atra, difference of colour in the sexes of.
+
+Orsodacna ruficollis.
+
+Orthoptera, metamorphosis of; stridulating apparatus of; colours of;
+rudimentary stridulating organs in female; stridulation of the, and
+Homoptera, discussed.
+
+Ortygornis gularis, pugnacity of the male.
+
+Oryctes, stridulation of; sexual differences in the stridulant organs
+of.
+
+Oryx leucoryx, use of the horns of.
+
+Osphranter rufus, sexual difference in the colour of.
+
+Ostrich, African, sexes and incubation of the.
+
+Ostriches, stripes of young.
+
+Otaria jubata, mane of the male.
+
+Otaria nigrescens, difference in the coloration of the sexes of.
+
+Otis bengalensis, love-antics of the male.
+
+Otis tarda, throat-pouch of the male; polygamous.
+
+Ouzel, ring-, colours and nidification of the.
+
+Ouzel, water-, singing in the autumn; colours and nidification of the.
+
+Ovibos moschatus, horns of.
+
+Ovipositor of insects.
+
+Ovis cycloceros, mode of fighting of.
+
+Ovule of man.
+
+Owen, Prof., on the Corpora Wolffiana; on the great toe in man; on
+the nictitating membrane and semilunar fold; on the development of the
+posterior molars in different races of man; on the length of the caecum
+in the Koala; on the coccygeal vertebrae; on rudimentary structures
+belonging to the reproductive system; on abnormal conditions of the
+human uterus; on the number of digits in the Ichthyopterygia; on the
+canine teeth in man; on the walking of the chimpanzee and orang; on the
+mastoid processes in the higher apes; on the hairiness of elephants in
+elevated districts; on the caudal vertebrae of monkeys; classification
+of mammalia; on the hair in monkeys; on the piscine affinities of the
+Ichthyosaurians; on polygamy and monogamy among the antelopes; on the
+horns of Antilocapra Americana; on the musky odour of crocodiles during
+the breeding season; on the scent-glands of snakes; on the Dugong,
+Cachalot, and Ornithorhynchus; on the antlers of the red deer; on the
+dentition of the Camelidae; on the horns of the Irish elk; on the voice
+of the giraffe, porcupine, and stag; on the laryngeal sac of the gorilla
+and orang; on the odoriferous glands of mammals; on the effects of
+emasculation on the vocal organs of men; on the voice of Hylobates
+agilis; on American monogamous monkeys.
+
+Owls, white, new mates found by.
+
+Oxynotus, difference of the females of two species of.
+
+Pachydermata.
+
+Pachytylus migratorius.
+
+Paget, on the abnormal development of hairs in man; on the thickness of
+the skin on the soles of the feet of infants.
+
+Pagurus, carrying the female.
+
+Painting, pleasure of savages in.
+
+Palaemon, chelae of a species of.
+
+Palaeornis, sexual differences of colour in.
+
+Palaeornis javanicus, colour of beak of.
+
+Palaeornis rosa, young of.
+
+Palamedea cornuta, spurs on the wings.
+
+Paleolithic period.
+
+Palestine, habits of the chaffinch in.
+
+Pallas, on the perfection of the senses in the Mongolians; on the
+want of connexion between climate and the colour of the skin; on the
+polygamous habits of Antilope Saiga; on the lighter colour of horses
+and cattle in winter in Siberia; on the tusks of the musk-deer; on
+the odoriferous glands of mammals; on the odoriferous glands of the
+musk-deer; on winter changes of colour in mammals; on the ideal of
+female beauty in North China.
+
+Palmaris accessorius, muscle variations of the.
+
+Pampas, horses of the.
+
+Pangenesis, hypothesis of.
+
+Panniculus carnosus.
+
+Pansch, on the brain of a foetal Cebus apella.
+
+Papilio, proportion of the sexes in North American species of; sexual
+differences of colouring in species of; coloration of the wings in
+species of.
+
+Papilio ascanius.
+
+Papilio Sesostris and Childrenae, variability of.
+
+Papilio Turnus.
+
+Papilionidae, variability in the.
+
+Papuans, line of separation between the, and the Malays; beards of the;
+teeth of.
+
+Papuans and Malays, contrast in characters of.
+
+Paradise, Birds of; supposed by Lesson to be polygamous; rattling of
+their quills by; racket-shaped feathers in; sexual differences in colour
+of; decomposed feathers in; display of plumage by the male; sexual
+differences in colour of.
+
+Paradisea apoda, barbless feathers in the tail of; plumage of; and P.
+papuana; divergence of the females of; increase of beauty with age.
+
+Paradisea papuana, plumage of.
+
+Paraguay, Indians of, eradication of eyebrows and eyelashes by.
+
+Parallelism of development of species and languages.
+
+Parasites, on man and animals; as evidence of specific identity or
+distinctness; immunity from, correlated with colour.
+
+Parental feeling in earwigs, starfishes, and spiders; affection, partly
+a result of natural selection.
+
+Parents, age of, influence upon sex of offspring.
+
+Parinae, sexual difference of colour in.
+
+Park, Mungo, negro-women teaching their children to love the truth; his
+treatment by the negro-women; on negro opinions of the appearance of
+white men.
+
+Parker, Mr., no bird or reptile in line of mammalian descent.
+
+Parrakeet, young of; Australian, variation in the colour of the thighs
+of a male.
+
+Parrot, racket-shaped feathers in the tail of a; instance of benevolence
+in a.
+
+Parrots, change of colour in; imitative faculties of; living in
+triplets; affection of; colours and nidification of the; immature
+plumage of the; colours of; sexual differences of colour in; musical
+powers of.
+
+Parthenogenesis in the Tenthredinae; in Cynipidae; in Crustacea.
+
+Partridge, monogamous; proportion of the sexes in the; Indian; female.
+
+Partridge-"dances."
+
+Partridges, living in triplets; spring coveys of male; distinguishing
+persons.
+
+Parus coeruleus.
+
+Passer, sexes and young of.
+
+Passer brachydactylus.
+
+Passer domesticus.
+
+Passer montanus.
+
+Patagonians, self-sacrifice by; marriages of.
+
+Patterson, Mr., on the Agrionidae.
+
+Patteson, Bishop, decrease of Melanesians.
+
+Paulistas of Brazil.
+
+Pavo cristatus.
+
+Pavo muticus, possession of spurs by the female.
+
+Pavo nigripennis.
+
+Payaguas Indians, thin legs and thick arms of the.
+
+Payan, Mr., on the proportion of the sexes in sheep.
+
+Peacock, polygamous; sexual characters of; pugnacity of the; Javan,
+possessing spurs; rattling of the quills by; elongated tail-coverts of
+the; love of display of the; ocellated spots of the; inconvenience of
+long tail of the, to the female; continued increase of beauty of the.
+
+Peacock-butterfly.
+
+Peafowl, preference of females for a particular male; first advances
+made by the female.
+
+Pediculi of domestic animals and man.
+
+Pedigree of man.
+
+Pedionomus torquatus, sexes of.
+
+Peel, J., on horned sheep.
+
+Peewit, wing-tubercles of the male.
+
+Pelagic animals, transparency of.
+
+Pelecanus erythrorhynchus, horny crest on the beak of the male, during
+the breeding season.
+
+Pelecanus onocrotalus, spring plumage of.
+
+Pelele, an African ornament.
+
+Pelican, blind, fed by his companions; young, guided by old birds;
+pugnacity of the male.
+
+Pelicans, fishing in concert.
+
+Pelobius Hermanni, stridulation of.
+
+Pelvis, alteration of, to suit the erect attitude of man; differences of
+the, in the sexes of man.
+
+Penelope nigra, sound produced by the male.
+
+Pennant, on the battles of seals; on the bladder-nose seal.
+
+Penthe, antennal cushions of the male.
+
+Perch, brightness of male, during breeding season.
+
+Peregrine falcon, new mate found by.
+
+Period of variability, relation of, to sexual selection.
+
+Periodicity, vital, Dr. Laycock on.
+
+Periods, lunar, followed by functions in man and animals.
+
+Periods of life, inheritance at corresponding.
+
+Perisoreus canadensis, young of.
+
+Peritrichia, difference of colour in the sexes of a species of.
+
+Periwinkle.
+
+Pernis cristata.
+
+Perrier, M., on sexual selection; on bees.
+
+Perseverance, a characteristic of man.
+
+Persians, said to be improved by intermixture with Georgians and
+Circassians.
+
+Personnat, M., on Bombyx Yamamai.
+
+Peruvians, civilisation of the, not foreign.
+
+Petrels, colours of.
+
+Petrocincla cyanea, young of.
+
+Petrocossyphus.
+
+Petronia.
+
+Pfeiffer, Ida, on Javan ideas of beauty.
+
+Phacochoerus aethiopicus, tusks and pads of.
+
+Phalanger, Vulpine, black varieties of the.
+
+Phalaropus fulicarius.
+
+Phalaropus hyperboreus.
+
+Phanaeus.
+
+Phanaeus carnifex, variation of the horns of the male.
+
+Phanaeus faunus, sexual differences of.
+
+Phanaeus lancifer.
+
+Phaseolarctus cinereus, taste for rum and tobacco.
+
+Phasgonura viridissima, stridulation of.
+
+Phasianus Soemmerringii.
+
+Phasianus versicolor.
+
+Phasianus Wallichii.
+
+Pheasant, polygamous; and black grouse, hybrids of; production of
+hybrids with the common fowl; immature plumage of the.
+
+Pheasant, Amherst, display of.
+
+Pheasant, Argus, display of plumage by the male; ocellated spots of the;
+gradation of characters in the.
+
+Pheasant, Blood- Pheasant, Cheer.
+
+Pheasant, Eared, length of the tail in the; sexes alike in the.
+
+Pheasant, Fire-backed, possessing spurs.
+
+Pheasant, Golden, display of plumage by the male; age of mature plumage
+in the; sex of young, ascertained by pulling out head-feathers.
+
+Pheasant, Kalij, drumming of the male.
+
+Pheasant, Reeve's, length of the tail in.
+
+Pheasant, Silver, triumphant male, deposed on account of spoiled
+plumage; sexual coloration of the.
+
+Pheasant, Soemmerring's.
+
+Pheasant, Tragopan, display of plumage by the male; marking of the sexes
+of the.
+
+Pheasants, period of acquisition of male characters in the family of
+the; proportion of sexes in chicks of; length of the tail in.
+
+Philters, worn by women.
+
+Phoca groenlandica, sexual difference in the coloration of.
+
+Phoenicura ruticilla.
+
+Phosphorescence of insects.
+
+Phryganidae, copulation of distinct species of.
+
+Phryniscus nigricans.
+
+Physical inferiority, supposed, of man.
+
+Pickering, on the number of species of man.
+
+Picton, J.A., on the soul of man.
+
+Picus auratus.
+
+Picus major.
+
+Pieris.
+
+Pigeon, female, deserting a weakened mate; carrier, late development of
+the wattle in; pouter, late development of crop in; domestic, breeds and
+sub-breeds of.
+
+Pigeons, nestling, fed by the secretion of the crop of both parents;
+
+changes of plumage in; transmission of sexual peculiarities in; Belgian,
+with black-streaked males; changing colour after several moultings;
+numerical proportion of the sexes in; cooing of; variations in plumage
+of; display of plumage by male; local memory of; antipathy of female,
+to certain males; pairing of; profligate male and female; wing-bars
+and tail-feathers of; supposititious breed of; pouter and carrier,
+peculiarities of, predominant in males; nidification of; Australian;
+immature plumage of the.
+
+Pigs, origin of the improved breeds of; numerical proportion of the
+sexes in; stripes of young; tusks of miocene; sexual preference shewn
+by.
+
+Pike, American, brilliant colours of the male, during the breeding
+season.
+
+Pike, reasoning powers of; male, devoured by females.
+
+Pike, L.O., on the psychical elements of religion.
+
+Pimelia striata, sounds produced by the female.
+
+Pinel, hairiness in idiots.
+
+Pintail, drake, plumage of; pairing with a wild duck.
+
+Pintail Duck, pairing with a widgeon.
+
+Pipe-fish, filamentous; marsupial receptacles of the male.
+
+Pipits, moulting of the.
+
+Pipra, modified secondary wing-feathers of male.
+
+Pipra deliciosa.
+
+Pirates stridulus, stridulation of.
+
+Pitcairn island, half-breeds on.
+
+Pithecia leucocephala, sexual differences of colour in.
+
+Pithecia Satanas, beard of; resemblance of, to a negro.
+
+Pits, suborbital, of Ruminants.
+
+Pittidae, nidification of.
+
+Placentata.
+
+Plagiostomous fishes.
+
+Plain-wanderer, Australian.
+
+Planariae, bright colours of some.
+
+Plantain-eaters, colours and nidification of the; both sexes of, equally
+brilliant.
+
+Plants, cultivated, more fertile than wild; Nageli, on natural
+selection in; male flowers of, mature before the female; phenomena of
+fertilisation in.
+
+Platalea, change of plumage in.
+
+Platyblemus.
+
+Platycercus, young of.
+
+Platyphyllum concavum.
+
+Platyrrhine monkeys.
+
+Platysma myoides.
+
+Plecostomus, head-tentacles of the males of a species of.
+
+Plecostomus barbatus, peculiar beard of the male.
+
+Plectropterus gambensis, spurred wings of.
+
+Ploceus.
+
+Plovers, wing-spurs of; double moult in.
+
+Plumage, changes of, inheritance of, by fowls; tendency to analogous
+variation in; display of, by male birds; changes of, in relation to
+season; immature, of birds; colour of, in relation to protection.
+
+Plumes on the head in birds, difference of, in the sexes.
+
+Pneumora, structure of.
+
+Podica, sexual difference in the colour of the irides.
+
+Poeppig, on the contact of civilised and savage races.
+
+Poison, avoidance of, by animals.
+
+Poisonous fruits and herbs avoided by animals.
+
+Poisons, immunity from, correlated with colour.
+
+Polish fowls, origin of the crest in.
+
+Pollen and van Dam, on the colours of Lemur macaco.
+
+Polyandry, in certain Cyprinidae; among the Elateridae.
+
+Polydactylism in man.
+
+Polygamy, influence of, upon sexual selection; superinduced by
+domestication; supposed increase of female births by. In the
+stickleback.
+
+Polygenists.
+
+Polynesia, prevalence of infanticide in.
+
+Polynesians, wide geographical range of; difference of stature among
+the; crosses of; variability of; heterogeneity of the; aversion of, to
+hairs on the face.
+
+Polyplectron, number of spurs in; display of plumage by the male;
+gradation of characters in; female of.
+
+Polyplectron chinquis.
+
+Polyplectron Hardwickii.
+
+Polyplectron malaccense.
+
+Polyplectron Napoleonis.
+
+Polyzoa.
+
+Pomotis.
+
+Pontoporeia affinis.
+
+Porcupine, mute, except in the rutting season.
+
+Pores, excretory, numerical relation of, to the hairs in sheep.
+
+Porpitae, bright colours of some.
+
+Portax picta, dorsal crest and throat-tuft of; sexual differences of
+colour in.
+
+Portunus puber, pugnacity of.
+
+Potamochoerus pencillatus, tusks and facial knobs of the.
+
+Pouchet, G., the relation of instinct to intelligence; on the instincts
+of ants; on the caves of Abou-Simbel; on the immunity of negroes from
+yellow fever; change of colour in fishes.
+
+Pouter pigeon, late development of the large crop in.
+
+Powell, Dr., on stridulation.
+
+Power, Dr., on the different colours of the sexes in a species of
+Squilla.
+
+Powys, Mr., on the habits of the chaffinch in Corfu.
+
+Pre-eminence of man.
+
+Preference for males by female birds; shewn by mammals, in pairing.
+
+Prehensile organs.
+
+Presbytis entellus, fighting of the male.
+
+Preyer, Dr., on function of shell of ear; on supernumerary mammae in
+women.
+
+Prichard, on the difference of stature among the Polynesians; on the
+connection between the breadth of the skull in the Mongolians and
+the perfection of their senses; on the capacity of British skulls of
+different ages; on the flattened heads of the Colombian savages; on
+Siamese notions of beauty; on the beardlessness of the Siamese; on
+the deformation of the head among American tribes and the natives of
+Arakhan.
+
+Primary sexual organs.
+
+Primates, sexual differences of colour in.
+
+Primogeniture, evils of.
+
+Prionidae, difference of the sexes in colour.
+
+Proctotretus multimaculatus.
+
+Proctotretus tenuis, sexual difference in the colour of.
+
+Profligacy.
+
+Progenitors, early, of man.
+
+Progress, not the normal rule in human society; elements of.
+
+Prong-horn antelope, horns of.
+
+Proportions, difference of, in distinct races.
+
+Protective colouring in butterflies; in lizards; in birds; in mammals.
+
+Protective nature of the dull colouring of female Lepidoptera.
+
+Protective resemblances in fishes.
+
+Protozoa, absence of secondary sexual characters in.
+
+Pruner-Bey, on the occurrence of the supra-condyloid foramen in the
+humerus of man; on the colour of negro infants.
+
+Prussia, numerical proportion of male and female births in.
+
+Psocus, proportions of the sexes in.
+
+Ptarmigan, monogamous; summer and winter plumage of the; nuptial
+assemblages of; triple moult of the; protective coloration of.
+
+Puff-birds, colours and nidification of the.
+
+Pugnacity of fine-plumaged male birds.
+
+Pumas, stripes of young.
+
+Puppies learning from cats to clean their faces.
+
+Pycnonotus haemorrhous, pugnacity of the male; display of under-tail
+coverts by the male.
+
+Pyranga aestiva, male aiding in incubation; male characters in female
+of.
+
+Pyrodes, difference of the sexes in colour.
+
+Quadrumana, hands of; differences between man and the; sexual
+differences of colour in; ornamental characters of; analogy of sexual
+differences of, with those of man; fighting of males for the females;
+monogamous habits of; beards of the.
+
+Quain, R., on the variation of the muscles in man.
+
+Quatrefages, A. de, on the occurrence of a rudimentary tail in man;
+on variability; on the moral sense as a distinction between man and
+animals; civilised men stronger than savages; on the fertility of
+Australian women with white men; on the Paulistas of Brazil; on the
+evolution of the breeds of cattle; on the Jews; on the liability of
+negroes to tropical fevers after residence in a cold climate; on the
+difference between field-and house-slaves; on the influence of climate
+on colour; colours of annelids; on the Ainos; on the women of San
+Giuliano.
+
+Quechua, see Quichua.
+
+Querquedula acuta.
+
+Quetelet, proportion of sexes in man; relative size in man and woman.
+
+Quichua Indians; local variation of colour in the; no grey hair among
+the; hairlessness of the; long hair of the.
+
+Quiscalus major, proportions of the sexes of, in Florida and Honduras.
+
+Rabbit, white tail of the.
+
+Rabbits, domestic, elongation of the skull in; modification of the skull
+in, by the lopping of the ear; danger-signals of; numerical proportion
+of the sexes in.
+
+Races, distinctive characters of; or species of man; crossed, fertility
+or sterility of; of man, variability of the; of man, resemblance of, in
+mental characters; formation of; of man, extinction of; effects of
+the crossing of; of man, formation of the; of man, children of the;
+beardless, aversion of, to hairs on the face.
+
+Raffles, Sir S., on the banteng.
+
+Rafts, use of.
+
+Rage, manifested by animals.
+
+Raia batis, teeth of.
+
+Raia clavata, female spined on the back; sexual difference in the teeth
+of.
+
+Raia maculata, teeth of.
+
+Rails, spur-winged.
+
+Ram, mode of fighting of the; African, mane of an; fat-tailed.
+
+Rameses II., features of.
+
+Ramsay, Mr., on the Australian musk-duck; on the regent-bird; on the
+incubation of Menura superba.
+
+Rana esculenta, vocal sacs of.
+
+Rat, common, general dispersion of, a consequence of superior cunning;
+supplantation of the native in New Zealand, by the European rat; common,
+said to be polygamous; numerical proportion of the sexes in.
+
+Rats, enticed by essential oils.
+
+Rationality of birds.
+
+Rattlesnakes, difference of the sexes in the; rattles as a call.
+
+Raven, vocal organs of the; stealing bright objects; pied, of the Feroe
+Islands.
+
+Rays, prehensile organs of male.
+
+Razor-bill, young of the.
+
+Reade, Winwood, suicide among savages in Africa; mulattoes not prolific;
+effect of castration of horned sheep; on the Guinea sheep; on the
+occurrence of a mane in an African ram; on singing of negroes; on the
+negroes' appreciation of the beauty of their women; on the admiration
+of negroes for a black skin; on the idea of beauty among negroes; on the
+Jollofs; on the marriage-customs of the negroes.
+
+Reason in animals.
+
+Redstart, American, breeding in immature plumage.
+
+Redstarts, new mates found by.
+
+Reduvidae, stridulation of.
+
+Reed-bunting, head-feathers of the male; attacked by a bullfinch.
+
+Reefs, fishes frequenting.
+
+Reeks, H., retention of horns by breeding deer; cow rejected by a bull;
+destruction of piebald rabbits by cats.
+
+Regeneration, partial, of lost parts in man.
+
+Regent bird.
+
+Reindeer, horns of the; battles of; horns of the female; antlers of,
+with numerous points; winter change of the; sexual preferences shown by.
+
+Relationship, terms of.
+
+Religion, deficiency of among certain races; psychical elements of.
+
+Remorse, deficiency of, among savages.
+
+Rengger, on the diseases of Cebus Azarae; on the diversity of the mental
+faculties of monkeys; on the Payaguas Indians; on the inferiority of
+Europeans to savages in their senses; revenge taken by monkeys; on
+maternal affection in a Cebus; on the reasoning powers of American
+monkeys; on the use of stones by monkeys for cracking hard nuts; on the
+sounds uttered by Cebus Azarae; on the signal-cries of monkeys; on
+the polygamous habits of Mycetes caraya; on the voice of the howling
+monkeys; on the odour of Cervus campestris; on the beards of Mycetes
+caraya and Pithecia Satanas; on the colours of Felis mitis; on the
+colours of Cervus paludosus; on sexual differences of colour in Mycetes;
+on the colour of the infant Guaranys; on the early maturity of the
+female of Cebus Azarae; on the beards of the Guaranys; on the emotional
+notes employed by monkeys; on American polygamous monkeys.
+
+Representative species, of birds.
+
+Reproduction, unity of phenomena of, throughout the mammalia; period of,
+in birds.
+
+Reproductive system, rudimentary structures in the; accessory parts of.
+
+Reptiles.
+
+Reptiles and birds, alliance of.
+
+Resemblances, small, between man and the apes.
+
+Retrievers, exercise of reasoning faculties by.
+
+Revenge, manifested by animals.
+
+Reversion, perhaps the cause of some bad dispositions.
+
+Rhagium, difference of colour in the sexes of a species of.
+
+Rhamphastos carinatus.
+
+Rhea Darwinii.
+
+Rhinoceros, nakedness of; horns of; horns of, used defensively;
+attacking white or grey horses.
+
+Rhynchaea, sexes and young of.
+
+Rhynchaea australis.
+
+Rhynchaea bengalensis.
+
+Rhynchaea capensis.
+
+Rhythm, perception of, by animals.
+
+Richard, M., on rudimentary muscles in man.
+
+Richardson, Sir J., on the pairing of Tetrao umbellus; on Tetrao
+urophasianus; on the drumming of grouse; on the dances of Tetrao
+phasianellus; on assemblages of grouse; on the battles of male deer; on
+the reindeer; on the horns of the musk-ox; on antlers of the reindeer
+with numerous points; on the moose; on the Scotch deerhound.
+
+Richter, Jean Paul, on imagination.
+
+Riedel, on profligate female pigeons.
+
+Riley, Mr., on mimicry in butterflies; bird's disgust at taste of
+certain caterpillars.
+
+Ring-ouzel, colours and nidification of the.
+
+Ripa, Father, on the difficulty of distinguishing the races of the
+Chinese.
+
+Rivalry, in singing, between male birds.
+
+River-hog, African, tusks and knobs of the.
+
+Rivers, analogy of, to islands.
+
+Roach, brightness of the male during breeding-season.
+
+Robbery, of strangers, considered honourable.
+
+Robertson, Mr., remarks on the development of the horns in the roebuck
+and red deer.
+
+Robin, pugnacity of the male; autumn song of the; female singing of the;
+attacking other birds with red in their plumage; young of the.
+
+Robinet, on the difference of size of the male and female cocoons of the
+silk-moth.
+
+Rodents, uterus in the; absence of secondary sexual characters in;
+sexual differences in the colours of.
+
+Roe, winter changes of the.
+
+Rohfs, Dr., Caucasian features in negro; fertility of mixed races
+in Sahara; colours of birds in Sahara; ideas of beauty amongst the
+Bornuans.
+
+Rolle, F., on the origin of man; on a change in German families settled
+in Georgia.
+
+Roller, harsh cry of.
+
+Romans, ancient, gladiatorial exhibitions of the.
+
+Rook, voice of the.
+
+Rossler, Dr., on the resemblance of the lower surface of butterflies to
+the bark of trees.
+
+Rostrum, sexual difference in the length of in some weevils.
+
+Royer, Madlle., mammals giving suck.
+
+Rudimentary organs, origin of.
+
+Rudiments, presence of, in languages.
+
+Rudolphi, on the want of connexion between climate and the colour of the
+skin.
+
+Ruff, supposed to be polygamous; proportion of the sexes in the;
+pugnacity of the; double moult in; duration of dances of; attraction of
+the, to bright objects.
+
+Ruminants, male, disappearance of canine teeth in; generally polygamous;
+suborbital pits of; sexual differences of colour in.
+
+Rupicola crocea, display of plumage by the male.
+
+Ruppell, on canine teeth in deer and antelopes.
+
+Russia, numerical proportion of male and female births in.
+
+Ruticilla.
+
+Rutimeyer, Prof., on the physiognomy of the apes; on tusks of miocene
+boar; on the sexual differences of monkeys.
+
+Rutlandshire, numerical proportion of male and female births in.
+
+Sachs, Prof., on the behaviour of the male and female elements in
+fertilisation.
+
+Sacrifices, human.
+
+Sagittal crest, in male apes and Australians.
+
+Sahara, fertility of mixed races in; birds of the; animal inhabitants of
+the.
+
+Sailors, growth of, delayed by conditions of life; long-sighted.
+
+Sailors and soldiers, difference in the proportions of.
+
+St. John, Mr., on the attachment of mated birds.
+
+St. Kilda, beards of the inhabitants of.
+
+Salmo eriox, and Salmo umbla, colouring of the male, during the breeding
+season.
+
+Salmo lycaodon.
+
+Salmo salar.
+
+Salmon, leaping out of fresh water; male, ready to breed before the
+female; proportion of the sexes in; male, pugnacity of the; male,
+characters of, during the breeding season; spawning of the; breeding of
+immature male.
+
+Salvin, O., inheritance of mutilated feathers; on the Humming-birds; on
+the numerical proportion of the sexes in Humming-birds; on Chamaepetes
+and Penelope; on Selasphorus platycercus; Pipra deliciosa; on
+Chasmorhynchus.
+
+Samoa Islands, beardlessness of the natives of.
+
+Sandhoppers, claspers of male.
+
+Sand-skipper.
+
+Sandwich Islands, variation in the skulls of the natives of the;
+decrease of native population; population of; superiority of the nobles
+in the.
+
+Sandwich Islanders, lice of.
+
+San-Giuliano, women of.
+
+Santali, recent rapid increase of the; Mr. Hunter on the.
+
+Saphirina, characters of the males of.
+
+Sarkidiornis melanonotus, characters of the young.
+
+Sars, O., on Pontoporeia affinis.
+
+Saturnia carpini, attraction of males by the female.
+
+Saturnia Io, difference of coloration in the sexes of.
+
+Saturniidae, coloration of the.
+
+Savage, Dr., on the fighting of the male gorillas; on the habits of the
+gorilla.
+
+Savage and Wyman on the polygamous habits of the gorilla.
+
+Savages, uniformity of, exaggerated; long-sighted; rate of increase
+among, usually small; retention of the prehensile power of the feet
+by; imitative faculties of; causes of low morality of; tribes of,
+supplanting one another; improvements in the arts among; arts of;
+fondness of, for rough music; on long-enduring fashions among; attention
+paid by, to personal appearance; relation of the sexes among.
+
+Saviotti, Dr., division of malar bone.
+
+Saw-fly, pugnacity of a male.
+
+Saw-flies, proportions of the sexes in.
+
+Saxicola rubicola, young of.
+
+Scalp, motion of the.
+
+Scent-glands in snakes.
+
+Schaaffhausen, Prof., on the development of the posterior molars in
+different races of man; on the jaw from La Naulette; on the correlation
+between muscularity and prominent supra-orbital ridges; on the mastoid
+processes of man; on modifications of the cranial bones; on human
+sacrifices; on the probable speedy extermination of the anthropomorphous
+apes; on the ancient inhabitants of Europe; on the effects of use and
+disuse of parts; on the superciliary ridge in man; on the absence of
+race-differences in the infant skull in man; on ugliness.
+
+Schaum, H., on the elytra of Dytiscus and Hydroporus.
+
+Scherzer and Schwarz, measurements of savages.
+
+Schelver, on dragon-flies.
+
+Schiodte, on the stridulation of Heterocerus.
+
+Schlegel, F. von, on the complexity of the languages of uncivilised
+peoples.
+
+Schlegel, Prof., on Tanysiptera.
+
+Schleicher, Prof, on the origin of language.
+
+Schomburgk, Sir R., on the pugnacity of the male musk-duck of Guiana; on
+the courtship of Rupicola crocea.
+
+Schoolcraft, Mr., on the difficulty of fashioning stone implements.
+
+Schopenhauer, on importance of courtship to mankind.
+
+Schweinfurth, complexion of negroes.
+
+Sciaena aquila.
+
+Sclater, P.L., on modified secondary wing-feathers in the males
+of Pipra; on elongated feathers in nightjars; on the species of
+Chasmorhynchus; on the plumage of Pelecanus onocrotalus; on the
+plantain-eaters; on the sexes and young of Tadorna variegata; on the
+colours of Lemur macaco; on the stripes in asses.
+
+Scolecida, absence of secondary sexual characters in.
+
+Scolopax frenata, tail feathers of;
+
+Scolopax gallinago, drumming of.
+
+Scolopax javensis, tail-feathers of.
+
+Scolopax major, assemblies of.
+
+Scolopax Wilsonii, sound produced by.
+
+Scolytus, stridulation of.
+
+Scoter-duck, black, sexual difference in coloration of the; bright beak
+of male.
+
+Scott, Dr., on idiots smelling their food.
+
+Scott, J., on the colour of the beard in man.
+
+Scrope, on the pugnacity of the male salmon; on the battles of stags.
+
+Scudder, S.H., imitation of the stridulation of the Orthoptera; on the
+stridulation of the Acridiidae; on a Devonian insect; on stridulation.
+
+Sculpture, expression of the ideal of beauty by.
+
+Sea-anemones, bright colours of.
+
+Sea-bear, polygamous.
+
+Sea-elephant, male, structure of the nose of the; polygamous.
+
+Sea-lion, polygamous.
+
+Seal, bladder-nose.
+
+Seals, their sentinels generally females; evidence furnished by, on
+classification; polygamous habits of; battles of male; canine teeth of
+male; sexual differences; pairing of; sexual peculiarities of; in the
+coloration of; appreciation of music by.
+
+Sea-scorpion, sexual differences in.
+
+Season, changes of colour in birds, in accordance with the; changes of
+plumage of birds in relation to.
+
+Seasons, inheritance at corresponding.
+
+Sebituani, African chief, trying to alter a fashion.
+
+Sebright Bantam.
+
+Secondary sexual characters; relations of polygamy to; transmitted
+through both sexes; gradation of, in birds.
+
+Sedgwick, W., on hereditary tendency to produce twins.
+
+Seemann, Dr., on the different appreciation of music by different
+peoples; on the effects of music.
+
+Seidlitz, on horns of reindeer.
+
+Selasphorus platycercus, acuminate first primary of the male.
+
+Selby, P.J., on the habits of the black and red grouse.
+
+Selection as applied to primeval man.
+
+Selection, double.
+
+Selection, injurious forms of, in civilised nations.
+
+Selection of male by female birds.
+
+Selection, methodical, of Prussian grenadiers.
+
+Selection, sexual, explanation of; influence of, on the colouring of
+Lepidoptera.
+
+Selection, sexual and natural, contrasted.
+
+Self-command, habit of, inherited; estimation of.
+
+Self-consciousness, in animals.
+
+Self-preservation, instinct of.
+
+Self-sacrifice, by savages; estimation of.
+
+Semilunar fold.
+
+Semnopithecus, long hair on the heads of species of.
+
+Semnopithecus chrysomelas, sexual differences of colour in.
+
+Semnopithecus comatus, ornamental hair on the head of.
+
+Semnopithecus frontatus, beard etc., of.
+
+Semnopithecus nasica, nose of.
+
+Semnopithecus nemaeus, colouring of.
+
+Semnopithecus rubicundus, ornamental hair on the head of.
+
+Senses, inferiority of Europeans to savages in the.
+
+Sentinels, among animals.
+
+Serpents, instinctively dreaded by apes and monkeys.
+
+Serranus, hermaphroditism in.
+
+Setina, noise produced by.
+
+Sex, inheritance limited by.
+
+Sexes, relative proportions of, in man; proportions of, sometimes
+influenced by selection; probable relation of the, in primeval man.
+
+Sexual and natural selection, contrasted.
+
+Sexual characters, effects of the loss of; limitation of.
+
+Sexual characters, secondary; relations of polygamy to; transmitted
+through both sexes; gradation of, in birds.
+
+Sexual differences in man.
+
+Sexual selection, explanation of; influence of, on the colouring of
+Lepidoptera; objections to; action of, in mankind.
+
+Sexual selection in spiders.
+
+Sexual selection, supplemental note on.
+
+Sexual similarity.
+
+Shaler, Prof., sizes of sexes in whales.
+
+Shame.
+
+Sharks, prehensile organs of male.
+
+Sharpe, Dr., Europeans in the tropics.
+
+Sharpe, R.B., on Tanysiptera sylvia; on Ceryle; on the young male of
+Dacelo Gaudi-chaudi.
+
+Shaw, Mr., on the pugnacity of the male salmon.
+
+Shaw, J., on the decorations of birds.
+
+Sheep, danger-signals of; sexual differences in the horns of; horns of;
+domestic, sexual differences of, late developed; numerical proportion
+of the sexes in; inheritance of horns by one sex; effect of castration;
+mode of fighting of; arched foreheads of some.
+
+Sheep, Merino, loss of horns in females of; horns of.
+
+Shells, difference in form of, in male and female Gasteropoda; beautiful
+colours and shapes of.
+
+Shield-drake, pairing with a common duck; New Zealand, sexes and young
+of.
+
+Shooter, J., on the Kaffirs; on the marriage-customs of the Kaffirs.
+
+Shrew-mice, odour of.
+
+Shrike, Drongo.
+
+Shrikes, characters of young.
+
+Shuckard, W.E., on sexual differences in the wings of Hymenoptera.
+
+Shyness of adorned male birds;
+
+Siagonium, proportions of the sexes in; dimorphism in males of.
+
+Siam, proportion of male and female births in.
+
+Siamese, general beardlessness of the; notions of beauty of the; hairy
+family of.
+
+Sidgwick, H., on morality in hypothetical bee community; our actions not
+entirely directed by pain and pleasure.
+
+Siebold, C.T., von, on the proportion of sexes in the Apus; on the
+auditory apparatus of the stridulent Orthoptera.
+
+Sight, inheritance of long and short.
+
+Signal-cries of monkeys.
+
+Silk-moth, proportion of the sexes in; Ailanthus, Prof. Canestrini, on
+the destruction of its larvae by wasps; difference of size of the male
+and female cocoons of the; pairing of the.
+
+Simiadae, their origin and divisions.
+
+Similarity, sexual.
+
+Singing of the Cicadae and Fulgoridae; of tree-frogs; of birds, object
+of the.
+
+Sirenia, nakedness of.
+
+Sirex juvencus.
+
+Siricidae, difference of the sexes in.
+
+Siskin, pairing with a canary.
+
+Sitana, throat-pouch of the males of.
+
+Size, relative, of the sexes of insects.
+
+Skin, dark colour of, a protection against heat.
+
+Skin, movement of the; nakedness of, in man; colour of the.
+
+Skin and hair, correlation of colour of.
+
+Skull, variation of, in man; cubic contents of, no absolute test of
+intellect; Neanderthal, capacity of the; causes of modification of
+the; difference of, in form and capacity, in different races of men;
+variability of the shape of the; differences of, in the sexes in man;
+artificial modification of the shape of.
+
+Skunk, odour emitted by the; white tail of, protective.
+
+Slavery, prevalence of; of women.
+
+Slaves, difference between field-and house-slaves.
+
+Sloth, ornaments of male.
+
+Smell, sense of, in man and animals.
+
+Smith, Adam, on the basis of sympathy.
+
+Smith, Sir A., on the recognition of women by male Cynocephali; on
+revenge by a baboon; on an instance of memory in a baboon; on the
+retention of their colour by the Dutch in South Africa; on the polygamy
+of the South African antelopes; on the polygamy of the lion; on the
+proportion of the sexes in Kobus ellipsiprymnus; on Bucephalus
+capensis; on South African lizards; on fighting gnus; on the horns
+of rhinoceroses; on the fighting of lions; on the colours of the Cape
+Eland; on the colours of the gnu; on Hottentot notions of beauty;
+disbelief in communistic marriages.
+
+Smith, F., on the Cynipidae and Tenthredinidae; on the relative size of
+the sexes of Aculeate Hymenoptera; on the difference between the
+sexes of ants and bees; on the stridulation of Trox sabulosus; on the
+stridulation of Mononychus pseudacori.
+
+Smynthurus luteus, courtship of.
+
+Snakes, sexual differences of; mental powers of; male, ardency of.
+
+"Snarling muscles."
+
+Snipe, drumming of the; coloration of the.
+
+Snipe, painted, sexes and young of.
+
+Snipe, solitary, assemblies of.
+
+Snipes, arrival of male before the female; pugnacity of male; double
+moult in.
+
+Snow-goose, whiteness of the.
+
+Sociability, the sense of duty connected with; impulse to, in animals;
+manifestations of, in man; instinct of, in animals.
+
+Social animals, affection of, for each other; defence of, by the males.
+
+Sociality, probable, of primeval men; influence of, on the development
+of the intellectual faculties; origin of, in man.
+
+Soldiers, American, measurements of.
+
+Soldiers and sailors, difference in the proportions of.
+
+Solenostoma, bright colours and marsupial sac of the females of.
+
+Song, of male birds appreciated by their females; want of, in brilliant
+plumaged birds; of birds.
+
+Sorex, odour of.
+
+Sounds, admired alike by man and animals; produced by fishes; produced
+by male frogs and toads; instrumentally produced by birds.
+
+Spain, decadence of.
+
+Sparassus smaragdulus, difference of colour in the sexes of.
+
+Sparrow, pugnacity of the male; acquisition of the Linnet's song by a;
+coloration of the; immature plumage of the.
+
+Sparrow, white-crowned, young of the.
+
+Sparrows, house-and tree-.
+
+Sparrows, new mates found by.
+
+Sparrows, sexes and young of; learning to sing.
+
+Spathura Underwoodi.
+
+Spawning of fishes.
+
+Spear, used before dispersion of man.
+
+Species, causes of the advancement of; distinctive characters of; or
+races of man; sterility and fertility of, when crossed; supposed, of
+man; gradation of; difficulty of defining; representative, of birds; of
+birds, comparative differences between the sexes of distinct.
+
+Spectrum femoratum, difference of colour in the sexes of.
+
+Speech, connection between the brain and the faculty of; connection of
+intonation with music.
+
+Spel, of the black-cock.
+
+Spencer, Herbert, on the influence of food on the size of the jaws;
+on the dawn of intelligence; on the origin of the belief in spiritual
+agencies; on the origin of the moral sense; on music.
+
+Spengel, disagrees with explanation of man's hairlessness.
+
+Sperm-whales, battles of male.
+
+Sphingidae, coloration of the.
+
+Sphinx, Humming-bird.
+
+Sphinx, Mr. Bates on the caterpillar of a.
+
+Sphinx moth, musky odour of.
+
+Spiders, parental feeling in; male, more active than female; proportion
+of the sexes in; secondary sexual characters of; courtship of male;
+attracted by music; male, small size of.
+
+Spilosoma menthastri, rejected by turkeys.
+
+Spine, alteration of, to suit the erect attitude of man.
+
+Spirits, fondness of monkeys for.
+
+Spiritual agencies, belief in, almost universal.
+
+Spiza cyanea and ciris.
+
+Spoonbill, Chinese, change of plumage in.
+
+Spots, retained throughout groups of birds; disappearance of, in adult
+mammals.
+
+Sprengel, C.K., on the sexuality of plants.
+
+Springboc, horns of the.
+
+Sproat, Mr., on the extinction of savages in Vancouver Island; on the
+eradication of facial hair by the natives of Vancouver Island; on the
+eradication of the beard by the Indians of Vancouver Island.
+
+Spurs, occurrence of, in female fowls; development of, in various
+species of Phasianidae; of Gallinaceous birds; development of, in female
+Gallinaceae.
+
+Squilla, different colours of the sexes of a species of.
+
+Squirrels, battles of male; African, sexual differences in the colouring
+of; black.
+
+Stag, long hairs of the throat of; horns of the; battles of; horns of
+the, with numerous branches; bellowing of the; crest of the.
+
+Stag-beetle, numerical proportion of sexes of; use of jaws; large size
+of male; weapons of the male.
+
+Stainton, H.T., on the numerical proportion of the sexes in the smaller
+moths; habits of Elachista rufocinerea; on the coloration of moths;
+on the rejection of Spilosoma menthastri by turkeys; on the sexes of
+Agrotis exclamationis.
+
+Staley, Bishop, mortality of infant Maories.
+
+Stallion, mane of the.
+
+Stallions, two, attacking a third; fighting; small canine teeth of.
+
+Stansbury, Captain, observations on pelicans.
+
+Staphylinidae, hornlike processes in male.
+
+Starfishes, parental feeling in; bright colours of some.
+
+Stark, Dr., on the death-rate in towns and rural districts; on the
+influence of marriage on mortality; on the higher mortality of males in
+Scotland.
+
+Starling, American field-, pugnacity of male.
+
+Starling, red-winged, selection of a mate by the female.
+
+Starlings, three, frequenting the same nest; new mates found by.
+
+Statues, Greek, Egyptian, Assyrian, etc., contrasted.
+
+Stature, dependence of, upon local influences.
+
+Staudinger, Dr., on breeding Lepidoptera; his list of Lepidoptera.
+
+Staunton, Sir G., hatred of indecency a modern virtue.
+
+Stealing of bright objects by birds.
+
+Stebbing, T.R., on the nakedness of the human body.
+
+Stemmatopus.
+
+Stendhal, see Bombet.
+
+Stenobothrus pratorum, stridulation.
+
+Stephen, Mr. L., on the difference in the minds of men and animals; on
+general concepts in animals; distinction between material and formal
+morality.
+
+Sterility, general, of sole daughters; when crossed, a distinctive
+character of species; under changed conditions.
+
+Sterna, seasonal change of plumage in.
+
+Stickleback, polygamous; male, courtship of the; male, brilliant
+colouring of, during the breeding season; nidification of the.
+
+Sticks used as implements and weapons by monkeys.
+
+Sting in bees.
+
+Stokes, Captain, on the habits of the great bower-bird.
+
+Stoliczka, Dr., on colours in snakes.
+
+Stoliczka, on the pre-anal pores of lizards.
+
+Stonechat, young of the.
+
+Stone implements, difficulty of making; as traces of extinct tribes.
+
+Stones, used by monkeys for breaking hard fruits and as missiles; piles
+of.
+
+Stork, black, sexual differences in the bronchi of the; red beak of the.
+
+Storks, sexual difference in the colour of the eyes of.
+
+Strange, Mr., on the satin bowerbird.
+
+Strepsiceros kudu, horns of; markings of.
+
+Stretch, Mr., on the numerical proportion in the sexes of chickens.
+
+Stridulation, by males of Theridion; of Hemiptera; of the Orthoptera and
+Homoptera discussed; of beetles.
+
+Stripes, retained throughout groups of birds; disappearance of, in adult
+mammals.
+
+Strix flammea.
+
+Structure, existence of unserviceable modifications of.
+
+Struggle for existence, in man.
+
+Struthers, Dr., on the occurrence of the supra-condyloid foramen in the
+humerus of man.
+
+Sturnella ludoviciana, pugnacity of the male.
+
+Sturnus vulgaris.
+
+Sub-species.
+
+Suffering, in strangers, indifference of savages to.
+
+Suicide, formerly not regarded as a crime; rarely practised among the
+lowest savages.
+
+Suidae, stripes of the young.
+
+Sulivan, Sir B.J., on speaking of parrots; on two stallions attacking a
+third.
+
+Sumatra, compression of the nose by the Malays of.
+
+Sumner, Archb., man alone capable of progressive improvement.
+
+Sun-birds, nidification of.
+
+Superciliary ridge in man.
+
+Supernumerary digits, more frequent in men than in women; inheritance
+of; early development of.
+
+Superstitions, prevalence of.
+
+Superstitious customs.
+
+Supra-condyloid foramen in the early progenitors of man.
+
+Suspicion, prevalence of, among animals.
+
+Swallow-tail butterfly.
+
+Swallows deserting their young.
+
+Swan, black, wild, trachea of the; white, young of; red beak of the;
+black-necked.
+
+Swans, young.
+
+Swaysland, Mr., on the arrival of migratory birds.
+
+Swifts, migration of.
+
+Swinhoe, R., on the common rat in Formosa and China; behaviour of
+lizards when caught; on the sounds produced by the male hoopoe; on
+Dicrurus macrocercus and the spoonbill; on the young of Ardeola; on the
+habits of Turnix; on the habits of Rhynchaea bengalensis; on Orioles
+breeding in immature plumage.
+
+Sylvia atricapilla, young of.
+
+Sylvia cinerea, aerial love-dance of the male.
+
+Sympathy, among animals; its supposed basis.
+
+Sympathies, gradual widening of.
+
+Syngnathous fishes, abdominal pouch in male.
+
+Sypheotides auritus, acuminated primaries of the male; ear-tufts of.
+
+Tabanidae, habits of.
+
+Tadorna variegata, sexes and young of.
+
+Tadorna vulpanser.
+
+Tahitians, compression of the nose by the.
+
+Tail, rudimentary, occurrence of, in man; convoluted body in the
+extremity of the; absence of, in man and the higher apes; variability
+of, in species of Macacus and in baboons; presence of, in the early
+progenitors of man; length of, in pheasants; difference of length of
+the, in the two sexes of birds.
+
+Tait, Lawson, on the effects of natural selection on civilised nations.
+
+Tanager, scarlet, variation in the male.
+
+Tanagra aestiva, age of mature plumage in.
+
+Tanagra rubra, young of.
+
+Tanais, absence of mouth in the males of some species of; relations of
+the sexes in; dimorphic males of a species of.
+
+Tankerville, Earl, on the battles of wild bulls.
+
+Tanysiptera, races of, determined from adult males.
+
+Tanysiptera sylvia, long tail-feathers of.
+
+Taphroderes distortus, enlarged left mandible of the male.
+
+Tapirs, longitudinal stripes of young.
+
+Tarsi, dilatation of front, in male beetles.
+
+Tarsius.
+
+Tasmania, half-castes killed by the natives of.
+
+Tasmanians, extinction of.
+
+Taste, in the Quadrumana.
+
+Tattooing, universality of.
+
+Taylor, G., on Quiscalus major.
+
+Taylor, Rev. R., on tattooing in New Zealand.
+
+Tea, fondness of monkeys for.
+
+Teal, constancy of.
+
+Tear-sacs, of Ruminants.
+
+Teebay, Mr., on changes of plumage in spangled Hamburg fowls.
+
+Teeth, rudimentary incisor, in Ruminants; posterior molar, in man;
+wisdom; diversity of; canine, in the early progenitors of man; canine,
+of male mammals; in man, reduced by correlation; staining of the; front,
+knocked out or filed by some savages.
+
+Tegetmeier, Mr., on the transmission of colours in pigeons by one sex
+alone; numerical proportion of male and female births in dogs; on
+the abundance of male pigeons; on the wattles of game-cocks; on the
+courtship of fowls; on the loves of pigeons; on dyed pigeons; blue
+dragon pigeons.
+
+Tembeta, S. American ornament.
+
+Temper, in dogs and horses, inherited.
+
+Tench, proportions of the sexes in the; brightness of male, during
+breeding season.
+
+Tenebrionidae, stridulation of.
+
+Tennent, Sir J.E., on the tusks of the Ceylon Elephant; on the frequent
+absence of beard in the natives of Ceylon; on the Chinese opinion of the
+aspect of the Cingalese.
+
+Tennyson, A., on the control of thought.
+
+Tenthredinidae, proportions of the sexes in; fighting habits of male;
+difference of the sexes in.
+
+Tephrodornis, young of.
+
+Terai, in India.
+
+Termites, habits of.
+
+Terns, white; and black.
+
+Terns, seasonal change of plumage in.
+
+Terror, common action of, upon the lower animals and man.
+
+Testudo elegans.
+
+Testudo nigra.
+
+Tetrao cupido, battles of; sexual difference in the vocal organs of.
+
+Tetrao phasianellus, dances of; duration of dances of.
+
+Tetrao scoticus.
+
+Tetrao tetrix, pugnacity of the male.
+
+Tetrao umbellus, pairing of; battles of; drumming of the male.
+
+Tetrao urogalloides, dances of.
+
+Tetrao urogallus, pugnacity of the male.
+
+Tetrao urophasianus, inflation of the oesophagus in the male.
+
+Thamnobia, young of.
+
+Thecla, sexual differences of colouring in species of.
+
+Thecla rubi, protective colouring of.
+
+Thecophora fovea.
+
+Theognis, selection in mankind.
+
+Theridion, stridulation of males of.
+
+Theridion lineatum.
+
+Thomisus citreus, and Thomisus floricolens, difference of colour in the
+sexes of.
+
+Thompson, J.H., on the battles of sperm-whales.
+
+Thompson, W., on the colouring of the male char during the breeding
+season; on the pugnacity of the males of Gallinula chloropus; on
+the finding of new mates by magpies; on the finding of new mates by
+Peregrine falcons.
+
+Thorax, processes of, in male beetles.
+
+Thorell, T., on the proportion of sexes in spiders.
+
+Thornback, difference in the teeth of the two sexes of the.
+
+Thoughts, control of.
+
+Thrush, pairing with a blackbird; colours and nidification of the.
+
+Thrushes, characters of young.
+
+Thug, remorse of a.
+
+Thumb, absence of, in Ateles and Hylobates.
+
+Thury, M., on the numerical proportion of male and female births among
+the Jews.
+
+Thylacinus, possession of the marsupial sac by the male.
+
+Thysanura.
+
+Tibia, dilated, of the male Crabro cribrarius.
+
+Tibia and femur, proportions of, in the Aymara Indians.
+
+Tierra del Fuego, marriage-customs of.
+
+Tiger, colours and markings of the.
+
+Tigers, depopulation of districts by, in India.
+
+Tillus elongatus, difference of colour in the sexes of.
+
+Timidity, variability of, in the same species.
+
+Tinca vulgaris.
+
+Tipula, pugnacity of male.
+
+Tits, sexual difference of colour in.
+
+Toads, male, treatment of ova by some; male, ready to breed before the
+female.
+
+Todas, infanticide and proportion of sexes; practice polyandry; choice
+of husbands amongst.
+
+Toe, great, condition of, in the human embryo.
+
+Tomicus villosus, proportion of the sexes in.
+
+Tomtit, blue, sexual difference of colour in the.
+
+Tonga Islands, beardlessness of the natives of.
+
+Tooke, Horne, on language.
+
+Tools, flint; used by monkeys; use of.
+
+Topknots in birds.
+
+Tortoise, voice of the male.
+
+Tortures, submitted to by American savages.
+
+Totanus, double moult in.
+
+Toucans, colours and nidification of the; beaks and ceres of the.
+
+Towns, residence in, a cause of diminished stature.
+
+Toynbee, J., on the external shell of the ear in man.
+
+Trachea, convoluted and imbedded in the sternum, in some birds;
+structure of the, in Rhynchaea.
+
+Trades, affecting the form of the skull.
+
+Tragelaphus, sexual differences of colour in.
+
+Tragelaphus scriptus, dorsal crest of; markings of.
+
+Tragopan, swelling of the wattles of the male, during courtship; display
+of plumage by the male; marking of the sexes of the.
+
+Tragops dispar, sexual difference in the colour of.
+
+Training, effect of, on the mental difference between the sexes of man.
+
+Transfer of male characters to female birds.
+
+Transmission, equal, of ornamental characters, to both sexes in mammals.
+
+Traps, avoidance of, by animals; use of.
+
+Treachery, to comrades, avoidance of, by savages.
+
+Tremex columbae.
+
+Tribes, extinct; extinction of.
+
+Trichius, difference of colour in the sexes of a species of.
+
+Trigla.
+
+Trigonocephalus, noise made by tail of.
+
+Trimen, R., on the proportion of the sexes in South African butterflies;
+on the attraction of males by the female Lasiocampa quercus; on
+Pneumora; on difference of colour in the sexes of beetles; on moths
+brilliantly coloured beneath; on mimicry in butterflies; on Gynanisa
+Isis, and on the ocellated spots of Lepidoptera; on Cyllo Leda.
+
+Tringa, sexes and young of.
+
+Tringa cornuta.
+
+Triphaena, coloration of the species of.
+
+Tristram, H.B., on unhealthy districts in North Africa; on the habits of
+the chaffinch in Palestine; on the birds of the Sahara; on the animals
+inhabiting the Sahara.
+
+Triton cristatus.
+
+Triton palmipes.
+
+Triton punctatus.
+
+Troglodyte skulls, greater than those of modern Frenchmen.
+
+Troglodytes vulgaris.
+
+Trogons, colours and nidification of the.
+
+Tropic-birds, white only when mature.
+
+Tropics, freshwater fishes of the.
+
+Trout, proportion of the sexes in; male, pugnacity of the.
+
+Trox sabulosus, stridulation of.
+
+Truth, not rare between members of the same tribe; more highly
+appreciated by certain tribes.
+
+Tulloch, Major, on the immunity of the negro from certain fevers.
+
+Tumbler, almond, change of plumage in the.
+
+Turdus merula, young of.
+
+Turdus migratorius.
+
+Turdus musicus.
+
+Turdus polyglottus, young of.
+
+Turdus torquatus.
+
+Turkey, wild, pugnacity of young male; wild, notes of the; swelling of
+the wattles of the male; variety of, with a top-knot; recognition of a
+dog by a; male, wild, acceptable to domesticated females; wild, first
+advances made by older females; wild, breast-tuft of bristles of the.
+
+Turkey-cock, scraping of the wings of, upon the ground; wild, display of
+plumage by; fighting habits of.
+
+Turner, Prof. W., on muscular fasciculi in man referable to the
+panniculus carnosus; on the occurrence of the supra-condyloid foramen
+in the human humerus; on muscles attached to the coccyx in man; on the
+filum terminale in man; on the variability of the muscles; on abnormal
+conditions of the human uterus; on the development of the mammary
+glands; on male fishes hatching ova in their mouths; on the external
+perpendicular fissure of the brain; on the bridging convolutions in the
+brain of a chimpanzee.
+
+Turnix, sexes of some species of.
+
+Turtle-dove, cooing of the.
+
+Tuttle, H., on the number of species of man.
+
+Tylor, E.B., on emotional cries, gestures, etc., of man; on the origin
+of the belief in spiritual agencies; remorse for violation of tribal
+usage in marrying; on the primitive barbarism of civilised nations; on
+the origin of counting; inventions of savages; on resemblances, of the
+mental characters in different races of man.
+
+Type of structure, prevalence of.
+
+Typhaeus, stridulating organs of; stridulation of.
+
+Twins, tendency to produce, hereditary.
+
+Twite, proportion of the sexes in.
+
+Ugliness, said to consist in an approach to the lower animals.
+
+Umbrella-bird.
+
+Umbrina, sounds produced by.
+
+United States, rate of increase in; influence of natural selection on
+the progress of; change undergone by Europeans in the.
+
+Upupa epops, sounds produced by the male.
+
+Uraniidae, coloration of the.
+
+Uria troile, variety of (=U. lacrymans).
+
+Urodela.
+
+Urosticte Benjamini, sexual differences in.
+
+Use and disuse of parts, effects of; influence of, on the races of man.
+
+Uterus, reversion in the; more or less divided, in the human subject;
+double, in the early progenitors of man.
+
+Vaccination, influence of.
+
+Vancouver Island, Mr. Sproat on the savages of; natives of, eradication
+of facial hair by the.
+
+Vanellus cristatus, wing tubercles of the male.
+
+Vanessae, resemblance of lower surface of, to bark of trees.
+
+Variability, causes of; in man, analogous to that in the lower animals;
+of the races of man; greater in men than in women; period of, relation
+of the, to sexual selection; of birds; of secondary sexual characters in
+man.
+
+Variation, laws of; correlated; in man; analogous; analogous, in plumage
+of birds.
+
+Variations, spontaneous.
+
+Varieties, absence of, between two species, evidence of their
+distinctness.
+
+Variety, an object in nature.
+
+Variola, communicable between man and the lower animals.
+
+Vaureal, human bones from.
+
+Veddahs, monogamous habits of.
+
+Veitch, Mr., on the aversion of Japanese ladies to whiskers.
+
+Vengeance, instinct of.
+
+Venus Erycina, priestesses of.
+
+Vermes.
+
+Vermiform appendage.
+
+Verreaux, M., on the attraction of numerous males by the female of an
+Australian Bombyx.
+
+Vertebrae, caudal, number of in macaques and baboons; of monkeys, partly
+imbedded in the body.
+
+Vertebrata, common origin of the; most ancient progenitors of; origin of
+the voice in air-breathing.
+
+Vesicula prostatica, the homologue of the uterus.
+
+Vibrissae, represented by long hairs in the eyebrows.
+
+Vidua.
+
+Vidua axillaris.
+
+Villerme, M., on the influence of plenty upon stature.
+
+Vinson, Aug., courtship of male spider; on the male of Epeira nigra.
+
+Viper, difference of the sexes in the.
+
+Virey, on the number of species of man.
+
+Virtues, originally social only; gradual appreciation of.
+
+Viscera, variability of, in man.
+
+Vlacovich, Prof., on the ischio-pubic muscle.
+
+Vocal music of birds.
+
+Vocal organs of man; of birds; of frogs; of the Insessores; difference
+of, in the sexes of birds; primarily used in relation to the propagation
+of the species.
+
+Vogt, Karl, on the origin of species; on the origin of man; on the
+semilunar fold in man; on microcephalous idiots; on the imitative
+faculties of microcephalous idiots; on skulls from Brazilian caves;
+on the evolution of the races of man; on the formation of the skull in
+women; on the Ainos and negroes; on the increased cranial difference of
+the sexes in man with race development; on the obliquity of the eye in
+the Chinese and Japanese.
+
+Voice in mammals; in monkeys and man; in man; origin of, in
+air-breathing vertebrates.
+
+Von Baer, see Baer.
+
+Vulpian, Prof., on the resemblance between the brains of man and the
+higher apes.
+
+Vultures, selection of a mate by the female; colours of.
+
+Waders, young of.
+
+Wagner, R., on the occurrence of the diastema in a Kaffir skull; on the
+bronchi of the black stork.
+
+Wagtail, Ray's, arrival of the male before the female.
+
+Wagtails, Indian, young of.
+
+Waist, proportions of, in soldiers and sailors.
+
+Waitz, Prof., on the number of species of man; on the liability of
+negroes to tropical fevers after residence in a cold climate; on the
+colour of Australian infants; on the beardlessness of negroes; on the
+fondness of mankind for ornaments; on negro ideas of female beauty; on
+Javan and Cochin Chinese ideas of beauty.
+
+Waldeyer, M., on the hermaphroditism of the vertebrate embryo.
+
+Wales, North, numerical proportion of male and female births in.
+
+Walkenaer and Gervais, spider attracted by music; on the Myriapoda.
+
+Walker, Alex., on the large size of the hands of labourers' children.
+
+Walker, F., on sexual differences in the diptera.
+
+Wallace, Dr. A., on the prehensile use of the tarsi in male moths;
+on the rearing of the Ailanthus silkmoth; on breeding Lepidoptera;
+proportion of sexes of Bombyx cynthia, B. yamamai, and B. Pernyi reared
+by; on the development of Bombyx cynthia and B. yamamai; on the pairing
+of Bombyx cynthia.
+
+Wallace, A.R., on the origin of man; on the power of imitation in man;
+on the use of missiles by the orang; on the varying appreciation of
+truth among different tribes; on the limits of natural selection in man;
+on the occurrence of remorse among savages; on the effects of natural
+selection on civilised nations; on the use of the convergence of the
+hair at the elbow in the orang; on the contrast in the characters of the
+Malays and Papuans; on the line of separation between the Papuans and
+Malays; on the birds of paradise; on the sexes of Ornithoptera Croesus;
+on protective resemblances; on the relative sizes of the sexes of
+insects; on Elaphomyia; on the pugnacity of the males of Leptorhynchus
+angustatus; on sounds produced by Euchirus longimanus; on the colours
+of Diadema; on Kallima; on the protective colouring of moths; on
+bright coloration as protective in butterflies; on variability in the
+Papilionidae; on male and female butterflies, inhabiting different
+stations; on the protective nature of the dull colouring of female
+butterflies; on mimicry in butterflies; on the bright colours of
+caterpillars; on brightly-coloured fishes frequenting reefs; on the
+coral snakes; on Paradisea apoda; on the display of plumage by
+male birds of paradise; on assemblies of birds of paradise; on the
+instability of the ocellated spots in Hipparchia Janira; on sexually
+limited inheritance; on the sexual coloration of birds; on the relation
+between the colours and nidification of birds; on the coloration of
+the Cotingidae; on the females of Paradisea apoda and papuana; on the
+incubation of the cassowary; on protective coloration in birds; on the
+Babirusa; on the markings of the tiger; on the beards of the Papuans; on
+the hair of the Papuans; on the distribution of hair on the human body.
+
+Walrus, development of the nictitating membrane in the; tusks of the;
+use of the tusks by the.
+
+Walsh, B.D., on the proportion of the sexes in Papilio Turnus; on the
+Cynipidae and Cecidomyidae; on the jaws of Ammophila; on Corydalis
+cornutus; on the prehensile organs of male insects; on the antennae
+of Penthe; on the caudal appendages of dragonflies; on Platyphyllum
+concavum; on the sexes of the Ephemeridae; on the difference of colour
+in the sexes of Spectrum femoratum; on sexes of dragon-flies; on the
+difference of the sexes in the Ichneumonidae; on the sexes of Orsodacna
+atra; on the variation of the horns of the male Phanaeas carnifex; on
+the coloration of the species of Anthocharis.
+
+Wapiti, battles of; traces of horns in the female; attacking a man;
+crest of the male; sexual difference in the colour of the.
+
+Warbler, hedge-; young of the.
+
+Warblers, superb, nidification of.
+
+Wariness, acquired by animals.
+
+Warington, R., on the habits of the stickleback; on the brilliant
+colours of the male stickleback during the breeding season.
+
+Wart-hog, tusks and pads of the.
+
+Watchmakers, short-sighted.
+
+Waterhen.
+
+Waterhouse, C.O., on blind beetles; on difference of colour in the sexes
+of beetles.
+
+Waterhouse, G.R., on the voice of Hylobates agilis.
+
+Water-ouzel, autumn song of the.
+
+Waterton, C., on the Bell-bird; on the pairing of a Canada goose with a
+Bernicle gander; on hares fighting.
+
+Wattles, disadvantageous to male birds in fighting.
+
+Weale, J., Mansel, on a South African caterpillar.
+
+Wealth, influence of.
+
+Weapons, used by man; employed by monkeys; offensive, of males; of
+mammals.
+
+Weaver-bird.
+
+Weaver-birds, rattling of the wings of; assemblies of.
+
+Webb, Dr., on the wisdom teeth.
+
+Wedderburn, Mr., assembly of black game.
+
+Wedgwood, Hensleigh, on the origin of language.
+
+Weevils, sexual difference in length of snout in some.
+
+Weir, Harrison, on the numerical proportion of the sexes in pigs and
+rabbits; on the sexes of young pigeons; on the songs of birds; on
+pigeons; on the dislike of blue pigeons to other coloured varieties; on
+the desertion of their mates by female pigeons.
+
+Weir, J. Jenner, on the nightingale and blackcap; on the relative sexual
+maturity of male birds; on female pigeons deserting a feeble mate; on
+three starlings frequenting the same nest; on the proportion of the
+sexes in Machetes pugnax and other birds; on the coloration of the
+Triphaenae; on the rejection of certain caterpillars by birds; on sexual
+differences of the beak in the goldfinch; on a piping bullfinch; on the
+object of the nightingale's song; on song-birds; on the pugnacity of
+male fine-plumaged birds; on the courtship of birds; on the finding
+of new mates by Peregrine falcons and Kestrels; on the bullfinch and
+starling; on the cause of birds remaining unpaired; on starlings and
+parrots living in triplets; on recognition of colour by birds; on hybrid
+birds; on the selection of a greenfinch by a female canary; on a case of
+rivalry of female bullfinches; on the maturity of the golden pheasant.
+
+Weisbach, Dr., measurement of men of different races; on the greater
+variability of men than of women; on the relative proportions of the
+body in the sexes of different races of man.
+
+Weismann, Prof., colours of Lycaenae.
+
+Welcker, M., on brachycephaly and dolichocephaly; on sexual differences
+in the skull in man.
+
+Wells, Dr., on the immunity of coloured races from certain poisons.
+
+Westring, on the stridulation of males of Theridion; on the stridulation
+of Reduvius personatus; on the stridulation of beetles; on the
+stridulation of Omaloplia brunnea; on the stridulating organs of the
+Coleoptera; on sounds produced by Cychrus.
+
+Westropp, H.M., on reason in a bear; on the prevalence of certain forms
+of ornamentation.
+
+Westwood, J.O., on the classification of the Hymenoptera; on the
+Culicidae and Tabanidae; on a Hymenopterous parasite with a sedentary
+male; on the proportions of the sexes in Lucanus cervus and Siagonium;
+on the absence of ocelli in female Mutillidae; on the jaws of Ammophila;
+on the copulation of insects of distinct species; on the male of Crabro
+cribrarius; on the pugnacity of the male Tipulae; on the stridulation
+of Pirates stridulus; on the Cicadae; on the stridulating organs of
+the cricket; on Ephippiger vitium; on Pneumora; on the pugnacity of the
+Mantides; on Platyblemnus; on difference in the sexes of the Agrionidae;
+on the pugnacity of the males of a species of Tenthredinae; on the
+pugnacity of the male stag-beetle; on Bledius taurus and Siagonium; on
+lamellicorn beetles; on the coloration of Lithosia.
+
+Whale, Sperm-, battles of male.
+
+Whales, nakedness of.
+
+Whately, Arch., language not peculiar to man; on the primitive
+civilisation of man.
+
+Whewell, Prof., on maternal affection.
+
+Whiskers, in monkeys.
+
+White, F.B., noise produced by Hylophila.
+
+White, Gilbert, on the proportion of the sexes in the partridge; on the
+house-cricket; on the object of the song of birds; on the finding of new
+mates by white owls; on spring coveys of male partridges.
+
+Whiteness, a sexual ornament in some birds; of mammals inhabiting snowy
+countries.
+
+White-throat, aerial love-dance of the male.
+
+Whitney, Prof., on the development of language; language not
+indispensable for thought.
+
+Widgeon, pairing with a pintail duck.
+
+Widow-bird, polygamous; breeding plumage of the male; female, rejecting
+the unadorned male.
+
+Widows and widowers, mortality of.
+
+Wilckens, Dr., on the modification of domestic animals in mountainous
+regions; on a numerical relation between the hairs and excretory pores
+in sheep.
+
+Wilder, Dr. Burt, on the greater frequency of supernumerary digits in
+men than in women.
+
+Williams, on the marriage-customs of the Fijians.
+
+Wilson, Dr., on the conical heads of the natives of North-Western
+Africa; on the Fijians; on the persistence of the fashion of compressing
+the skull.
+
+Wing-spurs.
+
+Wings, differences of, in the two sexes of butterflies and Hymenoptera;
+play of, in the courtship of birds.
+
+Winter, change of colour of mammals in.
+
+Witchcraft.
+
+Wives, traces of the forcible capture of.
+
+Wolf, winter change of the.
+
+Wolff, on the variability of the viscera in man.
+
+Wollaston, T.V., on Eurygnathus; on musical Curculionidae; on the
+stridulation of Acalles.
+
+Wolves, learning to bark from dogs; hunting in packs.
+
+Wolves, black.
+
+Wombat, black varieties of the.
+
+Women, distinguished from men by male monkeys; preponderance of,
+in numbers; selection of, for beauty; effects of selection of, in
+accordance with different standards of beauty; practice of capturing;
+early betrothals and slavery of; freedom of selection by, in savage
+tribes.
+
+Wonder, manifestations of, by animals.
+
+Wonfor, Mr., on sexual peculiarities, in the wings of butterflies.
+
+Wood, J., on muscular variations in man; on the greater variability of
+the muscles in men than in women.
+
+Wood, T.W., on the colouring of the orange-tip butterfly; on the habits
+of the Saturniidae; quarrels of chamaeleons; on the habits of Menura
+Alberti; on Tetrao cupido; on the display of plumage by male pheasants;
+on the ocellated spots of the Argus pheasant; on fighting of Menura
+superba; on the habits of the female cassowary.
+
+Woodcock, coloration of the.
+
+Woodpecker, selection of a mate by the female.
+
+Woodpeckers, tapping of; colours and nidification of the; characters of
+young.
+
+Woolner, Mr., observations on the ear in man.
+
+Wormald, Mr., on the coloration of Hypopyra.
+
+Wounds, healing of.
+
+Wren, young of the.
+
+Wright, C.A., on the young of Orocetes and Petrocincla.
+
+Wright, Chauncey, great brain-power requisite for language; on
+correlative acquisition; on the enlargement of the brain in man.
+
+Wright, Mr., on the Scotch deer-hound; on sexual preference in dogs; on
+the rejection of a horse by a mare.
+
+Wright, W. von, on the protective plumage of the Ptarmigan.
+
+Writing.
+
+Wyman, Prof., on the prolongation of the coccyx in the human embryo; on
+the condition of the great toe in the human embryo; on the occurrence of
+the supra-condyloid foramen in the humerus of man; on variation in the
+skulls of the natives of the Sandwich Islands; on the hatching of the
+eggs in the mouths and branchial cavities of male fishes.
+
+Xenarchus, on the Cicadae.
+
+Xenophon, selection in mankind advocated by.
+
+Xenorhynchus, sexual difference in the colour of the eyes in.
+
+Xiphophorus Hellerii, peculiar anal fin of the male.
+
+Xylocopa, difference of the sexes in.
+
+Yarrel, W., on the habits of the Cyprinidae; on Raia clavata; on
+the characters of the male salmon during the breeding season; on the
+characters of the rays; on the gemmeous dragonet; on colours of salmon;
+on the spawning of the salmon; on the incubation of the Lophobranchii;
+on rivalry in song-birds; on the trachea of the swan; on the moulting of
+the Anatidae; on the young of the waders.
+
+Yellow fever, immunity of negroes and mulattoes from.
+
+Youatt, Mr., on the development of the horns in cattle.
+
+Yura-caras, their notions of beauty.
+
+Zebra, rejection of an ass by a female; stripes of the.
+
+Zebus, humps of.
+
+Zigzags, prevalence of, as ornaments.
+
+Zincke, Mr., on European emigration to America.
+
+Zootoca vivipara, sexual difference in the colour of.
+
+Zouteveen, Dr., polydactylism; proportion of sexes at Cape of Good Hope;
+spiders attracted by music; on sounds produced by fish.
+
+Zygaenidae, coloration of the.
+
+
+THE END.
+
+
+
+
+
+
+
+
+
+
+End of the Project Gutenberg EBook of The Descent of Man, by Charles
+Darwin
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+*** END OF THIS PROJECT GUTENBERG EBOOK THE DESCENT OF MAN ***
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