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“edi

THE DESCENT OF MAN

AND
SELECTION IN RELATION TO SEX

BY

CHARLES DARWIN, M.A., LL.D., F.R.S.

PART TWO

NEW YORK

Pp. F. COLLIER & SON
MCMIT _ .
3 A$ -

SCIENCE

THE DESCENT OF MAN ©

AND

SELECTION IN RELATION TO SEX

CHAPTER XII

SECONDARY SEXUAL CHARACTERS OF FISHES, AMPHIBIANS,
AND REPTILES

FisHes: Courtship and battles of the males—Larger size of the females
—Males, bright colors and ornamental appendages; other strange
characters—Colors and appendages acquired by the males during the
breeding season alone—Fishes with both sexes brilliantly colored—
Protective colors—The less conspicuous colors of the female cannot
be accounted for on the principle of protection—Male fishes building
nests, and taking charge of the ova and young. AMPHIBIANS: Differ-
ences in structure and color between the sexes—Vocal organs. ReEp-
TILES: Chelonians—Crocodiles—Snakes, colors in some cases protec-
tive—Lizards, battles of—Ornamental appendages—Strange differences
in structure between the sexes—Colors—Sexual differences almost as
great as with birds

E have now arrived at the great sub-kingdom of

\ \ the Vertebrata, and will commence with the low-
est class, that of Fishes. The males of Plagi-

ostomous fishes (sharks, rays) and of Chimeeroid 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 tempo-
rarily developed during the breeding season; and Dr. Giin-
ther suspects that they are brought into action as prehensile

organs by the doubling inward and downward of the two
(481)

482 THE DESCENT OF MAN

sides of the body. It is a remarkable fact that the females
and not the males of some species, as of Rata clavata, have
their backs studded with large hook-formed spines.’

The males alone of the capelin (J/allotus villosus, one
of Salmonide) are provided with a ridge of closely set,
brush-like scales, by the aid of which two males, one on each
side, hold the female, while she runs with great swiftness
on the sandy beach, and there deposits her spawn.? The
widely distinct Monacanthus scopas presents a somewhat
analogous structure. The male, as Dr. Giinther informs
me, has a cluster of stiff, straight spines, like those of
a comb, on the sides of the tail; and these in a specimen
six inches long were nearly one and a half inch in length;
the female has in the same place a cluster of bristles, which
may be compared with those of a toothbrush. In another
species, J. peronti, the male has a brush like that possessed
by the female of the last species, while the sides of the tail
in the female are smooth. In some other species of the
game genus the tail can be perceived to bea 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 leiwrus)
has been described as ‘‘mad with delight’’ when the female
comes out of her hiding-place and surveys the nest which
he has made for her. ‘‘He darts round her in every direc-
tion, then to his accumulated materials for the nest, then
back again in an instant; and as she does not advance
he endeavors to push her with his snout,’and then tries
to pull her by the tail and side-spine to the nest.’?* The
males are said to be polygamists; * they are extraordinarily

1 See Yarrell’s ‘History of British Fishes,’ volume ii., 1836, pp. 41%, 425,
and 436. Dr. Giinther informs me that the spines in &. clavata are peculiar
to the female.

2 “The Am. Naturalist,’’ April, 1871, p. 119.

3 See Mr. R. Warington’s interesting articles in ‘‘The Annals and Magazine
of Natural History,’’ October, 1852, and November, 1855.

4 Noel Humphreys, ‘‘River Gardens,’’ 1857,

SEXUAL SELECTION 433

bold and pugnacious, while ‘‘the females are quite pacific.”
Their battles are at times desperate; ‘‘for these puny com-
batants 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 while fighting swim round and
round each other, biting and endeavoring to pierce each
other with their raised lateral spines. The same writer
adds,* ‘‘the bite of these little furies is very severe. 'They
also use their 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 colors 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 stickle-
back; 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, Superin-
tendent of Fisheries, informs me that he has often watched
from the bridge at Perth the males driving away their
rivals, while the females were spawning. ‘The males ‘‘are
constantly fighting and tearing each other on the spawning-
beds, and many so injure each other as to cause the death
of numbers, many being seen swimming near the banks of
the river in a state of exhaustion, and apparently in a
dying state.’’* Mr. Buist informs me that in June, 1868,
the keeper of the Stormontfield breeding-ponds visited the
northern Tyne and found about 300 dead salmon, all of
which with one exception were males; and he was convinced
that they had lost their lives by fighting.

The most curious point about the male salmon is that

5 Loudon’s ‘‘Mag. of Nat. History,’’ vol. ifi., 1830, p. 332.

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.

484 THE DESCENT OF MAN

during the breeding season, besides a slight change in color,
“the lower jaw elongates, and a cartilaginous projection
turns upward from the point, which, when the jaws are
closed, occupies a deep cavity between the intermaxillary

Pie. 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.]

bones of the upper jaw’’’ (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

* Yarrell, ‘History of British Fishes,” vol. ii., 1836, p. 10.

SEXUAL SELECTION 485

change, as Mr. J. K. Lord® 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.

Fia. 28.—Head of female salmon.

With the European salmon, according to Mr. Lloyd,° the
temporary hook-like structure serves to strengthen and pro-
ject the jaws, when one male charges another with wonder-
ful violence; but the greatly developed teeth of the male
American salmon may be compared with the tusks of many

8 ‘The Naturalist in Vancouver’s Jsland,’’ vol. i., 1866, p. 54.
9 “Scandinavian Adventures,’’ vol, i., 1854, pp. 100, 104.

436 THE DESCENT OF MAN

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 clavat) the adult male has sharp-pointed
teeth, directed backward, while those of the female are
broad and flat, and form a pavement; so that these teeth
differ in the two sexes of the same species more than is
usual in distinct genera of the same family. The teeth
of the male become sharp only when he is adult: while
young they are broad and flat like those of the female. As
so frequently occurs with secondary sexual characters, both
sexes of some species of rays (for instance #. 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 analo-
gous cases in certain birds, in which the male acquires the
plumage common to both sexes when adult, at a somewhat
earlier age than does the female. With other species of
rays the males, even when old, never possess sharp teeth,
and consequently the adults of both sexes are provided with
broad, flat teeth like those of the young, and like those of
the mature females of the above-mentioned species.” As the
rays are bold, strong, and voracious fish, we may suspect
that the males require their sharp teeth for fighting with
their rivals; but as they possess many parts modified and
adapted for the prehension of the female, it is possible that
their teeth may be used for this purpose.

In regard to size, M. Carbonnier™ maintains that the
female of almost all fishes is larger than the male; and
Dr. Gunther does not know of a single instance in which

10 See Yarrell’s account of’ the rays in his ‘‘Hist. of British Fishes,”
vol. ii., 1836, p. 416, with an excellent figure, and pp. 422, 432.
" As quoted in ‘‘The Farmer,’’ 1868, p. 369,

SEXUAL SELECTION 437

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, ac-
cording to M. Carbonnier, they are liable to be devoured
by the females of their own species when carnivorous, and
no doubt by other species. Increased size must be in some
manner of more importance to the females than strength
and size are to the males for fighting with other males;
and this perhaps is to allow of the production of a
vast number of ova.

In many species the male alone is ornamented with bright
colors; or these are much brighter in the male than in the
female. The male, also, is sometimes provided with ap-
pendages which appear to be of no more use to him for
the ordinary purposes of life than are the tail feathers to
the peacock. I am indebted for most of the following facts
to the kindness of Dr. Giinther. ‘There is reason to suspect
that many tropical fishes differ sexually in color and struc-
ture; 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 colors.’
When fresh caught from the sea the body is yellow of
various shades, striped and spotted with vivid blue on the
head; the dorsal fins are pale brown with dark longitudinal
bandas the ventral, caudal and anal fins being bluish black.
The female, or sordid dragonet, was considered by Linneus,
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 propor-
tional size of the head and mouth, and in the position of the
eye;” but the most striking difference is the extraordinary
elongation in the male (Fig. 29) of the dorsal fin. Mr. W.

12 T have drawn up this description from Yarrell’s ‘‘British = vol, {.,
1836, pp. 261 and 266.

438 THE DESCENT OF MAN

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.’’* The young males re-
semble the adult females in structure and color. Through-

Fie. 29.—Callionymus lyra. Upper figure, male; lower figure, female.
N.B.—The lower figure is more reduced than the upper.

out the genus Callionymus,“ the male is generally much
more brightly spotted than the female, and in several spe-
cies not only the dorsal but the anal fin is much elongated
in the males.

The male of the Cottus scorpius, or sea-scorpron, is slen-
derer and smaller than the female. There is also a great
difference in color between them. It is difficult, as Mr.

13 “Nature,”? July, 1873, p. 264.
14 “Catalogue of Acanth, Fishes in the British Museum,’? by Dr. Gtinther,
1861, pp. 138-151.

SEXUAL SELECTION 439

Lloyd” remarks, ‘‘for any one who has not seen this fish
during the spawning season, when its hues are brightest,
to conceive the admixture of brilliant colors with which
it, in other respects so ill-favored, is at that time adorned.”
Both sexes of the Labrus mixtus, although very different in
color, are beautiful; the male being orange with bright blue
stripes, and the female bright red with some black spots on
the back.

In the very distinct family of the Cyprinodontide—in-
habitants of the fresh waters of foreign lands—the sexes

Fie 0.—Xiphophorus Hellerii. Upper figure, male; lower figure, female.

someti.aes differ much in various characters. In the male
of the Mollienesia petenensis,’* the dorsal fin is greatly de-
veloped and is marked with a row of large, round, ocellated,
bright-colored spots; while the same fin in the female is
smaller, of a different shape, and marked only with irregu-
larly curved brown spots. In the male, the basal margin

16 “Game Birds of Sweden,’’ etc., 1871, p. 466.

16 With respect to this and the following species I am indebted to Dr.
Giinther for information: see also his paper on the ‘‘Fishes of Central America,’?
in “Transact. Zoolog. Soc.,’’ vol. vi., 1868, p, 485.

440 THE DESCENT OF MAN

of the anal fin is also a little produced and dark colored.
In the male of an allied form, the Xitphophorus Hellerié
(Fig. 80), the inferior margin of the caudal fin is devel-
oped into a long filament, which, as -I hear from Dr. Gtin-
ther, is striped with bright colors. This filament does nos
contain any muscles, and apparently cannot be of any direct
use to the fish. As in the case of the Callionymus, the
males while young resemble the adult females in color
and structure. Sexual differences such as these may be
strictly compared with those which are so frequent with
gallinaceous birds.’ :

In a siluroid fish, inhabiting the fresh waters of South
America, the Plecostomus barbatus (Fig. 31), the male has
its mouth and inter-operculum fringed with a beard of stiff
hairs, of which the female shows hardly a trace. These
hairs are of the nature of scales. In another species of
the same genus, soft flexible 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 there-
fore 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 te
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 Chimera monstrosa, the male -has a
hook-shaped bone on the top of the head, directed forward,
with its end rounded and covered with sharp spines; in the
female ‘‘this crown is altogether absent,’’ but what its use
may be to the male is utterly unknown.”

The structures as yet referred to are permanent in the
male after he has arrived at maturity; but with some Blen-

1” Dr. Ginther makes this remark, ‘‘Catalogue of Fishes in the British
Museum,”?’ vol. iii., 1861, p. 141.

18 See Dr. Ginther on this genus, in ‘‘Proc. Zoolog. Soc.,’’ 1868, p. 232.

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.

SEXUAL SELECTION 441

Wig. 81.—Plecostomus barbatus. Upper figure, head of male; lower figure, female,

442, THE DESCENT OF MAN

nies, and in another allied genus,* a crest is developed on
the head of the male only during the breeding season, and
the body at the same time becomes more brightly colored.
There can be little doubt that this crest serves as a tempo-
rary 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 pro-
vided. In many of the Chromide, for instance in Geophagus
and especially in Cichla, the males, as I hear from Prof.
Agassiz,*? have a conspicuous protuberance on the forehead
which is wholly wanting in the females and in the young
males. Prof. Agassiz adds, ‘‘] have often observed these
fishes at the time of spawning when the protuberance is
largest, and at other seasons when it is totally wanting,
and the two sexes show no difference whatever in the out-
line of the profile of the head. I never could ascertain that
it subserves any special function, and the Indians on the
Amazon know nothing about its use.’’ These protuberances
resemble, in their periodical appearance, the fleshy caruncles
of the heads of certain birds; but whether they serve as
ornaments must remain at present doubtful}.

I hear from Prof. Agassiz and Dr. Gunther, that the
males of those fishes which differ permanently in color
from the females often become more brilliant during the
breeding season. This is likewise the case with a multi-
tude of fishes, the sexes of which are identical in color at
all other seasons of the year. The tench, roach, and perch
may be given as instances. The male salmon at this season
is ‘‘marked on the cheeks with orange-colored stripes, which
give it the appearance cf a Labrus, and the body partakes of
a golden orange tinge. The females are dark in color, and
are commonly called blackfish.’’* An analogous and even
greater change takes place with the Salmo eriox or bull trout;
the males of the char (S. wmbla) are likewise at this season

20 Dr. Ginther, ‘‘Catalogue of Fishes,’’ vol. iii. pp. 221 and 240.
% See also ‘A Journey in Brazil,”’ by Prof. and Mrs. Agassiz, 1868, p. 220,
% Yarrell, ‘‘British Fishes,”’ vol. ii., 1836, pp. 10, 12, 35.

SEXUAL SELECTION 443

rather brighter in color than the females. The colors of
the pike (Hsox recticulatus) of the United States, especially
of the male, become, during the breeding season, exceed-
ingly intense, brilliant, and iridescent.” Another striking
instance out of many is afforded by the male stickleback
(Gasterosteus leiurus), which is described by Mr. Waring-
ton® 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 colors all change, the throat and belly
become of a paler red, the back more green, and the glowing
tints subside.

With respect to the courtship of fishes, other cases have
been observed, since the first edition of this book appeared, |
besides that already given of the stickleback. Mr. W. 8S.
Kent says that the male of the Labrus mixtus, which, as we
have seen, differs in color from the female, makes ‘‘a deep
hollow in the sand of the tank, and then endeavors, in the
most persuasive manner, to induce a female of the same
species to share it with him, swimming backward and for-
ward between her and the completed nest, and plainly ex-
hibiting 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 ex-
cavate a hollow asa nest. ‘‘Hach male now mounts vigilant
guard over his respective hollow, and vigorously attacks and
drives away any other fish of the same sex. Toward his
companions of the opposite sex his conduct is far different;

23 W. Thompson, in ‘‘Annals and Mag. of Nat. History,’’ vol. vi., 1842,
. 440.
. 2% “The American Agriculturist,’’ 1868, p. 100.
35 “‘Annals and Mag. of Nat. Hist.,’’ Oct. 1852.

444 THE DESCENT OF MAN

many of the latter are now distended with spawn, and these
he endeavors by all the means in his power to lure singly to
his prepared hollow, and there to deposit the myriad ova
with which they are laden, which he then protects and
guards with the greatest care.’’ *

A more striking case of courtship, as well as of display,
by the males of a Chinese Macropus, has been given by M.
Carbonnier, who carefully observed these fishes under con-
finement.” The males are most beautifully colored, more
so than the females. During the breeding season they con-
tend for the possession of the females; and, in the act of
courtship, expand their fins, which are spotted and orna-
mented with brightly-colored rays, in the same manner, ac-
cording to M. Carbonnier, as the peacock. They then also
bound about the females with much vivacity, and appear by
‘‘l’étalage de leurs vives couleurs chercher 4 attirer l’atten-
tion des femelles, lesquelles ne paraissaient indifférentes &
ce manége, 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 disk
of froth by blowing air and mucus out of his mouth. He
then collects the fertilized ova dropped by the female, in
his mouth; and this caused M. Carbonnier much alarm, as ©
he thought that they were going to be devoured. But the
male soon deposits them in the disk of froth, afterward
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 be-
lieve 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.

8 “Nature,’? May, 1873, p. 25.
% “Bull, de la Soc, d’Acclimat.,’? Paris, July, 1869, and Jan. 1870,

SEXUAL SELECTION 445

To return to our more immediate subject. The case
stands thus: female fishes, as far as I can learn, never
willingly spawn except in the presence of the males; and
the males never fertilize the ova except in the presence
of the females. The males fight for the possession of the
females. In many species, the males while young resemble
the females in color; but ‘when adult become much more
brilliant, and retain their colors throughout life. In other
species the males become brighter than the females and
otherwise more highly ornamented, only during the season
of love. The males sedulously court the females, and in
one case, as we have seen, take pains in displaying their
beauty before them. Can it be believed that they 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. lf the
female exerts such choice, all the above facts on the orna-
mentation of the males become at once intelligible by the
aid of sexual selection.

We have next to inquire whether this view of the bright
colors of certain male fishes having been acquired through
sexual selection can, through the law of the equal transmis-
sion 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 (£. pavo),
described,** with pardonable exaggeration, as formed of
polished scales of gold, incrusting lapis-lazuli, rubies, sap-
phires, emeralds, and amethysts—we may, with much prob-
ability, accept this belief; for we have seen that the sexes
in at least one species of the genus differ greatly in color.
With some fishes, as with many of the lowest animals, splen-
did colors may be the direct result of the nature of their tis-
sues and of the surrounding conditions, without the aid of

28 Bory de Saint Vincent, in ‘‘Dict. Class. d’Hist. Nat.,’’ tom. ix., 1826,
p. 151.

446 THE DESCENT OF MAN

selection of any kind. The gold-fish (Cyprinus auratus),
judging from the analogy of the golden variety of the com-
mon carp, is perhaps a case in point, as it may owe its splen-
did colors to a single abrupt variation, due to the conditions
to which this fish has been subjected under confinement. It
is, however, more probable that these colors have been in-
tensified through artificial selection, as this species has been
carefully bred in China from a remote period.” Under natu-
ral conditions it does not seem probable that beings so highly
organized as fishes, and which live under such complex re-
lations, should become brilliantly colored without suffer-
ing some evil or receiving some benefit from so great a
change, and consequently without the intervention of nat- —
ural selection.

What, then, are we to conclude in regard to the many
fishes both sexes of which -are splendidly colored? Mr.
Wallace” believes that the species which frequent reefs,
where corals and other brightly colored organisms abound,
are brightly colored in order to escape detection by their
enemies; but according to my recollection they were thus
rendered highly conspicuous. In the fresh waters of the
tropics there are no brilliantly colored corals or other
organisms for the fishes to resemble; yet many species in
the Amazons are beautifully colored, and many of the
carnivorous Cyprinide in India are ornamented with “bright
longitudinal lines of various tints.’’*" Mr. McClelland, in
describing these fishes, goes so far as to suppose that “the
peculiar brilliancy of their colors’’ serves as ‘‘a better mark

2° 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
color. It is universally admired, and there is not a household where it is not
cultivated, in rivalry as to tts color and as a source of profit.’’

30 “‘Westminster Review,’’ July, 1867, p. 7.

31 “Indian Cyprinids,’ by Mr. J. McClelland, ‘‘Asiatic Researches,’’ vol.
xix. part ii, 1839, p. 230. we

SEXUA# SELECTION 447

tor kingfishers, 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 cater-
pillars; 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 colored, is that their colors were acquired by the
males as a sexual ornament, and were transferred equally,
or nearly so, to the other sex.

We have now to consider whether when the male
differs in a marked manner from the female in color or in
other ornaments, he alone has been modified, the variations
being inherited by his male offspring alone; or whether
the female has been specially modified and rendered incon-
spicuous for the sake of protection, such modifications being
inherited only by the females. It is impossible to doubt
that color has been gained by many fishes as a protection:
no one can examine the speckled upper surface of a flounder,
and overlook its resemblance to the sandy bed of the sea
on which it lives. Certain fishes, moreover, can, through
the action of the nervous system, change their colors in
adaptation to surrounding objects, and that within a short
time.” One of the most striking instances ever recorded
of an animal being protected by its color (as far as it can be
judged of in preserved specimens), as well as by its form,
is that given by Dr. Gunther® 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

82 G. Pouchet, L’Institut, Nov. 1, 1871, p. 134.
33 “Proc. Zoolog, Soc.,”’ 1865, p. 32%, pl. xiv. and xv.

448 THE DESCENT OF MAN

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 ag
there is any difference, the males, from being generally
smaller and from wandering more about, are exposed to
greater danger than the females; and yet, when the sexes
differ, the males are almost always the more conspicuously
colored. The ova are fertilized immediately after being
deposited; and when this process lasts for several days, a3
in the case of the salmon,™ the female, during the whole
time, is attended by the male. After the ova are fertilized
they are, in most cases, left unprotected by both parents,
so that the males and females, as far as oviposition is con-
cerned, are equally exposed to danger, and both are equally
important for the production of fertile ova; consequently
the more or less brightly colored individuals of either sex
would be equally liable to be destroyed or preserved, and
both would have an equal influence on the colors of
their offspring.

Certain fishes, belonging to several families, make nesta,
and some of them take care of their young when hatched.
Both sexes of the bright-colored Crenilabrus massa and
melops work together in building their nests with sea-weed,
shells, etc.** But the males of certain fishes do all the
work, and afterward take exclusive charge of the young.
This is the case with the dull-colored gobies,* in which
the sexes are not known to differ in color, and likewise with
the sticklebacks (Gasterosteus), in which the males become
brilliantly colored during the spawning season. The male
of the smooth-tailed stickleback (G@. leturus) performs the

*% Yarrell, ‘‘British Fishes,’ vol. ii. p. 11.

% According to the observations of M. Gerbe; see Giinther’s ‘‘Record of
Zoolog. Literature,’’ 1865, p. 194.

38 Cuvier, ‘“‘Régne Animal,’’ vol. ii, 1829, p. 242.

SEXUAL SELECTION 449

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.”

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.”
I am informed by Prof. Agassiz that the males of the Ama-
zonian 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 Prof. Agassiz
likewise informs me, sexual differences in color may be
observed, ‘‘whether they lay their eggs in the water among
aquatic plants or deposit them in holes, leaving them ‘to
come out without further care, or build shallow nests in
the river mud, over which they sit, as our Pomotis does.
It ought also to be observed that these sitters are among
the brightest species in their respective families; for in-
stance, Hygrogonous 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

37 See Mr. Warington’s most interesting description of the habits of the
Gasterosteus leiwrus, in ‘‘Annals and Mag. of Nat. Hist.,’? November, 1855.

38 Prof. Wyman, in ‘‘Proc. Boston Soc. of Nat. Hist.,°? Sept. 15, 1867.
Also Prof. Turner, in “Journal of Anatomy and Phys.,’® Nov. 1, 1866, p. 78.
Dr. Giinther has likewise described other cases,

450 THE DESCENT OF MAN

parents has had little or no influence on the differences in
color between the sexes. It is further manifest, in all the
cases in which the males take exclusive charge of the nests
and young, that the destruction of the brighter-colored
males would be far more influential on the character of the
race than the destruction of the brighter-colored females;
for the death of the male during the period of incubation
or nursing would entail the death of the young, so that they
could not inherit his peculiarities; yet, in many of these
very cases, the males are more conspicuously colored than
the females.

In most of the Lophobranchii (Pipe-fish, Hippocampi,
etc.) the males have either marsupial sacs or hemispherical
depressions on the abdomen, in which the ova laid by the
female are hatched. The males also show great attachment
to their young.” The sexes do not commonly differ much
in color; but Dr. Gunther believes that the male Hippocampi
are rather brighter than the females. The genus Solenos-
toma, however, offers a curious exceptional case,“ for the
female is much mere vividly colored and spotted than
the male, and she alone has a marsupial sac and hatches
the eggs; so that the female of Solenostoma differs from
all the other Lophobranchii in this latter respect, and
from almost all other fishes, in being more brightly colored
than the male. It is improbable that this remarkable double
inversion of character in the female should be an accidental
coincidence. As the males of several fishes, which take
exclusive charge of the eggs and young, are more brightly
colored than the females, and as here the female Solenos-
toma takes the same charge and is brighter than the male,
it might be argued that the conspicuous colors of that sex,
which is the more important of the two for the welfare of
the offspring, must be in some manner protective. But

39 Yarrell, “Hist. of British Fishes,’® vol. ii., 1836, pp. 329, 338.

4 Dr, Giinther, since publishing an account of this species in ‘‘The Fishes
of Zanzibar,’? by Col. Playfair, 1866, p. 137 bas re-examined the specimens,
and has given me the above information.

SEXUAL SELECTION 451

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 color or in other ornamental
characters, the males originally varied, with their variations
transmitted to the same sex, and accumulated through
sexual selection by attracting or exciting the females. In
many cases, however, such characters have been transferred,
either partially or completely, to the females. In other
cases, again, both sexes have been colored alike for the
sake of protection; but in no instance does it appear that
the female alone has had her colors or other characters
specially modified for this latter purpose.

The last point which need be noticed is that fishes are
known to make various noises, some of which are described
as being musical. Dr. Dufossé, who has especially attended
to this subject, says that the sounds are voluntarily pro-
duced in several ways by different fishes: by the friction
of the pharyngeal bones—by the vibration of certain muscles
attached to 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

452 THE DESCENT OF MAN

swim-bladder.*? The drumming of the Umbrinas in the
European seas is said to be audible from a depth of twenty
fathoms; and the fishermen of Rochelle assert ‘‘that the
males alone make the noise during the spawning time; and
that it is possible, by imitating it, to take them without
bait.”’“* 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.—I will begin with the tailed amphibians. ‘Phe
sexes of salamanders or newts often differ much both ia

Fic. 32.—Triton cristatus (half natural size, from Bell's “British Reptiles”). Upper
figure, male during the breeding season; lower figure, female.

color and structure. In some species prehensile claws are
developed on the fore-legs of the males during the breeding

41 “Comptes Rendus.”” Tom. xlvi., 1858, p. 353. Tom. xlvii., 1858,
p. 916. Tom. liv., 1862, p. 393. The noise made by the Umbrinas (Sciena
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.

#2 The Rev. ©, Kingsley, in ‘‘Nature,’’ May, 1870, p. 40.

SEXUAL SELECTION 453

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.** This structure
no doubt aids the male in his eager search and pursuit of the
female. While courting her he rapidly vibrates the end
of his tail. With our common newts (Triton punctatus
and cristatus) a deep, much indented crest is' developed
along the back and tail of the male during the breeding
season, which disappears during 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 colors,
there can hardly be a doubt that it is a masculine ornament.
In many species the body presents strongly contrasted,
though lurid tints, and these become more vivid during the
breeding season. The male, for instance, of our common
little newt (Triton punctatus) is ‘‘brownish gray above, pass-
ing into yellow beneath, which in the spring becomes a rich
bright orange, marked everywhere with round dark spots.”
The edge of the crest also is then tipped with bright red or
violet. The female is usually of a yellowish brown color
with scattered brown dots, and the lower surface is often
quite plain.“ The young are obscurely tinted. The ova
are fertilized during the act of deposition, and are not
subsequently tended by either parent. We may therefore
conclude that the males have acquired their strongly
marked colors and ornamental appendages through sexual
selection; these being transmitted either to the male off-
spring alone, or to both sexes.

Anura or Batrachia.—With many frogs and toads the
colors 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 colored

Bell, ‘‘History of British Reptiles,” 2d edit., 1849, pp. 166-159.
4 Tbid., pp. 146, 151.
Descent—Vou. I1.—2

454 THE DESCENT OF MAN

toad which I ever saw, the Phryniscus nigricans,* had the
whole upper surface of the body as black as ink, with
the soles of the feet and parts of the abdomen spotted
with the brightest vermilion. It crawled about the bare
sandy or open grassy plains of La Plata under a scorching
sun, and could not fail to catch the eye of every passing
creature. These colors are probably beneficial by making
this animal known to all birds of prey as a nauseous
mouthful. —

In Nicaragua there is a little frog ‘‘dressed in a bright
livery of red and blue’ which does not conceal itself like
most other species, but hops about during the daytime, and
Mr. Belt says‘ that as soon as he saw its happy sense of
security, he felt sure that it was uneatable. After several
trials he succeeded in tempting a young duck to snatch up
a young one, but it was instantly rejected; and the duck
‘went about jerking its head, as if trying to throw off some
unpleasant taste.”’

With respect to sexual differences of color, Dr. 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.*” 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 ob-

45 “Zoology of the Voyage of the Beagle,”? 1843. Bell, ibid., p. 49.

48 “The Naturalist in Nicaragua,’’ 1874, p. 321.

41 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.

SEXUAL SELECTION 455

served by Prof. Hoffman in Giessen fighting ad 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 over-
whelming sounds emitted by male bull-frogs and some other
species, seems, according to our taste, a singularly inappro-
priate expression. Nevertheless, certain frogs sing in a
decidedly pleasing manner. Near Rio Janeiro I used often
to sit in the evening to listen toa number of little Hyla,
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.** 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.” 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, while that of the female
is only a slight groaning noise.” In the several genera of
the family the vocal organs differ considerably in structure,
and their development in all cases may be attributed to
sexual selection.

REPTILES

Chelonia.—Tortoises and turtles do not offer well-marked
sexual differences. In some species the tail of the male is
longer than that of the female. In some the plastron or
lower surface of the shell of the male is slightly concave

# Bell, “‘History of British Reptiles,”” 1849, p. 9
# J. Bishop, in ‘‘Todd’s Oyclop. of Anat. and Phys. ,”? vol. iv. p. 1503.
5 Bell, ibid. p. 112-114.

456 THE DESCENT OF MAN

in relation to the back of the female. The male of the
mud-turtle of the United States (Chrysemys picta) has claws
on its front feet twice as long as those of the female; and
these are used when the sexes unite.” With the huge
tortoise of the Galapagos Islands (Zestudo 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.”

With the Zestudo 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.” ®

Crocodilia.—The sexes apparently do not differ in color;
nor do I know that the males fight together, though this is
probable, for some kinds make a prodigious display before
the females. Bartram™ describes the male alligator as
striving to win the female by splashing and roaring in the
midst of a lagoon, ‘‘swollen to an extent ready to burst,
with its head and tail lifted up, he spins or twirls round
on the surface of the water, like an Indian chief rehearsing
his feats of war.’’ During the season of love a musky odor
is emitted by the submaxillary glands of the crocodile, and
pervades their haunts.**

Ophidia.—Dr. 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 color, he can almost
always distinguish the male from the female by his more
strongly pronounced tints; thus the black zigzag band on
the back of the male English viper is more distinctly de-
fined than in the female. The difference is much plainer

51 Mr. C. J. Maynard, ‘‘The American Naturalist,’? Dec. 1869, p. 555.

52 See my “Journal of Researches during the Voyage of the Beagle,”
1845, p. 384,

53 Dr. Gimther, ‘“‘Reptiles of British India,’’ 1864, p. 7.

54 ““Dravels through Carolina,’’ etc., 1791, p. 128.

5 Owen, ‘‘Anatomy of Vertebrates,’’ vol. i, 1866, p. 615.

SEXUAL SELECTION 457

in the rattlesnakes of North America, the male of which,
as the keeper in the Zoological Gardens showed me, can at
once be distinguished from the female by having more
lurid yellow about its whole body. In South Africa the
Bucephalus capensis presents an analogous difference, for
the female ‘‘is never so fully variegated with yellow on the
sides as the male.’’* The male of the Indian Dipsas eyno-
don, on the other hand, is blackish brown, with the belly
partly black, while the female is reddish or yellowish olive,
with the belly either uniform yellowish or marbled with
black. In the Tragops dispar of the same country, the
male is bright green, and the female bronze colored.” No
doubt the colors of some snakes are protective, as shown
by the green tints of tree-snakes, and the various mottled
shades of the species which live in sandy places; but it is
doubtful whether the colors of many kinds, for instance
of the common English snake and viper, serve to conceal
them; and this is still more doubtful with the many foreign
species which are colored with extreme elegance. The
colors of certain species are very different in the adult
and young states.“

During the breeding season the anal scent-glands of
snakes are in active function;® and so it is with the same
glands in lizards, and, as we have seen, with the submaxil-
lary 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 inteliectual powers are higher than
might have been articipated. In the Zoological Gardens

% Sir Andrew Smith, ‘‘Zoolog. of 8. Africa: Reptilia,’ 1849, pl. x.

51 Dr. A. Ginther, ‘‘Reptiles of British India,’’ Ray Soc., 1864, pp. 304, 308,

8 Dr. Stoliczka, ‘Journal of Asiatic Soc. of Bengal,’ vol. xxxix., 1870,
pp. 205, 211.

* Owen, ‘‘Anatomy of Vertebrates,”® vol. i, 1866, p. 615.

458 THE DESCENT OF MAN

they soon learn not to strike at the iron bar with which
their cages are cleaned; and Dr. Keen of Philadelphia
informs me that some snakes which he kept learned after
four or five times to avoid a noose with which they were
at first easily caught. An excellent observer in Ceylon,
Mr. E. Layard, saw® a cobra thrust its head through a
narrow hole and swallow a toad. ‘‘With this encumbrance
he could not 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 learned, 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, distin-
guish him from all other persons. Cobras kept together
in the same cage apparently feel some attachment toward
each other.”

It does not, however, follow, because snakes have some
reasoning power, strong passions, and mutual affection, that
they should likewise be endowed with sufficient taste to
admire brilliant colors in their partners, so as to lead to the
adornment of the species through sexual selection. Never-
theless, it is difficult to account in any other manner for the
extreme beauty of certain species? for instance, of the coral-
snakes of South America, which are of a rich red with
black and yellow transverse bands. I well remember how
much surprise I felt at the beauty of the first coral-snake
which I saw gliding across a path in Brazil. Snakes colored
in this peculiar manner, as Mr. Wallace states on the au-
thority of Dr. Gunther,” are found nowhere else in the

‘Rambles in Ceylon,” in ‘‘Annals and Mag. of Nat. Hist.,’? 2d series,
vol. ix., 1852, p. 333.

61 Dr, Giinther, ‘Reptiles of British India,’ 1864, p. 340.

6 <‘Westminster Rev.,’’ July 1, 1867, p. 32.

SEXUAL SELECTION 459

world except in South America, and here no less than four
genera occur. One of these, Elaps, is venomous, a second
and widely distinct genus is doubtfully venomous, and the
two 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 dis-
tinguish the harmless from the poisonous kinds.’’ Hence,
as Mr. Wallace believes, the innocuous kinds have probably
acquired their colors as a protection, on the principle of
imitation; for they would naturally be thought dangerous
by their enemies. The cause, however, of the bright colors
of the venomous Elaps remains to be explained, and this
may perhaps be sexual selection.

Snakes produce other sounds besides hissing. The
deadly Hchis 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.’’ * With respect to the rattling of the rattle-
snake, we have at last some definite information: for Prof.
Aughey states,“ that on two occasions, being himself un-
seen, he watched from a little distance a rattlesnake coiled
up with head erect, which continued to rattle at short inter-
vals 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 para-
lyzing their prey with fear. Some other snakes also make
a distinct noise by rapidly vibrating their tails against

68 Dr, Anderson, ‘‘Proc. Zoolog. Soc.,’’ 1871, p. 196,
6 “The American Naturalist,’’ 1873, p. 85.

460 THE DESCENT OF MAN

the surrounding stalks of plants; and I have myself heard
this in the case of a Trigonocephalus in South America.

Lacertilia.—The males of some, probably of many, kinds
of lizards fight together from rivalry. Thus the arboreal
Anolis cristatellus of South America is extremely pugna-
cious: ‘‘During the spring and early part of the summer,
two adult males rarely meet without a contest. On first
seeing one another, they nod their heads up and down
three or four times, and at the same time expanding the
frill or pouch beneath the throat; their eyes glisten with
rage, and after waving their tails from side to side for a
few seconds, as if to gather energy, they dart at each other
furiously, rolling over and over, and holding firmly with
their teeth. The conflict generally ends in one of the com-
batants losing his tail, which is often devoured by the
victor.’’ The male of this species is considerably larger
than the female;* and this, as far as Dr. 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
odor.

The sexes often differ greatly in various external char-
acters. The male of the above-mentioned Anolis is fur-
nished 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 de-
veloped in both sexes, as in the Iguana tuberculata. In the
genus Sitana, the males alone are furnished with a large
throat-pouch (Fig. 38), which can be folded up like a fan,

66 Mr, N. L, Austen kept these animals alive for a considerable time; see
“Tand and Water,’’ July, 186%, p. 9.
8 Stoliczia, ‘Journal of Asiatic Soc. of Bengal,” vol, xxxiv., 1870, p. 166,

SEXUAL SELECTION 461

and is colored blue, black, and red; but these splendid
colors are exhibited only during the pairing season. The
female does not possess even a rudiment of this appen-
dage. 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 colors bafile
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

5 Fig. 83.—Sitana minor, Male with
developed when the male arrives the gular pouch expanded (from

Gunther's ‘Reptiles of India”).

at maturity, at which age the ;
middle appendage is sometimes twice as long as the head.
Most of the species likewise have a low crest running
along the neck; and this is much more developed in the
full-grown males than in the females or young males.”

A Chinese species is said to live in pairs during the
spring; ‘‘and if one is caught, the other falls from the tree
to the ground, and allows itself to be captured with im-
punity’’—I presume from despair.”

There are other and much more remarkable differences
between the sexes of certain lizards. The male of Cerato-

81 All the foregoing statements and quotations, in regard to Cophotis,
Sitana, and Draco, as well as the following facts in regard to Ceratophora and
Chameleon, are from Dr. Ginther himself, or from his magnificent work on the
“Reptiles of British India,’’ Ray Soc., 1864, pp. 122, 130, 135.

68 Mr, Swinhoe, ‘‘Proc. Zoolog. Soc., 1870, p. 240.

462 THE DESCENT OF MAN

phora aspera bears on the extremity of his snout an append-
age 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 color, but assumes
a purplish tint when the animal is excited. In the adult
male of this latter species the horn is half an inch in length,
but it is of quite minute size in the female and in the
young. These appendages, as Dr. Gunther has remarked
to me, may be compared with the
combs of gallinaceous birds, and
apparently serve as ornaments.

In the genus Chameleon we come
to the acme of difference between
the sexes. The upper part of the
skull of the male (C. bifurcus, Fig.
85), an inhabitant of Madagascar, is
produced into two great, solid, bony
projections, covered with scales like
the rest of the head; and of this

da, taper eee Sue; ~wonderful modification of structure

hae a aa the female exhibits only a rudi-

ment. Again, in Chameleon Owenti (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

SEXUAL SELECTION 463

they are used by the males for fighting together; and, as
these animals are very quarrelsome,” this is probably a
correct view. Mr. T. W. Wood also informs me that he
once watched two individuals of C. pumilus fighting vio-
lently on the branch of a tree; they flung their heads about
and tried to bite each other; they. then rested for a time,
and afterward continued their battle.

With many lizards, the sexes diffet slightly in color,

{Y

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 Acan-
thodactylus capensis of South 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

89 Dr, Bucholz, ‘‘Monatsbericht K, Preuss, Akad.,’’ Jan, 1874, p. 78.

464 THE DESCENT OF MAN

a still greater difference; the lips also of the male are
black, while those of the female are green. In our com-
mon little viviparous lizard (Zootoca vivipara) ‘‘the under
side of the body and base of the tail in the male are bright
orange, spotted with black; in the female these parts are
pale grayish green without spots.’’" We have seen that
the males alone of 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.” In many cases the
males retain the same colors throughout the year, but in
others they become
much brighter dur-
ing the breeding sea-
son; 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.” -

Both sexes of many
species are beautifully
colored exactly alike;
and there is no reason te. 86.—Chameleon Owenii. Upper figure, male ;
to suppose that such nen ee eee
colors are protective. No doubt with the bright green
kinds, which live in the midst of vegetation, this color
serves to conceal them, and in North 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.

7 Bell, ‘‘History of British Reptiles,”’ 2d edit., 1849, p. 40.

1 For Proctotretus, see ‘“‘Zoology of the Voyage of the Beagle: Reptiles,”
by Mr. Bell, p. 8. For the Lizards of 8. 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. Giimther, p. 143.

® GQiinther in ‘‘Proc. Zoolog. Soc.,”’ 1870, p. 778, with a colored figure.

SEXUAL SELECTION 465

But the bright colors with which so many lizards are orna-
mented, 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 al-
most as important a part with reptiles as with birds; and
the less conspicuous colors of the females in comparison
with the males cannot be accounted for, as Mr. Wallace
believes to be the case with birds,’by the greater exposure
of the females to danger during incubation.

466 THE DESCENT OF MAN

CHAPTER XIII

SECONDARY SEXUAL CHARACTERS OF BIRDS

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

and conspicuous in birds, though not perhaps entail-

ing 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 sacs,
topknots, 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 colored. ‘The males sometimes pay their court
by dancing, or by fantastic antics performed either on the
ground or in the air. In one instance, at least, the male
emits a musky odor, which we may suppose serves to charm
or excite the female; for that excellent observer, Mr. Ram-
say,’ says of the Australian musk-duck (Biziwra 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 odor during the pairing sea-
son, that it can be detected long before the bird can be

Ge cone sexual characters are more diversified

1 “This,” vol. iii. (new series), 1867, p. 414.

SEXUAL SELECTION 487

seen.* On the whole, birds appear to be the most sasthetic
of all animals, excepting of course man, and they have
nearly the same taste for the beautiful as we have. This
is shown by our enjoyment of the singing of birds, and by
our women, both civilized and savage, decking their heads
with borrowed plumes, and using gems which are hardly
more brilliantly colored than the naked skin and wattles
of certain birds. In man, however, when cultivated, the
sense of beauty is manifestly a far more complex feeling,
and is associated with various intellectual ideas.

Before treating of the sexual characters with which we
are here more particularly concerned, I may just allude
to certain differences between the sexes which apparently
depend on differences in their habits of life; for such cases,
though common in the lower, are rare in the higher, classes,
Two humming-birds belonging to the genus Eustephanus,
which inhabit the island of Juan Fernandez, were long
thought to be specifically distinct, but are now known,
as Mr. Gould informs me, to be the male and female of
the same species, and they differ slightly in the form of tha
beak. In another genus of humming-birds (@rypus), 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, while
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

® Gould, ‘‘Handbook to the Birds of Australia,’? 1865, vol. ii. p. 388,

468 THE DESCENT OF MAN

might be made to differ greatly through natural selection.
In some of the above cases, however, it is possible that the
beaks of the males may have been first modified in relation
to their contests with other males; and that this afterward
led to slightly changed habits of life.

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® describes
a battle in which a pair seized hold of each other’s beaks,
and whirled round and round, till they almost fell to the
ground; and M. Montes de Oca, in speaking of another
genus of humming-bird, says that two males rarely meet
without a fierce aérial 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.’’* 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 inter-
fered; the female all the time looking on as a quiet spec-
tator.° 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 hemorrhous),
which ‘‘fight with great spirit.’’ °

3 Quoted by Mr. Gould, ‘Introduction to the Trochilides,”? 1861, p. 29.

4 Gould, ibid., p. 52,

5 W. Thompson, ‘“‘The Natural History of Ireland: Birds,’’ volume if.,
21850, p. 327.

6 Jerdon, ‘‘Birds of India,’’ 1863, vol. il, p. 96.

SEXUAL SELECTION 469

The polygamous ruff (Machetes pugnaz, Fig. 87) is notori-
ous 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 pro-
pose 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 colors, probably serves in chief part as an ornament.
Like most pugnacious birds, they seem always ready to
fight, and when closely confined often kill each other; but
Montagu observed that their pugnacity 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.’ Of the pug-
nacity 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 (Catrina mos-
chata); and where these fights have occurred the river is
covered for some distance with feathers.’’* Birds which
seem ill-adapted for fighting engage in fierce conflicts; thus
the stronger males of the pelican drive away the weaker
ones, snapping with their huge beaks and giving heavy
blows with their wings. Male snipe fight together, ‘‘tug-
ging and pushing each other with their bills in the most
curious manner imaginable.’’ Some few birds are believed
never to fight; this is the case, according to Audubon, with
one of the woodpeckers of the United States (Picus auratus),

1 Macgillivray, ‘‘Hist. Brit. Birds,’’ vol. iv., 1852, pp. 177-181.
8 Sir BR. Schomburgk in ‘‘ Journal of Royal Geographical Society,’’ vol,
xiii., 1843, p. 31.

470 THE DESCENT OF MAN

although ‘‘the hens are followed by even half a dozen of

Mo

their gay suitors.

Fie. 37.—The Ruff or Machetes pugnax (from Brehm’s “Thierleben”),

The males of many birds are larger than the females,
and this no doubt is the result of the advantage gained by

® “Ornithological Biography,”’ vol. i, p. 191. For pelicans and snipes, see
vol iii, pp. 138, 477

SEXUAL SELECTION 471

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 Cincloram-
phus cruralis (allied to our pipits) are by measurement
actually twice as large as their respective females.” With
many other birds the females are larger than the males;
and, as formerly remarked, the explanation often given,
namely, that the females have most of the work in feed-
ing 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” that in Derbyshire a kite struck at a game-hen ac-
companied by her chickens, when the cock rushed to the
rescue, and drove his spur right through the eye and skull
of the aggressor. The spur was with difficulty drawn from
the skull, and as the kite, though dead, retained his grasp,
the two birds were firmly locked together; but the cock
when disentangled was very little injured. The invincible
courage of the game-cock is notorious: a gentleman who
long ago witnessed the brutal scene told me that a bird had
both its legs broken by some accident in the cock-pit, and
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,”’

1 Gould, ‘‘Handbook of Birds of Australia,’’ vol. i. p. 395, vol. ii. p. 383.
" Mr. Hewitt in the ‘Poultry Book by Tegetmeier,”’ 1866, p. 134.

472 THE DESCENT OF MAN

13

so that one of the combatants is frequently found dead.
An Indian partridge (Ortygornis gularis), the male of which
is furnished with strong and sharp spurs, is so quarrelsome,
‘that the scars of former fights disfigure the breast of al-
most every bird you kill.’’”

The males of almost all gallinaceous birds, even those
which are not furnished with spurs, engage during the
breeding season in fierce conflicts. The Capercailzie and
Black-cock (Zetrao urogallus and 7. 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

9 Layard, ‘‘Annals and Mag. of Nat. Hist.,’? vol. xiv., 1854, p. 63.
% Jerdon, ‘‘Birds of India,’’ vol. iii. p. 574.

SEXUAL SELECTION 473

in the course of one morning several Balz-places, which
remain the same during successive years."

The peacock with his long train appears more like a
dandy than a warrior, but he sometimes engages in fierce
contests: the Rev. W. Darwin Fox informs me that at some
little distance from Chester two peacocks became so excited
while fighting that they flew over the whole city, still en-
gaged, until they alighted on the top of St. John’s tower.

The spur, in those gallinaceous birds which are thus
provided, is generally single; but Polyplectron (see Fig.
51, p. 512) has two or more on each leg; and one of the
Blood-pheasants (Jthaginis 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 erythropthalmus) possess spurs. In Galloper- |
dix it is usual for the males to have two spurs, and for the
females to have only one on each leg."* 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.

Various birds have spurs on their wings. But the
Egyptian goose (Chenalopex egyptiacus) has only ‘‘bare ob-
tuse knobs,’’ and these probably show us the first steps
by which true spurs have been developed in other species.
In the spur-winged goose, Plectropterus gambensis, the males
have much larger spurs than the females; and they use -
them, as I am informed by Mr. Bartlett, in fighting to-
gether, so that, in this case, the wing-spurs serve as sexual

%6 Brehm, “‘Illust. Thierleben,’’ 1867, B. iv. s. 351. Some of the fore-
going Lage are taken from L. Lloyd, “The Game Birds of Sweden,”
etc., 1867, p

is serdoas Tinds of India: on Ithaginis,’’ vol. iii. p. 523; on Galloperdix,
p. 541.

474 THE DESCENT OF MAN

weapons; but, according to Livingstone, they are chiefly
used in the defence of the young. The Palamedea (Fig. 88)

1

va
ne
S
\

}

Pie. 38.—Palamedea cornuta (from Brehm), showing the double wing-spurs,
and the filament on the head.

is armed with a pair of spurs on each wing; and these are
such formidable weapons that a single blow has been

SEXUAL SELECTION 475

known to drive a dog howling away. But it does not
appear that the spurs in this case, or in that of some of
the spur-winged rails, are larger in the male than in the
female.’* In certain plovers, 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 Z. lobatus both sexes have spurs, but these
are much larger in the males than in the females. In an
allied bird, the Holopterus armatus, the spurs do not in-
crease 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 sidewise at each other, sometimes with fatal re-
sults. Thus also they drive away other enemies.”

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,” are ready to
fight whenever they meet. The presence of the female is
the teterima belli causa. The Bengali baboos make the
pretty little males of the amadavat (Hstrelda 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.”
When many males congregate at the same appointed spot
and fight together, as in the case of grouse and various other

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
PAmérique mérid.,’’ tom. iv., 1809, pp. 179, 253.

See, on our peewit, Mr. R. Carr in ‘‘Land and Water,’? August 8, 1868,
p. 46. In regard to Lobivanellus, see Jerdon’s ‘‘Birds of India,’’ vol. iii. p.
647, and Gould’s ‘‘Handbook of Birds of Australia,’’ vol. ii. p. 220. For the
Holopterus, see Mr. Allen in the ‘‘Ibis,’’ vol. v., 1863, -p. 156.

18 Audubon, ‘‘Ornith. Biography,’’ vol. ii. p. 492° vol. i. pp. 4-13.

10 Mr, Blyth, ‘‘Land and Water,’’ 1867, p. 212.

476 THE DESCENT OF MAN

birds, they are generally attended by the females,” which
afterward pair with the victorious combatants. But in some
cases the pairing precedes instead of succeeding the combat:
thus, according to Audubon,” several males of the Vir-
ginian goat-sucker (Caprimulgus virginianus) ‘‘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 in-
deed 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, ne doubt, commonly
gains his desire; but some of these battles are caused by
wandering ales trying to distract the peace of an nlroady
mated pair.”

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 gener-
ally decorated with various ornaments, which often become
more brilliant during the breeding season, and which are
sedulously displayed before the females. The males also
endeavor to charm or excite their mates by love-notes,
songs, and antics; and the courtship is, in many instances,
a prolonged affair. Hence it is not probable that the

% Richardson on Tetrao wmbellus, ‘‘Fauna Bor. Amer.: Birds,’’ 1831, p. 343.
L. Lloyd, ““Game Birds of Sweden, iD 1867, pp. 22, 19, on the capercailzie and
black-cock. Brehm, however, , asserts (“Thierleben,” ete., B. iv. 8, 352) that in
Germany the gray-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 Sean-
dinavia, and with other species in N orth America, ;

31 “‘Ornithological Biography,’” vol. ii. p. 275.

22 Brehm, ‘‘Thierleben,’’ etc., B. iv., Piset, p. 980. Audubon, *Ornith.
Biography ’’ vol, ii. p. 492

SEXUAL SELECTION 417

females are indifferent to the charms of the opposite sex,
or that they are invariably compelled to yield to the victori-
ous males. It is more probable that the females are excited,
either before or after the conflict, by certain males, and thus
unconsciously prefer them. In the case of Tetrao umbellus,
a good observer” goes so far as to believe that the battles
of the males ‘‘are all a sham, 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.’ *

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 some-
times used to excite terror, as in the case of the hissing
noise made by some nestling-birds. Audubon* relates that
a night-heron (Ardea nycticorax, Linn.) which he kept tame
used to hide itself when a cat approached, and then ‘‘sud-
denly start up uttering one of the most frightful cries, ap-
parently enjoying the cat’s alarm and flight.’’ The common
domestic cock clucks to the hen, and the hen to her chick-

88 “‘Tand and Water,’ July 25, 1868, p. 14.

*4 Audubon’s ‘‘Ornitholog. Biography’’; on Tetrao cupido, vol. ii, p. 492;
on the Sturnus, vol. ii. p, 219.

% “Ornithological Biography,’’ vol. v. p. 601.

Descent—Vo.. II.—3

478 THE DESCENT OF MAN

ens when a dainty morsel is found. The hen, when she has
laid an egg, ‘‘repeats the same note very often, and con-
cludes with the sixth above, which she holds for a longer
time;’’ * 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 sports-
man knows to his cost, are understood by the same species
and by others. The domestic cock crows, and the hum-
ming-bird chirps, in triumph over a defeated rival. The
true song, however, of most birds and various strange cries
are chiefly uttered during the breeding season, and serve as
a charm, or merely as a call-note, to the other sex.
Naturalists are much divided with respect to the object of
the singing of birds. Few more careful observers ever lived
than Montagu, and he maintained that the ‘‘males of song-
birds and of many others do not in general search for the
female, but, on the contrary, their business in the spring is
to perch on some conspicuous spot, breathing out their full
and amorous notes, which, by instinct, the female knows,
and repairs to the spot to choose her mate.’’*” Mr. Jenner
Weir informs me that this is certainly the case with the
nightingale. Bechstein, who kept birds during his whole
life, asserts, ‘‘that the female canary always chooses the
best singer, and that in a state of nature the female finch
selects that male out of a hundred whose notes please her
most.’’*° There can be no doubt that birds closely attend
to each other’s song. Mr. Weir has told me of the case of
a bullfinch which had been taught to pipe a German waltz,

% The Hon. Daines Barrington, ‘‘Philosoph. Transact.,’? 1773, p. 252.

21 “Ornithological Dictionary,’’ 1833, p. 475.

% ‘‘Naturgeschichte der Stubenvégel,’’ 1840, 8.4. Mr. Harrison Weir like.
wise writes to me: ‘‘I am informed that the best singing males generally get a
mate first, when they are bred in the same room.”’

SEXUAL SELECTION — 479

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, consist-
ing 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.” Barrington, however, admits
that ‘‘superiority in song gives to birds an amazing ascen-
dency 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,”
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™
as singing while 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 pro-
tected, while 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,

% ‘‘Philosophical Transactions,’’ 1773, p. 263. White’s ‘‘Natural History
of Selborne,”? 1825, vol. i. p. 246.

% “‘Naturgesch, der Stubenvégel,’’ 1840, 8. 252.

*1 Mr. Bold, ‘‘Zoologist,’? 1843-1844, p, 659.

480 THE DESCENT OF MAN

although the price of an ordinary male chaffinch is only six-
pence, 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 while 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 re-
marks, pour forth fairly melodious strains. In some of
these cases the habit of singing may be in part attributed
to the females having been highly fed and confined,™ for
this disturbs all the usual functions connected with the
reproduction of the species. Many instances have already
been given of the partial transference of secondary mascu-
line characters to the female, so that it is not at all sur-
prising that the females of some species should possess the
power of song. It has also been argued that the song
of the male cannot serve as a charm, because the males
of certain species, for instance, of the robin, sing during
the autumn. But nothing is more common than for ani-
mals to take pleasure in practicing whatever instinct they
follow at other times for some real good. How often do we
see birds which fly easily, gliding and sailing through the
air obviously for pleasure? 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 breed-
ing season are generally ready to fight at all times; and the

3 D. Barrington, ‘‘Phil. Transact.,’? 1773, p. 262. Bechstein, ‘‘Stuben-
vogel,”? 1840, s. 4.

33 This is likewise the case with the water-ouzel; see Mr. Hepburn in the
“Zoologist,’? 1845-1846, p. 1068. ;

SEXUAL SELECTION 481

males of the capercailzie sometimes hold their Balzen or
leks at the usual place of assemblage during the autumn.
Hence it is not at all surprising that male birds should con-
tinue singing for their own amusement after the season for
courtship is over.

As shown in a previous chapter, singing is to a certain
extent an art, and is much improved by practice. Birds
can be taught various tunes, and even the unmelodious
sparrow has learned to sing like a linnet. They acquire
the song of their foster parents,** and sometimes that of
their neighbors. 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,” though they never
sing, and do not naturally modulate their voices to any
great extent. Hunter asserts” that with the true songsters
the muscles of the larynx are stronger in the males than
in the females; but with this slight exception there is no
difference in the vocal 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. It is also remarkable that birds

4 L. Lloyd, ‘‘Game Birds of Sweden,’’ 1867, p. 25.

3% Barrington, ibid., p. 264. Bechstein, ibid., s. 5.

% Dureau de la Malie gives a curious instance (“‘Annales des Sc. Nat.,’? 3a
series, Zoolog., tom. x. p. 118) of some wild blackbirds in his garden in Paris
which naturally learned a republican air from a caged bird.

31 Bishop, in ‘‘Todd’s Cyclop. of Anat. aud Phys.”’ vol. iv. p. 1496.

38 As stated by Barrington in ‘‘Philosoph, Transact.,’’ 1773, p. 262.

89 Gould, ‘‘Handbook to the Birds of Australia,’ vol. i., 1865, pp. 308-310,
Gee also Mr. T. W. Wood in the “‘Student,’’ April, 1870, p. 125.

482 THE DESCENT OF MAN

which sing well are rarely decorated with brilliant colors
or other ornaments. Of our British birds, excepting the
bullfinch and goldfinch, the best songsters are plain-
colored. he kingfisher, bee-eater, roller, hoopoe, wood-

) Se————_\

mes

wae py
>

a

Wane

ra
is
s

2

Fia. 39.—Tetrao cupido: male (T. W. Wood)

Sey

LON

peckers, etc., utter harsh cries; and the brilliant birds of
the tropics are hardly ever songsters.*° Hence bright colors
and the power of song seem to replace each other. We can
perceive that if the plumage did not vary in brightness, or

; : See remarks to this effect in Gould’s ‘‘Introduction to the Trochilide,’’
861, p. 22.

SEXUAL SELECTION 4838

if bright colors were dangerous to the species, other means
would be employed to charm the females; and melody of
voice offers one such means.

In some birds the vocal organs differ greatly in the two
sexes. In the Tetrao cupido (Fig. 39) the male has two bare,
orange-colored sacs, one on each side of the neck; and
these are largely inflated when the male, during the breed-
ing season, makes his curious hollow sound, audible at a
great distance. Audubon proved that the sound was in-
timately connected with this apparatus (which reminds us
of the air-sacs on each side of the mouth of certain male
frogs), for he found that the sound was much diminished
when one of the sacs 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 in-
flation.’’** The male of. another kind of grouse (Tetrao
urophasianus), while courting the female, has his ‘“‘bare
yellow csophagus 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 cesophagus of the female is not in any way
remarkable.*

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
“ock.’?* A crow-like bird inhabiting South America

41 “The Spertsman 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 excelient 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.

# Richardson, ‘‘Fauna Bor. American: Birds,’? 1831, p. 359. Audubon,
Shid., vol. iv. p. 507. ; : :

# The following papers have been lately written on this subject: Prof. A,

484 THE DESCENT OF MAN

(Cephalopterus ornatus, Fig. 40) is called the umbrella-bird,
from its immense topknot, 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

Ficiat

Fic. 40.—The Umbrella-bird or Cephalopterus ornatus (male, from Brehm).

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.

Newton, in the “This,” 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 sac distended. It is a sin-
gular fact that the sac is not developed in all the males of the same species.

SEXUAL SELECTION 485

Bates found that it is connected ‘‘with an unusual develop-
ment 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 rudi-
mentary in the female.*

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 imbedded
in the sternum. In the wild swan (Cygnus ferus) it is
more deeply imbedded in the adult male than in the adult
female or young male. In the male Merganser the en-
larged portion of the trachea is furnished with an addi-
tional pair of muscles.** 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.‘
But the meaning of these differences in the trachea of the
two sexes of the Anatide is not understood; for the male
is not always the more vociferous; thus with the common
duck, the male hisses, while the female utters a loud
quack.*7 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.** Highly important struc-
tures have, therefore, in these cases been modified ac-
cording to sex.

It is often difficult to conjecture whether the many

“4 Bates, ‘“The Naturalist on the Amazons,’ 1863, vol. ii. p. 284; Wallace,
in ‘‘Proc. Zool. Soc.,’’ 1850, p. 206. A new species, with a still larger neck-
appendage (C@. penduliger), has lately been discovered, see ‘‘Ibis,”’ vol. i. p. 457.

45 Bishop, in ‘“Todd’s Cyclop. of Anat. and Phys.,’’ vol. iv. p. 1499.

4 Prof. Newton, ‘‘Proc. Zoolog. Soc.,’’ 1871, p. 651.

# 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 per-
haps they are now tending toward abortion.

# “Elements of Comp. Anat.,”? by R. Wagner, Eng. translat., 1845, p. 111.
With respect to the swan, as given above, Yarrell’s ‘‘Hist. of British Birds,”*
2d edit., 1845, vol. iii. p. 193.

486 THE DESCENT OF MAN

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.*® 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 fe-
males which are present are thus charmed.” The voice
of the common rook is known to alter during the breeding
season, and is therefore in some way sexual.” 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 color, judging by the
inharmonious contrast of their bright yellow and blue
plumage? It is, indeed, possible that, without any ad-
vantage 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 practice, 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 seme
kinds of grouse thus produce a buzzing sound. Another

® ©. L. Bonaparte, quoted in the “‘Naturalist Library: Birds,”? vol. xiv.

126.
Pio L. Lloyd, ‘‘The Game Birds of Sweden,” etc., 1867, pp 22, 81.

5 Janien “Philosoph. Transactions, ’’ 1834, p. 20.

SEXUAL SELECTION 487

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 neighborhood,’’ drums by rap-
idly 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 un-
like the sound produced by shaking a stiff piece of cloth.”
On the west coast of Africa the little black weavers (Plo-
ceus?) 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 ata
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 per-
pendicularly down against a stone or the trunk of a tree,
“when the breath being forced down the tubular bill pro-

488 THE DESCENT OF MAN

duces 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 cesophagus thus becomes
much swollen; and this probably acts as a resonator, not
only with the hoopoe, but with pigeons and other birds."
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 com-
mon 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

Fig. 41.—Outer tail-feather of Scolopax gallinago (from “Proc. Zool. Soc.,’’ 1858).

after zigzagging 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

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, Jer-
don, ‘‘Birds of India,’’ vol. iii. p. 533. On the Weavers, ‘‘Livingstone’s Ex-
pedition 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
Nighi-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.

SEXUAL SELECTION 489

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. 48), 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
Wilsonit of the United States makes a switching noise
while descending rapidly to the earth.”

In the male of the Chamepetes unicolor (a large gallina-
ceous bird of America) the first primary wing-feather is
arched toward the tip and is
much more attenuated than
in the female. In an allied Fie. 42.—Outer tail-feather of Scolopax
bird, the Penelope nigra, nee,

Mr. Salvin observed a male
which, while it flew downward 2 :
“with outstretched wings, Fie. 48,—Outer tail-feather of Scolopax
gave forth a kind of crashing en

rushing noise,’’ like the falling of a tree.“* 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 while
courting the female.” 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 toward the
extremity. The male, for instance, of-Selasphorus platy-

53 See Mr. Meves’ interesting paper in “‘Proc, Zool, Soc.,’’ 1858, p. 199.
For the habits of the snipe, Macgillivray, ‘‘Hist. British Birds,’ vol. iv. p.
871. For the American snipe, Capt. Blakiston, ‘*Ibis,”’ vol. v., 1863, p. 181,

54 Mr. Salvin, in ‘‘Proc. Zool. Soc.,’? 1867, p. 160, Iam much indebted to
this distinguished oruithologist for sketches of the feathers of the Chameepetes,
and for other information.

55 Jerdon, ‘‘Birds of India,’ vol. iii. pp. 618, 622

.

490 THE DESCENT OF MAN

cercus, when adult, has the first primary wing-feather
(Fig. 44) thus excised. While flying from flower to Hower
he makes ‘‘a shrill, almost whistling noise;’’ * but it did
not appear to Mr. Salvin that the noise was intentionally
made.

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 colored P. deliciosa the first
three secondaries are thick-stemmed and curved toward
the body; in the fourth and fifth (Fig. 45, a) the change
is greater; and in the sixth and seventh (6, c) the shaft
‘tis thickened to an extraordinary degree, forming a solid,
horny lump.’’ The barbs also are
greatly changed in shape, in com-
parison with the corresponding feath-
ers (d, e, f) in the female. Hven the
bones of the wing, which support
- these singular feathers in the male,
sketch by Mr. Salvin) Upper are said by Mr. Fraser to be much
ure, corresponding ‘feather of thickened. These little birds make

an extraordinary noise, the first
‘‘sharp note being not unlike the crack of a whip.” ”

The diversity of the sounds, both vocal and instru-
mental, made by the males of many birds during the breed-
ing 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 re-
minded 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,

56 Gould, ‘Introduction to the Trochilide,’’ 1861, p. 49. Salvin, ‘Proce,
Zoolog. Soc.,’? 1867, p. 160.

51 Sclater, in ‘‘Proc. Zool. Soc.,’’ 1860, p. 90, and in ‘‘Ibis,’’ vol. iv., 1862,
p. 175. Also Salvin, in ‘‘Ibis,’’ 1860, p. 37.

SEXUAL SELECTION 491

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

Fia. 45.—Secondary wing-feathers of Pipra deliciosa (from Mr. Sclater, in “Proc.
Zcol. Soc.,” 1860). The three upper feathers, a, 6, 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,
eand/f, seventh secondary, lower surface.
the strongest or thickest, or most attenuated feathers, situ-
ated 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 on:y

492 THE DESCENT OF MAN

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, 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 (Cath-
artes 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

8 ‘‘The Nile Tributaries of Abyssinia,” 1867. p. 203:

SEXUAL SELECTION 493

tittle 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 while courting the
female, as has been figured by Wolf. An allied Indian
bustard (Otis bengalensis) at such times ‘‘rises perpendicu-
larly 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.”

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 practiced under confinement, and Mr.
Strange has described™ 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

5 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, “‘Ornith. Biography,’’ vol. ii. p, 51, and vol.
iii. p. 89. On the White-throat, Macgillivray, ‘‘Hist. British Birds,’’ vol. ii.
p. 364. On the Indian Bustard, Jerdon, ‘Birds of India,”’ vol. iii. p. 618.

® 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

494 THE DESCENT OF MAN

erect, run round the bower and become so excited that his
eyes appear ready to start from his head; he continues

y =
Wee:
Hien

Fig. 46.—Bower-bird, Chlamydera maculata, with Bonen (@om Brehm),

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

SEXUaL SELECTION 495

female goes gently toward him.’’ Captain Stokes has de-
scribed the habits and ‘‘play-houses’’ of another species,
the Great Bower-bird, which was seen ‘‘amusing itself by
flying backward and forward, 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 labor. 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 colored than the male. As with the artificial
ornaments used by savage and civilized men, so with the
natural ornaments of birds, the head is the chief seat of
decoration.” The ornaments, as mentioned at the com-
mencement 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 colors are fully
displayed. Elegant ear-tufts (see Fig. 39, ante) are occa-
sionally present. The head is sometimes covered with vel-
vety down, as with the pheasant, or is naked and vividly
colored. The throat, also, is sometimes ornamented with
a beard, wattles, or caruncles. Such appendages are gen-
erally brightly colored, and no doubt serve as ornaments,
though not always ornamental in our eyes; for while the
male is in the act of courting the female, they often swell
and assume vivid tints, as in the male turkey. At such

61 See remarks to this effect, on the ‘‘Feeling of Beauty Among Animals,’?
by Mr. J. Shaw, in the ‘‘Athenzum,”’ Nov. 24, 1866, p. 681.

496 THE DESCENT OF MAN

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 topknot; and these are then colored of the
most intense blue which I have ever beheld.” The African
hornbill (Bucoraz abyssinicus) inflates the scarlet bladder-
like wattle on its neck, and with its wings drooping and
tail expanded ‘‘makes quite a grand appearance.’’* Even
the iris of the eye is sometimes more brightly colored 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
colored more conspicuously in the male than in the female;
and ‘‘the oblique grooves upon the sides of the lower man-
dible are peculiar to the male sex.’’

The head, again, often supports fleshy appendages, fila-
ments, 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,*° who shows that they are formed either of can-
cellated 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 con-
necting 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 orna-
mental appendages. Hlongated feathers or plumes spring
from almost every part of the body. The feathers on
the throat and breast are sometimes developed into beau-

§ See Dr. Murie’s account with colored figures in ‘‘Proc. Zoolog. Soc.,’*
1872, p. 730.

6 Monteiro, ‘‘Ibis,’’ vol. iv., 1862, p. 339.

4 “Tand and Water,’’ 1868, p. 217.

8 “‘Ueber die Schadelhocker,’’ etc., ‘‘Niederlandischen Archiv fir Zoolo-
gie,” B. I. Heft 2, 1872.

SEXUAL SELECTION 497

tiful yaffs 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.° 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,” and that of the beautifully
ocellated secondary wing-feathers nearly three feet. In a.
small African night-jar (Cosmetornis vewillarius) one of the
primary wing-feathers, during the breeding season, attains
a length of twenty-six inches, while 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 disk.”
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 términate in a disk; or are, as they are sometimes
called, spoon or racket-shaped. Feathers of this kind oc-
cur in the tail of a motmot (Zumomota superciliaris), of
a kingfisher, finch, humming-bird, parrot, several Indian
drongos (Dicrurus and Edolius, in one of which the disk
stands vertically), and in the tail of certain birds of para-
dise. In these latter birds, similar feathers, beautifully

66 Dr. W. Marshall, ‘‘Ueber den Vogelschwanz,”’ ibid., B. I. Heft 2, 1872.

61 Jardine’s ‘‘Naturalist Library: Birds,’’ vol. xiv. p. 166.

68 Sclater, in the ‘‘Ibis,”’ vol. vi., 1864, p. 114. Livingstone, ‘‘Expedition
to the Zambesi,’’ 1865, p. 66.

498 THE DESCENT OF MAN

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 disks.” It is a most
singular fact that the motmots, as Mr. Salvin has clearly
shown,” give to their tail-feathers the racket-shape by
biting off the barbs, and, further, that this continued muti-
lation has produced a certain amount of inherited effect.
Again, the barbs of the feathers in various widely dis-
tinct birds are filamentous or plumose, as with some herons,
ibises, birds of paradise, and Gallinacee. 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;” 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 coloring of the feathers in the male appears to
have been admired by the female. The fact of the feath-
ers 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 topknots have appeared in several species.
In an extinct variety of the turkey, the topknot 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

69 Jerdon, ‘‘Birds of India,’’ vol. iii. p. 620.

” ‘Proc. Zoolog. Soc.,’’ 1873, p. 429.

7 Wallace, in ‘‘Annals and Mag. of Nat. Hist.,’’ vol. xx., 1857, p. 416; and
in his ‘‘Malay Archipelago,”’ vol. ii, 1869, p. 390.

SEXUAL SELECTION 499

are greatly elongated, curled, or even spirally twisted, with
the margins plumose.”

Fia. 47,—Paradisea Papuana (T. W. Wood).

In regard to color hardly anything need here be said, for
every one knows how splendid are the tints of many birds,

7 See my work on ‘‘The Variation of Animals and Plants Under Domesticar
tion,’’ vol. i. pp. 289, 293.

500 THE DESCENT OF MAN

and how harmoniously they are combined. The colors 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 colored and destitute of all orna-
ments, while the males are probably the most highly deco-
rated 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 vi-
brate, 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.’’” In another most beau-
tiful species the head is bald, ‘‘and of a rich cobalt blue,
crossed by several lines of black velvety feathers.’’

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
showed me, to a wonderful extreme in some species be-
longing to nearly every sub-group. Such cases are curi-
ously like those which we see in our fancy breeds, reared
by man for the sake of ornament: certain individuals orig-
inally 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 shown by the tail of
the fan-tail pigeon, the hood of the jacobin, the beak and
wattle of the carrier, and so forth. The sole difference be-

78 Quoted from M. de Lafresnaye, in ‘‘Annals and Magazine of Natural His-
tory,” vol. xiii., 1854, p. 15%; see also Mr. Wallace’s much fuller account in
vol. xx., 1867, p. 412, and in his ‘‘Malay Archipelago.’’

4 Wallace, ‘“‘The Malay Archipelago,”’ vol. ii., 1869, p. 405.

SEXUAL SELECTION 501

tween the cases is that in the one the result is due to man’s
selection, while in the other, as with humming-birds, birds

Fia. 48.—Lophornis ornatus, male and female (from Brehm).

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 color between the sexes, namely, the fa-

mous bell-bird (Chasmorhynchus niveus) of South America,
Descent—Vou. I.—4

502 THE DESCENT OF MAN :

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, while the female is

,

nt

=

Fia. 49.—Spathura underwoodi, male and female (from Brehm).
dusky-green; aud white is a very rare color in terrestria’
species of moderate size and inoffensive habits. The male
also, as described by Waterton, has a spiral tube, nearly

SEXUAL SELECTION 503

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, while the-~
females, as described by Mr. Sclater in_a--very interesting
paper, closely resemble each other, thts offering an excel-
lent instance of the common rpfé 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 dur-
ing the breeding season is of a fine green color. Ina third
species (@. 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 filamen-
tous projections half as long as the body—one rising from
the base of the beak, and the other two from the corners of
the mouth.”

The colored 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 fre-
quently change color, 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.” 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

% Mr. Sclater, ‘‘Intellectual Observer,’ January, 1867. ‘‘Waterton’s Wan-
derings,’? p. 118. See also Mr. Salvin’s interesting paper, with a plate, in the
““This,”? 1865, p. 90.

% ‘Land and Water,’’ 1867, p. 394.

504 THE DESCENT OF MaN

shore of an island ina lake in Nevada was found covered
with these curious exuvie.”

Changes of color in the plumage according to the sea-
son depend, first, on a double annual moult; secondly, on
an actual change of color in the feathers themselves; and,
thirdly, on their dull-colored 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.”°

With respect to the birds which annually undergo a
double moult, there are, first, some kinds, for instance,
snipes, swallow-plovers (Glareole), and curlews, in which
the two sexes resemble each other, and do not change color
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 color. Secondly, there are birds, for in
stance, certain species of Totanus and other Grallatores, the
sexes of which resemble each other, but in which the sum-
mer and winter plumage differ slightly in color. The differ-
ence, 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 color; but the females, though moulting
twice, retain the same colors throughout the year, while
the males undergo a change of color, sometimes a great
one, as with certain bustards. Fifthly and lastly, there
are birds the sexes of which differ from each other in

™ Mr. D. G. Elliott, in ‘‘Proc. Zool. Soc.,’? 1869, p. 589.
78 Nitusch's ‘‘Pterylography,’’ edited by P. L. Sclater. Ray Soc., 1867, p. 14

SEXUAL SELECTION. 508

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 pug-
nax) offers a good instance.

With respect to the cause or purpose of the differences
in color between the summer and winter plumage, this may
in some instances, as with the ptarmigan,” 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, topknots, 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 orna-
ments 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 com-
mon to both sexes, partakes of the nature of the exclusively
masculine plumage of many other birds.”

7 The brown mottled summer plumage of the ptarmigan is of as much im-
portance 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 Wil-
helm von Wright, in Lloyd, “Game Birds of Sweden,’’ 1867, p. 125,

6 In regard to the previous statements on moulting, seo, on snipes, etc.,
Macgillivray, ‘‘Hist. Brit, Birds,” vol. iv. p. 371; on Glareols, curlews, and
bustards, Jerdon, ‘‘Birds of India,’’ vol. iii. pp. 615, 630, 683; on Totanua,
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.

506 | THE DESCENT OF MaN

From the foregoing facts, more especially from neither
sex of certain birds changing color 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 colors
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 dur-
ing the breeding season; but that the double moult, having
been originally acquired for some distinct purpose, has sub-
sequently been taken advantage of in certain cases for gain-
ing 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 black-cock only once; some of the splendidly
colored honey-suckers (Nectariniz) of India and some sub-
genera of obscurely colored pipits (Anthus) have a double,
while others have only a single annual moult.” But the
gradations in the manner of moulting, which are known to
occur with various birds, show 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 color. 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 disk-formed tail-feathers
of certain drongos (Bhringa) in India, and with the elon-
gated feathers on the back, neck, and crest of certain

8 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.

SEXUAL SELECTION 507

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
afterward; 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 com-
pletely 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.”

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

8 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,
*This,’? vol. ifi., 1861, p. 133. On the Drongo-shrikes, Jerdon, ibid., vol. i.
p. 435. On the vernal moult of the Herodias bubulcus, Mr. 8. 8. Allen, in
“Ibis,”? 1863, p. 33. On Gallus bankiva, Blyth, in “Annals and Mag. of Nat.
Hist.,’’ vol. i., 1848, p. 455; see, also, on this subject, my Variation of Ani-
mals under Domestication,”’ vol. i. p. 236.

508 THE DESCENT OF MAN

female. The male pintail-duck (Anas acuta) loses his plu-
mage 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 sur-
prise at finding gradations of all kinds. If the male pintail
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 com-
pletely lost.®

Some male birds, as before stated, become more brightly
colored in the spring, not by a vernal mount, but either by
an actual change of color in the feathers or by their ob-
scurely colored deciduary margins being shed. Changes
of color thus caused may last for a longer or shorter time.
In the Pelecanus onocrotalus a beautiful rosy tint, with
lemon-colored 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 be-
come brighter colored, while other finches undergo no such
change. Thus the Pringilla tristis of the United States (as
well as many other American species) exhibits its bright
colors only when the winter is past, while 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

% See Macgillivray, ‘Hist. British Birds’ (vol. v. pp. 34, 70 and 223),
on the moulting of the Anatide, with quotations from Waterton and Montagu,
Also Yarrell, ‘‘Hist. of British Birds,” vol. iii. p. 243.

SEXUAL SELECTION 509

the plumage of allied species is not surprising, for with the
common linnet, which belongs to the same family, the crim-
son forehead and breast are displayed only during the sum-
mer in England, while in Madeira these colors are retained
throughout the year.” :

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 show off his
finery before poultry, or even pigs.*° 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 en-
deavoring in various ways to charm the female. Mr.
Gould, after describing some peculiarities in a male hum-
ming-bird, says he has no doubt that it has the power of
displaying them to the greatest advantage before the female.
Dr. Jerdon® 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.

It must be a grand sight in the forests of India ‘to come
suddenly on twenty or thirty peafowl, the males displaying
their gorgeous trains, and strutting about in all the pomp of

® On the pelican, see Sclater, in ‘Proc. Zoolog. Soc.,’? 1868, p. 265. On
the American finches, see Audubon, ‘‘Ornith. Biography,”’ vol. i. pp. 174, 221,
and Jerdon, “Birds of India,’ vol. ii. p. 383. On the Fringilla cannabina of
Madeira, Mr. EB. Vernon Harcourt, ‘‘Ibis,’’ vol. v., 1863, p. 230.

8 See also “Ornamental Poultry,” by Rev. E. 8. Dixon, 1848, p. 8.

&% ‘Birds of India,’’ introduct. vol. i. p. 24; on the peacock, vol. iii, p, 507.
See Gould’s ‘Introduction to the Trochilide,’’ 1861, pp. 15 and 111,

510 THE DESCENT OF MAN

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 gro-
tesque, 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 court-
ship; he found one of their meeting-places where ten males
and two females were present. The space was from four to

SEXUAL SELECTION 511

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 hop-
ping 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.” With
birds of paradise a dozen or more full-plumaged males con-
gregate in a tree to hold a dancing-party, as it is called by
the natives; and here they fly about, raise their wings, ele-
vate 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 ab-
sorbed 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.”

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 toward the female
on whichever side she may be standing, obviously in order
that a large surface may be displayed before her.” They

8 See the “Journal of the Royal Geographical Society,” vol. x., 1840,
. 236.
» 8 Annals and Mag. of Nat. Hist.,”’ vol. xiii., 1854, p. 157; also Wallace,
fbid., 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,
8 Mr. T. W. Wood has given (“‘The Siudent,’? 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.

12 THE DESCENT OF MAN

likewise turn their beautiful tails and tail-coverts a little
toward the same side. Mr. Bartlett has observed a male
Polyplectron (Fig. 51) in the act of courtship, and. has

Fic. 51.—Polyplectron chinquis, male (T. W. Wood).
shown 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,

SEXUAL SELECTION 618

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 show off, at the same time, his rich
blue throat and breast. But the breast of the Polyplectron
is obscurely colored, and the ocelli are not confined to the
tail-feathers. Consequently the Polyplectron does not stand
in front of the femaie; 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 toward 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 op-
posite to the female, and which would otherwise be con-
cealed, so that nearly all the beautifully spotted feathers
are exhibited at the same time.

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 color, like those
on the skin of a tiger and leopard combined. These beau-
tiful 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 @ 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

514 THE DESCENT OF MAN

perfect skins sent from the East, found a place between
two of the feathers which was much frayed, as if the head

Bia. 62.—Bide view of male Argus pheasant, while displaying before fhe female. Ob-
served and sketched from nature by Mr. T. W. Weo

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.

SEXUAL SELECTION 515

The ocelli on the wing-feathers are wonderful objects;
for they are so shaded that, as the Duke of Argyll re-
marks,” 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 downward, 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 natu-
rally 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 colored, 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 colored of a lighter
chestnut, and is thickly dotted with minute white points.
I have shown 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 ex-
panded together so as to form the great fan or shield.

% “The Reign of Law,’’ 1867, p. 203.

516 THE DESCENT OF MAN

The case of the male Argus pheasant is eminently inter-
esting, because it affords good evidence that the most re-
fined 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 dis-
played, and the ball and socket ornaments are not exhibited
in full perfection, until the male assumes the attitude of
courtship. he Argus pheasant does not possess brilliant
colors, 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 in-
credible 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-colored Hared and Cheer pheasants
(Crossoptilon auritum and Phasianus wallichit); 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 EHared pheasant.
Mr. Jenner Weir, also, finds that all male birds with rich
or strongly characterized plumage are more quarrelsome
than the dull-colored species belonging to the same groups.
he goldfinch, for instance, is far more pugnacious than the
dinnet, and the blackbird than the thrush. Those birds
which undergo a seasonal change of plumage likewise |

SEXUAL SELECTION 517

become much more pugnacious at the period when they
are most gayly ornamented. No doubt the males of some
obscurely colored birds fight desperately together, but it
appears that when sexual selection has been highly influen-
tial, and has given bright colors 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 colors have rarely been both acquired
by the males of the same species; but in this case the ad-
vantage gained would have been the same, namely, success
in charming the female. Nevertheless it must be owned
that the males of several brilliantly colored 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 orna-
mented in any high degree, but which nevertheless display
during their courtship whatever attractions they may pos-
sess. 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 Fringillide
and Emberizide. The facts have been selected from a large
body of valuable notes kindly sent me by him. The bull-
finch 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 showing 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 conspiguous. The
common linnet distends his rosy breast, slightly expands
his brown wings and tail, so as to make the best of them

518 . THE DESCENT OF MAN

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 beau-
tiful. 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 colored birds; but
in the spring the feathers on the head of the male reed-
bunting (Lmberiza scheniculus) acquire a fine black color
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 colored 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.’ This species, when courting the female, slightly
spreads out and vibrates these party-colored tail-coverts in
a very peculiar manner. The male Amadina Lathami be- -
haves 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 hemorrhous) has its under tail-
coverts of a crimson color, 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

*1 For the description of these birds, see Gould’s ‘‘Handbook to the Birds
of Australia,’’ vol. i., 1865, p. 417.

SEXUAL SELECTION 519

even from above.”’” 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 while court-
ing the female, thus showing 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, while 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 show with what
care male birds display their various charms, and this they
do with the utmost skill. While 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 cer-
tainly 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

‘Birds of India,’’ vol. ii. p. 96.

520 THE DESCENT OF MAN

pheasant are said ‘‘almost entirely to deprive the bird of
flight.’’ The fine plumes of male birds of paradise troubie
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 colors 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-colored and com-
paratively tame females, or than the young and as yet un-
adorned males.”

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,
‘Gs 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,

PB)

% 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. 16%. On Birds of Paradise, Lesson, quoted by Brehm, ‘‘Thier-
leben,’’ 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.

SEXUAL SELECTION 521

he has him entirely in his power. Even supposing that
the bird is not killed, the loss of blood suffered by an un-
dubbed cock is much greater than that sustained by one
that has been trimmed.’’* 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 per-
haps be objected that the comb and wattles are not orna-
mental, 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.

% Tegetmeier, ‘‘The Poultry Book,’’ 1866, p. 139.

§22 THE DESCENT OF MAN

%

CHAPTER XIV
BIRDS—continued

Choice exerted by the female—Length of courtship—Unpaired birds—
Mental qualities and taste for the beautiful—Preference or antipathy
shown 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

HEN the sexes differ in beauty, or in the power

\V \ 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. Hach 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

SEXUAL SELECTION 523

it is to a large extent the external attractions of the male;
though no doubt his vigor, 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 court-
ship being a prolonged affair, and partly on reiteration in
the act of pairing. Thus in Germany and Scandinavia the
balzing 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 Hastern Siberia,’ follow nearly the same
habits. The fowlers discover the hillocks where the ruffs
congregate by the grass being trampled bare, and this shows
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 congre-
gate. 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

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 Z. urogailus.

524 THE DESCENT OF MAN

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 utter-
ing the strangest cries.’

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 indis-
pensable 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 (Aenura superba) forms ‘‘small round hillocks,’”’ and
the W/. 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 &.
superba are sometimes very large; and an account has lately
been published® by a traveller, who heard in a valley be-
neath him, thickly covered with scrub, ‘‘a din which com-
pletely astonished’’ him; on crawling onward he beheld to
his amazement about one hundred and fifty of the magnifi-
cent 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

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,’’ 186%,
pp. 19, 78. Richardson, ‘‘Fauna Bor. Americana: Birds,” p. 362. References
in regard to the assemblages of other birds have already been given. On Para-
disea see Wallace, in “Annals and Mag. of Nat. Hist.,”’ vol. xx., 185%, p. 412.
On the snipe, Lloyd, ibid., p. 221.

® Quoted by Mr. T. W. Wood in the “Student,’’ April, 1870, p. 125.

SEXUAL SELECTION 525

the favors 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.*

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
‘“‘oreat magpie marriage.’” Some years ago these birds
abounded in extraordinary numbers, so that a gamekeeper
killed in one morning nineteen niales, 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, chat-
tering, 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 num-
bers, great assemblages cannot, of course, be held, and the
same species may have different habits in different coun-
tries. 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 trouble-
some 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.

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. 2129.

Descent—VoL. I.—5

526 THE DESCENT OF MAN

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.* 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 while bringing food to the sitting females.
Macgillivray, however, gives, on the authority of an ex-
cellent observer, an instance of three magpies successively
killed on the same nest, which were all females; and an-
other case of six magpies successively killed while 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 afterward to find
the survivor rematched. Mr. Fox, Mr. F. Bond, and others
have shot one of a pair of carrion-crows (Corvus corone), but

5 On magpies, Jenner, in ‘‘Phil. Transact.,’? 1824, p. 21. Macgillivray,
‘Hist. British Birds,’’ vol. i. p. 570. Thompson, in ‘‘Annals and Mag. of
Nat, Hist.,’’ vol. viii., 1842, p. 494,

SEXUAL SELECTION 527

the nest was soon again tenanted by a pair. These birds
are rather common; but the peregrine-falcon (Falco pere-
grinus) 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, notwith-
standing such casualties, are sure to turn out their comple-
ment 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 tin-
nunculus), all males, were killed one after the other while
attending the same nest; two of these were in mature
plumage, but the third was in the plumage of the pre-
vious year. Even with the rare golden eagle (Aquila
chrysattos), 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 (Phenicura 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 neighborhood.
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

¢

628 THE DESCENT OF MAN

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 con-
sisted of both males and females, but in what proportion
he could not say; nevertheless, after all this destruction,
a brood was reared.° ‘

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, showing that they have either
lost or never gained a mate. Death from accident or dis-

XN
® 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 Phcenicura, 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.

SEXUAL SELECTION 529

ease 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 in-
duced 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.’ Such contin-
gencies as these probably explain most of the foregoing
cases. 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 im-
probable after we have seen what strong antipathies and
preferences female birds occasionally evince toward par-
ticular males.

17 See White (‘‘Nat. Hist. of Selborne,”? 1825, vol. i. p. 140) on the exist-
ence, 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 genera-
tive 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 Nat. Hist.,’? 1846, p. 87.

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 acopted feeling to succor the orphan. These two he killed, and then left
the nest, On returning afterward 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 or the like fruitless errand.”

530 THE DESCENT OF MAN

Mental Qualities of Birds, and their Taste for the Beauti-
Jul.—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 gen-
erally, and perhaps justly, ranked as low; yet some facts
could be given’ leading to an opposite conclusion. 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 affec-
tion 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 afterward uttering a plaintive call;
and Mr. St. John gives various facts proving the attachment
of mated birds."° Mr. Bennett relates” 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. Aiter an interval of three weeks the stolen drake
was recovered, and instantly the pair recognized 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

® T 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.”’

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.’?

ul “Wanderings in New South Wales,”’ vol. ii, 1834, p. 62.

SEXUAL SELECTION 531

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 afterward matched with other birds, the two,
when brought together again, rarely, if ever, recognize
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 shown 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 frostbitten 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,
‘Gt was ridiculous to see the extravagant interest taken in
the matter by the others of the same species.’’ These par-
rots also evinced unbounded curiosity, and clearly had ‘‘the
idea of property and possession.’’ * They have good memo-
ries, for in the Zoological Gardens they have plainly recog-
nized their former masters after an interval of some months.

Birds possess acute powers of observation. Every mated
bird, of course, recognizes its fellow. Audubon states that
a certain number of mocking-thrushes (Mimus polyglottus)
remain all the year round in Louisiana, while others migrate
to the Eastern States; these latter, on their return, are in-
stantly recognized, and always attacked, by their southern
brethren.. Birds under confinement distinguish different
persons, as is proved by the strong and permanent antip-
athy or affection which they show, without any apparent
cause, toward certain individuals. I have heard of numer-
ous instances with jays, partridges, canaries, and especially

% ‘¢Aeclimatization of Parrots,”? by OC, Buxton, M.P. ‘“‘Annals and Mag.
of Nat. Hist.,’’ Nov. 1868, p. 381.

532 THE DESCENT OF MAN

bullfinches. Mr. Hussey has described in how extraordi-
nary a manner a tamed partridge recognized everybody; and
its likes and dislikes were very strong. This bird seemed
‘“‘fond of gay colors, and no new gown or cap could be
put on without catching his attention.’”’"* 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 afterward 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 recognized each other as old friends.”

Mr. Jenner Weir is convinced that birds pay particular
attention to the colors of other birds, sometimes out of jeal-
ousy, and sometimes as a sign of kinship. Thus he turned
a reed-bunting (Hmberiza scheniculus), which had acquired
its black headdress, 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 com-
rades, 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
color; and though generally peaceable, it attacked 8. ciris,

18 “The Zoologist,’” 1847-1848, p. 1602.

%4 Hewitt on wild-ducks, ‘Journal of Horticulture,’ Jan. 13, 1863, p. 39.
Audubon on the wild turkey, ‘‘Ormith. Biography,’’ vol. i. p. 14. On the
mocking-thrush, ibid., vol. i. p. 110.

SEXUAL SELECTION 583

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 toward the species which resemble them
most in color, and settle by their sides.

As male birds display their fine plumage and other orna-
ments 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 them-
selves in a looking-glass (of which many instances have
been recorded) we cannot feel sure that it is not from jeal-
ousy of a supposed rival, though this is not the conclusion
of some observers. In other cases it is difficult to distin-
guish between mere curiosity and admiration. It is per-
haps the former feeling which, as stated by Lord Lilford,’*
attracts the ruff toward any bright object, so that, in the
Tonian Islands, ‘‘it will dart down to a bright-colored hand-
kerchief, regardless of repeated shots.’? The common lark
is drawn down from the sky, and is caught in large num-
bers, 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

8 The “Ibis,” vol. ii, 1860, p. 344.

534 THE DESCENT OF MAN |

beautiful is afforded by the three genera of Australian
bower-birds already mentioned. Their bowers (see Fig.
46, p. 494), 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 gayly-
colored articles, such as the blue tail-feathers of paroquets,
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 rearranged and carried about
by the birds while at play. The bower of the Spotted
bower-bird ‘‘is beautifully lined with tall grasses, so dis-
posed 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 de-
scribed by Mr. Ramsay, ornaments its short bower with
bleached land-shells belonging to five or six species and
with ‘‘berries of various colors, 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 color, 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 dis-
covered’’; and the taste, as we see, of the several species
certainly differs."

Preference for Particular Males by the Females.—Having
made these preliminary remarks on the discrimination and

16 On the ornamented nests of Humming-birds, Gould, ‘‘Introduction to
the Trochilidz,’’ 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.

SEXUAL SELECTION 5385

taste of birds, I will give all the facts known to me, which
bear on the preference shown by the females for particular
males. It is certain that distinct species of birds occasion-
ally 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.” Several years ago eigh-
teen cases had been recorded of the occurrence in Great
Britain of hybrids between the black grouse and pheasant;’
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 in-
tercourse 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’
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 widgeon (Mareca penelope), living with
females of the same species, has been known to pair with
a pintail duck, Querquedula acuta. Lloyd describes the re-
markable attachment between a shield-drake (Zadorna vul-

panser) 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 to-
gether well know what unaccountable attachments they are
frequently forming, and that they are quite as likely to pair

“Hist. of British Birds,”’ vol. ii. p. 92.

18 “Zoologist,’? 1853-1854, p. 3946.

19 Waterton, ‘‘Essays on Nai. Hist.,’? 2d series, pp. 42 and 11%. For the
following statements, see on the widgeon,. 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. 18, 1868, p. 40; Bechstein, *‘Stubenvégel,’’ 1840, s. 230.
Mr. J. Jenner Weir has lately given me an analogous case with ducks of two

species,

536 THE DESCENT OF MAN

and rear young with individuals of a race (species) appar-
ently 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 com-
mon 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 Chi-
nese gander seems to have had prepotent charms over the
common gander. I will give only one other case: Mr. Hew-
itt states that a wild-duck, reared in captivity, ‘‘after breed-
ing a couple of seasons with her own mallard, at once shook
him off on my placing a Pintail on the water. It was evi-
dently 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. Color,
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 ob-
served with domesticated or confined birds; but these are

SEXUAL SELECTION 537

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 in-
stincts 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 stimu-
lated 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 oppor-
tunity for exerting a choice, as she is almost invariably
pursued by many males. Audubon—and we must remem-
ber 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 shown for one.’’ The
female of the red-winged starling (Ageleus pheniceus) is
likewise pursued by several males, ‘‘until, becoming fa-
tigued, she alights, receives their addresses, and soon
makes a choice.’’ He describes also how several male
night-jars repeatedly plunge through the air with aston-
ishing rapidity, suddenly turning, and thus making a sin-
gular 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

4

538 THE DESCENT OF MAN

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 bach-
elors 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.’’*° 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 learned 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 game
cock, 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 excit-
ing 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 re-
sort to. the game cock, even though that bird may not ac-

2 Audubon, ‘‘Ornitholog Biography,” vol. i. pp. 191, 349; vol. ii. pp. 42,
276; vol. iii. p. 2.

SEXUAL SELECTION 539

tually 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 cer-
tain 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, how-
ever, describes how a quarrelsome hen was subdued by
the gentle courtship of a Shanghai cock.”

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.” Mr,
Harrison Weir has lately heard from a trustworthy ob-
server, who keeps blue pigeons, that these drive away all
other colored 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 im-
mediately 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 (¢.e., very pale blue) male, and
at last mated with him. Nevertheless, as a general rule,
color appears to have little influence on the pairing of pig-
eons. 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 to-
ward certain males, without any assignable cause. Thus MM.
Boitard and Corbié, whose experience extended over forty-
five years, state: ‘‘Quand une femelle éprouve de l’antipa-

21 “Rare and Prize Poultry,”’ 1854, p. 27. :
2 ‘Phe Variation of Animals and Plants under Domestication,’’ vol. ii,

p. 103.

540 THE DESCENT OF MAN

thie pour un male avec lequel on veut l’accoupler, malgré
tous les feux de l'amour, malgré l’alpiste et le chénevis
dont on la nourrit pour augmenter son ardeur, malgré un
emprisonnement de six mois et méme d’un an, elle refuse
constamment ses caresses; les avances empressées, les aga-
ceries, les tournoiemens, les tendres roucoulemens, rien ne
peut lui plaire ni l’émouvoir; gonflée, boudeuse, blottie
dans un coin de sa prison, elle n’en sort que pour boire et
manger, ou pour repousser avec une espéce de rage des
caresses devenues trop pressantes.’’* On the other hand,
Mr. Harrison Weir has himself observed, and has heard
from- several breeders, that a female pigeon will occasion-
ally take a strong fancy for a particular male, and will
desert her own mate for him. Some females, according to
another experienced observer, Riedel,” are of a profligate
disposition, and prefer almost any stranger to their own
mate. Some amorous males, called by our English fan-
ciers ‘‘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 Audu-
bon, ‘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.”

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 fre-
quently great preference to a particular peacock. They were
all so fond of an old pied cock that one year, when he was
confined, though still in view, they were constantly assem-
bled close to the trellis-walls of his prison, and would not

28 Boitard and Corbié, ‘‘Les Pigeons,” etc., 1824, p. 12. Prosper Lucas
4Traité de ’Héréd. Nat.,’’ tom. ii., 1850, p. 296) has himself observed nearly
similar facts with pigeons.

24 “Die Taubenzucht,’’ 1824, s. 86.

2 ‘Ornithological Biography,’’ vol. i. p. 13. See to the same effect, Dr.
Bryant, in ‘‘Allen’s Mammals and Birds of Florida,’’ p. 344.

SEXUAL SELECTION 541

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.’’** 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 excel-
lent 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 feath-
ers with which he is ornamented during the breeding season.
I presume that this observation must have been made on
birds under confinement.” Here is an analogous case: Dr.
Jaeger,” director of the Zoological Gardens, of Vienna,
states that a male silver-pheasant, who had been trium-
phant 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 afterward held the flock.

It is a remarkable fact, as showing how important color
is in the courtship of birds, that Mr. Boardman, a well-known
collector and observer of birds for many years in the North-
ern United States, has never in his large experience seen an
albino paired with another bird; yet he has had opportuni-
ties of observing many albinos belonging to several species.”
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 colored comrades.

6 **Proe. Zool, Soc.,°” 1835, p. 64. The japanned peagock 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.

7 Rudolphi, ‘‘Beytrage zur Anthropologie,’’ 1812, s, 184.

98 “Die Darwin’sche Theorie, und ihre Stellung zu Moral und Religion,”
1869, s. 59.

® This statement is given by Mr. A. Leith Adams, in his ‘‘Field and Forest
Rambles,’’ 1873, p. 76, and accords with his own experience.

542, : THE DESCENT OF MAN

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 fe-
males flit round the male while he is parading at one of the
places of assemblage, and solicit his attention. 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 the male, as they fight so much
together. The following instance of rivalry is more sur-
prising, as it relates to bullfinches, which usually pair for
life. Mr. Jenner Weir introduced a dull-colored and ugly
female into his aviary, and she immediately attacked another
mated female so unmercifully that the latter had to be sep-
arated. 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, ex-
ceptions to this rule apparently occur in some few groups.
With domesticated birds I have heard of only one case of
males showing any preference for certain females, namely,
that of the domestic cock, who, according to the high au-
thority of Mr. Hewitt, prefers the younger to the. older
hens. On the other hand, in -effecting hybrid unions be-
tween the male pheasant and common hens, Mr. Hewitt is

.. © In regard to Saget see Sir R. Heron, ‘‘Proc. Zoolog. Soc., > 1835,

p. 54, and the Rev. E. 8. Dixon, ‘‘Ornamental Poultry, > 1848, p. 8. For the
turkey, Audubon, ibid., p. 4. For the capercailzie, Lloyd, “Game Birds ot
Sweden,’ 1867, p. 23.

SEXUAL SELECTION 543

convinced that the pheasant invariably prefers the older
birds. He does not appear to be in the least influenced
by their color, but ‘tis most capricious in his attach-
ments;’’*' from some inexplicable cause he shows 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), ‘tit has been re-
marked,’”’ says M. Hkstrém, ‘‘that certain females are
much more courted than the rest. Frequently, indeed,
one sees an individual surrounded by six or eight amo-
rous males.’’ Whether this statement is credible I know
not; but the native sportsmen shoot these females in or-
der to stuff them as decoys.”

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 pow-
ers of observation, and they seem to have some taste for the
beautiful both in color and sound. It is certain that the fe-
males occasionally exhibit, from unknown causes, the strong-
est antipathies and preferences for particular males. When
the sexes differ in color or in other ornaments, the males,
with rare exceptions, are the more decorated, either perma-
nently or temporarily, during the breeding season. They
sedulously display their various ornaments, exert their

31 Mr, Hewitt, quoted in ‘‘Tegetmeier’s Poultry Book,”’ 1866, p. 165.
3? Quoted in Lloyd’s ‘‘Game Birds of ees ” p, 345.

544 THE DESCENT OF MAN

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
tisk 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 justi-
fied 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 melo-
dious, or gallant males. Nor need it be supposed that the
female studies each stripe or spot of color; 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-bespangied 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

SEXUAL SELECTION 545

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 compati-
ble with the existence of the species.

Variability of Birds, and especially of their Secondary Sex-
ual Characters.—Variability and inheritance are the founda-
tions for the work of selection. That domesticated birds
have varied greatly, their variations being inherited, is cer-
tain. That birds in a state of nature have been modified
into distinct races is now universally admitted. Variations
may be divided into two classes: those which appear to our
ignorance to arise spontaneously, and those which are di-
rectly 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 ob-
served with care by Mr. J. A. Allen,* who shows that in

88 According to Dr. Blasius (‘‘Ibis,’’ vol. ii. 1860, p. 297), there are 426
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 shows 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
pow considered to be local races.

34 “Mammals and Birds of East Florida,’’ also an ‘‘Ornithological Recon-
noissance of Kansas,’ etc. Notwithstanding the influence of climate on the
colors 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 colored species can be explained on
the principle of protection, for on the Pampas, which are equally open, though
eovered by green grass, and where the birds would be equally exposed to
danger, many brilliant and conspicuously colored species are common, I have

546 THE DESCENT OF MAN

the United States many species of birds gradually become
more strongly colored in proceeding southward, and more
lightly colored 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 colors 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 consti-
tutional 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.*© Nevertheless it may be worth while to give
the few cases which I have been able to collect, relating
chiefly to color—simple albinism and melanism being ex-
cluded. Mr. Gould is well known to admit the existence
of few varieties, for he esteems very slight differences as
specific; yet he states* 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

sometimes speculated whether the prevailing dull tints of the scenery in the
above named countries may not have affected the appreciation of bright colors
by the birds inhabiting them.

3 ‘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 indi-
vidual differences, and this led me ito 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, 186%, p. 289, e¢ 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.

% ‘*Introduct. to the Trochilide,”’ p. 102.

SEXUAL SELECTION 547

in the coloring 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 paroquets ‘‘the
thighs in some are scarlet, in others grass green.’’ In an-
other paroquet 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.’’*” In the United
States some few of the males of the Scarlet Tanager (Tana-
gra rubra) have ‘‘a beautiful transverse band of glowing red
on the smaller wing-coverts;’’ * but this variation seems to
be somewhat rare, so that its preservation through sexual
selection would follow only under unusually favorable cir-
cumstances. 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 South-
ern India ‘‘a well-marked occipital crest, formed of several
graduated feathers.’’ °°

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. Al-
though the characters of this variety are not quite constant,
yet it has been named by several distinguished ornitholo-
gists as a distinct species. The fact of the pied birds being
pursued and persecuted with much clamor by the other ra-
vens of the island was the chief cause which led Briinnich
to conclude that they were specifically distinct; but this is
now known to be an error.*° This case seems analogous

81 Gould, ‘“Handbook to Birds of Australia,’’ vol. ii. pp. 32 and 38,
38 Audubon, ‘‘Ornitholog. Biography,’’ 1838, vol. iv. p. 389.
89 Jerdon, ‘‘Birds of India,’’ vol. i. p. 108; and Mr. Blyth, in ‘‘Land and
Water,’’ 1868, p. 381. ;
4 Graba, ‘“‘Tagebuch, Reise nach Faro,’? 1830, s. 61-54, Macgillivray,
-- “Hist, British Birds,’’ vol, iii. p. 745. ‘Ibis,’ vol. v., 1863, p. 469.

548 THE DESCENT OF MAN

to that lately given of albino birds not pairing from being
rejected by their comrades.

In various parts of the northern seas a remarkable vari-
ety of the common Guillemot (Uria troile) is found; and in
Feroe, one out of every five birds, according to Graba’s esti-
mation, presents this variation. It is characterized“ 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 inter-
mediate gradations have never been seen; nor is this sur-
prising, for variations which appear suddenly are often, as
I have elsewhere shown,” transmitted either unaltered or
not at all. We thus see that two distinct forms of the
same species may coexist in the same district, and we can-
not doubt that if the one had possessed any advantage over
the other, it would soon have been multiplied to the exclu-
sion 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 domestica-
tion.” 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

4! Graba, ibid., s. 54. Macgillivray, ibid., vol. v. p. 327.

# “Variation of Animals and Plants under Domestication,’’ vol. ii. p. 92.

# On these points see also ‘‘Variation of Animals and Plants under Domes
tication,” vol. i, p. 253; vol. ii. pp. 73, 75.

SEXUAL SELECTION 549

are highly favorable for sexual selection. Whether charac-
ters 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 cer-
tain 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 splen-
did colors 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 con-
clude with respect to certain birds in which, for instance,
the eyes differ slightly in color in the two sexes? ** In some
cases the eyes differ conspicuously; thus with the storks of
the genus Xenorhynchus, those of the male are blackish
hazel, while those of the females are gamboge-yellow; with
many hornbills (Buceros), as I hear from Mr. Blyth,** 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. color of the eyes have
been preserved or augmented through sexual selection in
the males? This is very doubtful; for Mr. Bartlett showed
me in the Zoological Gardens that the inside of the mouth
of this Buceros is black in the male and flesh colored in the
female; and their external appearance or beauty would not
be thus affected. I observed in Chile** 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,

4 See, for instance, on the irides of a Podica and Gallicrex in ‘‘Tbia,’’
vol. ii., 1860, p. 206; and vol. v., 1863, p. 426.

# See also Jerdon, ‘‘Birds of India,” vol. i. pp. 243-245.

#% «Zoology of the Voyage of H.M.S. Beagle, ’? 1841, p. 6.
Descent—Vot. II.—6

550 THE DESCENT OF MAN

leaden-colored, fleshy crest or comb. The comb of many
gallinaceous birds is highly ornamental, and assumes vivid
colors during the act of courtship; but what are we to think
of the dull-colored comb of the condor, which does not ap-
pear 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 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 topknot,
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; while those on the head of
the female are of the ordinary shape. The color also of the
hackles forming the topknot 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 ana Silver-
spangled Polish, the Houdans, and Créve-ccour breeds. In
some natural species we may observe exactly the same cor-
relation in the colors of these same feathers, as in the males
of the splendid Gold and Amherst pheasants.

SEXUAL SELECTION 551

The structure of each individual feather generally causes
any change in its coloring 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 colored 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 colored 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, ex-
cepting toward 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 deter-
mines 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 sym-
metrically shaded, like those which give so much elegance
to the plumage of many natural species. I have also no-
ticed 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 col-
ored 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 colored 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 colored in a
manner almost exactly the opposite of what is natural;
the aboriginal pigeon has a blue tail, with the terminal

552 THE DESCENT OF MAN

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.”

Formation and Variability of the Ocelli or Hyelike Spots on
the Plumage of Birds.—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 Lepidop-
tera and other insects, they deserve to be especially noticed.
An ocellus consists of a spot within a ring of another color,
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 (Va-
nessa). Mr. Trimen has given me a description of a South
African moth (Gyananis 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, sur-
rounded 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 Lepi-
doptera as the ocelli, both in number and size.’’ Mr. Wal-
lace, who first called my attention to this subject, showed me
a series of specimens of our common meadow-brown butter-
fly (Hipparchia janira) exhibiting numerous gradations from
a simple minute black spot to an elegantly shaded ocellus.
In a South African butterfly (Cyllo leda, Linn.), belonging
to the same family, the ocelli are even still more variable.

4" Bechstein, ‘“‘Naturgeschichte Deutschlands,”’ B. iv., 1795, s. 31, on @
sub-variety of the Monck pigeon.

SEXUAL SELECTION 558

In some specimens (A, Fig. 58) large spaces on the upper
surface of the wings are colored black, and include irregu-
lar white marks; and from this state a complete gradation
can be traced into a tolerably perfect ocellus (A‘), and this
results from the contraction of the irregular blotches of
color. 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 symmet-

Fia. 53.—Cyllo leda, Linn., from a drawing by Mr. Trimen, showing the extreme
range of variation in the ocelli.

A. Specimen, from Mauritius, upper surface of fore-wing.
Al, Specimen, from Natal, ditto.

B. Specimen, from Java, upper surface of hind-wing.
Bi, Specimen, from Mauritius, ditto.

rical and large ocelli (B’).** In cases like these, the devel-
opment 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.

4 This woodcut has been engraved from a beautiful drawing, most kindly
made for me by Mr. Trimen; sce also his description of the wonderful amount
of variation in the coloration and shape of the wings of this butterfly, in his
“‘Rhopalocera Afric Australis,”’ p. 186

554 THE DESCENT OF MAN

In the Tragopan pheasant faint white lines in the female rep-
resent the beautiful white spots in the male; “ and something
of the same kind may be observed in the two sexes of
the Argus pheasant. However this may be, appearances
strongly favor the belief that, on the one band, a dark spot
is often formed by the coloring matter being drawn toward
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 color being dviven away from a cen-
tral point, so that it accumulates in a surrounding darker
zone. In either case an ocellus is the result. The color-
ing 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 sur-
rounded by many successive zones of color, have been
generated, I will not pretend to say. But the zoned
feathers of the mongrels from differently colored 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.—Cases of
gradation are important, as showing us that highly com-
plex 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 colors or

4 Jerdon, ‘‘Birds of India,’’ vol. iii. p. 517.

SEXUAL SELECTION 555

other ornaments, we ought to behold the long line of his
extinct progenitors; but this is obviously impossible. We
may, however, generally gain a clew 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 bas 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 toward the extremity of the shaft forming
the oval disk 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 disk 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 disk is
surrounded by an almost transparent. zone, which gives it a
highly finished aspect. But I have elsewhere described ®
an exactly analogous variation in the hackles of a sub-
variety of the game-cock, in which the tips, having a
metallic lustre, ‘tare separated from the lower part of the
feather by a symmetrically shaped transparent zone, com-
posed 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 surround-

5 ‘Variation of Animals and Plants under Domestication,’’ vol. i, p, 254.

556 THE DESCENT OF MAN

ing zones likewise show traces, as may be seen in the draw-
ing (Fig. 54), of indentations, or rather breaks. These
indentations are common to the Indian and Java peacocks
(Pavo cristatus and P. muticus), and they seemed to deserve
particular attention, as probably connected with the devel-
opment of the ocellus; but for a long time I could not con-
jecture their meaning.

If we admit the principle of gradual evolution, there

Fia. 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 disk.

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 colored spots
on other birds; and so with all the other characters of the

SEXUAL SELECTION 557

peacock. Tet us look to the allied Gallinacezw for any still-
existing gradations. The species and sub-species of Poly-
plectron 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 com-
paratively plain-colored 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, p. 514) of a Polyplectron. In P. napo-
leonis the ocelli are confined to the tail and the back is
of a rich metallic blue; in which respects this species ap-
proaches the Java peacock. P. hardwickit possesses a pe-
culiar topknot, 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, iri-
descent, greenish blue or greenish purple disk, with a black
border. This border in P. chinquis shades into brown,
edged with cream-color, so that the ocellus is here sur-
rounded with variously shaded, though not bright, concen-
tric 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.

Notwithstanding this approach, the first species of Poly-
plectron 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

558 THE DESCENT OF MAN

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 colored
zones are likewise indented.
Asingle ocellus is thus formed
on each tail-covert, though

Fig. 56.--Part of a tail-covert of

Fig. 55.—Part of a tail-covert of Polyplectron malaccense, with the
Polyplectron chinquis, with the two ocelli partially confluent, of
two ocelli of natura] size. natural size.

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 toward
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

SEXUAL SELECTION 559

manifest that if the convergence were strongly pronounced
and the confluence complete, the indentation at the conver-
gent end would tend to disappear.

The tail-feathers in both species of 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 orna-
mented 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
showed any tendency to disappear; and to my great satis-
faction 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 or-
namented, each with two brightly-colored 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 ac-
quired, 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 color, we shall see

660 THE DESCENT OF MAN

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 con-
ceal the tail-feathers, the latter having already partially
lost their ocelli. The indentation of the central disk and
of the surrounding zones of the ocellus, in both species of
peacock, speaks plainly in favor of this view, and is other-
wise 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 of the
most beautiful males, rendered the peacock the most splen-
did of living birds.

Argus Pheasant.—Another excellent case for investiga-
tion is offered by the ocelli on the wing-feathers of the
Argus pheasant, which are shaded in so wonderful a man-
ner as to resemble balls lying loose within sockets, and con-
sequently 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 coloring matter. That these orna-
ments 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 in-
tended at first to draw the human figure. In order to dis-
cover how the ocelli have been developed, we cannot look to
along 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 clew 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.

SEXUAL SELECTION 561

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 be-
come confluent, either in
the line of the row—and
then they form a longitu-
dinal stripe—or transverse-
ly, that is, with the spots
in the adjoining rows, and
then they form transverse
stripes. A spot sometimes
breaks up into smallerspots,
which still stand in their
proper places.

It will be convenient
first to describe a perfect
ball -and-socket ocellus.
This consists of an in-
tensely 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 LZ
well engraved, but a wood- . Fie. 57.—Part of secondary wing-feather of

neg Ar; pheasant, showing two perfect ocelli, a
cut cannot exhibit the ex- and 6. A, B, C, D, ete., are dark stripes run-

A ning obliquely down, each to an ocellus.
quisite shading of the origi- , [iiviar of the shaft has boon out oy
nal. The ring is almost
always slightly broken or interrupted (see Fig. 57) at
& point in the upper half, a little to the right of, and
above the white shade on the inclosed ball; it is also some-
times broken toward the base on the right hand. These
little breaks have an important meaning. The ring is al-
ways much thickened, with the edges ill-defined toward the

562 THE DESCENT OF MAN

left hand upper corner, the feather being held erect, in
the position in which it is here drawn. Beneath this thick-
ened part there is on the surface of the ball an oblique
almost pure white mark, which shades off downward into
a pale leaden hue, and this into yellowish and brown tints,
which insensibly become darker and darker toward 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 exam-
A ined, 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 dif-
ference in color, which cannot,
of course, be shown in a wood-
cut, does not in the least inter-
fere with the perfect shading of
the ball. It should be particu-
larly observed that each ocellus
Fig. 58.—Basal part of the secondary stands in obvious connection
wing-feather nearest to the body. either with a dark stripe, or
with a longitudinal row of dark spots, for both occur in-
differently on the same feather. Thus in Fig. 57 stripe A
runs to ocellusa; Bruns 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 HE and F. Lastly, the
several ocelli are separated from each other by a pale sur-
face bearing irregular black marks.
I will next describe the other extreme of the series;
namely, the first trace of an ocellus. The short secondary

SEXUAL SELECTION 563

wing-feather (Fig. 58), nearest to the body, is marked fike
the other feathers, with oblique, longitudinal, rather irregu-
lar 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 orna-
ment, which cannot be called an ocellus, and which I will
name, from the want of a better term, an ‘‘elliptic orna-
ment.’’ These are shown in the accompanying figure (Fig.
59). We here see several oblique rows, A, B, ©, D, ete.
(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 ex-
actly 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 (6) is thicker and considerably longer than the
upper spots, and has its left extremity pointed and curved
upward. This black mark is abruptly bordered on its upper
side by a rather broad space of richly shaded tints, begin-
ning with a narrow brown zone, which passes into orange,
and this into a pale leaden tint, with the end toward the
shaft much paler. These shaded tints together fill up the
whole inner space of the elliptic ornament. The mark
(6) corresponds in every respect with the basal shaded

564 THE DESCENT OF MAN

spot of the simple feather described in the last paragraph
(Fig. 58), but is more highly developed and more brightly
colored. Above and to the right of this spot (0, Fig. 59),
with its bright shading, there is a long narrow black mari
{c), belonging to the same row, and which is arched a little
downward 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 ¢, in the

wing-feathers near to the body, showing
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 c. The next succeeding spot or mark in

down to and forming the elliptic or- the same row.
naments, d. Apparently a broken prolongation of
b. Lowest spot or mark in row B. the spot c in the same row B,

same oblique direction, but always more or less distinct
from it, there is another black mark (d). This mark is gen-
erally sub-triangular and irregular in shape, but in the
one lettered in the diagram it is unusually narrow, elon-
gated and regular. It apparently consists of a lateral and
broken prolongation of the mark c, together with its con-
fluence with a broken and prolonged part of the next spot

SEXUAL SELECTION 565

above; but I do not feel sure of this. These threc marks,
6, ec, and d, with the intervening bright shades, form to-
gether the so-called elliptic ornament. These ornaments,
placed parallel to the shaft, manifestly correspond in posi-
tion with the ball-and-socket ocelli. Their extremely ele-
gant appearance cannot be appreciated in the drawing, as
the orange and leaden tints, con-
trasting so well with the black
marks, cannot be shown. :
Between one of the elliptic orna-
ments 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 (6, Fig. 59), and more
especially of the upper one (c), to-
gether with the contraction of the {Ih ka
elongated sub-triangular or narrow Fis. 60.—An ocellus in an inter
mark (d), so that at last these three fiptic omament and tae perfect
marks become confluent, forming an iinet eget
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
(o, 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 colored
than in a perfect ball-and-socket ocellus. Even in the most
perfect ocelli, traces of the junction of three or four elon-

566 THE DESCENT OF MAN

gated 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
equalization, 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 (see Fig. 57), and this follows from the lower black
mark of the elliptic ornament (6, 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, 8, c, d, of the elliptic ornament.
The irregular zig-zag black marks between the successive
ocelli (see again 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 leaden 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 toward the left-hand corner ren-
dered 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-
colored shades of the elliptic ornaments. Thus almost every
minute detail in the shape and coloring of the ball-and-socket
ocelli can be shown 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 al-
most simple spots, the lower one (Fig. 58) having some dull
fulvous shading on its upper side.

The extremities of the longer secondary feathers, which

SEXUAL SELECTION 567

bear the perfect ball-and-socket ocelli, are peculiarly orna-
mented (Fig. 61). The oblique longitudinal stripes sud-
denly cease upward and become confused; and above this
limit the whole upper end of the feather oe is aidan with
white dots, surrounded by little
black rings, standing on a dark
ground. The oblique stripe be-
longing to the uppermost ocellus
(0) 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 under-
stand, from what has gone be-
fore, 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, ap-
pears as if its top had been ob-
liquely sliced off. It would, I

think, perplex any one, who be- one sr the secondary” wing-teathe

. ers, bearing perfect ball-and-socket
lieves that the plumage of the ocelli, a. ‘Inamented upper part.

b. Uppermost, imperfect ball-and-
Argus pheasant was created as We sockét ocellus. (The shading above

now see it, to account for the im- the ocallus is here a little too dari)
perfect condition of the upper- © P°"fect ocellvs.

most ocellus. I should add that on the secondary wing-
feather furthest 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 men-
tioned. The imperfection here seems to be connected with
the fact that the spots on this feather show less tendency

568 THE DESCENT OF MAN

than usual to become confluent into stripes; they are, on
the contrary, often broken up into smaller spots, so that
twe or three rows run down to the same ocellus.

There still remains another very curious point, first ob-
served by Mr. 'T. W. Wood," 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 sur-
face, are at the upper or further end, that is, are directed
upward; and the bird while 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 ap-
pear 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 illu-
minated 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 toward
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 ina part modified through natural
selection for real use; for instance, in that wondrous organ,
the human eye. And we know what Helmholtz, the high-
est authority in Hurope 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.”

5) The ‘*Field,’? May 28, 1870.
52 ‘‘Popular Lectures on Scientific Subjects,’’ Eng. trans., 1873, pp. 219,
227, 269, 390.

SEXUAL SELECTION 569

We have now seen that a perfect series can be followed,
from simple spots to the wonderful ball-and-socket orna-
ments. 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 show us the steps passed through by the extinct
progenitors of the species; but they probably give us the
clew to the actual steps, and they at least prove to demon-
stration 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 color, into one of the so-called elliptic
ornaments. These latter ornaments have been shown to
many persons, and all have admitted that they are beauti-
ful, 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 in-
creased in diameter, their colors 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 domesti-
cated 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

570 THE DESCENT OF MAN

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 Uresticte 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 owder tail-feathers on
each side are tipped with white, so that the male has the four
central, while the female has the six exterior feathers orna-
mented with white tips. What makes the case more curious
is that, although the coloring 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,“
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 re-
cently 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 Uro-
sticte [ 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

8 “The Reign of Law,” 1867, p. 247.

SEXUAL SELRCTION 871

white ear tufts, certainly add, as the Duke of Argyll ad-
mits, to the beauty of the male; and whiteness is appar-
ently appreciated by other birds, as may be inferred from
suoh 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 splendor of these feathers. We have,
moreover, good evidence that humming-birds take especial
pains in displaying their tail-feathers; Mr. Belt," after de-
scribing the beauty of the Florisuga mellivora, says, ‘‘T have
seen the female sitting on a branch, and two males display-
ing 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 show 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. While 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 Uro-
sticte, adds, ‘‘that ornament and variety is the sole object
Ihave myself but little doubt.’”’* 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.

6 “The Naturalist in Nicaragua,’’ 1874, p. 112.
% **Introduction to the Trochilidz,’’ 1861, p. 110,

572 THE DESCENT OF MAN

CHAPTER XV
BIRDS—continued

Disoussion a3 to why the males alone of some species, and both sexes of
others, are brightly colored—On sexually limited inheritance, as sp-
plied to various structures and to brightly colored plumage—Nidifica-
tion in relation to color—Loss of nuptial plumage during the winter

‘ X y% HAVE in this chapter to consider why the

females of many birds have rot 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 colored than the male.

In my “Origin of Species’’’ I briefly suggested that
the long tail of the peacock would be inconvenient, and
the conspicuous black color of the male capercailzie dan-
gerous, 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 in-
clined 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 colora-
tion has been discussed in some very interesting papera by

‘ Fourth edition, 1866, p. 241.

SEXUAL SELECTION 573

Mr. Wallace,* who believes that in almost all cases the suc-
cessive variations tended at first to be transmitted equally
to both sexes; but that the female was saved, through
natural selection, from acquiring the conspicuous colors
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 subse-
quently limited in its transmission to one sex alone by
means of natural selection. We must bear in mind, as
shown 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 illus-
tration will best aid us in seeing the difficulty cf the case.
We may suppose that a fancier wished to make a breed of
pigeons in which the males alone should be colored of a
pale blue, while 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 sexu-
ally 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 re-
eurred, would be to make his whole stock of a lighter
blue. But our fancier would be compelled to match, gen-
eration after generation, his pale-blue males with slaty
females, for he wishes to keep the latter of this color.
The result would generally be the production either of a
mongrel piebald lot, or more probably the speedy and com-
plete loss of the pale-blue tint; for the primordial slaty
color would be transmitted with prepotent force. Suppos-
ing, however, that some pale blue males and slaty females

9 ‘Westminster Review,”’ July, 1867. ‘‘Journal of Travel,’’ vol. 1., 1868, -
p. 8
Descent—Vot. I.—?

574 THE DESCENT OF MAN

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 color 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 color 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 Soommerring’s pheasant
has a tail thirty-seven inches in length, while 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 Scemmerring pheas-
ant with her short tail were crossed with the male common
‘pheasant, there can be no doubt that the male hybrid off-
spring would have a much longer tail than that of the pure
ofispring of the common pheasant. On the other hand, if
the female common pheasant, with a tail much longer than
that of the female Soommerring 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 Scem-
merring’s pheasant.*

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

8 Temminck says that the tail of the female Phasianus Semmerringié is
only six inches Jong. ‘‘Planches coloriées,”’ vol. v., 1838, pp. 487 and 488:
the measurements above given were made for me by Mr. Sclater. For the
eommon pheasant, see Macgillivray, ‘‘Hist. Brit. Birds,” vol. i. pp. 118-121.

SEXUAL SELECTION 576

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 car-
ried 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‘ in which the males alone are marked with black
strie. So again Mr. Tegetmeier has recently shown®
that dragons not rarely produce silver-colored birds,
which are almost always hens; and he himself has bred
ten such females. It is, on the other hand, a very un-
usual 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 ten-
dency 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 col-
ored; he was, however, disappointed, for the young male re-
verted to the blue color 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 colored alike; and this very
process has been followed with success by Mr. Esquilant
in the case of silver turbits.

4 Dr. Chapuis, “‘Le Pigeon Voyageur Belge,’’ 1865, p. 87.
5 The “Field,” Sept, 1872.

576 THE DESCENT OF MAN —

With fowls, variations of color, limited in their transmis-
sion 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,

_ he 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 color.

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, un-
less the successive variations were from the first sexually
limited on both sides, and then there would be no diffi-
culty. 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 excel- ©
lence by continued selection, which would be impossible
unless the distinctive characters of both were limited in
their transmission. The Spanish fowl offers a more curi-
ous 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

SEXUAL SELECTION 577

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, other-
wise it would prevent the comb of the male from being
perfectly upright, which would be abhorrent to every fan-
cier. 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
ease, I am unwilling to admit that this has been effected
in natural species. On the other hand, by means of suc-
cessive variations, which were from the first sexually lim-
ited in their transmission, there would not be the least diffi-
culty in rendering a male bird widely different in color 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 colors are of service to the males in their
rivalry with other males, such colors 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 colors 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

- 678 THE DESCENT OF MAN

transmitting to their female offspring their own brightness,
would have to be eliminated by a change in the form of in-
heritance; and this, as shown by our previous illustration,
would be extremely difficult. The more probable result of
the long-continued destruction of the more brightly colored
females, supposing the equal form of transmission to prevail,
would be the lessening or annihilation of the bright colors
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 favored or selected, for the male usually ac-
cepts 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 colored than the males.

In the eighth chapter instances were given, to which
many might here be added, of variations occurring at vari-
ous ages, and inherited at the corresponding age. It was
also shown that variations which occur late in life are com-.
monly transmitted to the same sex in which they first ap-
pear; while 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 fur-
ther shown that if a male bird varied by becoming brighter
while young, such variations would be of no service until
the age for reproduction had arrived, and there was compe-
tition between rival males. But in the case of birds living
on the ground and commonly in need of the protection of
dull colors, bright tints would be far more dangerous to the
young and inexperienced than to the adult males. Conse-
quently the males which varied in brightness while young
would suffer much destruction and be eliminated through
natural selection; on the other hand, the males which varied

SEXUAL SELECTION 579

in this manner when nearly mature, notwithstanding that
they were exposed to some additional danger, might sur-
vive, and, from being favored through sexual selection,
would procreate their kind. As a relation often exists be-
tween the period of variation and the form of transmission,
if the bright colored young males were destroyed and the
mature ones were successful in their courtship, the males
alone would acquire brilliant colors and would transmit
them exclusively to their male offspring. But 1 by no
means wish to maintain that the influence of age on the
form of transmission is the sole cause of the great differ.
ence in brilliancy between the sexes of many birds.

When the sexes of birds differ in color, 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 selec-
tion for the sake of protection. I will, therefore, discuss
this question at some length, even more fully than its in-
trinsic importance deserves; for various curious collateral
points may thus be conveniently considered.

Before we enter on the subject of color, 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 Ger-
many,’ in which the hens were furnished with spurs; they
were good layeis, 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 Gallinacex 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 de-
veloped in the female as in the male; though in not a few

6 Bechstein ‘‘Naturgesch. Deutschlands,”’ 1793, B. iii, a, 339,

580 THE DESCENT OF MAN

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-de-
veloped 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, Aco-
mus, 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, while
the females have been saved from inheriting them, on ac-

SEXUAL SELECTION 581

count 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 multi-
tude of birds which with impunity gladden the country with
their voices during the spring.’ It isa safer conclusion that,
as vocal and instrumental organs are of special service only
to the males during their courtship, these organs were de.
veloped 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 trans-
mission to the male offspring.

Many analogous cases could be adduced; those, for in-
stance, 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 selec-
tion. But I will take a more favorable 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 while accom-
panying her young. Hence there is not the least @ priori
improbability in the development of her tail having been
ehecked 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

™ Daines Barrington, however, thought it probable (‘‘Phil. Transact.,’? 1773,
p. 164) that few female birds sing, because the talent would have been danger-
ous to them during incubation, He adds, that a similar view may possibly
account for the inferiority of the female to the male in plumage.

582 THE DESCENT OF MAN

manage her tail during incubation; but it is now known*®
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 king-
fisher (Zanysiptera 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 inconven-
iently 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 acquir-
ing 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 Hared pheasant (Crossoptilon auritum) the tail is of
equal length in both sexes, namely, sixteen or seventeen

8 Mr, Ramsay, in ‘‘Proc. Zoolog. Soc.,’? 1868, p. 50.

SEXUAL SELECTION 583

inches; in the common pheasant it is about twenty inches
long in the male and twelve in the female; in Scommerring’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 re-
gard to the sexual coloration of birds. He believes that
the bright tints originally acquired through sexual selec-
tion 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,® that when both sexes are colored ina
very conspicuous manner, the nest is of such a nature as to
conceal the sitting bird; but when there is a marked con-
trast of color between the sexes, the male being gay and
the female dull colored, the nest is open and exposes the
sitting bird to view. This coincidence, as far as it goes,
certainly seems to favor 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 an-
other and more probable explanation, namely, that conspic-

® ‘Journal of Travel,’’ edited by A. Murray, vol. i., 1868, p. 78.

584 THE DESCENT OF MAN

uous females have acquired the instinct of building domed
nests oftener than dull-colored birds. Mr. Wallace admits
that there are, as might have been expected, some excep-
tions 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” that a large domed nest is more con-
spicuous to an enemy, especially to all tree-haunting car-
nivorous 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 estiva," one of
the most splendid birds in the United States, the male
being vermilion, and the female light brownish green.
Now if brilliant colors had been extremely dangerous to
birds while 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
colored, 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 Pittide, the females are conspicuously colored,
yet build open nests; but he urges that the birds of the
first group are highly pugnacious and could defend them-
selves; that those of the second group take extreme care
in concealing their open nests, but this does not invariably
hold good; and that with the birds of the third group the
females are brightly colored chiefly on the under surface.
Besides these cases, pigeons, which are sometimes brightly
and almost always conspicuously colored, and which are
notoriously liable to the attacks of birds of prey, offer a
serious exception to the rule, for they almost always build

10 “¢Journal of Travel,’’ edited by A. Murray, vol. i., 1868, p. 281.

Nn Audubon, “‘Ornithological Biography,’ vol. i. p. 233.

2 Jerdon, ‘Birds of India,’’ vol. ii. p. 108. Gould’s ‘Handbook of the
Birds of Australia,”’ vol. i. p. 463.

SEXUAL SELECTION 585

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 colored. Nor can it be maintained
that all female humming-birds, which are brightly colored,
escape detection by their tints being green, for some display
on their upper surfaces red, blue, and other colors.”

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; so that it is no valid objection to his view that
many birds having both sexes obscurely colored build con-
cealed nests." 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 excre-
ment 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;’* yet female horn-bills are not more
conspicuously colored 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 colored and the females
obscure, and yet the latter hatch their eggs in domed nests.

18 For instance, the female Zupetomena 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 Hulampts 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.

4 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.

15 [ may specify, as instances of dull-colored birds building concealed nests,
the species belonging to eight Australian genera, described in Gould’s ‘‘Hand-
book of the Birds of Australia,’’ vol. i. pp. 340, 362, 365, 383, 387, 389,
391, 414.

16 Mr. C. Horne, ‘‘Proc. Zoolog. Soc. *? 1869, p. 243.

és

586 THE DESCENT OF MAN

This is the case with the Gralline of Australia, the Superb
Warblers (Maluridz) of the same country, the Sun-birds
(Nectariniz), and with several of the Australian Honey-
suckers or Meliphagids.”

lf we look to the birds of England we shall see that
there is no close and general relation between the colors 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 colors of the female goldfinch, bullfinch, or black-
bird, 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 re-
maining twenty-eight being inconspicuous.’* Nor is there
any close relation within the same genus between a well
pronounced difference in color 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 dis-
tinguished, while the sexes of the pied fly-catcher (J/. luc-
tuosa) differ considerably, and both species build in holes
or conceal their nests. The female blackbird (Turdus

1’ On the nidification and colors of these latter species, see Gould’s ‘‘Hand-
book,”’ ete., vol. i. pp. 504, 527.

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; Motacilla 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. ceruleus,
Upupa, Picus, 4 sp.; Coracias, Alcedo, and Merops.

SEXUAL. SELECTION 587

merula) differs much, the female ring-ouzel (7. torquatus)
differs less, “and the female common thrush (7. 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 muchas in the ring-ouzel.
The black and red grouse (Tetrao tetriz 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 colored (and in this
case the males with rare exceptions are equally conspicu-
ous) build concealed nests for the sake of protection. Mr.
Wallace enumerates” along 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 (Capitonidee), plantain-eaters (Musophagee), wood-
peckers and parrots. Mr. Wallace believes that in these
groups, as the males gradually acquired through sexual
selection their brilliant colors, 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
colors. 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 colors 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

‘® “Journal of Travel,’’ edited by A. Murray, vol. i. p. 78.

588 THE DESCENT OF MAN

United States,” 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 colors of female birds and their manner
of nesting, receives some support from certain cases occur-
ring in the Sahara Desert. Here, as in most other deserts,
various birds and many other animals have had their colors
adapted in a wonderful manner to the tints of the surround-
ing surface. Nevertheless there are, as I am informed by
the Rey. Mr. Tristram, some curious exceptions to the rule;
thus the male of the Monticola cyanea is conspicuous from
his bright blue color, and the female almost equally con-
spicuous from her mottled brown and white plumage; both
sexes of two species of Dromolea are of a lustrous black;
so that these three species are far from receiving protection
from their colors, 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 colored 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 afterward transmitted this instinct,
together with their bright colors, to their modified descend-
ants. As far as it can be trusted, the conclusion is inter-
esting, 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 in-

3% 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 Societa Italiana,” vol. xi., 1869, p. 487.

SEXUAL SELECTION 589

eubation, have not had their bright colors eliminated through
natural selection, the males often differ in a slight, and occa-
sionally in a considerable, degree from the females. This
is a significant fact, for such differences in color 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, espe-
cially 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” of both sexes
of twenty-five species, in all of which, with one partial ex-
ception, the sexes differ sometimes slightly, sometimes con-
spicuously, in color—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 Aus-
tralian species the colors of the females are rather less vivid
than those of the male; and in one splendidly colored spe-
cies, the sexes differ so much that they were at first thought
to be specifically distinct.” Mr. R. B. Sharpe, who has es-
pecially studied this group, has shown 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-colored, 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 showing how the same peculiar
style of sexual coloring often characterizes allied forms, that
in three species of Dacelo the male differs from the female
only in the tail being dull blue banded with black, while
that of the female is brown with blackish bars; so that

2 See his ‘‘Monograph of the Trogonide,”? first edition. — :
8 Namely, Cyanalcyon. Gould’s ‘Handbook to the Birds of Australia,’
vol. i. p. 183; see, also, pp. 130, 136.

590 THE DESCENT OF MAN

here the tail differs in color 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 bril-
liantly colored and indistinguishable, but in not a few spe-
cies the males are colored rather more vividly than the fe-
males, 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,
while the throat and chest of the female is green tinged with
red; in the Huphema splendida there is a similar difference,
the face and wing-coverts moreover of the female being of
a paler blue than in the male.* In the family of the tits
(Parine) which build concealed nests, the female of our
common blue tomtit (Parus ceruleus) is ‘much less brightly
colored’’ than the male; and in the magnificent Sultan yellow
tit of India the difference is greater.”*

Again, in the great group of the woodpeckers” the sexes
are generally nearly alike, but in the Megapicus validas 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, while
that of the female is plain, it occurred to me that this color
might possibly make the female dangerously conspicuous,
whenever she put her head out of the hole containing her
nest, and consequently that this color, in accordance with
Mr. Wallace’s belief, had been eliminated. This view is
strengthened by what Malherbe states with respect to Indo-
picus carlotta; namely, that the young females, like the
young males, have some crimson about their heads, but
that this color disappears in the adult female, while it is

% Hvery gradation of difference between the sexes may be followed in the
parrots of Australia. See Gould’s “‘Handbook,”’ etc., vol. ii. pp. 14-102.

% Macgillivray’s ‘‘British Birds,” vol. ii. p. 433. Jerdon, ‘‘Birds of India,’’
vol. ii. p. 282.

25 All the following facts are taken from M. Malherbe’s magnificent ‘‘Mono-
graphie des Picidées,’’ 1861,

SEXUAL SELECTION 591

intensified in the adult male. Nevertheless the following
considerations render this view extremely doubtful; the
male takes a fair share in incubation,®* and would be thus
almost equally exposed to danger; both sexes of many spe-
cies 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 coloring
of the head in the two sexes ton differs slightly in other
ways.

The cases, as yet given, of slight and graduated differ-
ences in color 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.” 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. Simi-
lar cases may be observed with parrots and pigeons. The
differences in color between the sexes of the same species
are also of the same general nature as the differences in color
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 colored in a
quite new style. Hence we may infer that within the same
group the special colors of both sexes, when they are alike,

26 Audubon’s ‘‘Ornithological Biography,’’ vol. ii. p. 75; see, also, the
“This,’’ vol. i. p. 268.
%Gould’s “Handbook to the Birds of Australia,” vol. ii. pp. 109-149,

592 THE DESCENT OF MAN

and the colors of the male, when he differs slightly or even
considerably from the female, have been in most cases de-
termined by the same general cause; this being sexual
selection.

It is not probable, as has already been remarked, that
differences in color 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. There-
fore we can hardly admit that the numerous females which
differ very slightly in color from their males are now all
commencing to become obscure for the sake of protection.
Even if we consider somewhat more marked sexual differ-
ences, 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? IL
cannot think so; and still less with the slight differences be-
tween the sexes of those birds which build concealed nests.
On the other hand, the differences in color between the
sexes, whether great or small, may to a large extent be
explained on the principle of the successive variations ac-
quired 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.”

As far as I can discover, there are few large groups of
birds in which all the species have both sexes alike and
brilliantly colored, but I hear from Mr. Sclater that this

28 See remarks to this effect in my work on ‘‘Variation ‘under Domestica-
tion,’ vol. ii. chap. xii.

SEXUAL SELECTION 593

appears to be the case with the Musophage or plantain
eaters. Nor do I believe that any large group exists in
which the sexes of all the species are widely dissimilar
in color: Mr. Wallace informs me that the chatterers of
South America (Cotingide) offer one of the best instances;
but with some of the species, in which the male has a splen-
did red breast, the female exhibits some red on her breast;
and the females of other species show traces of the green
and other colors of the males. Nevertheless we have a near
approach to close sexual similarity or dissimilarity through-
out 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 plu-
mage; so that it has been noticed as an unusual circum-
stance when in certain sub-breeds they resemble each other.
On the other hand, the domestic pigeon has likewise pro-
duced 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 pre-
dict 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 transmis-
sion has generally prevailed under nature throughout the
same groups, although marked exceptions to this rule oc-
cur. Thus within the same family, or even genus, the
sexes may be identically alike or very different in color.
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 Chloe-
phaga, a genus of geese, the male cannot be distinguished
from the females, except by size; while in two others, the

594 THE DESCENT OF MAN

sexes are so unlike that they might easily be mistaken for
distinct species.”

The laws of inheritance can alone account for the follow-
ing cases, in which the female acquires, late in life, certain
characters proper to the male, and ultimately comes to re-
semble 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 consider-
ably 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), ac-
cording 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, while 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 striz and spots on the axillary feathers;
and does not completely assume the uniform black color
of the male for three years. The same excellent observer
remarks that in the spring of the second year thc female
spoonbill (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 ap-
pendages, which like beads of red sealing-wax ornament
the wing-feathers,* are not developed in her so early in

29 The ‘‘Ibis,’’? vol. vi., 1864, p. 122.

30 When the male courts the female, these ornaments are vibrated, and ‘‘are
shown off to great advantage,’’ on the outstretched wings; A. Leith Adams,
“Field and Forest Rambles *’ 1873, p. 153.

SEXUAL SELECTION 595

life as in the male. In the male of an Indian paroquet
(Paleornis javanicus) the upper mandible is coral red from
his earliest youth, but in the female, as Mr. Blyth has ob-
served 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.”

These cases must not be confounded with those where
diseased or old females abnormally assume masculine char-
acters, nor with those where fertile females, while young,
acquire the characters of the male, through variation or
some unknown cause.” 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 de-
velopment 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 pendent feathers, crests, etc., of egrets, herons, and

81 On Ardetta, Translation of Cuvier’s ‘‘Régne 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
“Ornithol. Biography,’’ vol. i. p. 229. On the Paleornis, 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. B. Sharpe, ‘‘Proc. Zoolog. Soc.,’? 1872, p. 496.

% Of these latter cases Mr. Blyth has recorded (Translation of Cuvier’s
“Régne Animal,’’ p, 158) various instances with Lanius, Ruticilla, Linaria,
and Anas. Audubon has also recorded a similar case (‘‘Ornith. Biog.,”’ vol. v.
p. 519) with Lyranga estiva.

596 THE DESCENT OF MAN

many other birds, which are developed and retained only
during the summer, serve for ornamental and nuptial pur-
poses, 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 color. 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, remem-
ber 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 Gallinaces,
renders a double moult impossible, for the ptarmigan moulta
thrice in the year.* Hence it must be considered as doubt-
ful whether the many species which moult their ornamental
plumes or lose their bright colors 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
fn the year was in most or all cases first acquired for some
distinct purpose, perhaps for gaining a warmer winter cov-
ering; and that variations in the plumage occurring’ during
the summer were accumulated through sexual selection and

% See Gould’s “Birds of Great Britain.”

SEXUAL SELECTION 597

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 endeavored in this chapter to show that the
arguments are not trustworthy in favor of the view that
weapons, bright colors and various ornaments are now con-
fined 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 colors 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 1 treat, in the fol-
lowing chapter, of the differences in plumage between the
young and old.

Descent—Vot. I.—8

598 THE DESCENT OF MAN

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 as-
suming the characters of the male—Plumage of the young in relation
to the summer and winter plumage of the adulis—On the increase
of beauty in the birds of the world—Protective coloring—Conspicu-
ously colored birds—Novelty appreciated—Summary of the four chap-
ters on birds

‘ , JE MUST now consider the transmission of char-
acters, as limited by age, in reference to sexual
selection. The truth and importance of the prin-

ciple 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 in-
cluded, it will be well to make a few preliminary remarks.

With animals of all kinds when the adults differ in color
from the young, and the colors 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 be-

SEXUAL SELECTION 599

liever 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 while 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 (Suide), and in certain
rather distantly allied animals, such as the tapir, are marked
with dark, longitudinal stripes; but here we have a char-
acter apparently derived from an extinct progenitor, and
now preserved by the young alone. In all such cases the
old have had their colors changed in the course of time,
while 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 Gallinacez, and of some dis-
tantly allied birds, such as ostriches, are covered with lon-
gitudinally 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 redpole and female siskin, as well as
the young of the goldfinch, greenfinch and some other allied
species. The young of many kinds of buntings (Hmberiza)
resemble one another, and likewise the adult state of the
common bunting, #. 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 mot-
tled before they are moulted for the first time, and this char-
acter is retained for life by certain eastern species. The young
of many species of shrikes (Lanius), of some woodpeckers,

600 THE DESCENT OF MAN

and of an Indian pigeon (Chalcophaps indicus), are trans-
versely 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 color, but the young cannot be dis-
tinguished. The young of an Indian goose (Sarkidiornis
melanonotus) closely resemble in plumage an allied genus,
Dendrocygna, when mature." 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 cer-
tain other species, for instance, the red grouse or 7’. scoticus.
Finally, as Mr. Blyth, who has attended closely to this sub-
ject, 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 shows
us the former or ancestral condition of the species.

Although many young birds, belonging ‘to various fami-
lies, thus give us a glimpse of the plumage of their remote
progenitors, yet there are many other birds, both dull col-
ored and bright colored, in which the young closely resem:
ble 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 plu-
mage of their progenitors, excepting in so far that, when
the young and the old are colored in the same general
manner throughout a whole group of species, it is prob-
able that their progenitors were similarly colored.

1 In regard to thrushes, shrikes, and woodpeckers, seo Mr. Blyth, in
Charlesworth’s ‘‘Mag. of Nat. Hist.,’’ vol. i., 1837, p. 304; also footnole to
his translation of Cuvier’s ‘‘Régne Animal,” p. 159. I give the case of Loxia .
on Mr. Blyth’s information. On thrushes, see, also, Audubon, ‘‘Ornith. Biog-
raphy,’’ vol. ii. p. 195. On Chrysococeyx and Chalcophaps, Blyth, as quoted
in Jerdon’s ‘‘Birds of India,’’ vol. iii. p. 485. On Sarkidiornis, Blyth, in
**This,’? 1867, p. 175.

SEXUAL SELECTION 601

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 re-
quire 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 compe-
tent 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, Jer-
don on those of India, and Gould on those of Australia. I
may here premise, first, that the several cases or rules grad-
uate 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 colors 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 conspicu-
ous 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.

TV. 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

602 THE DESCENT OF MaN

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 re-
sembling more or less closely the adult males, and the young
females more or less closely the adult females.

Crass I.—In this class, the young of both sexes more or
less closely resemble the adult female, while 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 shown 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, king-
fishers, pigeons, etc., the young of both sexes resemble the
adult female.* We see the same fact exhibited still more

? See, for instance, Mr. Gould’s account (‘‘Handbook to the Birds of Aus-
tralia,’’ vol. i. p. 133) of Cyanaleyon (one of the Kingfishers), in which, how-
ever, the young male, though resembling the adult female, is less brilliantly

SEXUAL SELECTION 603

clearly in certain anomalous cases; thus the male of Helio-
thriz auriculata (one of the humming-birds) differs con-
spicuously from the female in having a splendid gorget
and fine ear-tufts, but the female is remarkable from hav-
ing 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.* Again,
the plumage of the male goosander (Mergus merganser) is
more conspicuously colored 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 en-
tirely resemble the adult female, so that their crests are
actually of greater length, though narrower, than in the
adult male.‘

When the young and the females closely resemble each
other, and both differ from the males, the most obvious con-
clusion 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

colored. 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 Paleornis rosa, in which the young are more like the
female than the male. See Audubon (‘‘Oruith. Biography,” vol. ii. p. 475) on
the two sexes and the young of Columba passerina.

3 I owe this information to Mr. Gould, who showed me the specimens;
gee, also, his ‘‘Introduction to the Trochilidw,’’ 1861, p. 120.

4 Macgillivray, ‘‘Hist. British Birds,’’ vol. v. pp. 207-214

604 THE DESCENT OF MAN

cause, and transmitted in their diminished state to their male
offspring alone, when arrived at the corresponding age of ma-
turity. 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,*® with respect to closely allied species which
represent each other in distinct countries. For with sev-
eral of these representative species the adult males have
undergone a certain amount of change and can be dis-
tinguished; the females and the young from the distinct
countries being indistinguishable, and therefore absolute-
ly unchanged. This is the case with certain Indian
chats (Thamnobia), with certain honey-suckers (Nectari-
nia), shrikes (Tephrodornis), certain kingfishers (Tanysip-
tera), Kalij pheasants (Gallophasis), and tree-partridges
(Arboricola).

In some analogous cases, namely, with birds having a dif-
ferent summer and winter plumage, but with the two sexes
nearly alike, certain closely allied species can easily be dis-
tinguished in their summer or nuptial plumage, yet are in-
distinguishable in their winter as well as in their immature
plumage. This is the case with some of the closely allied
Indian wagtails or Motacille. Mr. Swinhoe® 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 im-
mature 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

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. introduc-
tion, p. xxix, In regard to Tanysiptera, Prof. Schlegel told Mr. Blyth that he
could distinguish several distinct races, solely by comparing the adult males.

® 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,” Jan. 1861, p. 26.

SEXUAL SELECTION 605

winter and summer, nearly the same plumage as that pos-
sessed 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 shows us how the progenitors of the genus were
colored. 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 modi-
fied, while 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 dis-
tinct 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 sim-
ilarly exposed, have not been affected. Hardly any fact
shows 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 vari-
ations, 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. Neverthe-
less, 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 impor-
tance to the accumulated results of selection. Judging, how-
ever, from a widespread analogy, when a species migrates into
a new country (and this must precede the formation of repre-
sentative 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 sex-

606 THE DESCENT OF MAN

ual selection, which depends on an element liable to change
—the taste or admiration of the female—will have had new
shades of color or other differences to act on and accumu-
late; 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 in-
habiting separate districts, which can never cross and thus
blend their newly acquired characters, were not, after a
sufficient lapse of time, differently modified. These re-
marks 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 rep-
resentative species, together with their young, differ hardly
at all from one another, so that the males alone can be dis-
tinguished, 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 Gallinacez: 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 color, while the males differ to an extraordi-
nary degree. So it is with the females of most of the Co-
tingide, Fringillide, 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, how-
ever, 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;’ the female of the
latter species having the under surface pure white, while the
female P. apoda is deep brown beneath. So again, as I hear
from Prof. Newton, the males of two species of Oxynotus
(shrikes), which represent each other in the islands of Mau-
ritius and Bourbon,® differ but little in color, while the

1 Wallace, ‘‘The Malay Archipelago,’’ vol. ii., 1869, p. 394.
8 These species are described with colored figures, by M. F. Pollen, in
“This,” 1866, p. 275.

SEXUAL SELECTION 607

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.’’ ‘hese differences may be
compared with those inexplicable ones which occur inde-
pendently of man’s selection in certain sub-breeds of the
game fowl, in which the females are very different, while
the males can hardly be distinguished.°

As I account so largely by sexual selection for the differ-
ences between the males of allied species, how can the dif-
ferences 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, lt 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 charac-
ters 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 colors 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, while with other species there
has been a partial or even complete transference of charac-
ter 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 colors being much duller. In the guinea-fowl

9 “Variation of Animals,’’ ete., i. p. 251.

608 THE DESCENT OF MAN

the two sexes are indistinguishable. There is no improba-
bility in the plain, though peculiarly spotted plumage of
this latter bird having been acquired through sexual selec-
tion by the males, and then transmitted to both sexes; for
it is not essentially different from the much more beauti-
fully spotted plumage, characteristic of the males alone
of the Tragopan pheasants.

It should be observed that, in some instances, the trans-
ference of characters from the male to the female has been
effected apparently at a remote period, the male having sub-
sequently 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 (7. scoticus); and we may consequently infer that the
black grouse is descended from some ancient species, of
which both sexes were colored 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," we may conclude that his plumage has been influ-
enced by sexual selection, at least to a certain extent. If
so, we may further infer that the 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 shows 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 selec-
tion, both during former and recent times. But it deserves

10 Macgillivray, ‘‘Hist. British Birds,’’ vol. i, pp. 172-174.

SEXUAL SELECTION 609

especial attention that brilliant colors have been transferred
much more rarely than other tints. For instance, the male
of the red-throated bluebreast (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 fe-
male, but the central space is fulvous instead of red, and
is surrounded by mottled instead of blue feathers. The
Gallinacez offer many analogous cases; for none of the
species, such as partridges, quails, guinea fowl, etc., in
which the colors of the plumage have been largely trans-
ferred from the male to the female, is brilliantly colored.

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 auri-
tum and Phasianus wallichit) the sexes closely resemble
each other and their colors 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 colored, 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 colors 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, while 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
favored 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 Hared and Cheer pheasants, would
not have been dangerous, and if they appeared during

610 THE DESCENT OF MAN

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 differ-
ences between the females of closely allied species may be
attributed to the direct or definite action of the conditions
of life.” With the males any such action would generally
have been masked by the brilliant colors gained through
sexual selection; but not so with the females. Hach of the
endless diversities in plumage which we see in our domes-
ticated 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 color, thus induced,
uniform in character.

No one doubts that both sexes of many birds have had
their colors 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 diffi-
cult, perhaps an impossible process, as shown in the last
chapter, to convert one form of transmission into another
through selection, there would not be the least difficulty in
adapting the colors 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 trans-
mission 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 doubt-
ful. I wish I could follow Mr. Wallace to the full extent;
for the admission would remove some difficulties. Any vari-
ations which were of no service to the female as a protection
would be at once obliterated, instead of being lost simply

1 See, on this subject, chap. xxiii. in the ‘‘Variation of Animals and Plants
under Domestication, ”’

SEXUAL SELECTION 611

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 re-
spect to which we have no sufficient evidence of the action
of sexual selection. We ought, however, to be cautious in
concluding that colors which appear to us dull are not at-
tractive 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 colors, at least in part, for the sake of
protection. We know how well they are thus concealed; we
know that ptarmigans, while 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 colored, 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 cer-
tain gallinaceous birds in the Hast he thinks that such slight
differences are beneficial. For-myself I will only say that
I am not convinced.

Formerly when 1 was inclined to lay much stress on pro-
tection as accounting for the duller colors of female birds,
it occurred to me that possibly both sexes and the young
might aboriginally have been equally bright-colored; but
that subsequently the females, from the danger incurred

612 THE DESCENT OF MAN

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
1n imagination expose during past times the females and the
young to danger, from which it has subsequently been neces-
sary 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 mark-
ings, 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 colored as
the males, it is also a somewhat strange fact that the females
have never been rendered dull colored 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-colored. 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
afterward either decreases into a mere circular red line in-
the adults of both sexes, or quite disappears in the adult
females.”

Finally, with respect to our present class of cases, the
most probable view appears to be that successive varia-
tions in brightness or in other ornamental characters, oc-
curring in the males at a rather late period of life, have
alone been preserved; and that most or all of these varia-
tions, 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

12 Audubon, ‘‘Ornith. Biography,’’ vol. i. p. 193. Macgillivray, ‘‘Hist.
British Birds,” vol. iii. p. 85 See, also, the case before given of Indopicus

carlotia.

SEXUAL SELECTION 613

is much more common) will have been partially modified by
receiving through transference from the male some of his
successive variations. Both sexes have, perhaps, been di-
rectly acted on by the conditions of life to which they have
long been exposed; but the females, from not being oth-
erwise 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 ac-
quired the same dull-colored plumage.

Cuiass 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 col-
ored 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
ealled attention to the singular relation which exists between
the less bright colors of the males and their performing the —
duties of incubation, lays great stress on this point,” as a
erucial test that obscure colors 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 un-
usual circumstance with the Gallinacesw. In most of the
species the female is more distinctly colored and brighter

18 “Westminster Review,’ July, 1867, and A. Murray, ‘‘Journal of Travel,”
1868, p. 83.

614 TH! DESCENT OF MAN

than the male," but in some few species the sexes are alike.
In Turnix tatgoor 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 Tur-
nix 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 earshot run rapidly
to the spot, and commence fighting with the caged bird.”
In this way from twelve to twenty birds, all breeding fe-
males, may be caught in the course of a single day. The
natives assert that the females after laying their eggs asso-
ciate 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.*®* Mr. Blyth believes that the young of both
sexes resemble the adult male.

The females of the three species of Painted Snipes
(Rhynchea, Fig. 62) ‘‘are not only larger but much more
richly colored than the males.’”’** 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 Rhynchea australis it is simple in the male, while
in the female it makes four distinct convolutions before
entering the lungs.” The female, therefore, of this species
has acquired an eminently masculine character. Mr. Blyth

14 For the Australian species, see Gould’s ‘‘Handbook,”’ ete., vol. fi. pp.
178, 180, 186, and 188. In the British Museum specimens of the Australian
Plain-wanderer (Pedionomus torquatus) may be seen, showing similar sexual
differences.

1’ Jerdon, ‘‘Birds of India,”’ vol. iii. p. 596. Mr. Swinhoe, in ‘‘Ibis,”
1865, p. 542; 1866, pp. 131, 405.

16 Jerdon, “Birds of India,” vol. iii. p. 677.

" Gould’s ‘‘Handbook to the Birds of “Australia, ” vel ii. p. 275.

SEXUAL SELECTION 615

ascertained, by examining many specimens, that the trachea
is not convoluted in either sex of R. bengalensis, which spe-
cies resembles &. australis so closely that it can hardly be
distinguishd except by its shorter toes. This fact is an-
other striking instance of the law that secondary sexual

Fig. 62.—Rhynchea capensis (from Brehm).

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.’® There is also reason to be-
lieve that the male undertakes the duty of incubation, for

18 *‘The Indian Field,’’ Sept. 1858, p. 3.

616 THE DESCENT OF MAN

Mr. Swinhoe' 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 gayly at-
tired than the males.’’ But the difference in color between
the sexes is far from conspicuous. According to Prof.
Steenstrup, the male alone of P. fulicarius‘undertakes the
duty of incubation; this is likewise shown by the state of
his breast feathers during the breeding season. The female
of the dotterel plover (Hudromias morinellus) is larger than
the male, and has the red and black tints on the lower sur-
face, 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 like-
wise attends to the young.” I have not been able to dis-
cover 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 com-
mon cassowary (Casuarius galeatus) would be thought by any
one to be the female, from his smaller size and from the ap-
pendages and naked skin about his head being much less
brightly colored; 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.”” The

8 “‘This,’? 1866, p. 298.

20 For these several statements, see Mr. Gould’s ‘‘Birds of Great Britain.??
Prof. Newton informs me that he has Ieng 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 ‘‘show much greater devotion toward 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 colors than the males.

1 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.

SEXUAL SELECTION 617

female is said by Mr. T. W. Wood ™ to exhibit during the
breeding season a most pugnacious disposition; and her
wattles then become enlarged and more brilliantly colored.
So, again, the female of one of the emus (Dromeus irrora-
tus) is considerably larger than the male, and she possesses
a slight topknot, 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 endeav-
ors to destroy them. For months afterward it is unsafe to
put the parents together, violent quarrels being the inevi-
table result, in which the female generally comes off con-
queror.’’** 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 fe-
males being savage, quarrelsome and noisy, the males gen-
tle 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 colors;
nevertheless, he undertakes the whole duty of incubation.™

I will specify the few other cases known to me in which

2 “The Student,’’ April, 1870, p. 124.

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.

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 colors; yet he takes sole
charge of the eggs and of the young, just as does the male of the common
species of Rhea. ‘

618 THE DESCENT OF MAN

the female is more conspicuously colored than the male,
although nothing is known about the manner of incuba-
tion. With the carrion-hawk of the Falkland Islands
(Milwago leucurus) I was much surprised to find by dis-
section that the individuals which had all their tints
strongly pronounced, with the cere and legs orange col-
ored, were the adult females, while those with duller
plumage and gray legs were the males or the young. In
an Australian tree-creeper (Climacteris erythrops) the fe-
male differs from the male in ‘‘being adorned with beau-
tiful, 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 conspic-
uous than in the female.’ *

We thus see that the cases in which the female birds are
more conspicuously colored than the males, with the young
in their immature plumage resembling the adult males in-
stead 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 incom-
parably 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 ener-

2% For the Milvago, see ‘‘Zoology of the Voyage of the Beagle’’: Birds,
1841, p. 16. For the Climacteris and night-jar (Hurostopodos), see Gould’s
‘‘Handbook to the Birds of Australia,’ vol. i. pp. 602 and 97. The New Zea-
land shieldrake (Zadorna 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 color, and his back is clothed with
finely pencilled slate-colored 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 (‘‘Proc. Zool. Soc.,”’ 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, while the males and the young have retained
a former state of plumage.

SEXUAL SELECTION 619

getically or less persistently than on the males in the last
class. Mr. Wallace believes that the males have had their
colors 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 suffi-
ciently great for this view to be safely accepted. In some
of the cases the brighter tints of the female are almost con-
fined to the lower surface, and the males, if thus colored,
would not have been exposed to danger while sitting on the
eggs. It should also be borne in mind that the males are
not only in a slight degree less conspicuously colored than
the females, but are smaller and weaker. They have, more-
over, 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,
color, size, and of some points of structure, has been ef-
fected between the two sexes.

Now if we might assume that the males in the present
class have lost some of that ardor 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 In.
dian Turnix the females are said to be ‘‘much more com-
monly met with than the males’’**—then it is not improbable
that the females would have been led to court the males, in-
stead 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. Tak-
ing 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 en-
deavor to drive away rival females, in order to gain posses-
sion of the male; and on this view all the facts become clear;
for the males would probably be most charmed or excited by

% Jerdon, ‘‘Birds of India,’’ vol. iii. p. 598

620 THE DESCENT OF MAN

the females which were the most attractive to them by their
bright colors, 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.

Cuass IIT. When the adult male resembles the adult je-
male, 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 plu-
mage. The male and female of the splendid scarlet ibis are
alike, while the young are brown; and the scarlet color,
though common to both sexes, is apparently a sexual char-
acter, for it is not well developed in either sex under con-
finement; and a loss of color 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 colored, while the mature birds are pure white; but it
would be superfluous to give additional instances. These
differences between the young and the old apparently de-
pend, asin the last two classes, on the young having re-
tained a former or ancient state of plumage, while the old
of both sexes have acquired a new one. When the adults
are bright colored, 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
colors 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. Con-
sequently, the sexes when mature resemble each other and
differ from the young

SEXUAL SELECTION 621

Crass IV. When the adult male resembles the adult fe-
male, 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 colored, 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-colored birds, such as the hedge-war-
bler 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 colored than
the adults, but many of the feathers on the lower surface
are edged with brown ”—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 Aus-
tralian genus of paroquets (Platycercus), the young of some
species closely resemble, while the young of other species
differ considerably, from their parents of both sexes, which
are alike.” Both sexes and the young of the common jay
are closely similar; but in the Canada jay (Perisorcus cana-
densis) the young differ so much from their parents that they
were formerly described as distinct species.”

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 es-
pecial interest in the subject had better pass them over.

The brilliant or conspicuous colors which characterize
many birds in the present class can rarely or never be of ser-
vice to them as a protection; so that they have probably
been gained by the males through sexual selection, and
then transferred to the females ad the young. It is, how-

2% Jerdon, ‘‘Birds of India,’ vol. i. pp. 222, 228, Gould’s ‘Handbook to
the Birds of Australia,’’ vol. i. pp. 124, 130.
% Gould, ibid., vol. ii. pp. 37, 46, 56.
% Audubon, ‘‘Ornith. Biography,’ vol. ii. p. 55.
Descent—Vot. IL. —9

622 THE DESCENT OF MAN

ever, possible that the males may have selected the more at-
tractive 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 gener-
ally resemble each other, ihe males of some few species are
in a slight degree more brightly colored than the females.
It is again possible that the females may have selected the
more beautiful males, these males having reciprocally se-
lected 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 se-
lection on one side alone. It is, therefore, the most prob-
able 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 colors, 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 while 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 charac-
ters, if acquired by the males when adult, may have been
panumiivied at first to the adults alone and at some subse-
uent 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 par-
ents. 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 glact-

% ‘Variation of Animals and Plants under Domestication,’’ vol. ii. p. 79.

SEXUAL SELECTION 623

alis which had assumed while young, in a quite anomalous
manner, the adult plumage of their parents. Again, the
oung 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 shown by the color of their beaks and legs,
which nearly resembled the same parts in the adults.”
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.** In the house-sparrow
Se domesticus) the male differs much from the female and
rom 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 show 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 coloring of their early progeni-
tor. This may have been effected by a male ancestor of the
tree-sparrow having varied, first, when nearly mature; or,
secondly, while 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 re
It is impossible to decide which of these three modes
has generally prevailed throughout the present class of
cases. That the males varied while young, and transmit-
ted their variations to their offspring of both sexes, is the
most probable. I may here add that I have, with little

31 Charlesworth’s ‘‘Mag. of Nat. Hist.,’’ vol. i., 1837, pp. 305, 306.

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).

32 I am indebted to Mr. Blyth for information in regard to this genus. The
sparrow of Palestine belongs to the sub-genus Petronia.

624 THE DESCENT OF MAN

success, endeavored, by consulting various works, to de-
cide 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 vari-
ations occurring late in life are transmitted to one and the
same sex, while those which occur early in life are trans-
mitted to both exes apparently hold good in the first,®™
second, and fourth classes of cases; but they fail in the
third, often in the fifth,** and in the sixth small class.
They apply, however, as far as I can judge, to a consider-
able majority of the species, and we must not forget the
striking generalization 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 ot
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 col-
ors of the adult plumage are first developed will falsely ap-
pear to us to be earlier than it really is. This may be illus-
trated by the practice followed by some bird-fanciers, who
ie out a few feathers from the breast of nestling bull-

nches, and from the head or neck of young ae pheasants,
in order to ascertain their sex; for in the males these feath-

*4 For instance, the males of Zanagra estiva 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
splendor until the end of the September in the following year.

% Thus the Ibis tantalus and Grus americanus take four years, the Fla-
mingo several years, and the Ardea ludovicana two years, before they acquire
their perfect plumaga See Audubon, ibid., vol. i. p, 221; vol. iii. pp, 133,
139, 211.

SEXUAL SELECTION 625

ers are immediately replaced by colored ones.” 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 while
retaining their immature 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
colors, plumes, etc., to the males, and, by means of equal
transmission, to the females of many species. The objec-
tion would be a valid one, if the younger and less orna-
mented 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 /bis tanialus as a rare event, as does Mr. Swin-
hoe, in regard to the immature males of Oriolus.* 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 ulti-
mately be modified.” If, on the other hand, the young

86 Mr. Blyth, in Charlesworth’s ‘‘Mag. of Nat. Hist.,’? vol. i., 1837, p. 300.
Mr. Bartlett has informed me in regard to gold pheasants. :

81 T 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 cerulea
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 colored 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 Hagle (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.

38 See the last footnote.

%? 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 while retaining their larval structure.
Fritz Miller has shown (‘Facts and Arguments for Darwin,’’ Eng. trans.,
1869, p. 79) that the males of several amphipod crustaceans become sexually
mature while young; and I infer that this is a case of premature breeding,

626 THE DESCENT OF MAN

never succeeded in obtaining a female, the habit of earl
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
eke and with the crest of the plumes of certain herons,

or instance, the Ardea ludovicana.” But it is doubtful
whether the continued development of such feathers is the
result .of the selection of successive beneficial variations
(one. this is the most probable view with birds of para-
ise) 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.

Ciass V. When the adults of both sexes have a distinct
winter and summer plumage, whether or not the male differs
Jrom 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. ith
the species, in which the male differs from the female during
the summer season alone, or which is rarer, during both sea-
sons,“ the young generally resemble the females—as with
the so-called goldfinch of North America, and apparently
with the splendid Maluri of Australia.*? With those species

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. ;

4 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 ad-
vantage over the younger males; see “‘Archives Néerlandaises,’’ tom, vi., 1871.
On Ardea, Audubon, ibid., vol. iii. p. 139.

41 For illustrative cases see vol. iv. of Macgillivray’s ‘‘Hist. Brit. Birds’’;
on Tringa, ete., pp. 229, 271; on the Machetes, p. 172; on the Charadrius
hiaticula, p.°118; on the Charadrius pluvialis, p. 94.

4 For the goldfinch of North America, Fringilla tristis, Linn., see Audubon,
“Ornith, Biography,’’ vol. i. p. 172. For the Maluri, Gould’s ‘‘Handbook to
the Birds of Australia,’’ vol. i, p. 318.

SEXUAL SELECTION 627

the sexes of which are alike during both the summer and
winter, the young may resemble the adults, first, 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 in-
stance 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 colors are reversed; for the young and the adults of
both sexes are gray and black during the winter, the adults
becoming white during the summer.** As an instance of the
second case, the young of the razor-bill ee torda, Linn.),
in an early state of plumage, are colored like the adults dur-
ing the summer; and the young of the white-crowned spar-
row 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.“
With respect to the third case, namely, that of the young
having an intermediate character between the summer and
winter adult plumages, Yarrell,** insists that this occurs
with many waders. Lastly, in regard to the young differ-
ing greatly from both sexes in their adult summer and win-
ter 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 sum-
mer dress, or the adults of both sexes in their winter dress,
the cases differ from those given under Olasses I. and III.
only in the characters originally acquired by the males dur-
ing the breeding season having been limited in their trans-
mission 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

48 Tam 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
“This,” 186%, p. 173.

44 On the Alca, see Macgillivray, ‘‘Hist. Brit. Birds,’ v. 347. On the
Fringilla leucophrys, Audubon, ibid., ii. p. 89. TI shall have hereafter to refer
to the young of certain herons and egrets being white.

45 **History of British Birds,’’ vol. i, 1839. p. 169. 7

628 THE DESCENT OF MAN

ancient state of plumage; we can account: by sexual selec-
tion 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 plu-
mage, 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 trans-
mission according to age, season, and sex; but it would not
be worth while to attempt to follow out these complex
relations.

Cuass 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 (Yurdus merula) can be distinguished in
the nest from the female. The two sexes of the mocking-
bird (Turdus polyglottus, Linn.) differ very little from eac
other, yet the males can easily be distinguished at a ver
early age from the females by showing more pure white.**
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, while the females are brown; and

® Audubon, ‘“‘Ornith. Biography,’’ vol. i. p. 118.

SEXUAL SELEUTION 629

the nestling males of both species have their main wing
and tail-feathers edged with blue, while those of the female
are edged with brown.*’ 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

resent class is that the males, differently from what occurs
in Class I., have transmitted their colors to their male off-
spring at an earlier age than that at which they were first
acquired; for, if the males had varied while quite young,
their characters would probably have been transmitted to
both sexes.**

In Atthurus polytmus, a humming-bird, the male is splen-
didly colored black and green, and two of the tail-feathers
are immensely lengthened; the female has an ordinary tail
and inconspicuous colors; now the young males, instead of
resembling the adult female, in accordance with the common
rule, begin from the first to assume the colors proper to their
sex, and their tail-feathers soon become elongated. I owe
this information to Mr. Gould, who has given me the fol-
_ lowing more striking and as yet unpublished case. Two

humming-birds belonging to the genus Eustephanus, both
beautifully colored, inhabit the small island of Juan Fer-
nandez, and have always been ranked as specifically distinct.
But it has lately been ascertained that the one, which is of
a rich chestnut brown color with a golden-red head, is the
male, while the other, which is elegantly variegated with
aan and white, with a metallic-green head, is the female.

ow the young from the first somewhat resemble the adults
of the corresponding sex, the resemblance gradually becom-
ing 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

41 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
“Mag, of Nat. History,’’ vol. i., 1837, p. 113.

4° 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 with 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, Saaicola 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 above one of EHustephanus.

63 THE DESCENT OF MAN

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
colors 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 Rhynchzxa
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, while 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-colored 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 colors or other orna-
ments, and transmitted them in various ways, in accordance
with the recognized 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 determin-
ing 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 color which occurred in the
males at an early age not being then selected—on the con-

SEXUAL SELECTION 631

trary being often eliminated as dangerous—while 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 coloring of
the progenitors of our existing species. Ina vast number
of species, in five out of our six classes of cases, the adults
of one sex or of both are bright colored, at least during the
breeding season, while the young are invariably less brightly
colored than the adults, or are quite dull colored, for no in-
stance is known, as far as I can discover, of the young of
dull-colored species displaying bright colors, or of the young
of bright-colored species being more brilliant than their par-
ents. 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 colored, and
as these form whole 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 Color of the Plumage in relation to Protection.—It
will have been seen that I cannot follow Mr. Wallace in the
belief that dull colors, when confined to the females, have
been in most cases specially gained for the sake of protec-
tion. There can, however, be no doubt, as formerly re-
marked, that both sexes of many birds have had their
colors modified, so as to escape the notice of their ene-
mies; 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’ that ‘‘it is only in the tropics, among forests
’ which never lose their foliage, that we find whole groups
of birds, whose chief color is green.’’ It will be admitted

4 ‘Westminster Review,”’ July, 1867, p. 5.

6382 THE DESCENT OF MAN

by every one who has ever tried, how difficult it is to dis-
tinguish 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 pro-
tective. 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 colors have been ac-
quired 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 colored so as to imitate the surrounding
surface. How difficult it is to see a partridge, snipe, wood-
cock, 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 colors. Mr. Tristram has re-
marked, in regard to the inhabitants of the Sahara, that all
are protected by their ‘‘isabelline or sand-color.’’” Call-
ing 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
colored nearly alike. Accordingly, I applied to Mr. Tris-
tram 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 mani-
festly have their plumage colored in a protective manner;
and this coloring 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 colored
in the same manner; but these belong to genera in which

50 “*This,’? 1859, vol. i. p. 429 et seg. Dr. Rohlfs, however, remarks to
me in a letter that, according to his experience of the Sahara, this statement
is too strong.

SEXUAL SELECTION 633

this rule commonly prevails, so that they tell us nothing
about the protective colors 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-colored hue in
the two sexes. So that in these ten species the upper sur-
faces of both sexes have been acted on and rendered alike,
through natural selection, for the sake of protection; while
the lower surfaces of the males alone have been diversitied,
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 colors 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 colored. No doubt if their colors had been bril-
liant 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. orna-
ment. We must, however, bear in mind that male birds,
though dull colored, often differ much from their females
(as with the common sparrow), and this leads to the belief
that such colors 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 shown that the best song-
sters 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 colors; but
not for both charms combined. Some species, which are

684 THE DESCENT OF MAN

manifestly colored 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 ex-
treme elegance. In such cases we may conclude that both
natural and sexual selection have acted conjointly for pro-
tection 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 colored that it would be rash to assume the
agency of sexual selection, and when no direct evidence
can be advanced showing that such colors serve as a pro-
tection, 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 colored, such as the numerous black, white, or
piebald species, and these colors are probably the result of
sexual selection. With the common blackbird, capercailzie,
black-cock,. black scoter-duck (Oidemia), and even with one
of the birds of paradise (Lophorina atra), the males alone
are black, while 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 transmis-
sion 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 colored, 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 black-cock and
capercailzie, in the brightly and variously colored beak of
the scoter-drake (Oidemia), in the red beak of the chough
(Corvus graculus, Linn.), of the black swan, and the black

§

SEXUAL SELECTION 635

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 color with which these organs are orna-
mented.” The naked skin, also, at the base of the beak
and round the eyes is likewise often brilliantly colored; and
Mr. Gould, in speaking of one species,” says that the colors
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 colors
(an object falsely appearing to us unimportant), than that
the male Argus pheasant and some other birds should be
encumbered with plumies so long as to impede their flight,

In the same manner as the males alone of various species
are black, the females being dull colored, 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., while 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 com-
pletely white plumage through sexual selection. In some
of these cases the plumage becomes white only at maturity.

51 No satisfactory explanation has ever been offered of the immense size,
and still less of the bright colors, 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 shown 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 while
nesting in a hole in a tree. ier

5) Ramphastos carinatus, Gould’s ‘‘Monograph of Ramphastide.

636 THE DESCENT OF MAN

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 sum-
mer; the young in their immature state, and the adults in
their winter dress, being gray and black. With many kinds
of gulls (Larus) the head and neck become pure white dur-
ing the summer, being gray 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 colored
than during the breeding season. _ These latter cases offer
another instance of the capricious manner in which sexual
selection appears often to have acted.”

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
ean easily defend themselves or escape from birds of prey,
to which, moreover, they are not much exposed. Conse-
quently, 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 con-
spicuous either by being perfectly white or intensely black;
so that these colors may possibly serve the same end as the
call-notes of many land-birds.“ A white or black bird

53 On Larus, Gavia, and Sterna, see Macgillivray, ‘‘Hist. Brit. Birds,’
vol. v. pp. 515, 584, 626. On the Anser hyperboreus, Audubon, ‘‘Ornith,
Biography,” vol. iv. p. 562. On the Anastomus, Mr. Blyth, in ‘‘Ibis,’’ 1867,
p. 173,

54 Tt 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

SEXUAL SELECTION 637

when it discovers and flies down to a carcass floating on
the sea or cast upon 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 colored individuals. Hence conspicuous colors
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 cocka-
toos, 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 color is agreeable to birds we may con-
clude 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 colored 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-colored
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.** And so many male birds have elongated tail-

or largely white, and that many others are black. So that here again conspicu-
ous colors may possibly aid the sexes in finding each other during the breeding

season.
585 See Jerdon on the genus Palwornis, ‘‘Birds of India,’’ vol. i. pp. 258-260.

688 THE DESCENT OF MAN

feathers or elongated crests for their chief ornament, the
shortened tail, formerly described in the male of a hum-
ming-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 coloring having, as it appears,
been appreciated for the sake of novelty. The young of
the Ardea asha are white, the adults being dark slate-col-
ored; and not only the young, but the adults in their win-
ter plumage, of the allied Buphus coromandus are white,
this color 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,** should for any special purpose have been ren-
dered pure white and thus made conspicuous to their en-
emies; 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 color to their
young; so that the young and the old became white like
certain existing egrets; and that the whiteness was after-
ward retained by the young, while 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 seé the adults
dark colored. I infer that this would be the case from
the analogy of many other birds, which are dark while

86 The young of Ardea rufescens and A. cerulea of the United States are
likewise white, the adults being colored in accordance with their specific names.
Audubon (‘‘Ornith. 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.”’

SEXUAL SELECTION 639

young, and when adult are white; and more especially
from the case of the Ardea gularis, the colors of which
are the reverse of those of A. asha, for the young are
dark colored and the adults white, the young having re-
tained 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 un-
dergone the following changes of color: 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 sav-
ages the taste of the female for certain colors or other or-
naments would not remain constant for many generations;
that first one color and then another would be admired,
and consequently that no permanent effect could be pro-
duced. 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 cer-
tain 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 cica-
trices on the skin, the same hideously perforated lips, nos-
trils, 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 forever, 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 ad-
mired for many generations, and still admire, the same
breeds; they earnestly desire slight changes, which are
considered as improvements, but any great or sudden

640 THE DESCENT OF MAN

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 colored 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 colors, 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 court-
ship. Many birds endeavor 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, topknots, and so forth, are by
far the commonest means. In some cases mere novelty ap-
pears to have acted asa charm. The ornaments of the males
must be highly important to them, for they have been ac-

SEXUAL SELECTION 641

quired 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 matur-
ity, or they assume it only during the breeding season, or
the tints then become more vivid. Certain ornamental ap-
pendages become enlarged, turgid, and brightly colored
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 court-
ship 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
jan be shown 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 un-
consciously 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 fe-
males; this is well shown in certain closely allied repre-
sentative species, in which the females can hardly be
distinguished, while 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 im-
mediately 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

642 THE DESCENT OF MAN

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 bril-
liant colors, topknots, 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 con-
ditions 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 groundwork 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 charac-
ters 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 deter-
mining cause. When the two sexes have inherited all char-
acters 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 dis-
similarity between the sexes. With many closely allied
species, following nearly the same habits of life, the malea

SEXUAL SELECTION 648 ©

have come to differ from each other chiefly through the
action of sexual selection, while 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 accumula-
tion through sexual selection of strongly pronounced colors
and other ornaments. The individuals of both sexes, how-
ever 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 color it is possi-
ble 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 ac-
quiring the bright colors’from the males by the destruc-
tion 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 col-
ored, the male being still kept bright colored by the se-
lection 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 modi-
fied must at present remain doubtful. When, through the
law of the equal transmission of characters to both sexes,
the females were.rendered as conspicuously colored 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 trans-
posed, for the females are larger, stronger, more vociferous,
and brighter colored than the males. They have, also, be-
come 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 prob-
able, such females habitually drive away their rivals, and by
the display of their bright colors or other charms endeavor

644 THE DESCENT OF MAN

to attract the males, we can understand how it is that they
have gradually been rendered, by sexual selection and sex-
ually 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 con-
stantly occurs with our poultry, and occasionally with other
birds—the young will be left unaffected, while the adults of
both sexes will be modified. If both these laws of inher-
itance 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 con-
spicuous characters occur early in life, as no doubt often
happens, they will not be acted on through sexual selec-
tion 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 ap-
parently 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 color 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 im-
mature plumage gives us an indirect record. Many birds,
especially those which live much on the ground, have un-

SEXUAL SELECTION 645

doubtedly been obscurely colored for the sake of protec-
tion. In some instances the upper exposed surface of the
_ plumage has been thus colored in both sexes, while the
lower surface in the males alone has been variously orna-
mented 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 colors, have generally been
acquired by the males through variation and sexual selec-
tion, 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.”

51 T am greatly indebied to the kindness of Mr. Sclater for having looked
ever these four chapiers 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 distin-
guished 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.

Descent—Von. IT.—10

646 THE DESCENT OF MAN

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—Weapous 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

ITH 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 some-
times 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.’’?
IT observed the same fact with the hides of the guanacos in
Patagonia; and on one occasion several were so absorbed
in fighting that they fearlessly rushed close by me. Living-
stone speaks of the males of the many animals in Southern
Africa as almost invariably showing the scars received in
former contests.
The law of battle prevails with aquatic as with terres-
trial mammals. It is notorious how desperately male seals
fight, both with their teeth and claws, during the breeding

1 See Waterton’s account of two hares fighting, ‘‘Zoologist,”’ vol. i., 1843,
p. 211. On moles, Bell, ‘‘Hist. of British Quadrupeds,”’ first edit. p. 100. On
squirrels, Audubon and Bachman, ‘‘Viviparous Quadrupeds of N. America,’?
1846, p. 269. On beavers, Mr. A. H. Green, in ‘Journal of Lin. Soc. Zoolog.,’’
vol. x., 1869, p. 362.

SEXUAL SELECTION 647

season; and their hides are likewise often covered with
sears. 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.?

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, showing how miserably the victor and
vanquished had perished.* 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, degener-
ated in size but not in courage, of the gigantic Bos primi-
genius. 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 neighboring wood. But a few days afterward
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 J. B. 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

$ Qn the battles of seals, see Capt. O. Abbott in ‘‘Proc. Zool. Soc.,’? 1868,
p. 191; also 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.

8 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 twe
gnus in the same condition.

648 THE DESCENT OF MAN

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,
while the other was driving away the mares, and had al-
ready 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 fur-
nished 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 ante-
lopes, 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.* In the
male elephant of India and in the male dugong* 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

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, ‘‘Proc. Zool. Soc.,’’ 1868, p. 429.

5 Owen, ‘‘Anatomy of Vertebrates,’’ vol. iii, p. 283,

SEXUAL SELECTION 649

point of another jammed into the broken place.”* The
tooth on the opposite side of the head in the male con-
sists of a rudiment about ten inches in length, which is
imbedded 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 ornitho-
rhynchus 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.’

When the males are provided with weapons which in the
females are absent, there can hardly be 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 espe-
cially 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 branch-
ing horns, and with female elephants the development of
immense tusks, would be a great waste of vital power, sup-
posing that they were of no use to the females. Conse-
quently, they would have tended to be eliminated in the

6 Mr. B. Brown, in ‘‘Proe. Zool. Soc.,’? 1869, p. 553, See Prof. Turner,
in ‘‘Sournal 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 “‘Proe. Zoclog. Soc.,”’ 1871, p. 42.

1 Owen on the cachalot and Ornithorhynchus, ibid., vol. iii. pp. 638, 641.
Harting is quoted by Dr. Zouteveen in the Dutch translat. of this work, voi.
ii. p 292.

650 LHE DESCENT OF MAN

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 whén they are fully
developed, namely, in September, throughout the winter
until April or May, when she brings forth her young.
Mr. Crotch made particular inquiries 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, toward the
end of November. As both sexes have the same require-
ments 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 dur-
ing 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,
‘“Amoonitates 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.

SEXUAL SELECTION 651

The horns of the reindeer are developed at a most un-
usually early age; but what the cause of this may be is
not known. The effect has apparently been the transfer-
ence 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.*° Moreover, the females of
some other species of deer exhibit, either normally or occa-
sionally, 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.’’’® 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 con-
sequent 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'’)—to those which have fairly developed
horns, but manifestly smaller and thinner than in the male
and sometimes of a different shape’—and ending with those

® Isidore Geoffroy St.-Hilaire, ‘“‘Essais de Zoolog. Générale,’’ 1841, p. 513.
Other masculine characters, besides the horns, are sometimes similarly trans-
ferred to the female; thus Mr. Boner, in speaking of an old female chamois
((‘Chamois Hunting in the Mountains of Bavaria,’’ 1860, 2d edit., 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.’” *

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 Acad. of Nat. Sciences,’’? May, 1868, p. 9. ;

1! Tam indebted to Dr. Caufield for this information; see, also, his paper

in ‘‘Proc. Zoolog. Soc.,’? 1866, p. 105. :
2 For instance the horng of the female Antilocapra euchore resemble those

G52 THE DESCENT OF MAN

in which both sexes have horns of equal size. As with the
reindeer, so with antelopes there exists, as previously
shown, 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 in 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 nor-
mally 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. 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 trust-
worthy 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
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, while
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.

of a distinct species, viz., the Ant. dorcas var, Corine; see Desmarest “Mam-
malogie,”’ p. 455.
18 Gray, ‘‘Catalogue Mamm. Brit. Mus.,’’ part iii., 1852, p. 160.

SEXUAL SELECTION 658

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." 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 son-
daicus) the horns are remarkably small, and inclined much
backward. 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.’’’® Dr. Forsyth Major also informs
me that a fossil skull, believed to be that of the female Bos
etruscus, has been found in the 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." From these va-
rious 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 com-
pletely 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 ex-
cepted, 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;" but as they are developed at a very

4 Richardson, ‘‘Fauna Bor. Americana,’’ p. 278.

18 **Tand and Water,’’ 1867, p. 346.

16 Sir Andrew Smith, ‘‘Zoology of S. Africa,’ pl. xix. Owen, “‘Anatomy
of Vertebrates,’’ vol. iii. p. 624. ,

11 This is the conclusion of Seidlitz, ‘“‘Die Darwin’sche Theorie,” 1871,
p. 47.

654 THE DESCENT OF MAN

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 Welsh sheep the horns of the males are consider-
ably reduced by castration; but the degree depends much
on the age at which the operation is performed, as is like-
wise the case with other animals. Merino rams have large
horns, while 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.’’'* 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 backward; 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 forward. 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 fe-
male probably shows 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 can-
not be explained with any certainty. Nevertheless, it seems

18 Tam much obliged to Prof. Victor Carus for having made inquiries 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 allogether dis-
appear or remain as mere rudiments; but Ido not know whether he refers to
merinos or to ordinary breeda

SEXUAL SELECTION 655

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,’® so here, the disturbance in the consti-
tution 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 dis-
tinct species, and here ‘‘not one in a hundred is found with
tusks, the few that possess them being exclusively males.’’ *°
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 pres-
ence 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 at-
tacking the tiger; according to Bruce, he scores the trunks
of trees until they can be thrown down easily, and he like-
wise thus extracts the farinaceous cores of palms; in Africa

19 T 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.

2 Sir J. Emerson Tennent, ‘‘Ceylon,’’ 1859, vol. ii. p. 274, For Malacca,
Journal of Indian Archipelago,’’ vol. iv. p. 35%.

656 THE DESCENT OF MAN

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 sec-
ondary uses to which the horns of an animal may be occa-
sionally put, is that observed by Captain Hutton” with the
wild goat (Capra egagrus) of the Himalayas, and, as it is
also said, with the ibex, namely, that when the rial acci-
dentally falls from a height he bends inward 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 Afghan-
istan,” 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 cimeter-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 ad-
versary, 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 Pem-
brokeshire 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 enor-
mous horns, measuring thirty-nine inches in a straight line

21 “Calcutta Journal of Nat. Hist.,’’ vol. ii., 1843, p. 526.

22 Mr. Blyth, in ‘‘Land and Water,’’ March, 186%, p. 134, on the authority
of Capt. Hutton and others. For the wild Pembrokeshire goats see the ‘‘Field,’?
1869, p. 150.

SEXUAL SELECTION 657

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 perma instinct which the common bull
does not possess."* Hence a dog who pins a buffalo by the
nose is immediately crushed. We must, however, remem-
ber that the Italian buffalo has been long domesticated, and
it is by no means certain that the wild parent form had sim-
ilar horns. Mr. Bartlett informs me that when a female
Cape buffalo (Bubalus caffer) was turned into an inclosure
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 shown digni-
fied 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 in-
dented by a single blow.

With antelopes it is sometimes difficult to imagine how
they can possibly use their curiously shaped horns; thus
the spring-boc (Ant. ewehore) has rather short upright horns,
with the sharp points bent inward 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 backward, and are of such length that their points
reach beyond the middle of the back, over which they ex-
tend 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,

% M. E. M. Bailly, “‘Sur usage des Cornes,” etc., “‘Annal. des Sc. Nat.,””
tom. ii,, 1824, p. 369.

658 THE DESCENT OF MAN

with their heads between their forelegs, and in this attitude
the horns stand nearly parallel and close to the ground, with
the points directed forward and a little upward. The com-
batants then gradually approach each other, and each en-
deavors 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 ani-
mals 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 horns with effect even against

Fig. 63.—Oryx leucoryx, male (from the Knowsley Menagerie). \

a lion; yet from being forceu to-ysuce’tis head between the »
forelegs in order to bring the points of the horns forward,
he would generally be under a great disadvantige’ when at-
tacked by any other animal. It is, therefore ‘not probable
that the horns have been modified into their piesent great
length and peculiar position as a protection agaist 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 backward, he would be compelled, in his
battles with rival males, to bend his head somewhat inward
or downward, as is now done by certain stag a and it is not
improbable that he might have acquired the hgbit of at first
‘

SEXUAL SELECTION 659

occasionally and afterward 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 grad-
ually 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.* From the manner in which the
horns are branched, and more especially from deer being
known occasionally to fight together by kicking with their
forefeet,* 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 ad-
vantage 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 downward, are a great protection to the fore-
head, and their points are likewise used in attack. Sir Philip

* 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. Iam indebted to Prof. Victor Carus for the Moritzburg case.

% Hon. J. D. Caton (‘Ottawa Acad. of Nat. Science,’’ May, 1868, p. 9)
says that the American deer fight with their forefeet, after “the question of
superiority. has been once settled and acknowledged in the herd.’’ Bailly,
“Sur Pusage des Cornes,’’ ‘Annales des Sc. Nat.,” tom. ii., 1824, p, 371.

660 THE DESCENT OF MAN

- 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 endeavors 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. Nev-
ertheless, 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 posi-
tion the ends of the horns were directed against his adver-
saries. ‘‘In rolling his head he necessarily raised it some-
what, 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 back-
ward to a distance of 150 or 200 feet, and the attacked man
was killed.”

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 ante-

26 See a most interesting account in the Appendix to Hon. J. D. Caton’s
paper, as above quoted.

SEXUAL SELECTION 661

jopes, 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

Fie. 64.—Strepsiceros Kudu (from Sir Andrew Smith’s “Zoology of South Africa”).

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 favor of this belief.

An interesting case has lately been published, from

662 THE DESCENT OF MAN

which it appears that the horns of a deer in one district
in the United States are now being modified through sex-
ual and natural selection. A writer in an excellent Ameri-
can journal ” 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 afterward 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 com-
mon antler. With this advantage the spike-horn bucks
are gaining upon the common bucks, and may, in time,
entirely supersede them in the Adirondacks. Undoubt-
edly, the first spike-horn buck was merely an accidental
freak of nature. But his spike-horns gave him an advan-
tage, 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 advan-
tageous, 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 shown by the case of the Ovis cycloceros,
who thus conquered a domestic ram famous for his fight-

® ‘The American Naturalist,’? Dec. 1869, p. 552.

SEXUAL SELECTION 663

ing 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 differ-
ently armed. In the foregoing case of the Oryx leucorya
it is almost certain that the victory would rest with an an-
telope 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 upward; the musk-deer downward
with serious effect.” The walrus, though having so short
a neck and so unwieldy a body, ‘‘can strike either upward
or downward or sidewise, with equal dexterity.’’* 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 forward
and upward he is able to fling a tiger toa great distance
—it is said to even thirty feet; when they are short and
turned downward he endeavors 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.”

Very few male quadrupeds possess weapons of two dis-
tinct kinds specially adapted for fighting with rival males.
The male muntjac-deer (Cervulus), however, offers an ex-
ception, 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 gen-
erally stands in an inverse relation with that of even mod-

%8 Pallas, ‘‘Spicilegia Zoologica,’’ fase. xiii., 1779, p. 18.

2% Lamont, ‘‘Seasons with the Sea-Horses,”’ 1861, p. 141.

% See, also, Corse (‘‘Philosoph. Transact.,’’ 1799, p. 212) on the manner
in which the short-tusked Mooknah variety attacks other elephants,

664 THE DESCENT OF MAN

erately developed canine teeth. Thus camels, guanacos,
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 Camelids have,
in addition to their true canines, a pair of canine-shaped
incisors in their upper jaws." 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.” 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 guanacos. Whenever the adult male possesses ca-
nines, now inefficient, while the female has either none or
mere rudiments, we may conclude that the early male pro-
genitor 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 fol-
lowed 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, oe their development consumes much or-
ganized matter. A single tusk of the Asiatic elephant—

3) Owen, ‘‘Anatomy of Vertebrates,”’ vol. iii. p. 349.

8 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.
Seo, also, Falconer (‘‘Paleont. Memoirs and Notes,’’ vol. i., 1868, p. 576) on
canines in an adult female deer. In old males of the musk-deer ie canines
(Pallas, ‘‘Spic. Zoolog.,”’ fasc. xili., 1779, p. 18) sometimes grow to the length
of three inches, while in old females a rudiment projects scarcely half an inch
above the gums,

SEXUAL SELECTION 665

one of the extinct woolly species—and of the African ele-
phant, have been known to weigh respectively 150, 160,
and 180 pounds; and even greater weights have been
given by some authors. 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
Trish 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 re-
newed 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 re-
tarded 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 while 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.’’** The tips of the horns of
the great Irish ell were actually eight feet apart! While
the horns are covered with velvet, which lasts with the 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.** 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

88 Emerson Tennent, ‘‘Ceylon,”’ 1859, vol. ii. p. 275; Owen, ‘British Fossil
Mammals,’’ 1846, p. 245.
34 Richardson, ‘‘Fauna Bor, Americana,’’ on the moose, Alces palmata,
p. 236, 237; on the expanse of the horns, ‘‘Land and Water,’’ 1869, p. 143,
Bee, also, Owen, ‘British Fossil Mammals,’’ on the Irish elk, pp. 447, 465.
35 «Forest Creatures,’’ by C. Boner, 1861, p. 60.

664 THE DESCENT OF MAN

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 Aus-
tralia, 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.” 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 monoga-
mous species differing but little. Whales also afford evi-
dence 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,” 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 selec-
tion, 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,

% See the very interesting paper by Mr. J. A. Allen in ‘Bull. Mus, Comp.
Zoolog. 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,” Jan. 1871. Prof. Shaler on the relative size of the sexes of
whales, ‘‘American Naturalist,’? Jan. 1873,

a “Animal Economy,” p. 45.

SEXUAL SELECTION 667

and were consequently to a large extent limited in their_
transmission to the same sex.. y
From these considerations I was anxious to obtain in-
formation as to the Scotch deer-hound, the sexes of which
differ more in size than those of any other breed (though
bloodhounds 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. Fiae 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. 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 fort-
night 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 ex-
perience 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

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.

- 668 , THE DESCENT OF MAN

both in weight and size. At birth, and for several weeks
afterward, 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 ‘ill 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; while 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 in-
forms 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.

The males of some few Auadvapede possess organs or
parts developed solely as a means of defence against the at-
tacks of other males. Some kinds of deer use, as we have
seen, the upper branches of their horns chiefly or exclu-
sively for defending themselves; and the Oryx antelope, as
TI am informed by Mr. Bartlett, fences most skilfully with
his long, gently curved horns; but these are likewise used

SEXUAL SELECTION 669

as organs of offence. The same observer remarks that rhi-
noceroses, 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 (see Fig. 65) the
tusks in the lower jaw are used for fighting, but they be-
come in old age, as Brehm states, so much curved inward
and upward 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 j
age 80 much in length Fia. 65.—Head of Common Wild Boar, in prime
and curve so much up- of life (from Brehm).

ward, 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.”

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, while the upper tusks
are so long and have their points so much curled inward,
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 hook-

%® Brehm, ‘‘Thierleben,’’ B. ii. 3. 729-732.
Descent—Vou, II.—11

‘670 THE DESCENT OF MAN

ing them on a branch\ Their convex surfaces, however, if
the head were held a little laterally, would serve as an ex-
cellent guard; and hence, perhaps, it is that in old animals
they ‘‘are generally broken off, as if by fighting.’ * Here,
then, we have a 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

Fia. 66.—Skull of the Babirusa Pig (from Wallace's ‘‘Malay Archipelago”’).

defence; while in the European boar the lower tusks as-
sume in a less degree, and only during old age, nearly the
game form, and then serve in like manner sofely for defence.

In the wart-hog (Phacochoerus ethiopicus, Fig. 67) the
tusks in the upper jaw of the male curve upward during the
prime of life, and from being pointed serve as formidable
weapons. The tusks in the lower jaw are sharper than

4 See Mr. Wallace’s interesting account of this animal, ‘‘The Malay Archi-
pelago,’’ 1869, vol. i. p. 435.

SEXUAL SELECTION 671

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 outward; and it ap-

" Bie. 67.~Head of female AXthiopian Wart-hog, from ‘Proc, Zool. Soc.,”’ 1869, show-
ing 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.

peared 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 upward, 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 eartilaginous knob on each side of the face be-
neath 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 Zoo-

672 THE DESCENT OF MAN

logical 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 showing the -purpose 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 lcs 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” several miocene species, in none
of which do the tusks appear to have been largely developed
in the males; and Prof. Rutimeyer was formerly struck with
this same Fach

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 terri-
ble 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 suc-
ceeded in ripping up his belly, and in a few minutes he was
dead.’’ *? 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)*
have great manes, while the females have small ones or
none. The male baboon of the Cape of Good Hope (Cyno-
cephalus porcarius) has a much longer mane and larger ca-

—

4 ‘Atti della Soc. Italiana di Se. Nat.,’? 1873, vol. xv. fase. iv.

# “The Times,’”’ Nov. 10, 185%. In regard to the Canada lynx, see Audu-
bon and Bachman, ‘‘Quadrupeds of N. America,’’ 1846, p. 39.

#8 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,

SEXUAL SELECTION 673

nine teeth than the female; and the mane probably serves
as a protection, for, on asking the keepers in the Zoologi-
eal Gardens, without giving them any clew 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, while 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 favored this be-
hef. The stallion has a thicker and fuller mane than the
mare; and [ have made particular inquiries of two great
trainers and breeders, who have had charge of many entire
horses, and am assured that they ‘‘invariably endeavor to
seize one another by the neck.’’ It does not, however, fol-
low, from the foregoing statements, that when the hair on
the neck serves as a defence, that it was originally devel-
oped 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 endeavor 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 Hither Sex of Quadrupeds.—Before
describing, in the next chapter, the differences between the
sexes in voice, odors emitted, and ornaments, it will be con-
venient 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

674 THE DESCENT OF MAN

supremacy; or does the male, when not a polygamist, se-
lect any particular female? The general impression among
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, showing that the female selects her
partner; and it would be a strange anomaly if female quad-
rupeds, 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, while they were fighting
together, of escaping with some one male, or at least of tem-
porarily 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.“

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“ on the authority of Capt. Bryant, who had ample
opportunities for observation. He says, ‘‘Many of the fe-
males 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

“4 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.

- 45 Mr. J. A. Allen, in ‘‘Bull, Mus. Comp. Zoolog. of Cambridge, United
States,’’ vol. ii., No. 1, p. 99. :

SEXUAL SELECTION 675

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 neighbors 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 endeavored 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 ani-
mals 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 afterward subdue. The passion, for such it really
is, becomes of a more than romantic endurance.”’ Mr. May-
hew, who attended chiefly to the smaller breeds, is convinced
_ that the females are strongly attracted by males of a large

676 THE DESCENT OF MAN

size.“ The well-known veterinary Blaine states” that hie
own female pug became so attached to a spaniel, and 2
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 enamored 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 neighbor to such a degree
that she had often to be dragged away from him. After
their permanent separation, although repeatedly showing
milk in her teats, she would never acknowledge the court-
ship of any other dog, and, to the regret of her owner, never
bore puppies. Mr. Cupples also states that, in 1868, a fe-
male deer-hound in his kennel thrice produced puppies, and
on each occasion showed a marked preference for one of the
largest and handsomest, but not the most eager, of four
deer-hounds living with her, all in the prime of life. Mr.
Cupples has observed that the female generally favors 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 toward strange fe-
males. 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 deer-hounds,
who would not take any notice of a particular female mas-
tiff, so that another deer-hound 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 par-

# “Dogs: their Management,”” by E. Mayhew, M.R.C.V.8., 3d edit., 1864,
pp. 18%~192.

47 Quoted by Alex. Walker, ‘‘On Iniermarriage,” 1838, p. 3%6; sea, also,
p. 244.

SEXUAL SELECTION 677

ticular individuals of opposite sexes show a decided prefer-
ence 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 color, and individual
characters, a well as by the degree of their previous
familiarity.”

In regard to horses, Mr. Blenkiron, the greatest breeder
of racehorses in the world, informs me that stallions are so
frequently capricious in Aisi 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 practiced. We can partly
see the reason why valuable racehorse 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 sta-
ble, so that the mare had to be cheated. Prosper Lucas*
quotes various statements from French authorities, and re-
marks, ‘‘On voit des étalons qui s’éprennent d’une jument,
et négligent toutes les autres.’’ He gives, on the authority
of Baélen, 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 Lap-
~ Jand, says, ‘‘Foeminz majores et fortiores mares pre cateris
admittunt, ad eos confugiunt, a junioribus agitate, qui hos
in fugam conjiciunt.’’ ** 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

48 ‘*Traité de PHérdd. Nat.’ tom. ii., 1850, p. 296.
#® “Amoonitates Acad.,”’ vol. iv., 1788, p. 160.

678 THE DESCENT OF MAN

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.

SEXUAL SELECTION 679

CHAPTER XVIII

SECONDARY SEXUAL CHARACTERS OF MAMMALS—continued

Voice—Remarkable sexual peculiarities in seals—Odor—Development of
the hair—Color of the hair and skin—Anomalous case of the female
being more ornamented than the male—Color and ornaments due to
sexual selection—Color acquired for the sake of protection—Color,
though common to both sexes, often due to sexual selection—On the
disappearance of spots and stripes in adult quadrupeds—On the colors
and ornaments of the Quadrumana—Summary

UADRUPEDS 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,'
are said to be completely mute excepting at thisseason. As
the throats (7.e, the larynx and thyroid bodies’) of stags
periodically become enlarged at the beginning of the breed-
ing 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 ex:
perienced observers, Mr. McNeill and Sir P. Egerton, it

1 Owen, ‘‘Anatomy of Vertebrates,”’ vol. iii. p. 585.
? Thid., p. 595.

680 THE DESCENT OF MAN

seems that young stags under three years old do not roar
or bellow, and that the old ones begin bellowing at the com-
mencement of the breeding season, at first only occasionally
and moderately, while they restlessly wander about in search
of the females. Their battles are prefaced by loud and pro-
longed 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 spas-
modic contraction of almost all the muscles of the body, as
when a man grinds his teeth and clinches 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 maneand thus instine-
tively 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 enlarge-
ment 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 hab-
its of other male quadrupeds. The voice of the female, on
the other hand, quickly brings to her one or more stags,’ 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

3 See Major W. Ross King (‘‘The Sportsman in Canada,’’ 1866, pp. 53, 131)
on the habits of the moose and wild reindeer,

SEXUAL SELECTION 681

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 evi-
dence in favo~ 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 court-
ship or battles, or in any other way. But may we not be-
lieve 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 sac, as is the adult male
orang.* The gibbons rank among the noisiest of monkeys,
and the Sumatra species (Hylobates syndactylus) is also fur-
nished with an air-sac; but Mr. Blyth, who has had oppor-
tunities for observation, does not believe that the male is
noisier than the female. Hence, these latter monkeys prob-
ably use their voices as a mutual call, and this is certainly
the case with some quadrupeds; for instance, the beaver.®
Another gibbon, the H. agilis, is remarkable from having
the power of giving a complete and correct octave of musi-
cal notes,* which we may reasonably suspect serves as a sex-
ual 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 dread-
fal concert, and often continue it during many hours, the

4 Owen, “Anatomy of Vertebrates,”’ vol. iff. p. 600.

5 Mr. Green, in the “Journal of the Linnzan Society,’’ vol. x. Zoology,
1869, p. 362. ;

8 ¢ L. Martin, ‘General Introduction to the Nat. Hist. of Mamm. Ani-
mals,”’ 1841, p. 431.

682 THE DESCENT OF MAN

females sometimes joining in with their less powerful voices.
An excellent observer, Rengger,’ 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 par-
ticular 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 peculiari-
ties 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 elong-

_ated 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 dis-

- tance 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 wat-
tles of male gallinaceous birds while 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 pro-
duced far backward and rises into an internal crest seven
inches in height. The hood is clothed with short hair, and
is muscular; it 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 ‘tis said to be sometimes so loud
as to be heard four miles off.’"” When attacked they like-
wise roar or bellow; and whenever irritated the bladder is
inflated and quivers. Some naturalists believe that the

* “Naturgeschichte der Sdugethiere von Paraguay,”’ 1830, s. 15, 2)

SEXUAL SELECTION 683

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 acci-
dents 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 de-
veloped in the males during youth.°

Odor.—With some animals, as with the notorious skunk
of America, the overwhelming odor 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 odor 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,® 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 al-
ways 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 odor. The males, and rarely the females, of many
kinds of bats have glands and protrudable sacs 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 persis-
tent. On the banks of the Plata I perceived the air tainted

8 On the sea-elephant, seo an article by Lesson, in ‘‘Dict. Clase. 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 ‘‘Proe. Zoolog. Soc.,”’ 1868, p. 435.

® 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.,’” fase. viii., 1779, p. 23) has well discussed the odoriferous glands of
mammals, Owen (‘‘Anat. of Vertebrates,’ vol. iii, p. 634) also gives an ac-
count of these glands, including those of the elephant, and (p. 763) those
of shrew-mice, On Bats, Mr. Dobson in ‘‘Proc. Zoolog. Soc.,’’ 1873, p. 241.

684 THE DESCENT OF MAN

with the odor 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, re-
tained, when first unfolded, traces of the odor for one year
and seven months. This animal does not emit its strong
odor until more than a year old, and if castrated while
young never emits it."° Besides the general odor, per-
meating the whole body of certain ruminants (for instance,
Bos moschatus) in the breeding season, many deer, ante-
_ lopes, sheep, and goats possess odoriferous glands in vari-
ous situations, more especially on their faces. The so-called
tear-sacs, or suborbital pits, come under this head. These
glands secrete a semifluid 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 castra-
tion.’’"' According to Desmarest they are altogether ab-
sent 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, while 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-sac of this deer is from its position necessarily con-
- fined 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 in-
erease in quantity, during the rutting season; nevertheless,
this naturalist admits that its presence is in some way con-
nected with the act of reproduction. He gives, however,

10 Rengger, ‘‘Naturgeschichte der Saugethiere von Paraguay,”’ 1830, s. 355.
This observer also gives some curious particulars in regard to the odor.

11 Owen, ‘Anatomy of Vertebrates,’’ vol. iii. p. 632. See, also, Dr. Murie’s
observations on these glands in the ‘‘Proc. Zoolog. Soc.,’’ 1870, p. 340. Des-
marest, on the Antilope subgutiurosa, ‘‘Mammalogie,’’ 1820, p. 455,

SEXUAL SELECTION 685

only a conjectural and unsatisfactory explanation of its
use.”

In most cases, when only the male emits a strong odor
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 cer-
tain essential oils, and cats by valerian, substances far from
agreeable to us; and that dogs, though they will not eat car-
rion, sniff and roll on it. From the reasons given when dis-
cussing the voice of the stag, we may reject the idea that
the odor 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
odor emitted must be of considerable importance to the
male, inasmuch as large and complex glands, furnished
with muscles for everting the sac, 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 leaving off-
spring to inherit their gradually perfected glands and
odors.

Development of the Hair.—We have seen that male
quadrupeds often have the hair on their necks and shoul-
ders 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 devel-
oped for this purpose is very doubtful. We may feel al-
most 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 nota place likely to be injured; nevertheless, such

2 Pallas, “Bpicilegia Zoolog.,”’ fase. xiii., 1799, p. 24; Desmoulins, ‘Dict.
Class, a’Hist. Nat.,’’ tom. iii. p. 586.

686 THE DESCENT OF MAN

crests:‘are sometimes confined to the males, or are much more
developed in them than in the females. Two antelopes, the
Tragelaphus scriptus * (see Fig. 70, p. 702) 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; * but it cannot be supposed that they have been
developed merely for the sake of exciting fear in their en-
emies. 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 forelegs 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 be-
lieve that this mantle is of the least use to the male, in whom
it is much more developed than in the female.

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.'’® 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 it is so small at other times that it may be
called rudimentary.’* With some monkeys the beard is con-
fined to the male, as in the orang; or is much larger in the
male than in the female, as in the Mycetes caraya and Pi-
thecia satanas (Fig. 68). So it is with the whiskers of some

18 Dr. Gray, ‘‘Gleanings from the Menagerie at Knowsley,”’ pl. 28.

4 Judge Caton on the Wapiti, “‘Transact. Ottawa Acad. Nat. Sciences, ’’
1868, pp. 36, 40; Blyth, ‘‘lLand and Water,’ on Capra egagrus, 1864,

3

. BT. :
P 18 “*Funter’s Essays and Observations,’ edited by Owen, 1861, vol. i.

. 236,
a See Dr. Gray’s “Cat. of Mammalia in British Museum,” part iii, 1852,
p. 144,

SEXUAL SELECTION 687

species of Macacus,"’ and, as we have seen, with the manes
of some species of baboons. But with most kinds of mon-
keys the various tufts of hair about the face and head are
alike in both sexes.

The males of various members of the ox family (Bovi-
dee) and of certain antelopes are furnished with a dewlap,

Fia. 68.—Pithecia satanas, male (from Brehm),

or great fold of skin on-the neck, which is much less devel-
oped 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 dewlap 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

11 Rengger, ‘‘Saugethiere,’’ etc., s. 14; Desmarest, ‘‘Mammalogie,’’ p. 66.

688 THE DESCENT OF MAN

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 prob-
able that the beard has been developed for a distinct pur-
pose from that served by the whiskers, mustache, 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 ap-
pendages 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, ap-
parently not derived through reversion from any wild
parent-form, are confined to the males, or are more de-
veloped 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 hindlegs, and the dewlap of the male
of the Berbura goat.’* 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 shown in my work
on ‘‘Variation Under Domestication,’’ in concluding that
any character, even with animals kept by semi-civilized
people, has not been subjected to selection by man, and
thus augmented, yet in the cases just specified this is im-
probable; 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

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-civilized people. For the Berbura goat, see Dr. .
Gray, ‘‘Catalogue,’’ ibid., p. 157.

SEXUAL SELECTION 689

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 develop-
ment of hair on the throat and forelegs of the male Am-
motragus, 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 colored than the female, and with
those monkeys in which the hair on the face is elegantly
arranged and colored 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 natural-
ists. 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 mam-
mals is doubtful.

Color of the Hair and of the Naked Shkin.—I will first give
briefly all the cases known to me of male quadrupeds differ-
ing in color from the females. With Marsupials, as I am
informed by Mr. Gould, the sexes rarely differ in this re-
spect; but the great red kangaroo offers a striking excep-

tion, ‘‘delicate blue being the prevailing tint in those parts
of the female which in the male are red.’’® In the Didel-
phis opossum of Cayenne the female is said to be a little
more red than the male. Of the Rodents Dr. Gray re-
marks: ‘‘ 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

18 Osphranter rufus, Gould, ‘‘Mammals of Australia,’’ 1863, vol. ii, On
the Didelphis, Desmarest, ‘‘Mammalogie,’’ p. 256.

690 THE DESCENT OF MAN

the male is generally brighter than that of the female.’ ”
Dr. Gray informs me that he specified the African squirrels,
because, from their unusually bright colors, 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.”
Mr. Dobson also remarks, with. respect to these animals:
‘Differences, depending partly or entirely on the posses-
sion 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 bear-
ing on the question whether bright colors are serviceable
to male animals from beiag 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
color, 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 color. The ocelot
(Felis pardalis), however, is exceptional, for the colors of
the female, compared with those of the male, are ‘‘moins
apparentes, le fauve étant plus terne, le blanc moins pur,
les raies ayant moins de largeur et les taches moins de di-
amétre.’’*? The sexes of the allied Felis mitis also differ,
but ina 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, some-

20 “Annals and Mag. of Nat. Hist.,’’ Nov. 186%, p. 325. On the Mus
minutus, Desmarest, ‘‘Mammalogie,’’ p. 304.

a J. A, Allen, in ‘‘Bulletin of Mus. Comp. Zgolog. of Cambridge, United
States,’? 1869, p. 207. Mr. Dobson on sexual characters in the Chiroptera,
“Proc. Zoolog. Soc.,”? 1873, p. 241. Dr. Gray on Sloths, ibid., 1871, p. 436.

2 Desmarest, ‘‘Mammalogie,’’ 1820, p. 220. On Felis mitis, Rengger,
ibid., s. 194.

SEXUAL SELECTION 691

times differ considerably in color, 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; while the
female, who acquires her adult tints earlier in life than
the male, is dark gray above, the young of both sexes
being of a deep chocolate color. The male of the north-
ern Phoca groenlandica is tawny gray, 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-color, 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
color thus acting as a protection.”’ **

With Ruminants sexual differences of color 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 gray 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 devel-
oped in the male than in the hornless female. I am in-
formed by Mr. Blyth that the male, without shedding his
hair, periodically becomes darker during the breeding sea-
son. 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 color. The importance of this
latter fact, as evidence that the coloring of the Portax is
of sexual origin, becomes obvious, when we hear that
neither the red summer-coat nor the blue winter-coat of

98 Dr, Murie on the Otaria, ‘“‘Proc. Zool. Soc.,’”? 1869, p. 108. Mr. R.
Brown, on the P. groenlandica, ibid., 1868, p. 417. See, also, on the colors
of seals, Desmarest, ibid., pp. 243, 249.

* Judge Caton, in dePransactions of the Ottawa Academy of Natural

Sciences, ’’ 1868, p. 4 ,

692 THE DESCENT OF MAN

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
erests 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 colors broader than in the female.
In the Cape eland, also, the male is slightly darker than
the female.” =

In the Indian black-buck (A. bezoartica), which belongs
to another tribe of antelopes, the male is very dark, almost
black; while the hornless female is fawn-colored. 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 color during the breeding sea- ©
son, 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 colored than the horn-
less female, and his chest and belly are blacker; in the
male A. caama, the marks and lines which occur on vari-
ous parts of the body are black, instead of brown, as in
the female; in the brindled gnu (A. gorgon) ‘‘the colors
of the male are nearly the same as those of the female,
only deeper, and of a brighter hue.’’** Other analogous
cases could be added.

The Banteng bull (Bos sondaicus) of the Malayan Archi-

%® 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 8. Africa,”?
pl. 41 and 42. There are also many of these antelopes in the Zoological
Gardens.

28 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 color, see
Sir 8. Baker, ‘“‘The Albert Nyanza,’’ 1866, vol. ii. p. 32%. For the A. sing-
sing, Gray, ‘‘Cat. B. Mus.”’ p. 100. Desmarest, ‘‘Mammalogie,”? p. 468, on
the A. caama. Andrew Smith, ‘‘Zoology of 8. Africa,’’ on the Gnu,

SEXUAL SELECTION 693

pelago 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 color.
The emasculated bull reverts to the color of the female.
The female Kemas goat is paler, and both it and the
female Capra egagrus are said to be more uniformly tinted
than their males. Deer rarely present any sexual differ-
ences in color. 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 color, 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 plu-
mage.” The females of Cervus paludosus of South 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.®
Lastly, as I am informed by Mr. Blyth, the mature male
of the beautifully colored: and spotted axis deer is consid-
erably 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, while the female is brown.” Of the Quadru-
mana of the New World, the females and young of Mycetes

x

% “Ottawa Academy of Sciences,’? May 21, 1868, pp. 3, 5.

%3 §, Miller, on the Banteng, ‘‘Zoog. Indischen Archipel.,’? 1839-44, tab.
35; see, also, Raffles, as quoted by Mr. Blyth, in ‘Land and Water,’’ 1867,
p. 476. On goats, Dr. Gray, ‘Cat. a —, Pp. eit ere ‘*Mam-
malogie,”’ p. 483. On the Cervus paludosus, r, ibid., 5. 346.

bd Sake, Bron Zool. Boc.,”” 1866, p. 1. The same fact has also been
fully ascertained by MM. Pollen and Van Dam. See, also, Dr. Gray in ‘‘An-
nals and Mag. of Nat. Hist.,’? May, 1871, p. 340.

Descent—Vot. I.—12

694 THE DESCENT OF MAN

caraya are grayish 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 color between the
sexes of Mycetes seniculus and Cebus capucinus; the young
of the former, and I believe of the latter species, resem-
bling 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. Turn-
ing 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. In
the beautiful Cercopithecus diana, the head of the adult
male is of an intense black, while that of the female
is dark gray; in the former the fur between the thighs is
of an elegant fawn-color, in the latter it is paler. In
the beautiful and curious mustache monkey (Cercopithecus
cephas) the only difference between the sexes is that the
tail of the male is chestnut and that of the female gray;
but Mr. Bartlett informs me that all the hues become more
pronounced in the male when adult, while in the female -
they remain as they were during youth. According to
the colored figures given by Solomon Muller, the male of
Semnopithecus chrysomelas is nearly black, the female being
pale brown. In the Cercopithecus cynosurus and griseovi-
ridis 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.

3 On Mycetes, Rengger, ibid., s. 14; and Brehm, ‘‘Illustrirtes Thierleben,”’
B. i. s. 96, 107. On Ateles, Desmarest, “‘Mammalogie,” p. 75. On Hylobates,
Blyth, “Land and Water,” 1867, p. 135. On the Semnopithecus, 8. Miller,
“Zoog. Indischen Archipel., ” tab, x,

SEXUAL SELECTION 695

_ Lastly, in the baboon family, the adult male pf Cyne-
cephalus hamadryas differs from the female not only by
his immense mane, but slightly in the color of the hair and
of the naked callosities. In the drill (C. leucopheus) the
females and young are much paler colored, with less green,
than the adult males. No other member in the whole class
of mammals is colored in so extraordinary a manner as the
adult male mandrill (C. mormon). The face at this age be-
comes 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 colors appear to be variable. On the
forehead there is a crest of hair, and on the chin a yellow
beard. ‘‘Toutes les parties supérieures de leurs cuisses et
le grand espace nu de leurs fesses sont également colorés du
rouge le plus vif, avec un mélange de bleu qui ne manque
réellement pas d’élégance.’’?* When the animal is excited
all the naked parts become much more vividly tinted. Sev-
eral authors have used the strongest expressions in describ-
ing these resplendent colors, which they compare with those
of the most brilliant birds. Another remarkable peculiarity
is that when the great canine teeth are fully developed, im-
mense protuberances of bone are formed on each cheek,
which are deeply furrowed longitudinally, and the naked
skin over them is brilliantly colored, 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 colored, the face being
almost black, tinged with blue. In the adult female, how-
ever, 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 colored than the female, and differs from the

31 Gervais, ‘Hist. Nat des Mammiféres,’’ 1854, p. 103. Figures are given
of the skull of the male. Also Desmarest, ‘‘Mammalogie,”’ p. 10. Geoffroy
8t.-Hilaire and F. Cuvier, ‘“Hist. Nat. des Mamm.,’’ 1824, tom. i. F

696 THE DESCENT OF MAN

young of both sexes. But as with some few birds it is
the female which is brighter colored than the male, so with
the Rhesus monkey (Jacacus 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 Zoologi-
cal Gardens, periodically becomes even yet more vivid, and

Fra. 69.—Head of male Mandrill (from Gervais, ‘Hist. Nat. des Mammiféres”),

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 Gar-
dens), neither the naked skin at the posterior end of the
body, nor the face, shows a trace of red. It appears, how-
ever, 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

SEXUAL SELECTION 697

female, yet in the larger size of his body, larger canine
teeth, more developed whiskers, more prominent supercili-
ary ridges, he follows the common rule of the male excelling
the female.

T have now given all the cases known to me of a ditfer-
ence in color between the sexes of mammals. Some of these
may be the result of variations confined to one sex and trans-
mitted 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, while the females are tortoise-
shell colored. Analogous cases occur in nature: Mr. Bart-
lett 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 possi-
ble that with some mammals a difference in color between
the sexes, especially when this is congenital, may simply be
the result, without the aid of selection, of the cccurrence
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 colors of certain
quadrupeds, for instance, of the above monkeys and ante-
lopes, can thus be accounted for. We should bear in mind
that these colors 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 colors and other orna-
mental 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 color between the sexes —
occurring almost exclusively, as may be collected from the
previous details, in those groups and sub-groups of mam-
mals which present other and strongly marked second-

698 - THE DESCENT OF MAN

ary sexual characters; these being likewise due to sexual
selection.

Quadrupeds manifestly take notice of color. SirS. Baker
repeatedly observed that the African elephant and rhinoc-
eros attacked white or gray horses with special fury. I
have elsewhere shown” that half-wild horses apparently
prefer to pair with those of the same color, and that herds
of fallow-deer of different colors, 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 color,
which had so strong an effect as to get the better of every-
thing else. But the male did not require this; the female
being an animal somewhat similar to himself was sufficient
to rouse him.” *

In an earlier chapter we have seen that the mental powers
of the higher animals do ngt 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’ “—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 colored face from having been thus rendered attrac-
tive to the female. No doubt it is to us a most grotesque
notion that the posterior end of the body should be colored

8 “The Variation of Animals and Plants under Domestication,” 1868,
vol. ii. pp. 102, 103. ;

33 **Hssays and Observations by J. Hunter,’’ edited by Owen, 1861, vol. i,
p. 194.

Sir S, Baker, ‘‘The Nile Tributaries of Abyssinia,’’ 1867.

SEXUAL SELECTION 699

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 favor of the belief that the females admire, or are excited
by, the ornaments and colors 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 orna-
mental appendages, and in their colors. In both classes,
when the male differs from the female, the young of both
sexes almost always resemble each other, and in a large ma-
jority 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
color 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. colored 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 odor-
iferous 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 individ-
uals of the opposite sex, combined with their success in
leaving a larger number of offspring to inherit their supe-
rior attractions.

700 THE DESCENT OF MAN

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 inquire how far this view applies to mam-
mals. With a considerable number of species, especially
of the smaller kinds, both sexes have been colored, inde-
pendently 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. Audu-
bon remarks that he often mistook the muskrat,** while
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 color; 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 favor their stealing
on their prey. In regions where snow never lies for long a
white coat would be injurious; consequently, species of this
color 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® states that in Siberia a change of
this nature occurs with the wolf, two species of Mustela,
the domestic horse, the Hquus 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
grayish-white winter coat; and the latter may perhaps serve

35 Fiber xzibethicus, Audubon and Bachman, ‘‘The Quadrupeds of N.
America,’’ 1846, p. 109.

36 “Novas species Quadrupedum e Glirium ordine,”? 1778, p. 7. What I
have called the roe is the Capreolus sibiricus subecaudatus of Pallas,

SEXUAL SELECTION 701

as a protection to the animal while wandering through the
leafless thickets, sprinkled with snow and hoarfrost. If the
above-named animals were gradually to extend their range
into regions perpetually covered with snow, their pale win-
ter coats would probably be rendered, through natural selec-
tion, 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 colored. 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 col-
ored 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 party-
colored brethren. The result was that, within eighteen
months, every one of these party-colored rabbits was
destroyed; and there was evidence that this was effected
by the cats. Color 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 volun-
tarily. attack one of these creatures, on account of the
dreadful odor which it emits when irritated; but during
the dusk it would not easily be recognized, and might be
attacked by a beast of prey. Hence it is, as Mr. Belt be-
lieves,*” that the skunk is provided with a great white
bushy tail, which serves as a conspicuous warning.
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 colors
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

31 “The Naturalist in Nicaragua,’’ p. 249.

702 THE DESCENT OF MAN

female; when we see that the colors 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 gimilar ditf-
ference between the sexes of the curiously ornamented
Zragelaphus scriptus (Fig. 70), we cannot believe that dif-

Fie. 70.--Tragelaphus scriptus, male (from the Knowsley Menagerie).

ferences 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 colors intensified through sexual selection,
and then partially transferred to the females. If this view
be admitted, there can be little doubt that the equally sin-

~~

SEXUAL SELECTION 703

gular colors and marks of many other antelopes, though
common to both sexes, have been gained and transmitted
ina 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 colored; in D. pygarga the back and neck are pur-

Fia. 71.—Damalis pygarga, male (from the Knowsley Menagerie).

plish red, shading on the flanks into black; and these
colors are abruptly separated from the white belly and
from a large white space on the buttocks; the head is
still more oddly colored, a large oblong white mask, nar-
rowly 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 Da-

704 THE DESCENT OF MAN

malis albifrons the coloring of the head differs from that
in the last species in a single white stripe replacing tho
three stripes, and in the ears being almost wholly white.”
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 colors of
many antelopes, though common to both sexes, are the re-
sult 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 color, even by
the dealers in wild beasts. Mr. Wallace believes® that
the striped coat of the tiger ‘‘so assimilates with the ver-
tical 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 colors are rather
brighter in the male than in the female. The zebra is con-
spicuously striped, and stripes cannot afford any protection
on the open plains of South Africa. Burchell, in describ-
ing 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 Equide the sexes are
identical in color, 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 ani-
mals belonging to any class follow nearly the same habits of

8 See the fine plates in A. Smith’s, “Zoology of 8. Africa,”’ and Dr. Gray’s
‘Gleanings from the Menagerie of Knowsley.”

%® “Westminster Review,” July 1, 1867, p. 5

# “Travels in South Africa, ?? 1824, vol. ii. p. "315.

SEXUAL SELECTION 705

life as their parents, and yet are colored in a different man-
ner, it may be inferred that they have retained the coloring
of some ancient and extinct progenitor. In the family of
pigs, and in the tapirs, the young are marked with longi-
tudinal 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 fol-
lowed from the axis deer, both sexes of which at all ages
and during all seasons are beautifully spotted (the male
being rather more strongly colored 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 Mant-
churian 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 color of the coat is lighter, than during the winter,
when the general color 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 win-
ter, when the coat is brown.*’ 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 cer-
tain species. From the existence of this perfect series, and

41 Dr. Gray, ‘‘Gleanings from the Menagerie of Knowsley,”’ p. 64. Mr.
Blyth, in speaking (‘‘Land and Water,’’ 1869, p. 242) of the hog-deer of Cey-
Jon, says it is more brightly spotted with white than the common hog-deer, at
the season when it renews its horns.

706 THE DESCENT OF MAN

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 sea-
sons. <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.”

A curious difficulty here arises. If we admit that col-
ored 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 orna-
ments? 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 Miiller has suggested to me that these ani-
mals, by the removal of their spots or stripes through
natural selection, would have been less easily seen by

#2 Falconer and Cautley, ‘‘Proc. Geolog. Soc.,’? 1843; and Falconer’s
“Pal. Memoirs,’’ vol. §. p. 196.

SEXUAL SELECTION 707

their enemies, and that they would have especially re-
quired 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, gray, 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-colored kinds, have stripes on any part of their
bodies, yet we have good reason to believe that the aborig-
inal horse was striped on the legs and spine, and probably
on the shoulders.“ 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 color 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 illus-
trates our ignorance of the laws which regulate the appear-
ance and disappearance of stripes; the species of Asinus
which inhabit the Asiatic continent are destitute of stripes,
not having even the cross shoulder-stripe, while those which
inhabit Africa are conspicuously striped, with the partial
exception of A. teniopus, which has only the cross shoul-
der-stripe and generally’ some faint bars on the legs; and
this species inhabits the almost intermediate region of
Upper Egypt and Abyssinia.**

Quadrumana.—Before we conclude, it will be well to
add a few remarks on the ornaments of monkeys. In most

48 “The Variation of Animals and Plants under Domestication,’’ 1868, vol,
i. pp. 61-64 ,

%4 “Proe, Zoolog. Soc.,”? 1862, p. 164. See, also, Dr. Hartmann, *‘Ann.
d. Landw.,’’ Bd, xliii, 5, 222.

708 : THE DESCENT OF MAN

of the species the sexes resemble each other in color, but
in some, as we have seen, the males differ from the females,
especially in the color of the naked parts of the skin, in the
development of the beard, whiskers, and mane. Many spe-
cies are colored 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

"Wile YY)
WO GTO

Fia. 72.—Head of Semnopithecus rubicundus. This and the following figures
(from Prof. Gervais) are given to show the odd arrangement
and development of the hair on the head.

characters as having been gained for the sake of ornament.
The accompanying figures (Figs. 72 to 76) serve to show the
arrangement of the hair on the face and head in several spe-
cies. It is scarcely conceivable that these crests of hair, and
the strongly contrasted colors of the fur and skin, can be the
result of mere variability without the aid of selection; and
it 1s inconceivable that they can be of use in any ordi-

SEXUAL SELECTION 709

nary 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

Fie. 75.—Head of Ateles marginatus, Fie. 76.—Head of Cebus vellerosus,

males, and in the greater development of their canine teeth,
in comparison with the females.

A few instances will suffice of the strange manner in which
both sexes of some species are colored, and of the beauty of
others. The face of the Cercopithecus petaurista (Vig. 77) is
black, the whiskers and beard being white, with a defined,
round white spot on the nose, covered with short white hair,

710 THE DESCENT OF MAN

which gives to the animal an almost ludicrous aspect. The
Semnopithecus frontatus likewise has a blackish face with a

Fie. 77.—Cercopithecus petaurista (from Brehm).

long black beard, and a large naked spot on the forehead of
a bluish white color. The face of Macacus lasiotus is dirty
flesh-colored, with a defined red spot on each cheek. The

SEXUAL SELECTION 711

appearance of Cercocebus ethiops 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 color from the rest of the head, and, when
different, are always of a lighter tint,** 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 color does not appear until the animal
is nearly mature.*® The naked skin of the face differs won-
derfully in color in the various species. It is often brown
or flesh-color, with parts perfectly white, and often as black
as that of the most sooty negro. Inthe Brachyurus the scar-
let 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 gray. In all the species known to Mr. Bartlett, in
which the adults of both sexes have strongly colored faces,
the colors are dull or absent during early youth. This like-
wise holds good with the mandrill and Rhesus, in which the
face and the posterior parts of the body are brilliantly col-
ored in one sex alone. In these latter cases we have reason
to believe that the colors were acquired through sexual se-
lection; and we-are naturally led to extend the same view
to the foregoing species, though both sexes when adult have
their faces colored in the same manner.

Although many kinds of monkeys are far from beautiful
according to our taste, other species are universally admired
for their elegant appearance and bright colors. The Semno-
pithecus nemeus, though peculiarly colored, 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

* T observed this fact in the Zoological Society’s Gardens; and many cases
may be seen in the colored plates in Geoffroy St. Hilaire and F. Cuvier, ‘'His-
toire Naturel des Mammiféres,’’ tom. i., 1824.

4 Bates, ‘“‘The Naturalist on the Amazons,’’ 1863, vol. ii. p. 310,

712 THE DESCENT OF MAN

gray, 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 differ-
ences in color, which renders it in some degree probable that

SRS ce NS | a = Sy

Fia. 78.—Cercopithecus diana (from Brehm).

both sexes owe their elegant appearance to sexual selection.
In the mustache-monkey (Cercopithecus cephus) the general
color 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
gray, shading into a blackish tint beneath the eyes, with

SEXUAL SELECTION 713

the upper lip of a delicate blue, clothed on the lower edge
with a thin black mustache; the whiskers are orange colored,
with the upper part black, forming a band which extends
backward 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
color of the fur is gray; 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 deli-
cate fawn colored, 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.‘

In these and many other monkeys, the beauty and singu-
lar arrangement of their colors, and still more the diversi-
fied 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 de-
pend 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.

47 T have seen most of the above monkeys in the Zoological Society’s Gar-
dens. The description of the Semnopithecus nemeus is taken from Mr. W. 0.
Martin’s ‘‘Nat. Hist. of Mammalia,” 1841, p. 460; see, also, pp. 475, 523,

714 THE DESCENT OF MAN

There is another and more peaceful kind of contest, in
which the males endeavor to excite or allure the females
by various charms. This is probably carried on in some
cases by the powerful odors emitted by the males during
the breeding season, the odorifercus glands having been ac-
quired 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 trans-
mitted 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 sus-
pect 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 color from the female, he gen-
erally 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 colored in some species. The colors
of the male in other cases may be due to simple variation,
without the aid of selection. But when the colors are diver-
sified and strongly pronounced, when they are not developed
until near maturity, and when they are lost after emascula-
tion, 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 exclu-
sively, to the same sex. When both sexes are colored in
the same manner, and the colors are conspicuous or curi-
ously arranged, without being of the least apparent use as
® protection, and especially when they are associated with

SEXUAL SELECTION 715

various other ornamental appendages, we are led by anal-
ogy to the same conclusion, namely, that they have been
acquired through sexual selection, although transmitted
to both sexes. That conspicuous and diversified colors,
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 equal transmission of characters to both
sexes, as far as color 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 ser-
vice to the females. As far as we can see, their absence in
shis sex can be accounted for only by the form of inheri-
tance 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 modi-
fied through sexual selection, far more commonly than the
_ females, either for fighting with each other or for alluring
the opposite sex.

PART THREE

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

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,’ 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 pow-
erful 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

We mankind the differences between the sexes are

1 Schaaffhausen, translation in ‘‘Anthropological Review,”’ Oct. 1868, pp.
419, 420, 427, .

(716)

SEXUAL SELECTION IN RELATION FO MAN 717

color of half-roasted coffee.”’* As the women labor in the
fields and are quite unclothed, it is not likely that they
differ in color from the men owing to less exposure to the
weather. European women are perhaps the brighter col-
ored of the two sexes, as may be seen when both have
Boon equally exposed.

Man is more courageous, pugnacious, and energetic than
| woman, and has a more inventive genius, His brain is ab-
' solutely 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;?
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 distinc-
tive 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 varia-
tions 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,
ultimateiy assumes certain distinctive characters, and in the
formation of her skull is said to be intermediate between
the child and the man.‘ Again, as the young of closely

* “The Heart of Africa,’? English transl., 1873, vol. i. p. 5

8 Heker, translation in “Anthropol logical "Review, »” Oct. 1368, pp. 351-356.
The comparison of the form of the skull in men and women has been followed
out with much care by Welcker.

* Ecker and Welcker, ibid., pp. 352, 365; Vogt, “‘Lectures on Man,” Eng.
tranelat., p 81.

Descent—Vou. I1.—13

“718 ‘| THE DESCENT OF MAN

fa

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.* In regard to color, the newborn negro child is red-
dish nut-brown, which soon becomes slaty gray; the black
color 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.®

I have specified the foregoing differences between the
male and female sex in mankind, because they are curi-
ously 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 the Cebus azare."| 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,® and agree in this respect
with mankind. In the gorilla and certain other monkeys,
the cranium of the adult male presents a strongly marked

5 Schaaffhausen, ‘‘Anthropolog. Review,” ibid., p. 429.

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,” ete.,
1822, p. 451. For the infants of the Guaranys, see Rengger, ‘‘Sdugethiere,’?’
etc., 8. 3. See, also, Godron, ‘‘De l’Espéce,’’ tom. ii., 1859, p. 253. For the
Australians, Waitz, ‘‘Introduct. to Anthropology,’’ Eng. translat:, 1863, p. 99.

1 Rengger, ‘‘Sdugethiere,’’ etc., 1830, s. 49.

8 As the Macacus cynomolgus (Desmarest, ‘‘Mammalogie,’’ p. 65) and in
Hylobates agitis (Geoffroy St.-Hilaire and F. Cuvier, ‘‘Hist. Nat. des Mamm.,’?
1824, tom. i. p. 2).

SEXUAL SELECTION IN RELATION TO MAN 72)

sagittal crest, which is absent in the female; ‘stu “Wicker
found a trace of a similar difference between the two sexes
in the Australians.° With monkeys, when there is any dif-
ference 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 de-
veloped in the female. No instance is known of the beard,
whiskers, or mustache being larger in the female than in
the male monkey. Even in the color of the beard there
is a curious parallelism between man and the Quadrumana,
for with man, when the beard differs in color from the hair
of the head, as is commonly the case, it is, I believe, al-
most always of a lighter tint, being often reddish. I have
repeatedly observed this fact in England; but two gentle-
men 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 color 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 excep-
tions 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 in Sikhim, the Bhoteas, Hindus, Burmese and
Chinese, most of which races have very little hair on the
face; and he always found that when there was any differ-
ence in color 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 strik-
ingly in color from the hair of the head, and in such eases
it is always of a lighter hue, being often pure white, some-
times yellow or reddish.”

% “‘Anthropolog. Rev.,’? Oct. 1868, p. 358,
10 Mr. Blyth informs me that he has only seen one instance of the beard,

“718 THE DESCENT OF MAN

In répzrd 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." 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 be-
tween the sexes, as in the size of the canine teeth, in the
development and color of the hair, and especially in the
color 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 ex-
cellent observations made on board the ‘‘Novara’’ * the male
Australians were found to exceed the females by only 65
millimetres in height, while with the Javans the average
excess was 218 millimetres; 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 backbone and of the arms,
in various races; and nearly all these measurements show

whiskers, etc., in a monkey becoming white with old age, as is so commonly the
ease with us. This, however, occurred in an aged Macacus cynomolgus kept
in confinement, whose mustaches 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 nicknamed. In
certain races of man the hair on the head hardly ever becomes gray; thus Mr.
D. Forbes has never, as he informs me, seen an instance with the Aymarus and
Quichuas of 8. America.

i This is the case with the females of severat 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.

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, 38. 216, 231, 234, 236, 239, 269.

\

\

SEXUAL SELECTION IN RELATION YO MAN 721

that the males differ much more from one another than do
the females. This fact indicates that, as far as these char-
acters are concerned, it is the male which has been chiefly
modified, since the several races diverged from their com-
mon 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 among ourselves. In the Island of
St. Kilda, according to Martin,’ the men do not acquire
beards until the age of thirty or upward, and even then
the beards are very thin. On the Huropxo-Asiatic conti-
nent, 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."* Eastward of India
beards disappear, as with the Siamese, Malays, Kalmucks,

hinese and Japanese; nevertheless the Ainos,’* who in-
(sn 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.”
On the other hand, the Papuans of the Malay Archipelago,
who are nearly as black as negroes, possess well-developed
beards." In the Pacific Ocean the inhabitants of the Fiji
Archipelago have large bushy beards, while those of the
not distant archipelagoes of Tonga and Samoa are beard-
less; 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 splen-

18 “Voyage to St. Kilda,’’ 3d edit., 1753, p. 37.

% Sir J. EH. Tennent, ‘‘Ceylon,’’ vol. ii., 1859, p. 107.

15 Quatrefages, ‘‘Revue des Cours Scientifiques,’? Aug. 29, 1868, p. 6303
Vogt, ‘Lectures on Man,’’ Eng. translat., p. 127.

18 On the beards of negroes, Vogt, ‘‘Lectures,’’ ete., p. 127; Waitz, ‘‘Tntro-
duct. to Anthropology,’ Eng. translat., 1863, vol. i p. 96. It is remarkable
that in the United States (“Investigations in Military and Anthropological Sta-
tistics of American Soldiers,’? 1869, p. 569) the pure negroes and their crossed
offspring seem to have bodies almost as hairy as Europeans.

11 Wallaca ‘‘The Malay Arch.,’’ vol. ii., 1869, p. 178.

,

722 THE DESCENT OF MAN

did beards’’; while on the other islands ‘‘they have, as a
rule, a dozen straggling hairs for a beard.’’

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 whis-
kers.** 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 Huropeans, 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 North 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.” This fact
is analogous with what occurs with some closely allied mon-
keys; thus the sexes of the chimpanzee are not as different
as those of the orang or gorilla.”

In the previous chapters we have seen that with mam-

18 Dr. J. Barnard Davis, On Oceanic Races, in ‘‘Anthropolog. Review,’’
April, 1870, pp. 185, 191.

bd Catlin, “North American Indians,” 3d edit., 1842, vol. ii. p. 22%. On the
Guaranys, see Azara, ‘‘Voyage dans |’ Amérique Mérid., ”? tom. ii., 1809, p. 58;
also Rengger, “‘ Saugethiere von Paraguay,” 8. 3.

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
nigher races, See, also, Rengger, ibid., p. 3, on the Guaranys.

1 Riitimeyer, “Die Grenzen der Thierwelt; eine Betrachtung'zu Darwin’s
Lehre,”? 1868, s, 54.

SEXUAL SELECTION IN RELATION hae) MAN 798

mals, birds, fishes, insects, ete., Many Sharacters, which
there is every reason to believe werg primarily gained
through sexual ‘selection by one se% have been trans-
ferred to the othen._ As this sarjg° form of transmission
has apparently elie With mankind, it will save
useless repetition if we discuss the origin of characters
peculiar to the male sex together with certain other char-
acters common to both sexes.

Law of Battle.—With savages, for instance the Austra-
lians, 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,” 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,” that the law of
battle had prevailed with man during the early stages of

22 **A4 Journey from Priace of Wales Fort,”’ 8vo. edit. Dublin, 1796, p. 104.
Sir J. Lubbock (‘‘Origin of Civilization,’ 1870, p. 69) gives other and similar
cases in North America. For the Guanas of S. America, see Azara, ‘‘Voyages,”’
etc., tom. ii, p. 94, .

23 On the fighting of the male gorillas, see Dr. Savage, in “Boston Journal
of Nat. Hist.,’” vol. v., 1847, p. 423. On Presbytis entellus, see the ‘Indian
Field,”? 1859, p. 146.

724 \ THE DESCENT OF MAN
,

= development” The occasional appearance at the p1
ent day of canit® teeth which project above the othe
with traces of a di$tema or open space.for the recept
of the opposite canines).!8 in all probe/bility a case of
version to a former state, when t Ogenitors of man w
provided with these weapons,” like so many existing m
Quadrumana. It was remarked in a former chapter that
man gradually became erect, and continually used his hai
and arms for fighting with sticks and stones, as well as
the other purposes of life, he would have used his jaws ¢
teeth less and less. The jaws, together with their muscl
would then have been reduced through disuse, as would -
teeth through the not well understood principles of corre
tion and economy of growth; for we everywhere see t.
parts which are no longer of service are reduced in si
By such steps the original inequality between the jaws a
teeth in the two sexes of mankind would ultimately he
been obliterated. The case is almost parallel with that
many male Ruminants in which the canine teeth have be
reduced to mere rudiments or have disappeared, apparen
in consequence of the development of horns. As the p
digious difference between the skulls of the two sexes
the orang and gorilla stands in close relation with the «
velopment of the immense canine teeth in the males,
may infer that the reduction of the jaws and teeth in {
early male progenitors of man must have led to a m
striking and favorable change in his appearance.
There can be little doubt that the greater size a
strength of man, in comparison with woman, together w:
his broader shoulders, more developed muscles, rugged o
line of body, his greater courage and pugnacity, are all d
in chief part to inheritance from his half-human male anc
tors. These characters would, however, have been preserv
or even augmented during the long ages of man’s savagei
by the success of the strongest and boldest men, both in t
general struggle for life and in their contests for wives:
success which would have insured their leaving a mc

SEXUAL SELECTION IN RET ATION TO MAN 727

numerous progeny than their legs favored brethren. It is
not probable that the greater st’sngth 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 com-
pelled to work at least as hard as the men. With civilized
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.

Differences 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 im-
portant part. Iam 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 pre-
sent 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 shown 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 to-
ward her infants in an eminent degree; therefore it is likely
that she would often extend them toward her fellow-creat-
ures. Man is the rival of other men; he delights in com-
petition, and this leads to ambition which passes too easily
into selfishness. These latter qualities seem to be his nat-
ural and unfortunate birthright. It is generally admitted
that with woman the powers of intuition, of rapid percep-
tion, and perhaps of imitation, are more strongly marked
than in man; but some, at least, of these faculties are char-

& THE DESCENT OF MAN

acteristic of the lower races, and therefore of a past and
lower state of civilization.
The chief distinction in the intellectual powers of the
two sexes is shown by man’s attaining to a higher emi-
i nence, 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, sculp-
_ ture, 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 compari-
son. 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.

Among the half-human progenitors of man and among
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 deter-
mined 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 ani-
mals, and to fashion weapons, requires the aid of the higher

ae 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.

SEXUAL SELECTION IR RELATION TO MAN 1727
2

\ X Now, when two men are #iw into competition, or a man
| with a woman, both possessed of every mental quality in
equal perfection, save that one has higher energy, perse-
verance, and courage, the latter will generally become more
eminent in every pursuit, and will gain the ascendency.**
He may be said to possess genius—for genius has been de-
clared by a great authority to be patience; and patience,
in this conse, imeina unlinching, undaunted persoverance,
ut this view of genius is perhaps deficient; for without
the higher powers of the imagination and reason, no emi-
nent 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 selec-
tion—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 modifi-
cation and reinforcement of many of our mental faculties
by sexual selection, that, first, they notoriously undergo
a considerable change at puberty, and, secondly, that
eunuchs remain throughout life inferior in these same
qualities. Thus man has ultimately become superior to
ie woman. It is, indeed, fortunate that the law of the equal
transmission of Clinracters to both sexes prevails with mam-
mals; 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

4 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 Jong hammering at single thoughts.”” What is this but energy and per-
severance ?

35 Maudsley, ‘‘Mind and Body,” p. 31.

728 THE DESQENT OF MAN

to be transmitted to both &,xe8, are rales 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 train-
ing. 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 im-
agination exercised to the highest point; and then she would
probably transmit these qualities chiefly to her adult daugh-
ters. 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 fami-
lies; and this will tend to keep up or even increase their
mental powers, and, as a consequence, the present inequal-
ity between the sexes.”

“Voice and Musical Powers.—In some species of Quadru-
mana 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 dif-
ference from his early progenitors. His vocal cords are |
about one-third longer than in woman, or than in boys;

% An observation by Vogt bears on this subject; he says, *‘It is a remark-
able 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.

SEXUAL SELECTION IN RELATION TO MAN 129

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.’’ * 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

ae sg ager caren According to Sir Duncan Gibb,*
the voice an m 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 con-
structed 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 ;* 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 ap-
paratus 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

—

% Owen, ‘Anatomy of Vertebrates,’’ vol. iii. p. 603.

% “Journal of the Anthropolog. Soc.,”’ April, 1869, pp. Ivii. and Ixvi.

% Dr. Scudder, ““Notes on Stridulation,”’ in ‘‘Proc. Boston Soc. of Nat.
Hist.,’’ vol. xi, April, 1868. :

730 THE DESCENT OF MAN

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 breed-
ing 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 fe-
male, either permanently or temporarily, during the breed
ing 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 Ameri-
can 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:
“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

® Given in W. ©. L. Martin’s ‘General Introduct. to Nat. History of Mamm.
Animals,”’ 1841, p. 432; Owen, ‘‘Anatomy of Vertebrates,’’ vol. iii. p. 600.

SEXUAL SELECTION IN RELATION TO MAN 782

not doubt that a good violinist would be able to give a cor-
rect idea of the gibbon’s composition, excepting as regards
its loudness.’’ Mr. Waterhouse then gives the notes. Prof.
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 hab-
its 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 while singing a ca-
dence 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. Lock-
wood,” 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 fre-
quently 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 a while, and wind up
with a quick chirp on C sharp and D. The distinctness
between the semitones was very marked, and easily appre-
ciable to a good ear.’’ Mr. Lockwood gives both songs in
musical notation; and adds that though this little mouse
‘thad no ear for time, yet she would keep to the key of B
(two flats) and strictly ina major key. ... Her soft clear
voice falls an octave with all the precision possible; then, at

% The “*American Naturalist,’? 1872, p. 761.

732 THE DESCENT OF MAN

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 shows some confusion on the subject; a noise is
the sensation resulting from the coexistence of several aérial
‘‘simple vibrations’’ of various periods, each of which inter-
mits so frequently that its separate existence cannot be per-
ceived. It is only in the want of continuity of such vibra-
tions, and in their want of harmony inéer 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 pro-
vided with auditory hairs of different lengths, which have
been seen to vibrate when the proper musical nutes are
struck. As stated in a previous chapter, similar observa-
tions have been made on the hairs of the antennew of gnats.
It has been positively asserted by good observers that spi-
ders are attracted by music. It is also well known that
some dogs howl when hearing particular tones.” Seals ap-
parently appreciate music, and their fondness for it ‘twas
well known to the ancients, and is often taken advantage
of by the hunters of the present day.’’ *

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

8 Helmholtz, ‘‘Théorie Phys, de la Musique,’’ 1868, p. 187.

83 Several accounts have been published to this effect. Mr. Peach writes
to me that he has repeatedly found 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.

% Mr, R, Brown, in ‘‘Proc, Zoolog. Soc.,”? 1868, p. 410.

SEXUAL SELECTION IN RELATION TO MAN 733

concerned with these, as music in harmony is a late inven-
tion. 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 analyzes 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 sec-
ond octave, etc., all harmonies ofthe fundamental predomi-
nant 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 com-
mon—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 cer-
tain 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 com-
plex 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 among the most mysterious with which he is en-
dowed. 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

784 ms DESCENT OF MAN

remarks on this subject,” ‘‘doubts whether, even among the
nations of Western urope, 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
eastward 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 practiced 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 devel-
opment, for Hottentots and Negroes have become excellent
musicians, although in their native countries they rarely
practice anything that we should consider music. Schwein-
furth, however, was pleased with some of the simple melo-
dies 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 learned 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

% “Journal of Anthropolog. Soc.,’’ Oct. 1870, p. clv. See, also, the several
later chapters in Sir John Lubbock’s "“Prehistorie Times,’ second edition, 1869,
which contain an admirable account of the habits of savages.

SEXUAL SELECTION IN RELATION 7O M. 735

may have been a songster. It is more remarkable that par-
rots, 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. Never-
theless 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 origi-
nally adapted for one purpose having been utilized for some
distinct purpose.** Hence the capacity for high musical de-
velopment, 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 ac-
quired 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
ardor for war. These powerful and mingled feelings may
well give rise to the sense of sublimity. We can concen-
trate, 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,

38 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 show in an
early chapter of this work, this principle has an important bearing on the acqui-
sition by man of some of his mental characteristics.

736 THE DESCENT OF MAN

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 pos-
sibility, and do not know the meaning; or, as Richter says,
tells us of things we have not seen and shall not see.’’ Con-
versely, 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, while the company, as if touched by a musical wave,
murmur a chorus in perfect unison.’?" Even monkeys ex-
press strong feelings in different tones—anger and impa-
tience by low—fear and pain by high notes. The sensa-
tions 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 the 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 ac-
quired 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 prin-
ciple of evolution if we were to admit that man’s musical
capacity has been developed from the tones used in impas-
sioned speech. We must suppose that the rhythms and

81 Winwood Reade, *“The Martyrdom of Man,’ 1872, p. 441, and ‘African
Sketch Book,’ 1873, vol. ii. p. 313.
%® Rengger, ‘‘Saugethiere von Paraguay,’’ s, 49.

SEXUAL SELECTION IN RELATION TO MAN 737

cadences of oratory are derived from previously developed
musical powers.” 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.*

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, en-
deavored 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.‘ But if so, this must have occurred long ago,

39 See the very interesting discussion on the ‘‘Origin and Function of Musie,”’
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 whieh music has been developed; while I conclude
that musical notes and rhythm were first acquired by the male or female pro-
genitors 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 associa-
tion, 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 ex-
pressive, both with man and the lower animals, of certain emotions. Mr. Spen-
cer gives also an interesting discussion on the relations between poetry, recita-
tive, and song.

4 T 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, ””

41 See an interesting discussion on this subject by Hiackel, ‘‘Generelle
Morph.,’’ B. ii., 1866, s. 246,

738 ' ‘THIE DESCENT OF MAN :

before our ancestors had become sufficiently human to treat
and value their women merely as useful slaves. The impas-
sioned orator, bard, or musician, when with his varied tones
and cadences he excites the strongest emotions in his hear-
ers, 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 civilized 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-civilized and
savage nations. If it can be shown that the men of different
races prefer women having various characteristics, or con-
versely with the women, we have then to inquire 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 show in some detail that savages
pay the greatest attention to their personal appearance.
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 Prof. Waitz remarks, ‘‘however poor and miserable man
is, he finds a pleasure in adorning himself.’’ The extrava-
gance of the naked Indians ot South America in decorating

4 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, Prof. Mante-
gazza, ‘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, ‘‘Introduct. to Anthropolog.,’? Eng. transl, vol. i, 1863, p. 275,
et passim. Lawrence also gives very full details in his ‘*Lectures on Physi-
ology,’? 1822. Since this chapter was written Sir J. Lubbock has published
his ‘‘Origin of Civilization,’? 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,

SEXUAL SELECTION IN RELATION TO MAN 739

themselves is shown ‘‘by a man of large stature gaining with
difficulty enough by the labor of a fortnight to procure in
exchange the chica necessary to paint himself red.’’* 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, arm-
lets, earrings, etc. They paint themselves in the most
diversified manner. ‘‘If painted nations,’’ as Humboldt
observes, ‘thad 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 colored black; in
another the nails are colored yellow or purple. In many
places the hair is dyed of various tints. In different coun-
tries 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 tat-
too 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 per-
sonal attractions.’’ In the Arab countries no beauty can be
perfect until the cheeks ‘‘or temples have been gashed.’’
In South America, as Humboldt remarks, ‘ta mother would
be accused of culpable indifference toward her children, if
she did not employ artificial means to shape the calf of the

4 Humboldt, ‘‘Personal Narrative,’? Eng. translat., vol. iv. p. 515; on the
imagination shown in painting the body, p. 522; on modifying the form of the
ealf of the leg, p. 466.

“4 “The Nile Tributaries, 1867; ‘‘The Albert N’yanza,”’ 1866, vol. i. p. 218,

740 THE DESCENT OF MAN

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** deem
a much flattened head ‘‘an essential point of beauty.”

The hair is treated with especial care in various coun-
tries; 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.’’*° 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’ remarks, gives the face a hideous appear-
ance, 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 quar-
ters 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

45 Quoted by Prichard, ‘‘Phys. Hist. of Mankind,”’ 4th edit., vol. i., 1852,
p. 321.

46 On the Papuans, Wallace, ‘“The Malay Archipelago,”’ vol. fi. p. 445. On
the coiffure of the Africans, Sir 8. Baker, ‘“The Albert N’yanza,”’ vol. i. p. 210.

a. “Travels,”’ p. 533.

SEXUAL SELECTION IN RELATION TO MAN 741

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 Boto-
cudos the hole in the lower lip is so large that a disk of
wood, four inches in diameter, is placed in it. Mantegazza
gives a curious account of the shame felt by a South Amer-
ican native, and of the ridicule which he excited, when he
sold his tembeta—the large colored 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, in-
describably ludicrous during conversation.’? The wife of
the chief of Latooka told Sir S. Baker 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 pelelé, 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 contrac-
tion 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 pelel6? She
would not be a woman at all with a mouth like a man, but
no beard.’’’ ®

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

# “The Albert N’yanza,’? 1866, vol. i. p. 217.
Livingstone, ‘‘British Association,’? 1860; report given im the ‘‘Athe-
neum,”’ July 7, 1860, p. 29.
Descent—Vot. II.—14

742 THE DESCENT OF MAN

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. Among sav-
ages the same fashions prevail for long periods,” and thus
mutilations, from whatever cause first made, soon come to
be valued as distinctive marks. But self-adornment, van-
ity, and the admiration of others seem to be the commonest
motives. In regard to tattooing, I was told by the mission-
aries 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” says, ‘‘to have fine tattooed faces was the
great ambition of the young, both to render themselves at-
tractive 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 attrac-
tions.” In most, but not all, parts of the world the men are
more ornamental 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 perforat-
ing the nose, lips, or ears, in removing or filing the teeth,
-etc., now prevail, and, have long prevailed, in the most dis-
tant quarters of the world. It is extremely improbable that

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 the invariability of the tat-
tooing of the Amazonian Indians.

51 Rey. R. Taylor, ‘‘New Zealand and its Inhabitants,’* 18556, p. 152

52 Mantegazza, ‘Viaggi e Studi,”’ p. 542.

\
\

SEXUAL SELECTION IN RELATION TO MAN 748

these practices, followed by + many distinct nations, should
be due to tradition from any common source. They indi-
cate 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 admira-
tion felt by savages for various ornaments, and for deformi-
ties 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 ornament-
ing themselves, or with their vanity. Burchell® gives an
amusing account of a Bushwoman who used as much grease,
red ochre, and shining powder ‘‘as would have ruined any
but a very rich husband.’’ She displayed also ‘‘much van-
ity 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. 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 Northwestern America.

Hearne,” 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

53 “Travels in 8. Africa,’ 1824, vol. i. p. 414.

54 See, for references, Gerland, ‘‘Ueber das Aussterben der Naturvélker,’?
1868, s. 51, 53, 55; also Azara, ‘‘Voyages,”’ etc., tom. ii. p. 116.

55 On the vegetable productions used by the Northwestern American Indians,
‘*Pharmaceutical Journal,’’ vol. x.

5 ‘*A& Journey from Prince of Wales Fort,’’ 8vo, edit. 1796, p. 89.

744 THE DESCENT OF MAN

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 Mandschti form; that is to say,
a broad face, high cheek-bones, very broad noses, and enor-
mous ears;’’*” and Vogt remarks that the obliquity of the
eye, which is proper to the Chinese and Japanese, is exag-
gerated 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 Cinga-
lese; 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 reck-
-oned beautiful in proportion as they display this form of
face.’’ The Siamese have small noses with divergent nos-
trils, a wide mouth, rather thick lips, a remarkably large
face, with very high and broad cheek-bones. It is, there-
fore, 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 Hurope.’’ *

It is well known that with many Hottentot women the
posterior part of the body projects in a wonderful manner;

51 Quoted by Prichard, ‘‘Phys, Hist. of Mankind,’’ 3d ed. vol. iv., 1844,
p. 519; Vogt, ‘*Lectures on Man,”’ Eng. trans., p. 129. On the opinion of the
Chinese on the Cingalese, E. Tennent, ‘*Ceylon,’’ 1859, vol. ii. p. 107.

58 Prichard, as taken from Crawfurd and Finlayson, ‘‘Phys. Hist. of Man-
kind,”’ vol. iv. pp. 534, 535.

SEXUAL SELECTION IN RELATION TO MAN 745

they are steatopygous; and Sir Andrew Smith is certain
that this peculiarity is greatly admired by the men.” 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, ac-
cording to Burton, the Somal men ‘‘are said to choose their
wives by ranging them in a line, and by picking her out
who projects furthest a tergo. Nothing can be more hateful
to a.negro than the opposite form.” °

With respect to color, 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 ‘‘honey mouth,”’ 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 2” On the
western coast, as Mr. Winwood Reade informs me, the ne-
groes admire a very black skin more than one of a lighter
tint. But their horror of whiteness may be attributed, ac-
cording 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 color, and, indeed, this color is considered hand-
some throughout the whole country’; so that here we have

59 Tdem illustrissimus viator dixit mihi preecinctorium vel tabulam foemina,
quod nobis teterrimum est, quondam permagno estimari ab hominibus in hae
gente. Nunc res mutata est, et censent talem conformationem minime optan-
dam esse.

8 “*The Anthropological Review,’? November, 1864, p. 237. For additional
references see Waitz, ‘“Introduct. to Anthropology,’’ Eng. translat., 1863, vol.
i. p. 105.

746 THE DESCENT OF MAN

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 color be-
ing a mixture of black and red, the most common shade
being chocolate. Dark complexions, as being most com-
mon, are naturally held in the highest esteem. To be told
that he is light colored, 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.’ Mr. Galton, in speaking tg me
\ about the natives of South 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 yel-
low, 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 color like that of
potato flowers.’? We have seen that the Chinese dislike
our white skin, and that the North Americans admire
‘“‘a tawny hide.’’ In South America, the Yuracaras, who
inhabit the wooded, damp slopes of the eastern Cordillera,
are remarkably pale colored, as their name in their own
language expresses; nevertheless they consider European
women as very inferior to their own.”

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

61 Mungo Park’s ‘‘Travels in Africa,’’ 4to, 1816, pp. 53, 131. Burton’s
statement is quoted by Schaaffhausen, ‘‘Archiv fiir Anthropolog.,’’ 1866, 8. 163.
On the Banyai, Livingstone, ‘‘Travels,’? p. 64. On the Kaffirs, the Rev. J.
Shooter, ‘‘The Kaffirs of Natal and the Zulu Country,’’ 1857, p. 1.

6? For the Javans and Cochin-Chinese, see Waitz, ‘‘Introduct. to Anthropol-
ogy,’ Eng. translat., vol. i, p. 305. On the Yuracaras, A. d’Orligny, as quoted
in Prichard, ‘‘Phys. Hist. of Mankind,’’ vol. v. 3d edit. p. 476,

SEXUAL SELECTION IN RELATION TO MAN 747

iongest hair of any man in the tribe, namely, ten feet and
seven inches. The Aymaras and Quichuas of South Amer-
ica 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
‘tas 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 hairs 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 eradi-
cate their eyebrows and eyelashes, saying that they do not
wish to be like horses.”

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 Ma-
lays, 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.2’ The New Zealanders have short, curled beards; yet
they formerly plucked out the hairs on the face. They had

68 ‘North American Indians,’’ by G. Catlin, 3d edit., 1842, vol. i. p. 49;
vol. ii. p. 227. On the natives of Vaucouver’s Island, see Sproat, ‘Scenes and
Studies of Savage Life,’’ 1868, p. 25. On the Indians of Paraguay, Azara,
“Voyages,”’ tom. ii. p. 106.

748 THE DESCENT OF MAN

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.™

On the other hand, bearded races admire and greatly
value their beards; among the Anglo-Saxons every part of
the body had a recognized value; ‘‘the loss of the beard
being estimated at twenty shillings, while the breaking of
a thigh was fixed at only twelve.” ** 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’’; while
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.”’

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 endeavored
to express their highest ideal of beauty and grandeur.”
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 bass-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 ne-
groes of the West Coast of Africa, but with those of the

6 On the Siamese, Prichard, ibid., vol. iv. p. 533. On the Japanese, Veitch
in ‘‘Gardeners’ Chronicle,’’ 1860, p. 1104. On the New Zealanders, Mante-
gazza, ‘Viaggi e Studi,’’ 1867, p. 526. For the other nations mentioned, see
references in Lawrence, ‘Lectures on Physiology,’ ete., 1822, p. 272.

6 Lubbock, ‘‘Origin of Civilization,’’ 1870, p. 321.

6 Dr. Barnard Davis quotes Mr. Prichard and others for these facts in regard
to the Polynesians, in ‘‘ Anthropological Review,’’ April, 1870, pp. 185, 191.

® Ch. Comte has remarks to this effect in his ‘‘Traité de Législation,”
3d edit.,.183%, p. 136.

SEXUAL SELECTION IN RELATION TO MAN 749

interior who have never associated with Europeans, is con-
vinced 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 appre-
ciated: a girl has been heard to say, ‘‘I do not want to
marry him, he has got no nose’’; and this shows 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 color of our skin; they look on blue eyes with aver-
sion, 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.°

The general truth of the principle, long ago insisted
on by Humboldt,” that man admires and often tries to
exaggerate whatever characters nature may have given
him, is shown in many ways. The practice of beardless

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 seon of ihe 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.

69 “*Personal Narrative,’? Eng. translat., vol. iv. p. 518, and elsewhere.
Mantegazza, in his ‘‘Viaggi e Studi,’ 186%, strongly insisis on this same
principle.

750 THE DESCENT OF MAN

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 practiced, especially in North and South 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 northwestern 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 favor-
ite 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 chil-
dren.’’ On the other hand, ‘‘a broad, well-rounded occi-
put is considered a great beauty’’ by the natives of the
Fiji islands.”

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.” The Chinese
have by nature unusually small feet;” and it is well known
that the women of the upper classes distort their feet to

On the skulls of the American tribes, see Nctt and Gliddon, ‘‘Types of
Mankind,’’ 1854, p. 440; Prichard, ‘‘Phys. History of Mankind,’’ vol. i, 3d
edit., p. 321; on the natives of Arakhan, ibid., vol. iv. p. 637. Wilson, ‘‘Phys-
ical Ethnology,’’ Smithsonian Institution, 1863, p. 288; on the Fijians, p. 290.
Sir J. Lubbock (‘‘Prehistoric Times,’’ 2d edit., 1869, p. 506) gives an excellent,
résumé on this subject.

7! On the Huns, Godron, ‘‘De 1l’Espéce,”’ tom. ii., 1859, p. 300. On the
Tahitians, Waitz, ‘‘Anthropolog,’’ Eng. translat., vol. i. p. 305. Marsden,
quoted by Prichard, ‘‘Phys. Hist. of Mankind,”’ 3d edit., vol. v. p. 67. Law-
rence, ‘Lectures on Physiology,”’ p. 337.

72 This fact was ascertained in the ‘‘Reise der Novara: Anthropolog. Thiel,”
Dr. Weisbach, 1867, 8. 265.

SEXUAL SELECTION IN RELATION TO MAN 751

make them still smaller. Lastly, Humboldt thinks that
the American Indians prefer coloring their bodies with red
paint in order to exaggerate their natural tint; and until
recently European women added to their naturally bright
colors 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 ex-
treme; 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 speak-
ing 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.’’"* The same
principle comes into play in the art of breeding; and we can
thus understand, as I have elsewhere explained,” the won-
derful development of the many races of animals and plants
which have been kept merely for ornament. Fanciers al-
ways 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 colors and certain forms, as well
as harmonious and rhythmical sounds, give pleasure and are

8 ‘Smithsonian Institution’? 1863, p. 289. On the fashions of Arab
women, Sir 8. Baker, ‘‘The Nile Tributaries,’’ 1867, p. 121.

™% “The Variation of Animals and Plants under Domestication,”’’ vol. i. p.
214; vol. ii. p. 240.

752 THE DESCENT OF MAN

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 favor of this belief; and if so, each race would
possess its own innate ideal standard of beauty. It has been
argued” that ugliness consists in an approach to the struc-
ture of the lower animals, and no doubt this is partly true
with the more civilized 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.” Men accustomed to a nearly oval
face, to straight and regular features, and to bright colors,
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 mold, there would
be no such thing as beauty. If all our women were to be-
come 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.

7 Schaaffhausen, ‘‘Archiv far Anthropologie,’’ 1866, s. 164.

7° 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 noue
is quite the same as that here given,

SEXUAL SELECTION IN RELATION £0 MAN 753

CHAPTER XX
SECONDARY SEXUAL CHARACTERS OF MAN—continued

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

E have seen in the last chapter that with all barbar-
\ \ ous races ornaments, dress, and external appear-
ance 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 con-
sequent 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 trans-
ferred 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. Civilized men are largely at-
tracted by the mental charms of women, by their wealth,
and especially by their social position; for men rarely marry

54 THE DESCENT OF MAN

into a much lower rank. The men who succeed in obtain-
ing 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 civilized 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 lat-
ter in life depends much on their intellectual powers and
energy, or on the fruits of these same powers in their fore-
fathers. No excuse is needed for treating this subject in
some detail; for, as the German philoscpher 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.’’!

There is, however, reason to believe that in certain civil-
ized and semi-civilized 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 stand-
ard, than the middle classes; yet the middle classes are
placed under equally favorable 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)

1 “Schopenhauer and Darwinism.”’ in ‘‘Journal of Anthropology,’’ Jan.
1872, p. 323.

SEXUAL SELECTION IN RELATION TO MAN 755

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 inter-
mixtures 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 Geor-
gian 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.’’* 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,* who states the fore-
going 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 from its curiosity. Mr. Winwood Reade in-
forms 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 look-
ing, 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 worse-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 ap-
pearance of his tribe to the long-continued elimination of
the ugly women is not so surprising as it may at first ap-

2 These quotations are taken from Lawrence (‘‘Lectures on Physiology,”
elc., 1822, p. 393), who attributes the beauty of the upper classes in England
to the men having long selected the more beautiful women.

3 “*Anthropologie,’’ ‘‘Revue des Cours Scientifiques,’’ Oct. 1858, p. 721.

756 THE DESCENT OF MAN

pear; for I have elsewhere shown‘ that negroes fully appre-
ciate the importance of selection in the breeding of their do-
mestic 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 be-
trothals; 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 hav-
ing had an advantage over others in their courtship. Now
it is asserted that there exist at the present day tribes which
practice 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,® 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

4 “The Variation of Animals and Plants under Domestication,’’ vol. i. p. 207.

5 Sir J. Lubbock, ‘The Origin of Civilization,’? 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 sav-
ages at the present time. Mr. L. H. Morgan, in his interesting memoir on the
classificatory system of relationship (‘‘Proc. American Acad. 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.

SEXUAL SELECTION IN RELATION TO MAN 757

the world, including therein the intermarriage of brothers
and sisters. The late Sir A. Smith, who had travelled
widely in South Africa, and knew much about the habits
of savages there and elsewhere, expressed to me the strong-
est opinion that no race exists in which woman is considered
as the property of the community. I believe that his judg-
ment 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 dur-
ing the breeding season or for the whole year, keeping pos-
session 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 recognized right protected by the tribe.

The indirect evidence in favor 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 com-
pletely 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 possi-
ble that the connection between the related members of the
same barbarous tribe, exposed to all sorts of danger, might

758 THE DESCENT OF MAN

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 birth 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 uni-
versal. 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 ex-
erted 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 relation-
ship, other lines of reasoning indicate the former wide preva-
lence 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 neighboring 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 honor so gained it might ulti-
mately have become the universal habit. According to Sir
J. Lubbock,® we can also thus understand ‘‘the necessity of

6 Address to British Association, ‘‘On the Social and Religious Condition
of the Lower Races of Man,’’ 1870, p. 20.

SEXUAL SELECTION IN RELATION TO MAN 759

expiation for marriage as an infringement of tribal rites,
since, according to old ideas, a man had no right to appro-
priate to himself that whieh belonged to the whole tribe.’
Sir J. Lubbock further gives a curious body of facts show-
ing that in old times high honor was bestowed on women
who were utterly licentious; and this, as he explains, is in-
telligible, if we admit that promiscuous intercourse was the
aboriginal, and therefore long revered, custom of the tribe."

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® 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 through-
out the world. Nevertheless, from the strength of the feel-
ing 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 show, is
certainly descended from some ape-like creature. With
the existing Quadrumana, as far as their habits ts are cuowmy
the males of some species are monogamou bnT ive during
only a part of the year with the femeles; of this the orang
seems to afford an instaice. Several kinds, for example
some of the Indian and American monkeys, are strictly
monogamous, and associate all the year round with their

1 “Origin of Civilization,’? 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.

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.

760 THE DESCENT OF MAN

wives. Others are polygamous, for example the gorilla
and several American species, and each family lives sepa-
rate. Even when this occurs, the families inhabiting the
same district are probably somewhat social; the chimpan-
zee, 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.° We may indeed con-
clude, 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 power-
ful, 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}~vhen the young male grows up, a contest takes place
* for mastery, and the strongest, by killing and driving ont
the others, establishés-himself as the head-or thé commu-
nity.” The younger males, beimg thus expelled and wan-
dering about, would, when at last successful in finding a
partner, prevent too close interbreeding within the limits
of the same family.

9 Brehm (‘‘Illust. 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 (‘‘Anat. of Verte-
brates, ”’ vol. iii. p. 746) on American monogamous species. Other references
might be added.

10 Dr. Savage, in ‘‘Boston Journal of Nat. Hist.,’? vol. v. 1845-47, p. 423,

SEXUAL SELECTION IN RELATION TO MAN 761

Although savages are now extremely licentious, and
although communal marriages may formerly have largely
prevailed, yet many tribes practice some form of marriage,
but of a far more lax nature than that of civilized 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,” ‘‘that death alone can separate husband
and wife.’’ An intelligent Kandyan chief, of course a
polygamist, ‘‘was perfectly scandalized at the utter barba-
rism of living with only one wife, and never parting until
separated by death.’’ It was, he said, ‘‘just like the Wan-
deroo 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 pass-
ing through a stage of promiscuous intercourse, I will not
pretend to conjecture.

Infanticide.—T his practice is now very common through-
out the world, and there is reason to believe that it prevailed
much more extensively during former times.” Barbarians
find it difficult to support themselves and their children, and
itis 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 extinc-
tion. 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. Wherever infanticide prevails the <truggle for
existence will be in so far less severe, and all the members
of the tribe will have an almost equally good chance of

11 **Prehistoric Times,’’ 1869, p. 424.
Mr. M‘Lennan, ‘‘Primitive Marriage,’? 1865. See especially on exogamy
and infanticide, pp. 130, 138, 165.

762 THE DESCENT OF MAN

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 hap-
pier fate, are assigned by the women themselves, and by
various observers, as additional motives for infanticide.
In Australia, where female infanticide is still common,
Sir G. Grey estimated the proportion of native women to
men as one to three; but others say as two to three. Ina
village on the eastern frontier of India, Colonel MacCulloch
found not a single female child.”

When, owing to'female infanticide, the women of a tribe
were few, the habit of capturing wives from neighboring
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 practiced during for-
mer times, even by the ancestors of civilized nations, is
clearly shown by the preservation of many curious cus-
toms 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 bride-
groom in the act of capture. Now as long as men habitually
procured their wives through violence and craft, they would
have been ylad to seize on any woman, and would not have
selected the more attractive ones. But as soon as the prac-

18 Dr. Gerland (‘‘Ueber das Aussterben der Naturvélker,’? 1868) has col-
lected much information on infanticide, see especially s. 27, 51, 54. Azara
(‘‘Voyages,’’ ete., tom. ii. pp. 94, 116) enters in detail on the motives. See,
also, M‘Lennan (ibid., p. 139) for cases in India,

SEXUAL SELECTION IN RELATION TO MAN 763

tice 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 in-
terfere 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 com-
mon 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.* 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 un-
usual care of their personal appearance. So among the
Todas of India, who practice polyandry, the girls can ac-
cept or refuse any man.’** 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 suc-
cessful 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. a

Beer

Early Betrothals and Slavery of Women.—With many
savages it is the custom to betroth the females while mere

M4 “Primitive Marriage,”? p. 208; Sir J. Lubbock, ‘‘Origin of Civilization,”’
p. 100. See, also, Mr. Morgan, loc. cit., on the former prevalence of polyandry,

16 Azara, ‘‘Voyages,”’ ete., tom. ii. pp. 92-95; Colonel Marshall, ‘‘Among
the Todas,”’ p. 212.

764 THE DESCENT OF MAN

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 afterward stolen or taken by force from their hus-
bands by the more powerful men; and this often happens
in Australia, America, and elsewhere. The'same conse-
quences with reference to sexual selection would to a cer-
tain 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 handsom-
est 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 condi-
tions of life to which savages are exposed, and some of
their habits, are favorable to natural selection; and this
comes into play at the same time with sexual selection.
Savages are known to suffer severely from recurrent fam-
ines; they do not increase their food by artificial means;
they rarely refrain from marriage, and generally marry
while young. Consequently they must be subjected to
occasional hard struggles for existence, and the favored
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 among 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 fe-
gmales. They would also succeed best in the general strug-

pzle for life, and in defending their females, as well as their
offspring, from enemies of all kinds. At this early period

%6 Burchill says (‘‘Travels in 8. 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’Amérique Mérid.,”’ tom,
fi., 1809, p. 21) makes precisely the same remark in regard to the wild Indians
of South America,

SEXUAL SELECTION IN RELATION TO MAN 765

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, com-
mon to all the lower animals, namely, the love of their
young offspring; and consequently they would not have
practiced female infanticide. Women would not have been
thus rendered scarce, and polyandry would not have been
practiced; 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 be-
lieve 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 burden. 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 ex-
ternal 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 peri-
odically excessively severe.. Thus during these times all
the conditions for sexual selection would have been more
favorable 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.
Descent—Vot, II.—15

766 THE DESCENT OF MAN

The Manner of Action of Sexual Selection with Mankind.
—With primeval men under the favorable 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 pro-
‘vided with the best weapons and possessed the most prop-
erty, such as a large number of dogs or other animals—
would succeed in rearing a greater average number of off-
spring 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 Zea-
land, who was pretty, or promised to be pretty, was tapu to
some chief. With the Kaffirs, as Mr. C. Hamilton states,"
“‘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 intro-
duced 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

17 “Anthropological Review,’’ Jan. 1870, p. xvi.

SEXUAL SELECTION IN RELATION TO MAN 769 |

or less amount of change, whenever the means of comparif
son 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 expecta-

tion 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.*° Hach

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, practicing 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 effec-
tually by the incessant wars between all barbarous nations.
The hordes would thus be exposed to slightly different con-
ditions 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 stand-
ard of beauty;’* and then unconscious selection would come
into action through the more powerful and leading men pre-
ferring certain women to others. Thus the differences be-
tween the tribes, at first very slight, would gradually and
inevitably be more or less increased.

18 “The Variations of Animals and Plants under Domestication,” vol. ii. pp.
210-217. ;

¥ 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.

: 766 THE DESCENT OF MAN

+e ‘With animals in a state of nature, many characters proper
w the males, such as size, strength, special weapons, courage,
and pugnacity, have been acquired through the law of bat-
tle. The semi-human progenitors of man, like their allies,
the Quadrumana, will almost certainly have been thus modi-
fied; 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 char-
acters proper to the males of the lower animals, such as
bright colors 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 selecters, instead of having been the se-
lected. We recognize such cases by the females being more
highly ornamented than the males—their ornamental charac-
ters 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 be-
come more beautiful, according to general opinion, than men.
Women, however, certainly transmit most of their charac-
ters, including some beauty, to their offspring of both sexes;
so that the continued preference by the men of each race for

SEXUAL SELECTION IN RELALION TO MAN 769

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 selecters, 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 afterward chang-
ing 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 South America,
according to Azara, divorce is quite optional. Among 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 com-
pelled to comply.” In Tierra del Fuego a young man first
obtains the consent of the parents by doing them some ser-
vice, 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 act-

770 THE DESCENT OF MAN

ual 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 for-
mer 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.’’ Among 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 re-
marks, 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 Kaffirs 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 con-
siderable 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 show
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 favored lover. So
again, Mr. Leslie, who was intimately acquainted with the
Kaffirs, says, ‘‘it is a mistake to imagine that a girl is sold
by her father in the same manner, and with the same au-
thority, with which he would dispose of a cow.’’ Among
the degraded Bushmen of South 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.’’ ”

2% Azara, ‘‘Voyages,”’ etc., tom. ii. p. 23. Dobrizhoffer, ‘‘An Account of

the Abipones,’’ vol. ii., 1822, p. 207, Capt. Musters, in ‘‘Proc. R. Geograph,
Soe.,”? vol. xv. p. 47, Williams on the Fiji Islanders, as quoted by Lubbock,
“Origin of Civilization,*’ 1870, p. 79. On the Fuegians, King and FitzRoy,
“Voyages of the Adventure and Beagle,”’ vol. ii., 1839, p. 182, On the Kal-

SEXUAL SELECTION IN RELATION TO MAN TT71

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 fall-
ing 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 be-
fore 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 favored. 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 selec-
tion 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 color of the
skin. We need say nothing about the great diversity in
the shape of the features and of the skull between the dif-

mucks, 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 Bushmen, Burchell, ‘‘Travels in 8. Africa,’’ vol. ii., 1824, p. 59. On
the Koraks by McKennan, as quoted by Mr. Wake, in ‘‘Anthropologia,’’ Oct,
1873, p. 75.

772 THE DESCENT OF MAN

ferent races, as we have seen in the last chapter how differ-
ent is the standard of beauty in these respects. These char-
acters 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
Janugo on the human feetus, and of rudimentary hairs scat-
tered over the body during maturity, we may infer that man
is descended from some animal which was born hairy and re-
mained 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 re-
marks, 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 natura! selection.” Nor, as shown
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 reason-
ably 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

1 “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 Assoc. for Science,”’ 1870), remarks, that
had Mr. Wallace ‘‘employed his usual ingenuity on the question of man’s hair-
less skin, he might have seen the possibility of its selection through its supe-
rior beauty or the health attaching to superior cleanliness.”’

SEXUAL SELECTION IN RELATION TO MAN 173

body of other species, have been denuded of hair; and this
we may safely attribute to sexual selection, for these sur-
faces are not only vividly colored, but sometimes, as with
the male mandrill and female rhesus, much more vividly in
the one sex than in the other, especially during the breed-
ing 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 color 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-colored 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 re-
mote period before the several races had diverged from a
common stock. While our female ancestors were gradually
acquiring this new character of nudity, they must have
transmitted it almost equally to their offspring of both
sexes while young; so that its transmission, as with the
ornaments of many mammals and birds, has not been lim-
ited 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 innumer-
able 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 injuri-
ous 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

T74 THE DESCENT OF MAN

sexual selection, it is well to bear in mind the New Zea-
land proverb, ‘‘There is no woman fora 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.”

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 Kuropean, 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 char-
acters 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; ex-
cepting perhaps with the negroes who have been reared dur-
ing several generations in the United States,” 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 rever-
sion, unchecked by any form of selection, its extreme vari-

22 “The Variation of Animals and Plants under Domestication,’’ vol. ii.,
1868, p. 327.

3 “*Tnvestigations into Military and Anthropological statistics of American
Soldiers,” by B. A. Gould, 1869, p. 568: Observations were carefully made
on the hairiness of 2,129 black and colored soldiers while they were bathing;
and by looking to the published table, ‘‘it is manifest at a glance that there ig
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 ob-
served that both pure blacks and mulattoes were included in the above enu-
meration; 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. :

SEXUAL SELECTION IN RELATION TO MAN ‘75

ability, even within the limits of the same race, ceases to
be remarkable.*

With respect to the beard in man, if we turn to our best
guide, the Quadrumana, we find beards equally developed
in both sexes in 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 colors of the hair about the heads of many mon-
keys, 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”® 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, while
woman lost her beard at the same time that her body became
almost completely divested of hair. Even the color of our
beards seems to have been inherited from an ape-like pro-
genitor; for when there is any difference in tint between
the hair of the head and the beard, the latter is lighter
colored 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

% Hardly any view advanced in this work has met with so much disfavor
(see, for instance, Spengel, ‘‘Die Fortschritte des Darwinismus,’’ 1874, p. 80)
as the above explanation of the loss of hair in mankind through sexual selec-
tion; but none of the opposed arguments seem to me of much weight, in com-
parison with the facts showing that the nudity of the skin is to a certain extent
@ secondary sexual character in man and in some of the Quadrumana,

% ‘Ueber die Richtung der Haare am Menschlichen Kérpe,”’ in Miller’s
“Archiv fir Anat. und Phys.,’’ 1837, s. 40.

776 THE DESCENT OF MAN

the same race; for this indicates reversion—long lost char-
acters being very apt to vary on reappearance.

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, while the men of the bearded races feel the great-
est pride in their beards. The women, no doubt, partici-
pate 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-Séquard has shown that if certain animals are
operated on in a particular manner, their offspring are af-
fected. Further evidence could be given of the inheritance
of the effects of mutilations; but a fact lately ascertained
by Mr. Salvin” has a more direct bearing on the present
question; for he has shown 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.” 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® 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 like.
wise indicated by the extraordinary difference in the length

% ‘On the tail feathers of Momotus,”’ ‘*Proc. Zoolog. Soc.,’? 1873, p. 429.
* Mr, Sproat has suggested (“Scenes and Studies of Savage Life,’? 1868, p.
25) this same view. Some distinguished ethnologists, among others M. Gosse
of Geneva, believe that artificial modifications of the skull tend to be inherited.
% “Ueber die Richtung,”’ ibid., s. 40.

SEXUAL SELECTION IN RELATION TO MAN TUT

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 Americen 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. §t. Paul says, ‘if a woman have long hair, it
ig a glory to her’’; and we have seen that in North America
a chief was ¢lected solely from the length of his hair.

the Skin.—The best kind of evidence that in
color of the skin has been modified through sex-

ual selection is scanty; for in most races the sexes do not
Alster in this respect, and only slightly, as we have seen,

in others. We know, however, from the many facts already
given, that the color 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 color. With mammals, when the
sexes differ in color, 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 color 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,

778 THE DESCENT OF MAN

orange, almost white and black tints 0» noir skin, even
when common to both sexes, as well as the bright colors
of their fur, and the ornamental tufts al 4 tne head, have
all been acquired through sexual selectio, 4. ee ae
of development during growth generally i dicates the order
in which the characters of a species have’ poen developed
and modified during previous generations; é44 as the newly
born infants of the various races of man don ,, a: nearly
as much in color as do the adults, although th, sin hudies are
as completely destitute of hair, we have som, slight evi-
dence that the tints of the different races were, acquired at
a period subsequent to the removal of the hair,’ which enust
have occurred at a very early period in the history af winti,

Summary.—We may conclude that the Breate .» ine. *
strength, courage, pugnacity, and energy of man, in ees
parison with woman, were acquired during primeval tims,
and have subsequently been augmented, chiefly through ~
the contests of rival males for the possession of the fe-
males. The greater intellectual vigor and power of inven-
tion 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 char-
acter 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 favorable for sexual

SEXUAL SELECTION IN RELATION TO MAN 779

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 practiced
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 re-
markable fact that at the most ancient period of which
we have 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 shown 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 promi-
nence or depression of the nose, the color 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

780 ; THE DESCENT OF MAN

characterized and therefore most attractive women. For
my own part, I conclude that of all the causes which have

/ ied to the differences in external appearance between the

\

\ lower animals, sexual selection has been the most efficient.

races of man, and to a certain extent between man and the

CHAPTER XXI
GENERAL SUMMARY AND CONCLUSION

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

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 false-
ness; and when this is done, one path toward 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
organized 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 rudi-

| BRIEF summary would be sufficient to recall to the

SEXUAL SELECTION IN RELATION TO MAN 781

ments 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 of facts are considered in connection with oth-
ers, 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 dis-
connected, 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 mam-
mals, independently of the uses to which the parts may be
put—the occasional reappearance 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 facul-
ties. 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 inheri-
tance 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 na-
ture is by no means requisite; slight fluctuating differences
in the individual suffice for the work of natural selection;

7382 THE DESCENT OF MAN

not that we have any reason to suppose that, in the same
species, all parts of the organization tend to vary to the
same degree. We may feel assured that the inherited ef-
fects 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 cor-
relation, 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 condi-
tions 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 occa-
sionally 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 labors of ex-
perimentalists, 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 ex-
citing organic changes of many kinds.

Through the means just specified, aided perhaps by oth-

SEXUAL SELECTION IN RELATION TO MAN 783

ers 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
ealled, sub-species. Some of these, such as the Negro and
rope, are so distinct that, if specimens had been brought
ito 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 unim-
portant details of structure and in so many mental peculiar-
ities, that these can be accounted for only by inheritance
) from a common progenitor; and a progenitor thus character-
_ized 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 con-
trary, 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 modi-
fications 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 inter-
crossing.

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.

784 THE DESCENT OF MAN

We thus learn that man is descended from a hairy, tailed
quadruped, probably arboreal in its habits, and an inhabi-
tant of the Old World. This creature, if its whole structure
had been examined by a naturalist, would have been classed
among the Quadrumana, as surely as the still more ancient
progenitor of the Old and New World monkeys. The Quad-
rumana 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 creat-
ure, 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 branchiz, 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 larve 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 evolu-
tion 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 varia-
tions are inherited. No one doubts that they are of the
utmost importance to animals in a state of nature. There-
fore the conditions are favorable for their development
through natural selection. The same conclusion may be
extended to man; the intellect must have been all-impor-
tant to him, even at a very remote period, as enabling him

SEXUAL SELECTION IN RELATION TO MAN 785

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 improve-
ment of language. As Mr. Chauncey Wright’ has well
remarked, the largeness of the brain in man, relatively to
his body, compared with the lower animals, may be attrib-
uted 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 ratioci-
nation, 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 inter-
esting 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 toward certain definite actions; but
the more important elements are love, and the distinct emo-
tion of sympathy. Animals endowed with the social in-
stincts 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 individ-
uals of the species, but only to those of the same commu-
nity. 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

1 “On the Limits of Natural Selection,”’ in the ‘‘North American Review,”’
Oct, 1870, p. 295.

786 THE DESCENT OF MAN

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 endeavored to
show that the moral sense follows, first, from the enduring
and ever-present nature of the social instincts; secondly,
from man’s appreciation of the approbation and disappro-
bation 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 ani-
mals. Owing to this condition of mind, man cannot avoid
looking both backward and forward, 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 feel-
ing 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.

P 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 im-

~~pelled by the same general wish to aid his fellows; but has

few or no special instincts. He differs also from the lower

f animals in the power of expressing his desires by words,

| which thus become a guide to the aid required and be-

stowed. 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

SEXUAL SELECTION IN RELATION TO MAN 1787

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 pow-
ers advance and experience is gained, the remoter effects
of certain lines of conduct on the character of the individ-
ual, and on the general good, are perceived; and then the
self-regarding virtues come within the scope of public opin-
ion, and receive praise, and their opposites blame. But
with the less civilized 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 viv-
idly 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 im-
pressions, 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 stand-
ard partly through the advancement of his reasoning pow-
ers, and consequently of a just public opinion, but especially
from his sympathies having been rendered more tender and

788 THE DESCENT OF MAN

widely diffused through the effects of habit, example, in-
struction, and reflection. It is not improbable that after
long practice virtuous tendencies may be inherited. With
the more civilized races, the conviction of the existence of
an all-seeing Deity has had a potent influence on the ad-
vance 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, con-
trolled 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, im-
possible, 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 fac-
ulties 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 be-
lief 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 ele-
vated by long-continued culture.

He who believes in the advancement of man co some
low organized form will naturally ask, How does this bear
on the belief in the immortality of the soul? The barbar-
ous races of man, as Sir J. Lubbock has shown, possess no

SEXUAL SELECTION IN RELATION TO MAN 78:

clear belief of this kind; but arguments derived from th:
primeval beliefs of savages are, as we have just seen, o
little or no avail. Few persons feel any anxiety from th:
impossibility of determining at what precise period in th:
development of the individual, from the first trace of :
minute germinal vesicle, man becmes an immortal being
and there is no greater cause for anxiety because the perio:
cannot possibly be determined in the gradually ascendin;
organic scale.?

I am aware that the conclusions arrived at in this worl
will be denounced by some as highly irreligious; but h
who denounces them is bound to show why it is mor
irreligious to explain the origin of man as a distinct spe
cies by descent from some lower form, through the laws o
variation and natural selection, than to explain the birtl
of the individual through the laws of ordinary reproduc
tion. The birth both of the species and of the individua
are equally parts of that grand sequence of events whicl
our minds refuse to accept as the result of blind chance
The understanding revolts at such a eonclusion, whethe
or not we are able to believe that every slight variatior
of structure—the union of each pair in marriage—the dis
semination of each seed—and other such events, have al
been ordained for some special purpose.

Sexual selection has been treated at great length in thi:
work; for, as I have attempted to show, it has played ar
important part in the history of the organic world. I an
aware that much remains doubtful, but I have endeavorec
to give a fair view of the whole case. In the lower divis
ions of the animal kingdom, sexual selection seems to have
done nothing: such animals are often affixed for life to th
same spot, or have the sexes combined in the same indi
vidual, or, what is still more important, their perceptive
and intellectual faculties are not sufficiently advanced t

® The Rev. J. A. Picton gives a discussion to this effect in his ‘“New Thea
ries and the Old Faith,’’ 1870.
Descent—Vou. I.—16

790 THE DESCENT OF MAN

allow of the feelings of love and jealousy, or of the exer-
tion of choice. When, however, we come to the Arthro-
poda 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 crusta-
ceans—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 qual-
ities 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 odor-
iferous glands. ‘They are ornamented with infinitely diver-
sified appendages, and with the most brilliant or conspicuous
colors, often arranged in elegant patterns, while 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 devel-
oped 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 fe-
male somewhat resembles her young offspring throughout
life. In almost every great class a few anomalous cases
occur, where there has been an almost complete transposi-
tion 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 dif-

SEXUAL SELECTION IN RELATION TO MAN 791

ferences 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 in-
dividuals over others of the same sex, in relation to the
propagation of the species; while 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 the individuals of the same
sex, generally the males, in order to drive away or kill their
rivals, the females remaining passive; while 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 se-
lection is closely analogous to that which man unintention-
ally, yet effectually, brings to bear on his domesticated pro-
ductions, when he preserves during a long period the most
pleasing or useful individuals, without any wish to modify
the breed.

The laws of inneritance determine whether characters
gained through sexual selection by either sex shall be trans-
mitted 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 spe-
cies, as well as through natural selection in relation to the
general purposes of life. Hence secondary sexual charac-
ters, when equally transmitted to both sexes, can be distin-
guished from ordinary specific characters only by the light
of analogy. The modifications acquired through sexual se-
lection are often so strongly pronounced that the two sexes
have frequently been ranked as distinct species, or even as

792 THE DESCENT OF MAN

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 con-
fined 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 devel-
oped 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 elabo-
rate 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, characterized in some peculiar manner, the
offspring would slowly but surely become modified in ‘this
same manner. I have not attempted to conceal that, except-
ing 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 larger number of
offspring to inherit their superiority in ornaments or other
charms than the less attractive males; but I have shown
that this would probably follow from the females—espe-
cially the more vigorous ones, which would be the first to

SEXUAL SELECTION IN RELATION TO MAN 793

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 re-
member the fact, given on excellent authority in a former
chapter, that several peahens, when debarred from an ad-
mired 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 ap-
preciate the exquisite shading of the ball-and-socket orna-
ments and the elegant patterns on the wing feathers 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 orna-
ment. 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 esthetic capacity of the
females having been advanced through exercise or habit,
jast as our own taste is gradually improved. In the male,
through the fortunate chance of a few feathers being left

794 THE DESCENT OF MAN

unchanged, we can distinctly trace how simple spots with
a little fulvous shading on one side may have been devel-
oped by small steps into the wonderful ball-and-socket or-
naments; and it is probable that they were actually thus
developed.

Every one 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 con-
clusions, 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 appar-
ently 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 difter from each other in various characters,
as well as from their ancient and lowly organized 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 quali-
ties. Courage, pugnacity, perseverance, strength and size
of body, weapons of all kinds, musical organs, both vocal
and instrumental, bright colors and ornamental appendages,
have all been indirectly gained by the one sex or the other,

SEXUAL SELECTION IN RELATION TO MAN 795

through the exertion of choice, the influence of love and
jealousy, and the appreciation of the beautiful in sound,
color, or form; and these powers of the mind manifestly
depend on the development of the brain.

* Man scans with scrupulous care the character and pedi-
gree 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 re-
frain from marriage if they are in any marked degree in-
ferior in body or mind; but such hopes are Utopian, and

ill never be even partially realized until the laws of in-
heritance are thoroughly known. Every one does good
service who aids toward 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,
while the reckless marry, the inferior members tend to sup-
plant the better members of society. Man, like every other
animal, has no doubt advanced to his present high condi-
tion 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

796 THE DESCENT OF MAN

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 in-
crease, 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 quali-
ties are advanced, either directly or indirectly, much more
through the effects of habit, the reasoning powers, instruc-
tion, religion, etc., than through natural selection; though
to this latter agency may be safely attributed the social in-
stincts 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 organized 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 abso-
lutely naked and bedaubed with paint, their long hair was
tangled, their mouths frothed with excitement, and their
expression was wild, startled, and distrustful. They pos-
sessed 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

ks

SEXUAL SELECTION IN RELATION TO MAN. 797

life of his keeper, or from that old baboon, who, descending
from the mountains, carried away in triumph his young com-
rade 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 _BTossest
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 fora 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
godlike 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.

INDEX

INDEX

A

Abbot, C., on the battles of seals, 647.

Abductor of the fifth metatarsal, pres-
ence of, in man, 65.

Abercrombie, Dr., on disease of the
brain affecting speech, 124,

Abipones, marriage customs of the,
769.

Abou-Simbel, caves of, 225.

Abortion, prevalence of the practice
of, 70-71.

Abstraction, power of,
117-118.

Acalles, stridulation of, 400.

Acanthodactylus capensis, sexual dif-
ferences of color in, 463.

Accentor modularis, 611.

Acclimatization, difference of, in dif-
ferent races of men, 224.

Achetide, stridulation of the, 371,
372, 375; rudimentary stridulating
organs in female, 378.

Acilius sulcatus, elytra of the female,
364,

Acomus, development of spurs in the
female of, 580.

Acridiidz, stridulation of the, 372,
376; rudimentary stridulating or-
gans in female, 378.

Acromio-basilar muscle, and quad-
rupedal gait, 65.

Acting, universality of, 238.

Actinie, bright colors of, 345.

Adams, Mr., migration of birds, 148;
intelligence of nut-hatch, 530; on
the Bombycilla carolinensis, 594.

Admiral butterfly, 407.

Adoption of the young of other ani-
mals by female monkeys, 101.

Advancement in the organic scale,
Von Baer’s definition of, 219.

Aeby, on the difference between the
skulls of man and the quadrumana,
200.

in animals,

4Gsthetic faculty, not highly devel-
oped in savages, 129-130.

Affection, maternal, 100; manifesta-
tion of, by animals, 101; parental
and filial, partly the result of nat-
ural selection, 144; mutual, of
birds, 529; shown by birds in ~
confinement, for certain persons,
631,

Africa, probably the birthplace of
man, 208; South, crossed popula-
tion of, 232; South, retention of
color by the Dutch in, 256; South,
proportion of the sexes in the but-
terflies of, 330; tattooing practiced
in, 7°9; Northern, coiffure of na-
tives of, 740.

Agassiz, L., on conscience in dogs,
142; on the coincidence of the
races of man with zoological proy-
inces, 226; on the number of spe-
cies of man, 232; on the courtship
of the lJand-snails, 347; on the
brightness of the colors of male
fishes during the breeding season,
442; on the frontai protuberance
of the males of Geophagus and
Cichla, 442, 449; male fishes
hatching ova in their mouths,
449; sexual differences in color of
chromids, 449; on the slight sex-
ual differences “of the South Ameri-
eans, 722;-on the tattgoing of the
Amazonian Indians, 742.

Age, in relation to the transmission of
characters in birds, 598; variation
in accordance with, in birds, 624.

Ageleus pheniceus, 29%, 537.

Ageronia feronia, noise produced by,
402.

Agrion, dimorphism in, 380.

Ramburit, sexes of, 380.

Agrionide, difference in the sexes of,
380.

Agrotis exclamationts, 413.

(801)

802

Ague, tertian, dog suffering from, 24.
Aithurus polytmus, young of, 629,
Ainos, hairiness of the, 721.

Albino birds, 541.

Alca torda, young of, 627.

Alces palmata, 665.

Alder and Hancock, MM., on the nu-
dibranch mollusea, 349.

Allen, J. A., vigor of birds earliest
hatched, 281, 282; effect of differ-
ence of temperature, light, etc., on
birds, 296; colors of birds, 545; on
the relative size of the sexes of
Callorhinus ursinus, 666; on the
mane,of Otaria jubata, 672; on
the pairing of seals, 674; on sex-
ual differences in the color of bats,
690.

-— 8., on the habits of Holopierus,
475; on the plumes of herons, 506;
on the vernal moult of Herodias
bubulcus, 507.

Alligator, courtship of the male, 292,
456; roaring of the male, 730.

Amadavat, pugnacity of male, 475.

Amadina Lathamt, display of plumage
by the male, 518.

— castanotis, display of plumage by
the male, 518.

Amazons, butterflies of the,
fishes of the, 446.

America, variation in the skulls of ab-
origines of, 46; wide range of abo-
Tigines of, 226; lice of the natives
of, 227; general beardlessness of
the natives of, 722.

, North, butterflies of, 330; In-
dians of, women a cause of strife
among the, 723; Indians of, their
notions of female beauty, 1743,
746, 747,

+—., South, character of the natives
of, 224; population of parts of, 231;
piles of stones in, 238; extinction
of the fossil horse of, 254; desert
birds of, 632; slight sexual differ-
ence of the aborigines of, 722;
prevalence of infanticide in, 761.

American languages, often highly ar-
tificial, 127.

Americans, wide geographical range
of, 50; native, variability of, 232;
and negroes, difference of, 261;
aversion of, to hair on the face,
744,

Ammophila, on the jaws of, 363.

330;

INDEX

Ammotragus tragelaphus, hairy fore-
legs of, 686, 689.

Amphibia, affinity of, to the ganoid
fishes, 212; vocal organs of the,
730.

Amphibians, 220, 452; breeding while
immature, 625. :

Amphioxus, or lancelet, 213, 220. —

Amphipoda, males sexually mature
while young, 625.

Amunoph III., negro character of
features of, 225.

Anal appendages of insects, 362.

Analogous variation in the plumage
of birds, 498.

Anas, 595.

acuta, male plumage of, 508.

boschas, male piumage of, 507.

—— histrionica, 625.

punctata, 485.

Anastomus oscitans, sexes and young
of, 62%; white nuptial plumage of,
637,

Anatide, voices of, 486.

Anax junius, differences in the sexes
of, 381.

Andaman islanders, susceptible to
change of climate, 249.

Anderson, Dr., on the tail of Macacus
brunneus, 86; the Bufo sitkimmen-
sis, 454; sounds of Echis carinata,
459.

Andrena fulva, 384.

Anglo-Saxons, estimation of the beard
among the, 748.

Animals, domesticated, more fertile
than wild, 69; cruelty of savages
to, 160; characters common to
man and, 196; domestic change
of breeds of, 766.

Annelida, 350; colors of, 350.

Anobium tessellatum, sounds produced
by, 400.

Anolis cristatellus, male, crest of, 460;
pugnacity of the male, 460; throat-
pouch of, 461.

Anser canadensis, 587.

— cygnoides, 536; knob at the base

of the beak of, 550.

hyperboreus, whiteness of, 636,

Antelope, prong-horned, horns of, 309.

Antelopes, generally polygamous, 2847 ;
horns of, 309, 651; canine teeth of
some male, 648; use of horns of,
657; dorsal crests in, 686; dewlaps
of, 687; winter change of two spe-

INDEX

cies of, 700; peculiar markings of,
702-703.

Antennsz, furnished with cushions in
the male of Penthe, 864.

Anthidium manicatum, large male of,
367-368.

Anthocharis cardomines, 403, 408;
sexual difference of color in, 420.

— genutia, 408,

—— sara, 408.

Anthophora acervorum, large male of,
367-368.

— retusa, difference of the sexes
in, 384. ?

Anthropide, 204.

Anthus, moulting of, 506.

Antics of birds, 492.

Antigua, Dr. Nicholson’s observations
on yellow fever in, 258.

Antilocapra americana, horns of, 309,
651, 655.

Antilope bezoartica, horned females of,
652, 654, 655; sexual difference in
the color of, 692.

—— Dorcas, 652, and euchore, 661.

=— euchore, horns of, 657.

—— montana, rudimentary canines in
the young male of, 664.

~—— niger, sing-sing, caama, and gor-
gon, sexual differences in the colors
of, 692.

—— oreas, horns of, 308-309.

saiga, polygamous habits of, 287.

=—— sirepsiceros, horns of, 308.

—— subguiturosa, absence of suborbi-
tal pits in, 684.

Antipathy, shown by birds in confine-
ment, to certain persons, 531.

Ants, 197-198; large size of the cere-
bral ganglia in, 80; soldier-, large
jaws of, 91; playing together, 99;
memory in, 106; communication of,
by means of the antennz, 125; hab-
its of, 197; difference of the sexes in,
383; recognition of each other by,
after separation, 383.

-— = white, habits of, 382.

Anura, 453.

Apatania muliebris, male unknown,
337.

Apathus, difference of the sexes in, 384,

Apatura Iris, 401, 403.

Apes, difference of the young, from the
adult, 26; semi-erect attitude of some,
48; mastoid processes of, 78; influ-
ences of the jaw-muscles on the

808

physiognomy of, 80; female, desti-
tute of large canines, 92; building
platforms, 116; imitative faculties
of, 1%4; anthropomorphous, 206;
probable speedy extermination of
the, 210; Gratiolet on the evolu-
tion of, 236; canine teeth cf male,
648; females of some, less hairy be-
neath than the males, 773.

Apes, long-armed, their mode of pro-
gression, 78,

Aphasia, Dr. Bateman on, 124.

Apis mellifica, large male of, 367-368,

Apollo, Greek statues of, 748.

Apoplexy in Cebus Azara@, 23.

Appendages, anal, of insects, 364,

Approbation, influence of the love of,
149, 158, 178.

Aprosmictus scapulatus, 690.

Apus, proportion of sexes, 33%.

Aquatic birds, frequency of white plu-
mage in, 638.

Aquila chrysaétos, 527,

Arab women, elaborate and peculiar
coiffure of, 751.

Arabs, fertility of crosses with other
races, 228; gashing of cheeks and
temples among the, 739.

Arachnida, 358.

Arakhan, artificial widening of the fore-
head by the natives of, 750.

Arboricola, young of, 604.

Archeopteryx, 212.

Arctiide, coloration of the, 410.

Ardea asha, rufescens, and cerulea,
change of color in, 638,

cerulea, breeding in immature
plumage, 625.

— gularis, change of plumage in,
639.

herodias, love-gestures of the
male, 492.

—— ludoviciana, age of mature plu-
mage in, 624; continued growth of
crest and plumes in the male of, 626.

nycticorax, cries of, 477.

Ardeola, young of, 604.

Ardetta, changes of plumage in, 568.

Argenteuil, dolmen at, 41.

Argus pheasant, 497, 519-520, 596;
display of plumage by the male, 513;
ocellated spots of the, 654; gradation
of characters in the, 560.

Argyll, Duke of, on the physical weak-
ness of man, 91; the fashioning of
impiements peculiar to man, 2116; on

804

the contest in man between right and
wrong, 169; on the primitive civili-
zation of man, 193; on the plumage
of the male Argus pheasant, 513;
on Urosticte Benjamini, 570; on the
nests of birds, 584.

Argynnis, coloring of the lower sur-
face of, 410-411.

Aricoris epitus, sexual differences in
the wings of, 365.

Aristocracy, increased beauty of the,
154,

Arms, proportions of, in soldiers and
sailors, 54; direction of the hair on
the, 203.

and hands, free use of, indirectly

correlated with diminution of ea-

nines, 79.
Arrests of development, 58,
Arrowheads, stone, general resem-

blance of, 238.

Arrows, use of, 238. .

Arteries, variations in the course of
the, 47.

Artery, effect of tying, upon the lateral
channels, 53.

Arthropoda, 350.

Arts, practiced by savages, 239.

Ascension, colored incrustation on the
rocks of, 349.

Ascidia, affinity of the lancelet to, 213;
tadpole-like larvee of, 213.

Ascidians, 347; bright colors of some,
345.

Asinus, Asiatic and African species of,
707.

—— teniopus, 70%.

Ass, color variations of the, 707.

Ateles, effects of brandy on an, 24;
absence of the thumb in, 76.

beelzebuth, ears of, 33.

marginatus, color of the ruff of,
694; hair on the head of, 709.

Ateuchus, stridulation of, 400.

-, cicatricosus, habits of, 393.

Athalia, proportions of the sexes in,
336.

Atropos pulsatorius, 382,

Attention, manifestations of, in ani-
mals, 105.

Audouin, V., on a hymenopterous para-
site with a sedentary male, 292.

Audubon, J. J., on the pinioned goose,
144; on the speculum of Mergus
cucullatus, 311; on the pugnacity
of male birds, 469, 476; on Tetrao

INDEX

cupido, 47%: on Ardea nycticorax,
477; on Sturnella ludoviciana, 4717;
on the vocal organs of Tetrao cupido,
483; on the drumming of the male
Tetrao umbellus, 487; on sounds
produced by the night-jar, 488; on
Ardea herodias and Cathartes jota,
492; on Mimus polyglottus, 531; on
display in male birds, 508; on spring
change of color in some finches, 508;
recognition of a dog by a turkey,
532; selection of mate by female
birds, 537; on the turkey, 532, 540;
on variation in the male scarlet tan-
ager, 547; on the muskrat, 700; on
the habits of Pyranga estiva, 584;
on local differences in the nests of
the same species of birds, 587; on
the habits of woodpeckers, 590;
on Bombycilla carolinensis, 594; on
young females of Tyranga estiva
acquiring male characters, 595; on
the immature plumage of thrushes,
599; on the immature plumage of
birds, 601 e¢ seg.; on birds breed-
ing in immature plumage, 625; on
the growth of the crest and plumes
in the male Ardea ludoviciana, 626;
on the change of color in some spe-
cies of Ardea, 638.

Audubon and Bachman, MM., on squir-
rels fighting, 646; on the Canadian
lynx, 672.

Aughey, Prof., on rattlesnakes, 459.

Austen, N. L., on Anolis cristatellus,
460-461.

Australia, not the birthplace of man,
208; lice of the natives of, 227;
half-castes killed by the natives of,
228; prevalence of female infanti-
cide in, 762.

——,, South, variation in the skulls of
aborigines of, 46.

Australians, color of newborn children
of, 718; relative height of the sexes
of, 720; women a cause of war among
the, 723.

Axis deer, sexual difference in the color
of the, 693.

Aymaras, measurements of the, 56-573
no gray hair among the, 719; hair-
lessness of the face in the, 722; long
hair of the, 722.

Azara, on the proportion of men and
women among the Guaranys, 321;
on Palumedea cornuta, 476; on the

INDEX

beards of the Guaranys, 322; on
strife for women among the Guanas,
723; on infanticide, 743, 762; on
the eradication of the eyebrows and
eyelashes by the Indians of Para-
guay, 747; on polyandry among
the Guanas, 763; celibacy unknown
among the savages of South Amer-
ica, 764; on the freedom of divorce
among the Charruas, 769.

Babbage, C., on the greater proportion
of illegitimate female births, 321.

Babirusa, tusks of the, 670.

Baboon, revenge in a, 100; rage ex-
cited in, by reading, 102; manifes-
tation of memory by a, 105; employ-
ing a mat for shelter against the sun,
11%; protected from punishment by
its companions, 141.

, Cape, mane of the male, 672;
Hamadryas, mane of the male, 673.

Baboons, effects of intoxicating liquors
on, 24; ears of, 33; diversity of the
mental faculties in, 48; hands of,
46; habits of, 76; variability of the
tail in, 85; manifestation of maternal
affection by, 100; using stones and
sticks as weapons, 115; co-operation
of, 139; silence of, on plundering
expeditions, 143; apparent polygamy
of, 287; polygamous and social hab-
its of, 760.

Bachman, Dr., on the fertility of mulat-
toes, 228.

Baer, K. E. von, on embryonic devel-
opment, 26.

Bagehot, W., on the social virtues
among primitive men, 159; slavery
formerly beneficial, 159; on the value
of obedience, 176; on human prog-
ress, 179; on the persistence of sav-
age tribes in classical times, 243.

Bailly, B. M., on the mode of fighting
of the Italian buffalo, 657; on the
fighting of stags, 659.

Bain, A., on the sense of duty, 135;
aid springing from sympathy, 141;
on the basis of sympathy, 145; on
love of approbation, etc., 149; on the
idea of beauty, 752.

Baird, W., on a difference in color be-
tween the males and females of some
Entozoa, 344.

805

Baker, Sir 8., on the fondness of the
Arabs for discordant music, 492; on
sexual difference in the colors of an
antelope, 692; on the elephant and
rhinoceros attacking white or gray
horses, 698; on the disfigurements
practiced by the negroes, 698; on
the gashing of the cheeks and tem-
ples practiced in Arab countries, 7393
on the coiffure of the North Africans,
"40; on the perforation of the lower
lip by the women of Latooka, 741;
on the distinctive characters of the
eoiffure of Central African tribes,
Gerd on the coiffure of Arab women,

51.

Baker, Mr., observation on the propor-
tion of the sexes in pheasant-chicks,
326.

‘“‘Balz’’ of the Black-cock, 472, 523.

Bantam, Sebright, 279, 314.

Banteng, horns of, 653; sexual differ-
ences in the colors of the, 693.

Banyai, color of the, 745.

Barbarism, primitive, of civilized na-
tions, 193,

Barbs, filamentous, of the feathers, in
certain birds, 498, 555. ‘

Barrago, F., on the Simian resem-
blances of man, 19.

Barr, Mr., on sexual preference in dogs,
676.

Barrington, Daines, on the language of
birds, 121; on the clucking of the
hen, 477; on the object of the song
of birds, 479; on the singing of fe-
male birds, 480; on birds acquiring
the songs of other birds, 481; on the
muscles of the larynx in song birds,
481; on the want of the power of
song by female birds, 581.

Barrow, on the widow-bird, 520.

Bartels, Dr., supernumerary mamme in
men, 59.

Bartlett, A. D., period of hatching of
birds’ eggs, 220; on the tragopan,
290; on the development of the
spurs in Crossoptilon auritum, 310;
on the fighting of the males of Plec-
tropterus gambensis, 473; on the
knot, 505; on display in male birds,
509; on the display of plumage by
the male Polyplectron, 512; on Crog-
soptilon auritum and Phasianus wal-
lichii, 516; ou the habits of Lopho-
phorus, 542; on the color of the

806

mouth in Buceros bicornis, 549; on
the incubation of the cassowary, 616;
on the Cape Buffalo, 657; on the use
of the horns of antelopes, 657; on
the fighting of male wart-hogs, 671;
on Ammotragus tragelaphus, 686; on
the colors of Cercopithecus cephus,
694; on the colors of the faces of

. Monkeys, 711; on the naked sur-
faces of monkeys, 772.

Bartram, on the courtship of the male
alligator, 456.

Basque language, highly artificial, 127.

Bate, C. §., on the superior activity of
male crustacea, 292; on the propor-
tions of the sexes in crabs, 338; on
the chelz of crustacea, 352; on the
relative size of the sexes in crustacea,
355; on the colors of crustacea, 357.

Bateman, Dr., tendency to imitation in
certain diseased states, 104; on Apha-
sia, 124,

Bates, H. W., on variation in the form
of the head of Amazonian Indians,
49; on the proportion of the sexes
among Amazonian butterflies, 330;
on sexual differences in the wings of
butterflies, 365; on the field-cricket,
372; on Pyrodes pulcherrimus, 386;
on the horns of Lamellicorn beetles,
387-389; on the colors of Epicaliz,
etc., 403; on the coloration of tropi-
cal butterflies, 406; on the variability
of Papilio sesostris and childrene,
417; on male and female butterflies
inhabiting different stations, 418; on
mimicry, 422; on the caterpillar of a
Sphinx, 424; on the vocal organs of
the umbrella-bird, 485; on the tou-
eans, 635; on Brachyurus calvus,
T11.

Batokas, knocking out two upper in-
cisors, 740.

Batrachia, 453; eagerness of male, 292.

Bats, scent-glands, 683; sexual differ-
ences in the color of, 690; fur of
male frugivorous, 690.

Battle, law of, 194; among beetles, 392;
among birds, 468; among mammals,
646 ef seg.; in man, 723.

Beak, sexual difference in the forms of
the, 467; in the color of the, 496.

Beaks of birds, bright colors of, 634.

Beard, development of, in man, 717;
analogy of the, in man and the quad-
rumana, 718; variation of the de-

INDEX

velopment of the, in different races
of men, 719; estimation of, among
bearded nations, 748; probable ori-
gin of the, 775,

Beard, in monkeys, 202; of mammals,
686.

Beautiful, taste for the, in birds, 530;
in the quadrumana, 698,

Beauty, sense of, in animals, 128; ap-
preciation of, by birds, 533; influence
of, 738, 741; variability of the stand-
ard of, 767.

Beavan, Lieut., on the development of
the horns in Cervus Eldi, 308.

Beaver, instinct and intelligence of the,
97-98; voice of the, 681; castoreum
of the, 683.

Beavers, battles of male, 646.

Bechstein, on female birds choosing the
best singers among the males, 478;
on rivalry in song birds, 479; on the
singing of female birds, 480; on birds
acquiring the songs of other birds,
481; on pairing the canary and sis-
kin, 536; on a sub-variety of the
monk pigeon, 552; on spurred hens,
579,

Beddoe, Dr., on causes of difference in
stature, 53.

Bee-eater, harsh cry of, 482.

Bees, 137; pollen-baskets and stings
of, 91; destruction of drones and
queens by, 145; female, secondary
sexual characters of, 275; proportion
of sexes, 336; difference of the sexes
in color and sexual selection, 383-384,

Beetle, luminous larva of a, 365.

Beetles, 385; size of the cerebral gan-
glia in, 80; dilatation of the fore
tarsi in male, 363; blind, 385-386;
stridulation of, 394.

Belgium, ancient inhabitants of, 242.

Bell, Sir C., on emotional muscles in
man, 20; ‘‘snarling muscles,’’ 64;
on the hand, 77.

Bell, T., on the numerical proportion
of the sexes in moles, 325; on the
newts, 453; on the croaking of the
frog, 455; on the difference in
the coloration of the sexes in Zoo-
toca vivipara, 464; on moles fight-
ing, 646.

Bell-bird, sexual difference in the color
of the, 501.

Bell-birds, colors of, 635.

Belt, Mr.; on the nakedness of tropical

INDEX 807

mankind, 84; on a spider-monkey
and eagle, 140; habits of ants, 198;
Lampyride distasteful to mammals,
365; mimicry of Leptolides, 423; col-
ors of Nicaraguan frogs, 454; display
of humming-birds, 571; on the tou-
cans, 635; protective coloring of
skunk, 701.

Benevolence, manifested by birds, 531.
Bennett, A. W., attachment of mated
birds, 530; on the habits of Dromzus
irroratus, 617.

, Dr., on birds of paradise, 511.
Berbers, fertility of crosses with other
races, 228,

Bernicla antarctica, colors of, 635.
Bernicle gander pairing with a Canada
goose, 535.

Bert, M., crustaceans distinguish colors,
357.

Bertillon, M., arrested development and
polydactylism, 60.

Bettoni, E., on local differences in the
nests of Italian birds, 588.

Beyle, M., see Bombet.

Bhoteas, color of the beard in, 719.
Bbhringa, disciform tail-feathers of, 506.

Bianconi, Prof., on structures as ex-

plained through mechanical princi-
ples, 44.

Bibio, sexual differences in the genus,
368.

Bichat, on beauty, 752.

Bickes, proportion of sexes in man, 319.
Bile, colored, in many animals, 346.

Bimana, 200.

Birds, imitations of the songs of other
birds by, 104; dreaming, 106; killed
by telegraph wires, 113; language
of, 121; sense of beauty in, 128;
pleasure of, in incubation, 143; male,
incubation by, 218; and reptiles, al-
liance of, 220; sexual differences in
the beaks of some, 276; migratory,
arrival of the male before the fe-
male, 280; apparent relation be-
tween polygamy and marked sexual
differences in, 290; monogamous, be-
coming polygamous under domesti-
cation, 290; eagerness of male in
pursuit of the female, 291; wild,
numerical proportion of the sexes
in, 326; secondary sexual charac-

_ ters of, 466; difference of size in the
sexes of, 471; fights of male, wit-
nessed by females, 477; display’ of

malo, to captivate the females, 477;
close attention of, to the songs of
others, 479; acquiring the song of
their foster-parents, 481; brilliant,
rarely good songsters, 482; love-
antics and dances of, 492; colora-
tion of, 499 e¢ seg.; moulting of,
504 ef seg.; unpaired, 525; male,
singing out of season, 529; mutual
affection of, 530; in confinement, dis-
tinguish persons, 531; hybrid, pro-
duction of, 535; Albino, 541; Euro-
pean, number of species of, 5453
variability of, 545; geographical dis-
tribution of coloring, 546; gradation
of secondary sexual characters in,
554; obscurely colored, building con-
cealed nests, 585; young female ac-
quiring male characters, 595; breed-
ing in immature plumage, 624;
moulting of, 625; aquatic, fre-
quency of white plumage in, 636;
vocal courtship of, 730; naked skin
of the head and neck in, 773.

Birgus latro, habits of, 356.

Birkbeck, Mr., on the finding of new
mates by golden eagles, 527.

Birthplace of man, 208.

Births, numerical proportions of the
sexes in, in animals and man, 284-
286; male and female, numerical
proportion of, in England, 319.

Bischoff, Prof., on the agreement be-
tween the brains of man and of the
orang, 22; figure of the embryo of
the dog, 27; on the convolutions of
the brain in the human fcetus, 28;
on the difference between the skulls
of man and the quadrumana, 200;
resemblance between the ape’s and
man’s, 264,

Bishop, J., on the vocal organs of
frogs, 455; on the vocal organs
of corvine birds, 481; on the tra-
chea of the Merganser, 485.

Bison, American, co-operation of, 139;
mane of the male, 673.

Bitterns, dwarf, coloration of the sexes
of, 594,

Biziura lobata, musky odor of the male,
466; large size of male, 471.

Blackbird, sexual differences in the,
289; proportion of the sexes in
the, 327; acquisition of a song by,
481; color of the beak in the sexes
of the, 496, 634; pairing with a

808

thrush, 535; colors and nidification
of the, 586; young of the, 629; sex-
ual difference in coloration of the,
634.

Black-buck, Indian, sexual difference
in the color of the, 692.

Blackcap, arrival of the male before the
female, 280; young of the, 628,

Black-cock, polygamous, 290; propor-
tion of the sexes in the, 326; pug-
nacity and love-dance of the, 472;
eall of the, 486; moulting of the,
506; duration of the courtship of
the, 523; and pheasant, hybrids
of, 535; sexual difference in color-
ation of the, 634; crimson eye-cere
of the, 634.

Blacklock, Dr., on music, 737.

Black-grouse, characters of young, 600,
608.

Blackwall, J., on the speaking of the
magpie, 125; on the desertion of
their young by swallows, 147; on
the superior activity of male spiders,
292; on the proportion of the sexes
in spiders, 337; on sexual variation
of color in spiders, 358; on male spi-
ders, 359.

Bladder-nose seal, hood of the, 682.

Blaine, on the affections of dogs, 676.

Blair, Dr., on the relative liability of
Europeans to yellow fever, 257.

Blake, C. C., on the jaw from La Nau-
lette, 63.

Blakiston, Capt., on the American
snipe, 489; on the dances of Tetrao
phasianellus, 493.

Blasius, Dr., on the species of Euro-
pean birds, 545.

Bledius taurus, hornlike processes of
male, 391.

Bleeding, tendency to profuse, 312.

Blenkiron, Mr., on sexual preference
in horses, 677.

Blennies, crest developed on the head
of male, during the breeding season,
441-442.

Blethisa multipunctata, stridulation of,
396.

Bloch, on the proportions of the sexes
in fishes, 328.

Blood, arterial, red color of, 346.

—— pheasant, number of spurs in, 473.

Bluebreast, red-throated, sexual differ-
ences of the, 609.

Blumenbach, on Man, 49; on the large

INDEX

size of the nasal cavities in American
aborigines, 56; on the position of
man, 200; on the number of species
of man, 232.

Blyth, E., on the structure of the hand
in the species of Hylobates, 76;
observations on Indian crows, 14];
on the development of the horns in
the Koodoo and Eland antelopes, 308;
on the pugnacity of the males of Gal-
licrex cristata, 468; on the presence
of spurs in the female Euplocamus
erythrophthalmus, 473; on the pug-
nacity of the amadavat, 475; on the
spoonbill, 485; on the moulting of
Anthus, 506; on the moulting of
bustards, plovers, and Gallus ban-
kiva, 507; on the Indian honey-
buzzard, 54%; on sexual differences
in the color of the eyes of hornbills,
649; on Oriolus melanocephalus, 594;
on Paleornis javanicus, 595; on the
genus Ardetta, 595; on the peregrine
falcon, 595; on young female birds
acquiring male characters, 595; on
the immature plumage of birds, 600;
on representative species of birds,
604; on the young of Turnix, 614;
on Rhynchea bengalensis, 615; on
anomalous young of Lanius rufus’
and Colymbus glacialis, 622; on the
sexes and young of the sparrows,
623; on dimorphism in some herons,
625; on the ascertainment of the sex
of nestling bullfinches by pulling
out breast-feathers, 624; on orioles
breeding in immature plumage, 625;
on the sexes and young of Buphus
and Anastomus, 627; on the young
of the blackcap and blackbird, 628;
on the young of the stonechat, 629;
on the white plumage of Anastomus,
636; on the horns of Bovine animals,
653; on the horns of Antilope bezo-
artica, 655; on the mode of fighting
of Ovis cycloceros, 656; on the voice
of the Gibbons, 681; on the crest of
the male wild goat, 686; on the col-
ors of Portax picta, 691; on the
colors of Antilope bezoartica, 692;
on the color of the Axis deer, 693;
on sexual difference of color in Hy-
lobates hoolock, 694; on the hog-
deer, 705; on the beard and whis-
kers in a monkey becoming white
with age, 719.

INDEX

Boar, wild, polygamous in India, 288;
use of the tusks by the, 663; fight-
ing of, 669.

Boardman, Mr., Albino birds in U. &.,
541.

Boitard and Corbié, MM., on the trans-
mission of sexual peculiarities in
pigeons, 303; on the antipathy
shown by some female pigeons to
certain males, 539-540.

Bold, Mr., on the singing of a sterile
hybrid canary, 479.

Bombet, on the variability of the stand-
ard of beauty in Europe, 767.

Bombus, difference of the sexes in, 384,

Bombycidz, coloration of, 409; pairing
of the, 415; colors of, 415.

Bombycilla carolinensis, red append-
ages of, 594.

Bombyx cynthia, 366; proportion of the
sexes in, 330, 334; pairing of, 415.

mori, difference of size of the

male and female cocoons of, 366;

pairing of, 415.

Pernyi, proportion of sexes of,

334, :

—— Yamamai, 366; M. Personnat on,
331; proportion of sexes of, 334.

Bonaparte, C. L., on the call-notes of
the wild turkey, 486.

Bond, F., on the finding of new mates
by crows, 526.

Bone, implements of, skill displayed in
making, 74.

Boner, C., on the transfer of male char-
acters to an old female chamois, 651;
on the habits of stags, 665; on the
pairing of red deer, 674.

Bones, increase of, in length and thick-
ness, when carrying a greater weight,
54,

Bonizzi, P., difference of color in sexes
of pigeons, 303.

Bonnet monkey, 202.

Bonwick, J., extinction of Tasmanians,
244-245.

Boomerang, 194.

Boreus hyemalis, scarcity of the male,
337.

Bory St. Vincent, on the number of
species of man, 232; on the colors
of Labrus pavo, 445.

Bos etruscus, 653.

gaurus, horns of, 653.

moschatus, 684.

—— primigenius, 647.

809

Bos sondaicus, horns of, 653; colors
of, 692.

Botocudos, 193; mode of life of, 261;
disfigurement of the ears and lower
lip of the, 740-741.

Boucher de Perthes, J. C. de, on the
antiquity of man, 18.

Bourbon, proportion of the sexes in a
species of Papilio from, 330.

Bourien, on the marriage-customs of
the savages of the Malay Archi-
pelago, 770.

Bovidee, dewlaps of, 687.

Bower-birds, 524; habits of the, 493;
ornamented playing-places of, 128,
534,

Bows, use of, 238.

Brachycephalic structure, possible ex-
planation of, 82-83.

Brachyura, 355.

Brachyurus calvus, scarlet face of, 711.

Bradley, Mr., abductor ossis metatarsi
quinti in man, 65.

Brain, of man, agreement of the, with
that of lower animals, 22; convolu- .
tions of, in the human feetus, 28;
influence of development of mental
faculties upon the size of the, 80;
influence of the development of, on
the spinal column and skull, 82;
larger in some exisling mammals
than in their tertiary prototypes,
114; relation of the development
of the, to the progress of language,
123; disease of the, affecting speech,
123-124; difference in the convolu-
tions of, in different races of men,
224; supplement on, by Prof. Hux-
ley, 263; development of the gyri
and sulci, 269-270.

Brakenridge, Dr., on the influence of
climate, 53.

Brandt, A., on hairy men, 38.

Braubach, Prof., on the quasi-religious
feeling of a dog toward his master,
133; on the self-restraint of dogs,
142.

Brauer, F., on dimorphism in Neuro-
themis, 381.

Brazil, skulls found in caves of, 225;
population of, 231; compression of
the nose by the natives of, 750.

Break betweeu man and the apes, 209.

Bream, proportion of the sexes in the,
329.

Breeding, age of, in birds, 625.

810 INDEX

Breeding season, sexual characters
making their appearance in the, in
birds, 503-504.

Brehm, on the effects of intoxicating
liquors on monkeys, 243 on the rec-
ognition of women by male Cyno-
cephali, 25; on the diversity of the
mental faculties of monkeys, 48; on
the habits of baboons, 76; on re-
venge taken by monkeys, 101; on
manifestations of maternal affection
by monkeys and baboons, 101; on
the instinctive dread of monkeys for
serpents, 102-103; on the use of
stones as missiles by baboons, 115;
on a baboon using a mat for shelter
from the sun, 117; on the signal-
cries of monkeys, 122; on sentinels
posted by monkeys, 138; on co-oper-
ation of animals, 139; on an eagle
attacking a young Cercopithecus,
139; on baboons in confinement
protecting one of their number from
punishment, 141; on the habits of
baboons when plundering, 143; on
polygamy in Cynocephalus and Ce-
bus, 287; on the numerical propor-
tion of the sexes in birds, 326; on
the love-dance of the black-cock,
472; on Palamedea cornuta, 475;
on the habits of the Black-grouse,
476; on sounds produced by birds
of paradise, 488; on assemblages of
grouse, 524; on the finding of new
mates by birds, 528; on the fighting
of wild boars, 669; on the habits of
Cynocephalus hamadryas, 760.

Brent, Mr., on the courtship of fowls,
538.

Breslau, numerical proportion of male
and female births in, 320.

Bridgman, Laura, 123.

Brimstone butterfly, 407; sexual differ-
ence of color in the, 412.

British, ancient, tattooing practiced by,
739.

Broca, Prof., on the occurrence of the
supra-condyloid foramen in the hu-
man humerus, 41; anthropomor-
phous apes more bipedal than
quadrupedal, 78; on the capacity
of Parisian skulls at different peri-
ods, 81; comparison of modern and
medieval skulls, 81; on tails of
quadrupeds, 85-86; on the influ-
ence of natural selection, 88; on

hybridity in man, 227; on human
remains from Les Hyzies, 242; on
the cause of the difference between
Europeans and Hindus, 255.

Brodie, Sir B., on the origin of the
moral sense in man, 135.

Bronn, H. G., on the copulation of in-
sects of distinct species, 362.

Bronze period, men of, in Europe, 173.

Brown, R., sentinels of seals geuerally
females, 138; on the battles of seals,
646; on the narwhal, 649; on the
occasional absence of the tusks in
the female walrus, 649; on the blad-
der-nose seal, 682; on the colors
of the sexes in Phoca Greenlandica,
691; on the appreciation of music
by seals, 732; on plants used as
love-philters, by North American
women, 1743.

Brown, Dr. Crichton, injury to infants
during parturition, 320.

Brown-Séquard, Dr., on the inheritance
of the effects of operativus by guinea-
pigs, 87, 776.

Bruce, on the use of the elephant’s
tusks, 655.

Brulerie, P. de la, on the habits of
Ateuchus cicatricosus, 393; on the
stridulation of Ateuchus, 400.

Brimnich, on the pied ravens of the
Feroe Islands, 547.

Bryant, Dr., preference of tame pigeon
for wild mate, 540.

, Capt., on the courtship of Cal-
lorbinus ursinus, 674.

Bubas bison, thoracic projection of, 390.

Bucephalus capensis, difference of the
sexes of, in color, 457.

Bueeros, nidification and incubation of,
585.

— bicornis, sexual differences in the
coloring of the casque, beak, and
mouth in, 549,

— corrugatus, sexual differences in
the beak of, 496.

Bichner, L., on the origin of man, 19;
on the use of the human foot as a
prehensile organ, 77; on the mode
of progression of the apes, 78; on
want of self-consciousness, etc., in
savages, 118.

Bucholz, Dr., quarrels of chameleons,
463.

Buckland, F., on the numerical propor-
tion of the sexes in rats, 325; on the

INDEX

proportion of the sexes in the trout,
329; on Chimera monstrosa, 440.
Buckland, W., on the complexity of

crinoids, 12'7.

Buckler, W., proportion of sexes of

Lepidoptera reared by, 334,

Buckinghamshire, numerical proportion
of male and female births in, 319.
Bucorax abyssinicus, inflation of the

neck-wattle of the male during court-

ship, 496.

Budytes Raii, 280.
Buffalo, Cape, 657.
, Indian, horns of the, 653.

—, Italian, mode of fighting of the,
657.

Buffon, on the number of species of
man, 232.

Bufo sikimmensis, 454.

Bugs, 369.

Buist, R., on the proportion of the
sexes in salmon, 328; on the pug-
nacity of the male salmon, 433.

Bulbul, pugnacity of the male, 468;
display of under tail-coverts by the
male, 518.

Bull, mode of fighting of the, 657;
curled frontal hair of the, 686.

Buller, Dr., on the Huia, 276; the at-
tachment of birds, 530.

Bullfinch, sexual differences in the,
289; piping, 478; female, singing
of the, 480; courtship of the, 517;
widowed, finding a new mate, 527;
attacking a reed-bunting, 532; nest-
ling, sex ascertained by pulling out
breast-feathers, 624.

Bullfinches distinguishing persons, 532;
rivalry of female, 542.

Bulls, two young, attacking an old one,
139; wild, battles of, 647.

Bull-trout, male, coloring of, during the

' breeding season, 442.

Bunting, reed, head feathers of the
male, 518; attacked by a bullfinch,
532.

Buntings, characters of young, 599.

Buphus coromandus, sexes and young
of, 62%; change of color in, 638,

Burchell, Dr., on the zebra, 704; on
the extravagance of a Bushwoman
in adorning herself, 743; celibacy
unknown among the savages of
South Africa, 764; on the mar-
riage-customs of the Bushwomen,
470.

811

Burke, on the number of species of
man, 233.

Burmese, color of the beard in, 719.

Burton, Captain, on negro ideas of
female beauty, 746; on a universal
ideal of beauty, 749.

Bushmen, 94.

Bushwoman, extravagant ornamenta-
tion of a, 743.

Bushwomen, hair of, 224; marriage-
customs of, 770.

Bustard, throat-pouch of the male, 483;
humming noise produced by a male,
489; Indian, ear-tufts of, 498.

Bustards, occurrence of sexual differ-
ences and of polygamy among the,
289; love-gestures of the male, 493;
double moult in, 505.

Butler, A. G., on sexual differences in
the wings of Aricoris epitus, 365;
courtship of butterflies, 401; on the
coloring of the sexes in species of
Thecla, 405; on the resemblance
of Iphias glaucippe to a leaf, 408;
on the rejection of certain moths and
eaterpillars by lizards and frogs, 424,

Butterfly, noise produced by a, 402;
Emperor, 401, 403; meadow brown,
instability of the ocellated spots of,
552.

Butterflies, proportion of the sexes in,
330; forelegs, atrophied in some
male, 364; sexual difference in the
neuration of the wings of, 365; pug-
nacity of male, 401; protective re-
semblances of the lower surface of,
409; display of the wings by, 410;
white, alighting upon bits of paper,
414; attracted by a dead specimen
of the same species, 414; courtship
of, 414; male and female, inhabiting
different stations, 418.

Buxton, C., observations on macaws,
140; on an instance of benevolence
in a parrot, 531.

Buzzard, Indian honey-, variation in
the crest of, 547.

a

c

Cabbage butterflies, 407.

Cachalot, large head of the male, 649.

Cadences, musical perception of, by
animals, 732-733.

Czcum, 39; large, in the early pro-
genitors of man, 216.

812

Cairina moschata, pugnacity of the
male, 469.

Californian Indians, decrease of, 341.

Callianassa, chelz of, figured, 353.

Callidryas, colors of sexes, 415.

Callionymus lyra, characters of the
male, 434,

Callorhinus ursinus, relative size of the
sexes of, 666; courtship of, 674.

Calotes maria, 464.

-—— nigrilabris, sexual difference in
the color of, 463.

Cambridge, O. Picard, on the sexes of
spiders, 337; on the size of male
Nephila, 360.

Camel, canine teeth of male, 648, 664.

Campbell, J., on the Indian elephant,
288; on the proportion of male and
female births in the harems of Siam,
322.

Campylopterus hemileucurus, 327.

Canaries distinguishing persons, 531.

Canary, polygamy of the, 290; change
of plumage in, after moulting, 313;
female, selecting the best singing
male, 478; sterile hybrid, singing
of a, 479; female, singing of the,
480; selecting a greenfinch, 536;
and siskin, pairing of, 536.

Cancer pagurus, 352.

Canestrini, G., on rudimentary charac-
ters and the origin of man, 19; on
rudimentary characters, 28; on the
movement of the ear in man, 31; on
the variability of the vermiform ap-
pendage in man, 40; on the abnor-
mal division of the malar bone in
man, 61; on abnormal conditions of
the human uterus, 61; on the per-
sistence of the frontal suture in man,
62; on the proportion of the sexes in
silk-moths, 330-332; secondary sex-
ual characters of spiders, 359.

Canfield, Dr., on the horns of the An-
tilocapra, 309.

Canine teeth in man, 724; diminution
of, in man, 79; diminution of, in
horses, 79; disappearance of, in male
ruminants, 79; large, in the early
progenitors of man, 215.

Canines, and horns, inverse develop-
ment of, 663.

Canoes, use of, 73, 240.

Cantharis, difference of color in the
sexes of a species of, 386.

Cantbarus lineatus, 443.

INDEX

Capercailzie, polygamous, 290; propor:
tion of the sexes in the, 326; pug-
nacity of the male, 472; pairing of
the, 476; autumn meetings of the,
481; call of the, 486; duration of
the courtship of, 523; behavior
of the female, 542; inconvenience
of black color to the female, 572;
sexual difference in the coloration
of the, 634; crimson eye-cere of the
male, 634,

Capitonidee, colors and nidification of
the, 587.

Capra, egagrus, 656; crest of the male,
686; sexual difference in the color
of, 693.

Capreolus Sibiricus subecaudatus, 700,

Caprice, common to man and animals,
130,

Caprimulgus, noise made by the males
of some species of, with their wings,
487.

virginianus, pairing of, 476.

Carabide, 396.

Carbonnier, on the natura] history of
the pike, 328; on the relative size
of the sexes jn fishes, 436; court-
ship of Chinese Macropus, 444.

Ca rcineutes, sexual difference of color
in, 589,

Carcinus meenas, 354-356.

Cardinalis virginianus, 297.

Carduelis elegans, sexual differences of
the beak in, 467.

Carnivora, marine, polygamous habits
of, 288-289; sexual differences in
the colors of, 691.

Carp, numerical proportion of the sexes
in the, 329.

Carr, R., on the peewit, 475.

Carrier pigeon, late development of
the wattle in the, 313.

Carrion beetles, stridulation of, 395.

Carus, Prof. V., on the development
of the horns in merino sheep, 309.

Cassowary, sexes and incubation of
the, 616.

Castina, mode of holding wings, 411.

Castoreum, 683.

Casuarius galeatus, 616. ,

Cat, convoluted body in the extremity
of the tail of a, 43; sick, sympathy
of a dog with a, 141.

Cataract in Cebus Azarse, 23.

Catarrh, liability of Cebus Azaree to, 23.

Catarrhine monkeys, 205.

INDEX

Caterpillars, bright colors of, 424.

Cathartes aura, 537,

jota, love-gestures of the male,
492,

Catlin, G., correlation of color and text-
ure of hair in the Mandans, 261; on
the development of the beard among
North American Indians, 722; on
the great length of the hair in some’
North American tribes, 746.

Caton, J. D, on the development of
the horns in Cervus virginianus and
strongyloceros, 308; on the pres-
ence of traces of horns in the female
wapiti, 651; on the fighting of deer,
659; on the crest of the male wapiti,
686; on the colors of the Virginian
deer, 692; on sexual differences of
color in the wapiti, 693; on the
spots of the Virginia deer, 705.

Cats, dreaming, 106; tortoise-shell,
303, 305, 313; enticed by valerian,
685; colors of, 701.

Cattle, rapid increase of, in South
America, 71; domestic, lighter in
winter in Siberia, 302; horns of,
308-309, 653; domestic, sexual dif-
ferences of, late developed, 312;
numerical proportion of the sexes
in, 324,

Caudal vertebree, number of, in ma-
caques and baboons, 85; basal, of
monkeys, imbedded in the body, 86.

Cavolini, observations on Serranus, 216,

Cebus, maternal affection in a, 100;
gradation of species of, 233.

Apella, 272.

Azare, liability of, to the same
diseases as man, 23; distinct sounds
produced by, 119; early maturity of
the female, 718.

—— capucinus, polygamous, 287 ; sex-
ual differences of color in, 694; hair
on the head of, 708-709.

vellerosus, hair on the head of,
708-709.

Cecidomyide, proportions of the sexes
in, 335,

Celibacy, unknown among the savages
of South Africa and South America,
164,

Centipeds, 361.

Cephalopoda, absence of secondary sex-
ual characters in, 348.
Cephalopterus ornatus, 484,

—— penduliger, 485.

Descent— VoL.

813

Cerambyx herds, stridulant organ of,
396,

Ceratodus, padila of, 60.

Ceratophora aspera, ‘nasal appendages
of, 461-462.

Stoddartii, nasal horn of, 462.

Cerceris, habits of, 382.

sai aa zethiops, whiskers, etc., of,
11.

Cercopithecus, young, seized by an
eagle, and rescued by the troop,
139-140; definition of species of,
233,

—— cephus, sexual difference of color
in, 694, 712.

—cynosurus and griseovir idis, color
of the scrotum in, 694,

Diana, sexual differences of color

iu, 694, 713.

griseo-viridis, 139.

petaurista, whiskers, etc., of, 710.

Ceres, of birds, bright colors of, 634,

Ceriornis Temminckii, swelling of the
wattles of the male during courtship,
496,

Cervulus, weapons of, 663.

moschatus, rudimentary horns of
the female, 651.

Cervus alces, 308.

—— campestris, odor of, 684.

eanadensis, traces of horns in the
female, 651; attacking aman, 660;
sexual difference in the color of,
693, *

——elaphus, battles of male, 647;
horns of, with numerous points,
659.

— Eldi, 308.

—— mantchuricus, 705,

—— paludosus, colors of, 693.

strongyloceros, 308.

virginianus, 308; horns of, in
course of modification, 661.

Ceryle, male black-belted in some spe-
cies of, 589.

Cetacea, nakedness of, 83.

Ceylon, frequent absence of beard in
the natives of, 721.

Chaffinch, proportion of the sexes in
the, 327; courtship of the, 518,

Chaffinches, 479; new mates found by,
52",

Chaleophaps indicus,
young, 600.

Chalcosoma atlas, sexual differences
of, 387.

Il.—17

characters of

814

Chameeleo, sexual differences in the
genus, 462,

bifurcus, 462,

— Owenii, 462.

pumilus, 463,

Chamepetes unicolor, modified wing-
feather in the male, 489.

Chameleons, 460.

Chamois, danger-signals of, 138; trans-
fer of male characters to an old
female, 651.

Champneys, Mr., acromio-basilar mus-
cle and quadrupedal gait, 65.

Chapuis, Dr., on the transmission of
sexual peculiarities in pigeons, 303;
on streaked Belgian pigeons, 313,
575.

Char, male, coloring of, during the
breeding season, 442.

Characters, male, developed in females,
300; secondary sexual transmitted
through, both sexes, 300; natural,
artificial, exaggeration of, by man,
750.

Charadrius hiaticula and _ pluvialis,
sexes and young of, 696.

Chardin, on the Persians, 755,

Charms, worn by women, 743.

Charruas, freedom of divorce among
the, 769.

Chasmorhynchus, difference of color in
the sexes of, 501; colors of, 635.

-——— niveus, 501.

— nudicollis, 503.

tricarunculatus, 503.

Chastity, early estimation of, 161.

Chatterers, the sexual differences in,
289.

Cheever, Rev. H. T., census of the
Sandwich Islands, 341.

Cheiroptera, abseace of secondary sex-
ual characters in, 288.

Chele of crustacea, 352, 358.

Chelonia, sexual differences in, 455-
456.

Chenalopex sgyptiacus, wing knobs
of, 473,

Chera progne, 507, 541.

Chest, proportions of, in soldiers and
sailors, 54; large, of the Quichua
and Aymara Indians, 56.

Chevrotains, canine teeth of, 664.

Chiasognathus, stridulation of, 400.

Grantii, mandibles of, 393-394.

Children, legitimate and illegitimate,
proportion of the sexes in, 321.

INDEX

Chiloe, lice of the natives of, 227;
population of, 231.

Chimera monstrosa, bony process on
the head of the male, 440.

Chimeroid fishes, prehensile organs of
male, 431,

Chimpanzee, 722; ears of the, 32; rep-
resentatives of the eyebrows in the,
37; hands of the, 75; absence of
mastoid processes in the, 79; plat-
forms built by the, 96; cracking
nuts with a stone, 114; direction
of the hair on the arms of the,
203; supposed evolution of the,
236; polygamous and social habits
of the, 760.

China, North, idea of female beauty
in, 744,

——,, Southern, inhabitants of, 260.

Chinese, use of flint tools by the, 195;
difficulty of distinguishing the races
of the, 223; color of the beard in,
719; general beardlessness of the,
721; opinions of the, on the appear-
ance of Europeans and Cingalese,
744; compression of the feet of, 750.

Chinsurdi, his opinion of beards, 741,
148.

Chlamydera maculata, 493.

Chloéon, pedunculated eyes of the male
of, 362.

Chloephaga, coloration of the sexes in,
593.

Chloroccelus Tanana (figured), 373.

Chorda Dorsalis, 215.

Chough, red beak of the, 634.

Chromide, frontal protuberance in
male, 442; sexual differences in
color of, 449.

Chrysemys picta, long claws of the
male, 456.

Chrysococcyx, characters of young of,
600

Chrysomelide, stridulation of, 395.

Cicada pruinosa, 371.

septendecim, 371.

Cicadee, songs of the, 370; rudiment-
ary sound-organs in females of, 377-
378.

Cicatrix of a burn, causing modification
of the facial bones, 82.

Cichla, frontal protuberance of male,
442,

Cimetiére du Sud, Paris, 41.

Cincloramphus cruralis, large size of
male, 471.

INDEX

Cinclus aquaticus, 587,

Cingalese, Chinese opinion of the ap-
pearance of the, 744,

Cirripeds, complemental males of, 275.

Civilization, effects of, upon natural
selection, 180; influence of, in the
competition of nations, 243.

Clanging of geese, etc., 478.

Claparéde, E., on natural selection ap-
plied to man, 73.

Clarke, on the marriage-customs of the
Kalmucks, 770.

Classification, 199.

Claus, C., on the sexes of Saphirina,
357,

Cleft- palate, inherited, 58.

Climacteris erythrops, sexes of, 618.

Climate, 52; cool, favorable to human
progress, 179; power of supporting
extremes of, by man, 242; want of
connection of, with color, 255.

Cloaca, existence of a, in the early pro-
genitors of man, 215.

Cloacal passage existing in the human
embryo, 26,

Clubs, used as weapons before disper-
sion of mankind, 239,

Clucking of fowls, 478.

Clythra 4-punctata, stridulation of, 395.

Coan, Mr., and the Sandwich Islanders,
249.

Cobbe, Miss, on morality in hypotheti-
eal bee-community, 137.

Cobra, ingenuity of a, 458.

Coccus, 197.

Coccyx, 42; in the human embryo, 26;
convoluted body at the extremity of
the, 43 ; imbedded in the body, 85-86.

Cochin-China, notions of beauty of the
inhabitants of, 744, 746.

Cock, blind, fed by its companions,
141; game, killing a kite, 471; comb
and wattles of the, 520; preference
shown by the, for young hens, 542;
game, transparent zone in the hackles
of a, 555-556.

Cock of the rock, 523.

Cockatoos, 634-635, 637; nestling, 531;
black, immature plumage of, 602.
Coelenterata, absence of secondary sex-

ual characters in, 344,

Coffee, fondness of monkeys for, 23-24.

Cold, supposed effects of, 53; power of
supporting, by man, 242.

Coleoptera, 385; stridulation of, 374;
stridulant organs of, discussed, 397.

315

Colias edusa and hyale, 416.

Collingwood, C., on the pugnacity of the
butterflies of Borneo, 402; on butter-
flies being attracted by a dead speci-
men of the same species, 414.

Colobus, absence of the thumb, 76.

Colombia, flattened heads of savages
of, 740.

Colonists, success of the English as,
191,

Coloration, protective, in birds, 631.

Color, supposed to be dependent on
light and heat, 63; correlation of,
with immunity from certain poisons
and parasites, 256; purpose of, in
lepidoptera, 412; relation of, to sex-
ual functions, in fishes, 446; differ-
ence of, in the sexes of snakes, 456-
457; sexual differences of, in lizards,
463; influence of, in the pairing of
birds of different species, 536; rela-
tion of, to nidification, 585, 587;
sexual differences of, in mammals,
689, 699; recognition of, by quad-
Tupeds, 698; of children, in different
races of man, 717-718; of the skin
in man, 777.

Colors, admired alike by man and ani-
mals, 128-129; bright, due to sexual
selection, 345; bright, among the
lower animals, 345-346; bright, pro-
tective to butterflies and moths, 409;
bright, in male fishes, 43%, 444;
transmission of, in birds, 577.

Colquhoun, example of reasoning in a
retriever, 110-111.

Columba passerina, young of, 602.

Colymbus glacialis, anomalous young
of, 622.

Comb, development of, in fowls, 314.

Combs and wattles in male birds, 520.

Community, preservation of variations
useful to the, by natural selection, 91.

Composite, gradation of species among
the, 233.

Comte, C., on the expression of the
ideal of beauty by sculpture, 748.

Conditions of life, action of changed,
upon man, 51; influence of, on plu-
mage of birds, 609.

Condor, eyes and comb of the, 549.

Conjugations, origin of, 127. :

Conscience, 155, 171; absence of, in
some criminals, 158,

Constitution, difference of, in different
races of men, 224 e¢ seg.

816

Consumption, liability of Cebus Azarz
to, 23; connection between complex-
ion and, 257-258.

Convergence of characters, 236.

Cooing of pigeons and doves, 486,

Cook, Capt., on the nobles of the Sand-
wich Islands, 754,

Cope, E. D., on the Dinosauria, 212.

Cophotis ceylanica, sexual differences
of, 460, 463,

Copris, 388.

Isidis, sexual differences of, 388.

—— lunaris, stridulation of, 396.

Corals, bright colors of, 345.

Coral-snakes, 458.

Cordylus, sexual difference of color in a
species of, 463.

Corfu, babits of the chaffinch in, 324.

Cornelius, on the proportions of the
sexes in Lucanus cervus, 335.

Corpora wolffiana, 215; agreement of,
with the kidneys of fishes, 26-27.

Correlated variation, 67.

Correlation, influence of, in the produc-
tion of races, 261.

Corse, on the mode of fighting of the
elephant, 663.

Corvus corone, 526.

— graculus, red beak of, 634.

— pica, nuptial assembly of, 525,

Corydalis cornutus, large jaws of the
male, 363.

Cosmetornis, 596,

vexillarius, elongation of wing
feathers in, 497, 519, 520.

Cotingide, sexual differences in, 289;
coloration of the sexes of, 593; re-
semblance of the females of distinct
species of, 606.

Cottus scorpius, sexual differences in,
438,

Coulter, Dr., on the Californian Indians,
341.

Counting, origin of, 193-194; limited
power of, in primeval man, 239.

Courage, variability of, in the same spe-
cies, 99; universal high appreciation
of, 161; importance of, 176; charac-
teristic of men, 726.

Courtship, greater eagerness of males
in, 292; of fishes, 432, 443-444; of
birds, 476, 623.

Cow, winter change of color, 700.

Crab, devil, 355.

, Shore, habits of, 354.

«-—-, soldier, male of the, 354,

INDEX

Crabro cribrarius, dilated tibiae of the
male, 364,

Crabs, proportions of the sexes in,
337-338,

Cranz, on the inheritance of dexterity
in seal catching, 54.

Crawfurd, on the number of species of
man, 233,

Crenilabrus massa and C. melops, nests
built by, 448.

Crest, origin of, in Polish fowls, 304.

Crests, of birds, difference of, in the
sexes, 603; dorsal hairy, of mam-
mals, 685.

Cricket, field-, stridulation of the, 373;
pugnacity of male, 379.

—— house-, stridulation of the, 372-
373. ‘

Crickets, sexual differences in, 380.

Crinoids, complexity of, 127.

Crioceridze, stridulation of the, 395,

Croaking of frogs, 455.

Crocodiles, musky odor of, during the
breeding season, 456.

Crocodilia, 456.

Crossbills, characters of young, 599.

Crosses in man, 230-231.

Crossing of races, effects of the, 254.

Crossoptilon auritum, 516, 582, 609;
adornment of both sexes of, 310;
sexes alike in, 593.

Crotch, G. R., on the stridulation of
beetles, 395, 398; on the stridulation
of Heliopathes, 399; on the stridula-
tion of Acalles, 400; habit of female
deer at breeding time, 650.

Crow Indians, long hair of the, 746.

, young of the, 621,

Crows, 634; vocal organs of the, 4813
living in triplets, 528.

——, carrion, new mates found by,
526.

, Indian, feeding their blind com-
panions, 141.

Cruelty of savages to animals, 160.

Crustacea, parasitic, loss of limbs by
female, 276; prehensile feet and an-
tenne of, 277; male, more active
than female, 292; parthenogenesis
in, 335; secondary sexual charac-
ters of, 350; amphipod, males sex-
ually mature while young, 526; audi-
tory hairs of, 732.

Crystal worn in the lower lip by some
Central African women, 741.

Cuckoo fowls, 314.

INDEX

Culicidee, 275, 369; attracted by each
other’s humming, 369.

Cullen, Dr., on the throat-pouch of the
male bustard, 483.

Cultivation of plants, probable origin
of, 180.

Cupples, Mr., on the numerical propor-
tion of the sexes in dogs, sheep, and
cattle, 323-324; on the Scotch deer
hound, 667; on sexual preference in

~ dogs, 676.

Curculionide, sexual difference in
length of snout in some, 276; horn-
like processes in male, 391; musi-
eal, 396.

Curiosity, manifestations of, by ani-
mals, 102.

Curlews, double moult in, 504,

Cursores, comparative absence of sexual
differences among the, 290.

Curtis, J., on the proportion of the
sexes in Athalia, 335-336,

Cuvier, F., on the recognition of women
by male quadrumana, 25,

, G., on the number of caudal ver-
tebre in the mandrill, 85; on instinct
and intelligence, 96; views of, as to
the position of man, 200; on the
position of the seals, 201; on Hecto-
cotyle, 348,

Cyanaleyon, sexual difference in colors
of, 589; immature plumage of, 602.

Cyanecula suecica, sexual differences
of, 609.

Cychrus, sounds produced by, 398.

Cycnia mendica, sexual difference of,
in color, 412,

Cygnus ferus, trachea of, 485.

olor, white young of, 623.

Cyllo Leda, instability of the ocellated
spots of, 552.

Cynanthus, variation in the genus, 546.

Cynipide, proportions of the sexes in,
335.

Cynocephalus, difference of the young
from the adult, 25; male, recognition
of women by, 25; polygamous habits
of species of, 287.

—— chacma, 101.

—— gelada, 115.

—— hamadryas, 115, 760; sexual dif-
ference of color in, 696.

leucophus, colors of the sexes of,
695.

~~—— mormon, colors of the male, 695—-
696, 711.

817

Cynocephalus porcarius, mane of the
male, 672.

patos, proportions of the sexes in,

37.

Cyprinids, proportion of the sexes in
the, 329,

——, Indian, 446,

Cyprinodontids, sexual differences in
the, 437, 439,

Cyprinus auratus, 446,

Cypris, relations of the sexes in, 337.

Cyrtodactylus rubidus, 460.

Cystophora cristata, hood of, 682.

D

Dacelo, sexual difference of color in,
589.

Gaudichaudi, young male of, 602.

Dal-ripa, a kind of ptarmigan, 326,

Damalis albifrons, peculiar markings
of, 703-704.

pe pygarga, peculiar markings of,

03.

Dampness of climate, supposed infi.-
ence of, on the color of the skin,
53, 256,

Danaide, 403.

Dances of birds, 492.

Dancing, universality of, 238.

Daniell, Dr., his experience of resi-
dence in West Africa, 258.

Darfur, protuberances artificially pro-
duced by natives of, 739.

Darwin, F., on the stridulation of Der-
mestes murinus, 395.

Dasychira pudibunda, sexual difference
of color in, 412,

Davis, A. H., on the pugnacity of the
male stag-beetle, 392.

—, J. B., on the capacity of the
skull in various races of men, 815
on the beards of the Polynesians,
722,

Death-rate higher in towns than in rural
districts, 187.

Death-tick, 400.

De Candolle, Alph., on a case of in-
herited power of moving the scalp,
30-31.

Declensions, origin of, 127.

Decoration in birds, 495.

Decticus, 375.

Deer, 308; development of the horns
in, 308; spots of young, 599, 706;

818

horns of, 650, 653; use of horn of,
659, 668; horns of a, in course of
modification, 660; size of the horns
of, 665; female pairing with one
male, while others are fighting for
her, 673; male, attracted by the
voice of the female, 680; male, odor
emitted by, 684.

Deer, Axis, sexual difference in the
eolor of the, 693.

-—, fallow, different colored herds
of, 698.

-——, Mantchurian, 705,

—, Virginian, 705; color of the, not
affected by castration, 692; colors
of, 693.

Deerhound, Scotch, greater size of the
male, 312, 667.

Defensive organs of mammals, 668,

De Geer, C., on a female spider destroy-
ing a male, 360.

Dekay, Dr., on the bladder-nose seal,
682.

Delorenzi, G., division of malar bone,
61.

Temerara, yellow fever in, 257.

Dendrocygna, 600.

Dendrophila frontalis, young of, 629.

Denison, Sir W., manner of ridding
themselves of vermin among the
Australians, 84; extinction of Tas-
manians, 244.

Denny, H., on the lice of domestic ani-
mals, 227.

Dermestes murinus, stridulation of the,
395.

Descent traced through the mother
alone, 757.

Deserts, protective coloring of animals
inhabiting, 632.

Desmarest, on the absence of suborbital
pits in Antilope subgutturosa, 684;
on the whiskers of Macacus, 687;
on the color of the opossum, 689; on
the colors of the sexes of Mus minu-
tus, 690; on the coloring of the
ocelot, 690; on the colors of seals,
691; on Antilope caama, 692; on
the colors of goats, 693; on sexual
difference of color in Ateles margi-
natus, 694; on the mandrill, 695; on
Macacus cynomolgus, 718.

‘Desmoulins, on the number of species
of man, 233; on the musk-deer,
685.

INDEX

Desor, on the imitation of man by mon-
keys, 104,

Despine, P., on criminals destitute of
conscience, 158,

Development, embryonic, of man, 25-
28; correlated, 550.

Devil, not believed in by the Fuegians,
132.

Devil-crab, 355,

Devonian, fossil insect from the, 378.

Dewlaps, cattle and antelopes furnished
with, 687.

Diadema, sexual differences of coloring
in the species of, 403.

Diamond-beetles, bright colors of, 385.

Diastema, occurrence of, in man, 58.

Diastylide, proportion of the sexes in,
337.

Dicrurus, racket-shaped feathers in,
497; nidification of, 584,

—— macrocercus, change of plumage
in, 594,

Didelphis opossum, sexual difference
in the color of, 689.

Differences, comparative, between dif-
ferent species of birds of the same
sex, 606.

Digits, supernumerary, more frequent
in men than in women, 295; super-
numerary, inheritance of, 306; su-
pernumerary, early development of,
312.

Dimorphism in females of water-beetles,
364; in Neurothemis and Agrion,
381-382.

Diodorus, on the absence of beard in
the natives of Ceylon, 721.

Dipelicus Cantori, sexual differences of,
388.

Diplopoda, prehensile limbs of the
male, 361.

Dipsas cynodon, sexual difference in
the color of, 457.

Diptera, 369.

Disease, generated by the contact of
distinct peoples, 243.

Diseases common to man and the lower
animals, 23; difference of liability
to, in different races of men, 224;
new, effects of, upon savages, 243;
sexually limited, 312.

Display, coloration of Lepidoptera for,
410; of plumage by male birds, 508,
519.

Distribution, wide, of man, 73; geo-

INDEX

graphical, as evidence of specific
distinctness in man, 226,

Wisuse, effects of, in producing rudi-
mentary organs, 29; and use of
parts, effects of, 53; of parts, in-
fluence of, on the races of men,
261.

Divorce, freelom of, among the Char-
Tuas, 769,

Dixon, E. §., on the pairing of different
species of geese, 535; on the court-
ship of peafowl, 542.

Dobrizhoffer, on the marriage-customs
of the Abipones, 770.

Dobson, Dr., on the Cheiroptera, 288;
scent-glands of bats, 683; frugivo-
rous bats, 689-690.

Dogs, suffering from tertian ague, 24;
memory of, 106; dreaming, 106; di-
verging when drawing sledges over
thin ice, 107; exercise of reasoning
faculties by, 110-111; domestic prog-
ress of, in moral qualities, 114; dis-
tinct tones uttered by, 119; paral-
lelism between his affection for his
master and religious feeling, 133;
sociability of the, 138; sympathy
of, with a sick cat, 141; sympathy
of, with his master, 141; their pos-
session of conscience, 142; possible
use of the hair on the forelegs of
the, 203; races of the, 235; nu-
merical proportion of male and fe-
male births in, 323; sexual affection
between individuals of, 677; howl-
ing at certain notes, 732; rolling in
carrion, 685.

Dolichocephalic
cause of, 82.

Dolphins, nakedness of, 83.

Domestic animals, races of, 235; change
of breeds of, 766-767.

Domestication, influence of, in remov-
ing the sterility of hybrids, 229-
230.

D’Orbigny, A., on the influence of
dampness and dryness on the color
of the skin, 256; on the Yuracaras,
7146.

Dotterel, 616.

Doubleday, H., on sexual differences in
the wings of butterflies, 365.

——, H., on the proportion of the sexes
in the smaller moths, 331; on the
attraction of the males of Lasio-

structure, possible

819

campa quercus and Saturnia carpini
by the female, 333; on the propor-
tion of the sexes in the Lepidoptera,
333; on the ticking of Anobium tes-
selatum, 400; on the structure of
Ageronia feronia, 402; on white but-
terflies alighting upon paper, 414.

Douglas, J. W., on the sexual differ-
ences of the Hemiptera, 369; on the
colors of British Homoptera, 372.

Down of birds, 504-505.

Draco, gular appendages of, 461.

Dragonet, Gemmeous, 437.

Dragon-flies, caudal appendages of
male, 364; relative size of the sexes
of, 367; difference in the sexes of,
381; want of pugnacity by the male,
382.

Drake, breeding plumage of the com-
mon, 507.

Dreams, 106; a possible source of the
belief in spiritual agencies, 131,

Drill, sexual difference of color in the,
695.

Dromeeus, irroratus, 61.

Dromolza, Saharan species of, 588.

Drongo shrike, 594.

Drongos, racket-shaped feathers in the
tails of, 497, 506.

Dryness, of climate, supposed influence
of, on the color of the skin, 256.

Dryopithecus, 208.

Duck, harlequin, age of mature plu-
mage in the, 624; breeding in imma-
ture plumage, 625.

——, long-tailed, preference of male,
for certain females, 542.

——,, pintail, pairing with a widgeon,
536. :

, voice of the, 485; pairing with a
shield-drake, 535; immature plu-
mage of the, 601-602.

——, wild, sexual differences in the,
289; speculum and male characters
of, 311; pairing with a pintail drake,
526.

Ducks, wild, becoming polygamous
under partial domestication, 290;
dogs and cats recognized by, 532.

Dufossé, Dr., sounds produced by fish,
451.

Dugong, nakedness of, 83; tusks of,
648.

Dujardin, on the relative size of the
cerebral ganglia in insects, 80.

820

Duncan, Dr., on the fertility of early
marriages, 186; comparative health
of married and single, 189.

Dupont, M., on the occurrence of the
supra-condyloid foramen in the hu-
merus of man, 41,

Durand, J. P., on causes of variation,
51,

Dureau de la Malle, on the songs of
birds, 121; on the acquisition of an
air by blackbirds, 481.

Dutch, retention of their color by the,
in South Africa, 256,

Duty, sense of, 134.

Duvaueel, female Hylobates washing
her young, 100-101.

Dyaks, pride of, in mere homicide, 159.

Dynastes, large size of males of, 367.

Dynastini, stridulation of, 397.

Dytiscus, dimorphism of females of,
364; grooved elytra of the female,
364.

E

Eagle, young Cercopithecus rescued
from, by the troop, 139-140.

, white-headed, breeding in imma-
ture plumage, 625.

Eagles, golden, new mates found by,
527

Ear, motion of the, 31; external shell
of the, useless in man, 32; rudi-
‘mentary point of the, in man, 33.

Ears, more variable in men than
women, 295; piercing and orna-
mentation of the, 740-741.

Earwigs, parental feeling in, 145.

Echidna, 209.

Echini, bright colors of some, 345.

Echinodermata, absence of secondary
sexual characters in, 344,

Echis carinata, 459,

Ecker, figure of the human embryo,
27; on the development of the gyri
and sulci of the brain, 270; on the
sexual differences in the pelvis in
man, 717; on the presence of a sa-
gittal crest in Australians, 719.

Edentata, former wide range of, in
America, 226; absence of second-
ary sexual characters in, 288.

Edolius, racket-shaped feathers in the,
497,

Edwards, Mr., on the proportion of the

INDEX

sexes in North American species of
Papilio, 330.

Eels, hermaphroditism of, 216.

Egerton, Sir P., on the use of the ant-
lers of deer, 659; on the pairing of
red deer, 647; on the bellowing —
of stags, 679.

Eggs, hatched by male fishes, 540.

Egret, Indian, sexes and young of the,
627.

Egrets, breeding plumage of, 631;
white, 635.

Ehrenberg, on the mane of the male
Hamadryas baboon, 673.

Ekstrém, M., on Harelda glacialis, 543.

Elachista rufocinerea, habits of male,
332.

Eland, development of the horns of
the, 309.

Elands, sexual differences of color in,
692

Elaphomyia, sexual differences in, 368
369. :

Elaphrus uliginosus, stridulation of,
396.

Elaps, 459.

Elaterids, proportions of the sexes in,
335.

Elaters, luminous, 366.

Elephant, 209; rate of increase of the,
71; nakedness of the, 83; Indian,
forbearance to his keeper, 142; po-
lygamous habits of the, 288; pug-
nacity of the male, 647; tusks of,
648, 649, 655, 656, 664; Indian, mcde
of fighting of the, 663; male, odor
emitted by the, 683; altacking white
or gray horses, 698.

a a of abode, modifying influence
of, 5%.

Elimination of inferior individuals, 188.

Elk, 656; winter change of the, 700.

——, Irish, horns of the, 665.

Ellice Islands, beards of the natives,
721-722, 748.

Elliot, R., on the numerical proportion
of the sexes in young rats, 325; on
the proportion of the sexes in sheep,
324,

—, D. G., on Pelecanus erythro-
rhynchus, 603.

—, Sir W., on the polygamous habits
of the Indian wild boar, 288.

Ellis, on the prevalence of infanticide
in Polynesia, 761.

INDEX

Gphinstone, Mr., on local differences
of stature among the Hindus, 52; on
the difficulty of distinguishing the
native races of India, 223.

Elytra, of the females of Dytiscus,
Acilius, Hydroporus, 364,

Emberiza, characters of young, 599.

miliaria, 599.

scheeniclus, 6532;
of the male, 518.

Embryo of man, 25-28; of the dog, 27.

Embryos of mammals, resemblance of
the, 45.

Emigration, 185.

Emotions experienced by the lower ani-
mals in common with man, 98-99;
manifested by animals, 100-102.

Emperor moth, 412.

Emu, sexes and incubation of, 617.

Emulation of singing-birds, 479.

Endurance, estimation of, 161.

Energy, a characteristic of man, 728.

England, numerical proportion of male
and female births in, 318-319.

Engleheart, Mr., on the finding of new
mates by starlings, 528.

English, success of, as colonists, 191.

Engravers, short-sighted, 55.

Entomostraca, 355.

Entozoa, difference of color between
the males and females of some, 344,

Envy, persistence of, 153.

Eocene period, possible divergence of
man during the, 209.

Eolide, colors of, produced by the
biliary glands, 346.

Epeira nigra, small size of the male of,
360. .

Ephemere, 362.

Ephemeridz, 380.

Ephippiger vitium, stridulating organs
of, 375, 378.

Epicalia, sexual differences of coloring
in the species of, 403.

Equus hemionus, winter change of, 700.

Erateina, coloration of, 411.

Ercolani, Prof., hermaphroditism in
eels, 216.

Erect attitude of man, 7%.

Eristalis, courting of, 369.

Eschricht, on the development of hair
in man, 37; on a lanuginous mus-
tache in a female foetus, 38; on the
want of definition between the scalp
and the forehead in some children,

_ head-feathers

821

202; on the arrangement of the hair
in the human foetus, 203; on the
hairiness of the face in the human
foetus of both sexes, 775-776.

Eskimo, 92, 179; their belief in the in-
heritance of dexterity in seal-catch-
ing, 54; mode of life of, 260.

Esmeralda, difference of color in the
sexes of, 387,

Esox lucius, 328,

——.reticulatus, 443,

Estrelda amandava, pugnacity of the
male, 475.

Eubagis, sexual differences of coloring
in the species of, 404.

Euchirus longimanus, sound produced
by, 397.

Eudromias morinellus, 616.

Eulampis jugularis, colors of the female,
685.

Euler, on the rate of increase in the
United States, 68.

Eumomota superciliaris, racket-shaped
feathers in the tail of, 497.

Eupetomena macroura, colors of the
female, 685.

Euphema splendida, 590.

Euplocamus erythrophthalmus, posses-
sion of spurs by the female, 473.

Europe, ancient inhabitants of, 242.

Europeans, difference of, from Hindus,
254; hairiness of, probably due to
reversion, 774.

Eurostopodus, sexes of, 618.

Eurygnathus, different proportions of
the head in the sexes of, 365.

Eustephanus, sexual differences of spe-
cies of, 467; young of, 629.

Exaggeration of natural characters by
man, 749.

Exogamy, 757, 760.

Expression, resemblanc-s in, between
man and the apes, 201-202.

Extinction of races, causes of the,
241,

Eye, destruction of the, 53; change of
position in, 82; obliquity of, re-
garded as a beauty by the Chinese
and Japanese, 744.

Eyebrows, elevation of, 30-31; devel

opment of long hairs in, 37; in mon-

keys, 202; eradicated in parts of
South America, and Africa, 740;
eradication of, by the Indians ot
Paraguay, 747.

822

Eyelashes, eradication of, by the In-
dians of Paraguay, 747.

Eyelids, colored black, in part of Africa,
739,

Byes, pillared, of the male of Chioéon,
862; difference in the color of, in the
sexes of birds, 549.

Eyton, 1. C., observations on the de-
velopment of the horns in the fallow-
deer, 308.

Eyzies, Les, human remains from, 242.

F

Fabre, M., on the habits of Corceris,
383.

Facial bones, causes of modification of
the, 82.

Faculties, diversity of, in the same race
of men, 47; inheritance of, 48; di-
versity of, in animals of the same
species, 59; mental, variation of,
in the same species, 96; of birds,
530. ‘

Fakirs, Indian, tortures undergone by,
161,

Falco leucocephalus, 625,

— peregrinus, 527, 594.

—— tinnunculus, 527,

Falcon, peregrine, new mate found by,

Falconer, H., on the mode of fighting
of the Indian elephant, 663; on ca-
uines in a female deer, 634; on Hyo-
moschus aquaticus, 706.

Falkland Islands, horses of, 241.

Fallow-deer, different colored herds of,
698.

Famines, frequency of, among savages,
70.

Farr, Dr., on the structure of the
uterus, 60; on the effects of profli-
gacy, 185; on the influence of mar-
riage on mortality, 188.

Farrar, F. W., on the origin of Jan-
guage, 122; on the crossing or
blending of languages, 126; on the
absence of the idea of God in certain
races of men, 130; on early mar-
riages of the poor, 186; on the mid-
dle ages, 190.

Fashions, long prevalence of, among
savages, 742, 751-752.

Faye, Prof., on the numerical propor-

INDEX

tion of male and female births in
Norway and Russia, 319; on the
greater mortality of male children at
and before birth, 320.

Feathers, modified, producing sounds,
488 et seq., 580; elongated, in male
birds, 496, 519; racket-shaped, 497;
barbless and with filamentous barbs
in certain birds, 498; shedding of
margins of, 508.

Feeding, high, probable influence of, in
the pairing of birds of different spe-
cies, 537.

Feet, thickening of the skin on the
soles of. the, 55; modification of, in
man, 77,

Felis canadensis, throat-ruff of, 672.

pardalis and F, mitis, sexual dif-
ferences in the coloring of, 690.

Female, behavior of the, during court-
ship, 292-293,

Female birds, differences of, 606.

Females, presence of rudimentary male
organs in, 216; preference of, for
certain males, 283; pursuit of, by
males, 292; occurrence of secondary
sexual characters in, 297; develop-
ment of male characters by, 300.

Females and males, comparative num-
bers of, 281, 284-286; comparative
mortality of, while young, 285.

Femur and tibia, proportions of, in the
Aymara Indians, 56.

Fenton, Mr., decrease of Maories, 245;
infanticide among the Maories, 339.

Ferguson, Mr., on the courtship of
fowls, 539.

Fertility lessened under changed condi-
tions, 249,

Fertilization, phenomena of, in plants,
293; in the lower animals, 293.

Fevers, immunity of Negroes and Mu-
lattoes from, 258.

Fiber zibethicus, protective coloring of
the, 700.

Fick, H., effect of conscription for mili-
tary service, 181.

Fidelity of savages to one another, 160;
importance of, 169,

Field-slaves, difference of, from house-
slaves, 260.

Fijians, burying their old and sick par-
ents alive, 140; estimation. of the
beard among the, 748; admiration
of, for a broad occiput, 750.

INDEX

Fiji Archipelago, population of the,
231.

Islands, beards of the natives,
721, 748; marriage-customs of the,
769-770.

Filial affection, partly the result of nat-
ural selection, 144,

Filum terminale, 42.

Finch, racket-shaped feathers in the
tail of a, 497.

Finches, spring change of color in, 508;
British females of the, 607.

Fingers, partially coherent, in species
of Hylobates, 76.

Finlayson, on the Cochin Chinese, 744.

Fire, use of, 73, 194, 239,

Fischer, on the pugnacity of the male
of Lethrus cephalotes, 393.

Fish, eagerness of male, 292; propor-
tion of the sexes in, 328-329; sounds
produced by, 451-452.

Fishes, kidneys of, represented by Cor-
pora wolffiana in the human embryo,
26-27; male, hatching ova in their
mouths, 218; receptacles for ova
possessed by, 275; relative size of
the sexes in, 436; fresh water, of
the tropics, 447; protective resem-
blances in, 447; change of color in,
448; nest building, 448; spawning
of, 449-450; sounds produced by,
451, 729; continued growth of, 624.

Flamingo, age of mature plumage in,
624.

Flexor pollicis longus, similar variation
of, in man, 66,

Flint tools, 195.

Flints, difficulty of chipping into form,
74.

Floresuga mellivora, 571.

Florida, Quiscalus major in, 32°,

Flounder, coloration of the, 447.

Flower, W. H., on the abductor of the
fifth metatarsal in apes, 65; on
the position of the seals, 201;
on the Pithecia monachus, 266; on
the throat pouch of the male bus-
tard, 483.

Fly-catchers, colors and nidification
of, 586.

Foetus, human, woolly covering of the,
38; arrangement of the hair on the,
203.

Food, influence of, upon stature, 52.

Foot, prehensile power of the, retained

823

-in some savages, 77; prenensile, in
the early progenitors of man, 215.
Foramen, supra-condyloid, exceptional
occurrence of, in the humerus of
man, 41, 67; in the early progeni-

tors of man, 215.

Forbes, D., on the Aymara Indians,
56; on local variation of color in the
Quichuas, 260; on the hairlessness
of the Aymaras and Quichuas, 722;
on the long hair of the Aymaras and
Quichuas, 722, 747.

Forel, F., on white young swans, 623.

Formica rufa, size of the cerebral gan-
glia in, 80.

Fossils, absence of, connecting man
with the apes, 209.

Fowl, occurrence of spurs in the fe-
male, 300; game, early pugnacity
of, 314; Polish, early development
of cranial peculiarities of, 314; varia-
tions in plumage of, 498; examples
of correlated development in the,
550; domestic, breeds and sub-
breeds of, 593.

Fowls, spangled Hamburg, 302, 314;
inheritance of changes of plumage
by, 302; sexual peculiarities in,
transmitted only to the same sex,
303; loss of secondary sexual char-
acters by male, 304; Polish, origin
of the crest in, 304; period of inheri-
tance of characters by, 313; cuckoo-,
314; development of the comb in,
314; numerical proportion of the
sexes in, 325; courtship of, 438;
mongrel, between a black Spanish
cock and different hens, 551; pen-
cilled Hamburg, difference of the
sexes in, 576; Spanish, sexual dif-
ferences of the comb in, 576; spurred,
in both sexes, 579.

Fox, W. D., on some half-tamed wild
ducks becoming polygamous, and on
polygamy in the guinea-fowl and
canary bird, 290; on the proportion
of the sexes in cattle, 324; on the
pugnacity of the peacock, 473; on
@ nuptial assembly of magpies, 526;
on the finding of new mates by
crows, 526; on partridges living in
triplets, 528; on the pairing of a
goose with a Chinese gander, 536.

Foxes, wariness of young, in hunting
districts. 114; black, 697,

824

Fraser, C., on the different colors of
the sexes in a species of Squilla, 357.

——, G., colors of Thecla, 407.

Frere, Hookham, quoting Theognis on
selection in mankind, 50.

Fringilla cannabina, 509.

—— ciris, age of mature plumage in,
624.

-—— cyanea, age of mature plumage in,
624,

—— leucophrys, young of, 627.

— spinus, 536.

tristis, change of color in, in
spring, 508; young of, 626,

Fringillidee, resemblance of the females
of distinct species of, 606.

Frogs, 453; male, temporary recepta-
cles for ova possessed by, 275;
ready to breed before the females,
281; fighting of, 455; vocal organs
of, 455,

Frontal bone, persistence of the suture
in, 62.

Fruits, poisonous, avoided by animals,
96.

Fuegians, 179-180, 193; difference of
stature among the, 52; power of
sight in the, 55; skill of, in stone-
throwing, 74; resistance of the, to
their severe climate, 92, 242; mental
capacity of the, 94; quasi-religious
sentiments of the, 132; resemblance
of, in mental characters, to Euro-
peans, 237; mode of life of the, 261;
aversion of, to hair on the face, 747;
said to admire European women,
149,

Fulgoride, songs of the, 371.

Fur, whiteness of, in arctic animals, in
winter, 302.

Fur-bearing animals, acquired sagacity
of, 113.

G

Gallicrex, sexual difference in the color
of the irides in, 549.

—— cristatus, pugnacity of male, 468;
red caruncle occurring in the male
during the breeding season, 603.

Gallinacess, frequency of polygamous
habits and of sexual differences in
the, 289-290; love gestures of, 492;
decomposed feathers in, 498; stripes
of young, 599; comparative sexual

INDEX

differences between the species of,
606-607; plumage of, 609.

Gallinaceous birds, weapons of the
male, 471; racket-shaped feathers
on the heads of, 498.

Gallinula chloropus, pugnacity of the
male, 468.

— cristata, pugnacity of the male,
468,

Galloperdix, spurs of, 473 ; development
of spurs in the female, 580.

Gallophasis, young of, 604.

Gallus bankiva, 576; neck hackles of,
507.
Stanleyi, pugnacity of the male,

471

Galls, 88.

Galton, Mr., on hereditary genius, 48;
gregariousness and independence in
animals, 143; on the struggle be-
tween the social and personal im-
pulses, 169; on the effects of nat-
ural selection on civilized nations,
180; on the sterility of sole daugh-
ters, 183; on the degree of fertility
of people of genius, 184; on the
early marriages of the poor, 186;
on the ancient Greeks, 189; on the
Middle Ages, 190; on the progress
of the United States, 191; on South
African notions of beauty, 746.

Gammarus, use of the chele of, 354.

marinus, 356,

Gannets, white only when mature, 636.

Ganoid fishes, 213, 220.

Gaour, horns of the, 653.

Gap between man and the apes, 209.

Gaper, sexes and young of, 627.

Gardner, on an example of rationality
in a Gelasimus, 356-357.

Garrulus glandarius, 526.

Gartner, on sterility of hybrid plants,
229,

Gasteropoda, 34%;
courtship of, 347.

Gasterosteus, 293; nidification of, 449.

leiurus, 432, 443, 449,

trachurus, 433.

Gastrophora, wings of, brightly colored
beneath, 411.

Gauchos, want of humanity among
the, 166.

Gaudry, M., on a fossil monkey, 206.

Gavia, seasonal change of plumage in,
636.

pulmoniferous,

INDEX

Geese, clanging noise made by, 478;
pairing of different species of, 535;
Canada, selection of mates by, 535.

Gegenbaur, C., on the number of digits
in the Ichthyopterygia, 60; on the
hermaphroditism of the remote pro-
genitors of the vertebrata, 216; two
types of nipple in mammals, 217.

Gelasimus, proportions of the sexes in
a species of, 338; use of the enlarged
chele of the male, 353; pugnacity
of males of, 356; rational actions of
a, 357; difference of color in the
sexes of a species of, 358.

Gemmules, dormant in one sex, 304,

Genius, 48; hereditary, 726.

——, fertility of men and women of,
184,

Geofiroy Saint-Hilaire, Isidore, on the
recognition of women by male quad-
rumana, 25; on monstrosities, 51;
coincidences of arrested development
with polydactylism, 60; on animal-
like anomalies in the human struct-
ure, 62; on the correlation of mon-
strosities, 67; on the distribution of
hair in man and monkeys, 84; on
the caudal vertebre of monkeys,
85; on correlated variability, 88;
on the classification of man, 197;
on the long hair on the heads of
species of Semnopithecus, 202; on
the hair in monkeys, 204; on the
development of horns in female
deer, 649; and F. Ouvier, on the
mandrill, 695; on Hylobates agilis,
718, 720.

Geographical distribution, as evidence
of specific distinctions in man, 226-
226.

Geometre, brightly colored beneath,
411.

Geophagus, frontal protuberance of
male, 442, 449; eggs hatched by
the male, in the mouth or branchial
cavity, 449.

Georgia, change of color in Germans
settled in, 260.

Geotrupes, stridulation of, 397.

Gerbe, M., on the nest-building of
Crenilabrus massa and C. melops,
448,

Gerland, Dr., on the prevalence of
infanticide, 159, 743, 762; on the
extinction of races, 243.

825

Gervais, P., on the hairmess of the
gorilla, 84° on the mandrill, 695.

Gesture-language, 238,

Ghost-moth, sexual difference of color
in the, 413.

Gibbs, Sir Duncan, on differences of
the voice and form of the larynx
in different races of men, 729.

Gibbon, Hoolock, nose of, 202.

Gibbons, noisiest of monkeys, voice of,
681-682.

Gill,: Dr., male seals larger than fe-
males, 289; sexual differences in
seals, 666.

Giraffe, its mode of using the horns,
657; mute, except in the rutting
season, 679.

Girard, M., disputes descent of verte-
brates from Ascidians, 214; color of
sponges and Ascidians, 346; musky
odor of Sphinx, 402.

Giraud-Teulon, on the cause of short
sight, 55. ;

Glanders, communicable to man from
the lower animals, 23.

Glands, odoriferous, in mammals, 683-
684.

Glareola, double moult in, 504; resem-
blance in sexes of, 504.

Glomeris limbata, difference of color in
the sexes of, 361.

Glow-worm, female, apterous,
luminosity of the, 365.

Gnats, dances of, 368-369; auditory
powers of, 732.

Gnu, sexual differences in the color of
the, 692.

Goat, male, wild, falling on his horns,
656; male, odor emitted by, 683;
male, wild, crest of the, 687; Ber-
bura, mane, dewlap, etc., of the
male, 687; Kemas, sexual differ-
ence in the color of the, 693.

Goats, sexual differences in the horns
of, 303; horns of, 309, 652; mode
of fighting of, 656; domestic, sex-
ual differences of, late developed,
312; beards of, 687.

Goatsucker, Virginia, pairing of the,
A476.

QGobies, dull-colored, nidification of,

2763

448,

God, want of the idea of, in some
races of men, 130-131.

Godron, M., on variability, 50; on

826 INDEX

difference of stature, 52; on the
want of connection between cli-
mate and the color of the skin,
256; on the odor of the skin, 262;
on the color of infants, 718.

Goldfinch, 482, 508; proportion of the
sexes in the, 32%; sexual differences
of the beak in the, 467; courtship of
the, 618.

——, North American, young of, 626,

Goldfish, reared in confinement from
antiquity, 446.

Gomphus, proportions of the sexes in,
336; difference in the sexes of, 381.

Gonepteryx Rhamni, 407; sexual dif-
ference of color in, 420.

Goodsir, Prof., on the affinity of the
lancelet or amphioxus to the ascid-
ians, 213,

Goosander, young of, resemble adult
female, 603.

Goose, Antarctic, colors of the, 635.

, Canada, pairing with a Bernicle
gander, 535,

—, Chinese, knob on the beak of
the, 550.

—., Egyptian, 473.

——,, Sebastopol, plumage of, 498.

——, Snow-, whiteness of the, 636.

——.,, Spur-winged, 473.

Gorilla, 722; semi-erect attitude of the,
78; mastoid processes of the, 78-79;
direction of the hair on the arms of
the, 202-203; manner of sitting,
203; supposed to be a kind of man-
drill, 236; polygamy of the, 286,
760; voice of the, 681; cranium
of adult male, 718; sagittal crest
absent in female, 719; fighting of
male, 723; difference in skul! of
male and female, 724; immense
canine teeth of male, 724.

Gosse, P. H., on the pugnacity of
the male Humming-bird, 468.

——, M., of Geneva, on the inheri-
tance of artificial modifications of
the skull, 776.

Gould, B. A., on variation in the
length of the legs in man, 46;
measurements of American soldiers,
52, 54; on the proportions of the
body and capacity of the lungs in
different races of men, 224; on the
inferior vitality of mulattoes, 228.

-——, J., on migration of swifts, 147;

on the arrival of male snipes before
the females, 280; on the numerical
proportion of the sexes in birds,
326; on Neomorpha Grypus, 467;
on the species of Eustephanus, 467;
on the Australian musk-duck, 466;
on the relative size of the sexes in
Briziura lobata and Cincloramphus
eruralis, 471; on Lobivauellus loba-
tus, 475; on the habits of Menura
Alberti, 481; on the rarity of song
in brilliant. birds, 481-482; on Selas-
phorus platycercus, 489; on the
Bower-birds, 493-494, 524; on the
ornamental plumage of the Hum.
ming-birds, 500; on the moulting
of the ptarmigan, 506; on the
display of plumage by the male
Humming-birds, 509; ‘on the shy-
ness of adorned male birds, 520;
on the decoration of the bowers of
Bower-birds, 534; on the decora-
tion of their nests by Humming- °
birds, 533; on variation in the
genus Cynanthus, 546; on the
color of the thighs in a male paro-
quet, 547; on Urosticte Benjamini,
570-571; on the nidification of the
Orioles, 584; on obscurely-colored
birds building concealed nests, 584;
on trogons and kingfishers, 589; on
Australian parrots, 590; on Austra-
lian pigeons, 591; on the moulting
of the ptarmigan, 596; on the im-
mature plumage of birds, 601 et seq.;
on the Australian species of Turnix,
613; on the young of Aithurus po-
lytmus, 629; on the colors of the
bills of toucans, 635; on the relative
size of the sexes in the Marsupials of
Australia, 666; on the colors of the
Marsupials, 689,

Goureaux, on the stridulation of Mu-
tilla europea, 385,

Gout, sexually transmitted, 312.

Graba, on the Pied Ravens of the Feroe
Islands, 547; variety of the Guille-
mot, 548,

Gradation of secondary sexual charac-
ters in birds, 554.

Grallatores, absence of secondary sex-
ual characters in, 290; double moult
in some, 504,

Grallina, nidification of, 5&6.

Grasshoppers, stridulation of the, 376.

INDEX

Gratiolet, Prof., on the anthropomor-
phous apes, 206; on the evolution
of the anthropomorphous apes, 236;
on the difference in the develop-
ment of the brains of apes and of
man, 269. :

Gray, Asa, on the gradation of species
among the Composite, 233.

—, J. E., on the caudal vertebree of
monkeys, 85; on the presence of
tudiments of horns in the female
of Cervulus moschatus, 651; on
the horns of goats and _ sheep,
652; on the beard of the ibex,
686; on the Berbura goat, 688;
on sexual differences in the colora-
tion of Rodents, 689; ornaments of
male sloth, 690; on the colors of the
Elands, 692: on the Sing-sing ante-
lope, 692; on the colors of goats,
693; on the hog-deer, 705.

“Greatest happiness principle,’? 162-
163,

Greeks, ancient, 190.

Green, A. H., on beavers fighting, 646;
on the voice of the beaver, 681.

Greenfinch, selected by a female ca-
nary, 536.

Greg, W. R., on the effects of natural
selection on civilized nations, 180; on
the early marriages of the poor, 186;
on the Ancient Greeks, 190.

Grenadiers, Prussian, 49.

Grey, Sir G., on female infanticide in
Australia, 762.

Greyhounds, numerical proportion of
the sexes in, 284; numerical propor-
tion of male and female births in,
323, 341-342.

Grouse, black, polygamous, 289; red,

monogamous, 289; pugnacity of
young male, 475; producing a
sound by scraping their wings

upon the ground, 486; duration
of courtship of, 523; colors and
nidification of, 587.

Gruber, Dr., on the occurrence of the
supra-condyloid foramen in the hu-
merus of man, 40; on division of
the malar bone, 61-62; stridulation
of locust, 374,

Grus americanus, age of mature plu-
mage in, 624; breeding in immature
plumage, 625.

virgo, trachea of, 485.

827

Gryllus campestris, 378; pugnacity of
male, 379.

—~—— domesticus, 374, ;

Grypus, sexual differences in the beak
in, 467.

Guanacos, battles of, 646; canine teeth
of, 664,

Guanas, strife for women among the,
723; polyandry among the, as de-
scribed by Azara, 763.

QGuanche skeletons, occurrence of the
supra-condyloid foramen in the hu-
merus of, 42.

Guaranys of Paraguay, proportion of
men and women among, 321; whit-
ish yellow. color of newborn children
of the, 718; acquiring in a few
weeks the brown tint of their par-
ents, 718; beards of the, 722.

Guenée, A., on the sexes of Hypery-
thra, 331. :

Guilding, L., on the stridulation of the

Locustide, 372.

Guillemot, variety of the, 548.

Guinea, sheep of, with males only
horned, 309,

Guinea-fowl, monogamous, 290; occa-
sional polygamy of the, 290; marke
ings of the, 554.

Guinea-pigs, inheritance of the effects
of operations by, 776.

Gulls, seasonal change of piumage in,
635; white, 635.

Giinther, Dr., on paddle of Ceratodus,
60; on hermaphroditism in Serranus,
216; on male fishes hatching ova in
their mouths, 218, 448; on mistak-
ing infertile female fishes for males,
328; on the prehensile organs of
male Plagiostomous fishes, 431;
spines and brushes on fishes, 431;
on the pugnacity of the male sal-
mon and trout, 433; on the relative
size of the sexes in fishes, 436-437;
on sexual differences in fishes, 438
et seqg.; on the genus Callionymus,
438; on a protective resemblance in
@ pipe-fish, 447; on the male Hip-
pocampi, 450; on the genus Soleno-
stoma, 450; on the coloration of
frogs and toads, 454; combats of
Testudo elegans, 456; on the sex-
ual differences in the Ophidia, 456;
on differences of the sexes of lizards,
460 ef seq.

828

Gynanisa Isis, ocellated spots of, 552. |

Gypsies, uniformity of, in various parts
of the world, 256.

Habits, bad, facilitated by familiarity,
167; variability of the force of, 169.

Hackel, E., on the origin of man, 20;
on rudimentary characters, 28; on
death caused by inflammation of the
vermiform appendage, 40; on the
projecting of the canine teeth im
man, 63; on the steps by which
man became a biped, 77; on man
as a member of the Catarrhine group,
208; on the position of the Lemuride
and Simiadez, 210; on the genealogy
of the Mammalia, 211; on the lance-
let or amphioxus, 213; on the trans-
parency of pelagic animals, 345; on
the musical powers of women, 737.

Hagen, H., and Walsh, B. D., on
American Neuroptera, 336.

Hair, development of, in man, 37-38;
character of, supposed to be deter-
mined by light and heat, 53; dis-
tribution of, in man, 83-84, 771-
775; possibly removed for orna-
mental purposes, 84; arrangement
and direction of, 202-203; of the
early progenitors of man, 214; dif-
ferent texture of, in distinct races,
224; and skin, correlation of color
of, 261; development of, in mam-
mals, 685-686; of the beard, differ-
ent in color from that of the head,
419; management of, among differ-
ent peoples, 740; great length of,
jn some North American tribes,
746-747; elongation of the, on the
human head, 776,

Hairiness, variation of, in races of men,
719; difference of, in the sexes in
man, 720.

Hairs and excretory pores, numerical
relation of, in sheep, 262.

Hairy family, Siamese, 774.

Halbertsma, Prof., hermaphroditism in

Serranus, 216.
Hamadryas baboon, turning over
stones, 139; mane of the male,

673,
Hamilton, C., on the cruelty of the

INDEX

Kaffirs to animals, 160; on the en-
grossment of the women by the
Kaffir chiefs, 766.

Hammering, difficulty of, 74.
Hancock, A., on the colors of the
nudibranch Mollusca, 346, 349.
Hands, larger at birth, in the chil-
dren of laborers, 55; structure of, in
the quadrumana, 75; and arms, free-
dom of, indirectly correlated with

diminution of canines, 80.

Handwriting, inherited, 124,

Handyside, Dr., supernumerary mam-
mee in men, 59.

Harcourt, E. Vernon, on Fringilla can-
nabina, 509.

Harelda glacialis, 543.

Hare, protective coloring of the, 700.

Hares, battles of male, 646.

Harlan, Dr., on the difference between
field- and house-slaves, 260,

Harris, J. M., on the relation of com-
plexion to climate, 258.

, T. W., on the Katydid locust,
372; on the stiidulation of the grass-
hoppers, 376; on Gicanthus nivalis,
380; on the coloring of Lepidoptera,
410; on the coloring of Saturnia Io,
412,

Harting, spur of the Ornithorhynchus,
649.

Hartman, Dr., on the singing of Cicada
septendecim, 371.

Hatred, persistence of, 153.
Haughton, §., on a variation of the
flexor pollicis longus in man, 66.
Hawks, feeding orphan nestling, 529.
Hayes, Dr., on the diverging of sledge-

dogs on thin ice, 10%.

Haymond, R., on the drumming of the
male, Tetrao umbellus, 487; on the
drumming of birds, 488,

Head, altered position of, to suit the
erect attitude of man, 82; hairiness
of, in man, 84; processes of, in male
beetles, 387; artificial alterations of
the form of the, 750.

Hearne, on strife for women among
the North American Indians, 723;
on the notion of female beauty among
the North American Indians, 743=
144; repeated elopements of a North
American woman, 769.

Heart, in the human embryo, 26.

Heat, supposed effects of, 53.

INDEX

Hectocotyle, 348,

sa alec 611, young of the,
621.

Heel, small projection of, in the Ay-
mara Indians, 57.

Hegt, M., on the development of the
spurs in peacocks, 310.

Heliconids, 403; mimicry of, by other
butterflies, 431.

Heliopathes, stridulation peculiar to the
male, 398.

Heliothrix auriculita, young of, 602-
603.

Helix pomatia, example of individual

attachment in, 347.

Hellins, J., proportions of sexes of Lepi-
doptera reared by, 334,

Helmholtz, on pleasure derived from
harmonies, 129; on the vibration of
the auditory hairs of crustacea, 732;
the physiology of harmony, 732-733.

Hemiptera, 369-370.

Hemitragus, beardless in both sexes,
686.

Hemsbach, M. von, on medial mamma
in man, 59, S

Hepburn, Mr., on the autumn song of
the water-ouzel, 480.

Hepialus humuli, sexual difference of
color in the, 413.

Herbs, poisonous, avoided by animals,
96.

Hermaphroditism of embryos, 216.

Herodias bubulcus, vernal moult of,
507.

Heron, Sir R., on the habits of pea-
fowl, 540, 542, 571.

Heron, love-gestures of a, 492.

Herons, decomposed feathers in, 498;
breeding plumage of, 505-506 ; young
of the, 620; sometimes dimorphic,
625; continued growth of crest and
plumes in the males of some, 626;
change of color in some, 638.

Hesperomys cognatus, 731; account
of musical powers of, by Rev. 8.
Lockwood, 731.

Heterina, proportion of the sexes in,
336; difference in the sexes of, 380.

Heterocerus, stridulation of, 396.

Hewitt, M., on a game-cock killing a
kite, 471; on the recognition of dogs
and cats by ducks, 532; on the pair-
ing of a wild duck with a pintail
drake, 536; on the courtship of

829

fowls, 538-839; on the coupling of
pheasants with common hens, 542<
643,

Hilgendorf, sounds produced by crus-
taceans, 361.

Hindu, his horror of breaking his caste,
165, 168.

Hindus, local difference of stature
among, 52; difference of, from Eu-
ropeans, 254-255; color of the beard
in, 719.

Hipparchia Janira, 416; instability of
the ocellated spots of, 552.

Hippocampus, development of, 218;
marsupial receptacles of the male,
450.

—— minor, 268.

Hippopotamus, nakedness of, 83.

Hips, proportions of, in soldiers and
sailors, 54.

Hodgson, Shadworth, on the sense of
duty, 135.

Hoffberg, on the horns of the reindeer,
650; on sexual preferences shown
by reindeer, 677.

Hoffman, Prof., protective colors, 370;
fighting of frogs, 455.

Hog-deer, 705.

Hog, wart-, 671; river-, 671.

Holland, Sir H., on the effects of new
diseases, 240.

Sac armatus, wing-spurs of,
475.

Homologous structures, correlated va-
riation of, 67.

Homoptera, 370; stridulation of the,
and Orthoptera, discussed, 378.

Honduras, Quiscalus major in, 327.

Honey-buzzard of India, variation in
the crest of, 547.

Honey-suckers, moulting of the, 506;
Australian, nidification of, 586.

Honor, law of, 164.

Hooker, Dr., forbearance of elephant
to his keeper, 142; on the color of
the beard in man, 719.

Hookham, Mr., on mental concepts in
animals, 11%.

Hoolock Gibbon, nose of, 202.

Hoopoe, harsh ery of, 482; sounds
produced by the male, 487.

Hornbill, African, inflation of the neck-
wattle of the male during courtship,
496.

Hornbills, sexual difference in the color

830

of the eyes in, 549; nidification and
incubation of, 585.

Horne, C., on the rejection of a brightly
colored locust by lizards and birds,
380.

Horns, sexual differences of, in sheep
and goats, 303; loss of, in female
merino sheep, 304; development of,
in deer, 308; development of, in an-
telopes, 309; from the head and
thorax, in male-beetles, 390; of
deer, 650, 653, 664; and canine
teeth, inverse development of, 663.

Horse, fossil, extinction of the, in
South America, 254; polygamous,
287; canine teeth of male, 648;
winter change of color, 700.

Horses, rapid increase of, in South
America, 71; diminution of canine
teeth in, 79; dreaming, 106; of the
Falkland Islands and Pampas, 241;
‘numerical proportion of the sexes in,
284-285; lighter in winter in Sibe-
ria, 302; sexual preferences in, 677;
pairing preferently with those of the
same color, 698; numerical propor-
tion of male and female births in,
322-323; formerly striped, 707.

Hottentot women, peculiarities of, 232.

Hottentots, lice of, 227; readily become
musicians, 734; notions of female
beauty of the, 745; compression of
nose by, 750.

Hough, Dr. 8., men’s temperature more
variable than women’s, 298; propor-
tion of sexes in man, 320.

House-slaves, difference of, from field-
slaves, 260.

Houzeau, on the baying of the dog,
106-107; on reason in dogs, 108;
birds killed by telegraph wires, 113;
on the cries of domestic fowls and
parrots, 120, 123; animals feel no
pity, 140; suicide in the Aleutian
Islands, 159.

Howorth, H. H., extinction of savages,
244,

Huber, P., on ants playing together,
99; on memory in ants, 106; on the
jntercommunication of ants, 125; on
the recognition of each other by
ants after separation, 383.

Hue, on Chinese opinions of the ap-
pearance of Europeans, 744.

Hua, the, of New Zealand, 276.

INDEX

Human, man classed alone in a, king-
dom, 197.

sacrifices, 133.

Humanity, unknown among some say-
ages, 160; deficiency of, among sav-
ages, 166.

Humboldt, A. von, on the rationality
of mules, 111; on a parrot preserv-
ing the language of a lost tribe, 240;
on the cosmetic arts of savages, 739;
on the exaggeration of natural char-
acters by man, 749-750; on the red
painting of American Indians, 751.

Hume, D., on sympathetic feelings,
149, i

Humming-bird, racket-shaped feathers
in the tail of a, 497; display of plu-
mage by the male, 509.

Humming-birds, ornament their nests,
128, 533; polygamous, 289; propor-
tion of the sexes in, 327, 629; sexual
differences in, 467, 570; pugnacity
of male, 468; modified primaries of
male, 489; coloration of the sexes
of, 500; display by, 571; nidifica-
tion of the, 585; colors of female,
585; young of, 629.

Humphreys, H. N., on the habits of
the stickleback, 291, 432.

Hunger, instinct of, 153.

Huns, ancient, flattening of the nose
by the, 750.

Hunter, J., on the number of species
of man, 232; on secondary sexual
characters, 274; on the general be-
havior of female animals during
courtship, 292; on the muscles of
the larynx in song-birds, 481; on
the curled frontal hair of the bull,
686; on the rejection of an ass by
a female zebra, 698.

—, W. W., on the recent rapid
increase of the Santali, 69; on the
Santali, 255,

Huss, Dr. Max, on mammary glands,
217.

Hussey, Mr., on a partridge distin-
guishing persons, 532.

‘Hutchinson, Col., example of reasoning

in a retriever, 111. ‘

Hutton, Capt., on the male wild goat
falling on his horns, 656.

Huxley, T. H., on the structural agree-
ment of man with the apes, 18; on
the agreement of the brain in man

INDEX

with that of lower animals, 22; on
the adult age of the orang, 25; on
the embryonic development of man,
26; on the origin of man, 19, 28;
on variation in the skulls of the
natives of Australia, 46; on the ab-
ductor of the fifth metatarsal in apes,
65; on the nature of the reasoning
power, 109; on the position of man,
201; on the suborders of primates,
204; on the Lemuridex, 211; on the
Dinosauria, 212; on the amphibian
affniues of the Ichthyosaurians,
212; on variability of the skull
in certain races of man, 232; on
the races of man, 235; supplement
on the brain, 263-273.

Hybrid birds, production of, 535.
Hydrophobia communicable between
man and the lower animals, 23.
Hydroporus, dimorphism of females

of, 364,

Hyelaphus porcinus, 507.

Hygrogonus, 449.

Hyla, singing species of, 455.

Hylobates, absence of the thumb in,
76; upright progression of some
species of, 78; maternal affection
in a, 100-101; direction of the hair
on the arms of species of, 203;
females of, less hairy below than
males, 720.

—— agilis, coherence of the toes, 76;
hair on the arms of, downward in
the ordinary manner, 203; musical
voice of the, 681; superciliary ridge
of, 718; voice of, 730.

—— hoolock, sexual difference of color
in, 694.

—— lar, coherence of the toes, 76;
hair on the arms of, in a transitional
state, 203.

—— leuciscus, coherence of the toes,
76; song of, 731.

—— syndactylus, coherence of the
toes, 76; laryngeal sac of, 681.

Hylophila prasinana, 402.

Hymenoptera, 382; large size of the
cerebral ganglia in, 80; classifica-
tion of, 199; sexual differences in
the wings of, 365; aculeate, relative
size of the sexes of, 367.

Hymenopteron, parasitic, with a sed-
entary male, 292.

Hyomoschus aquaticus, 706,

831

| Hyperythra, proportion of the sexes
in, 23]

Hypogymna dispar, sexual difference
of color in, 412.

Hypopyra, coloration of, 411.

I

Ibex, male, falling on his horns, 656;
beard of the, 686.

Ibis, white, change of colcr of naked
skin in, during the breeding season,
503; scarlet, young of the, 620.

tautalus, age of mature plumage
in, 624; breeding in immature plu-
mage, 625.

Ibises, decomposed feathers in, 498;
white, 635; and black, 637.

Ichneumonide, difference of the sexes
in, 382.

Ichthyopterygia, 60.

Ichthyosaurians, 212.

Idiots, microcephalous, their characters
and habits, 58; hairiness and animal
nature of their actions, 58; micro-
cephalous, imitative faculties of,
122.

Iguana luberculata, 460.

Iguanas, 460.

Illegitimate and legitimate children,
proportion of the sexes in, 321.
Imagination, existence of, in animals,

106-107.

Imitation, 99; of man by monkeys,
104; tendency to, in monkeys, mi-
crocephalous idiots and savages, 122;
influence of, 174.

Immature plumage of birds, 596, 601.

Implacentata, 211.

Implements, employed by monkeys,
114-115; fashioning of, peculiar to
man, 116-117.

Impregnation, period of, influence of,
upon sex, 322.

Improvement, progressive, man alone
supposed to be capable of, 113.
Incisor teeth, knocked out or filed by

some savages, 740.

Increase, rate of, 68; necessity of
checks in, 70-71.

Indecency, hatred of, a modern virtue,

161.
India, difficulty of distinguishing the
native races of, 223; Cyprinide of,

832

446; color of the beard in races of
men of, 719.

Indian, North American, honored for
scalping a man of another tribe, 159.

Individuality, in animals, 118-119,

Indopicus carlotta, colors of the sexes
of, 590.

Infanticide, prevalence of, 71, 159,
338; supposed cause of, 743; prev-
alence and cause of, 761 et seq.

Inferiority, supposed physical, of man,
92-93.

Inflammation of the bowels, occurrence
of, in Cebus Azare, 23.

Inheritance, 48; of Jong and short
sight, 55; of effects of use of vocal
and mental organs, 124; of moral
tendencies, 168-169; laws of, 299-
301; sexual, 305; sexually limited,
573.

Inquisition, influence of the, 190.

Insanity, hereditary, 48.

Insect, fossil, from the Devonian, 379.

Insectivora, 690; absence of secondary
sexual characters in, 288.

Insects, relative size of the cerebral
ganglia in, 80; male, appearance of,
before the females, 280; pursuit of
female, by the males, 292; period
of development of sexual characters
in, 311; secondary sexual charac-
ters of, 362; stridulation, 729.

Insessores, vocal organs of, 481. —

Instep, depth of, in soldiers and sail-
ors, 54.

Instinct and intelligence, 96.

—, migratory, vanquishing the ma-
ternal, 148, 154.

Instinctive actions, the result of inheri-
tance, 143-144,

Instinctive impulses, difference of the
force of, 150-152; and moral im-
pulses, alliance of, 151.

Instincts, 96; complex origin of,
through natural selection, 96; pos-
sible origin of some, 97; acquired,
of domestic animals, 143; variability
of the force of, 147; difference of
force between the social and other,
152, 169; utilized for new purposes,
735.

Instrumental music of birds, 487, 490.
Intellect, influence of, in natural selec-
tion in civilized society, 183-184.
Intellectual faculties, their influence

INDEX

on natural selection in man, 171-
172; probably perfected through
natural selection, 173.

Intelligence, Mr. H. Spencer on the
dawn of, 97.

Intemperance, not a cause for reproach
among savages, 161; its destruct-
iveness, 185,

Intoxication in monkeys, 24.

Iphias glaucippe, 408.

Iris, sexual difference in the color of
the, in birds, 449, 496.

Ischio-pubic muscle, 64.

Ithaginis cruentus, number of spurs
in, 473.

Tulus, tarsal suckers of the males of,
361.

I

Jackals learning from dogs to bark,
104.

Jack-snipe, coloration of the, 634.

Jacquinot, on the number of species
of man, 232.

Jaeger, Dr., length of bones increased
from carrying weights, 54; on the
difficulty of approaching herds of
wild animals, 138; male silver-
pheasant, rejected when his plu-
mage was spoiled, 541.

Jaguars, black, 697.

Janson, E. W., on the proportions of
the sexes in Tomicus villosus, 335;
on stridulant beetles, 395.

Japan, encouragement of licentiousness
in, 70-71.

Japanese, general beardlessness of the,
421; aversion of the, to whiskers,
Wy.

Jardine, Sir W., on the Argus pheas-
ant, 497, 520.

Jarrold, Dr., on modifications of the
skull induced by unnatural position,
82.

Jarves, Mr., on infanticide in the Sand-
wich Islands, 340.

Javans, relative height of the sexes of,
720; notions of female beauty among
the, 746.

Jaw, influence of the muscles of the,
upon the physiognomy of the apes,
79-80.

Jaws, smaller proportionately to the
extremities, 55; influence of food

INDEX

upon the size of, 55; diminution of,
in man, 80; in man, reduced by cor-
relation, 724.

Jay, young of the, 621; Canada, young
of the, 621.

Jays, new mates found by, 526; dis-
tinguishing persons, 531.

Jeffreys, J. Gwyn, on the form of the
shell in the sexes of the Gasteropoda,
347; on the influence of light upon
the colors of shells, 348.

Jelly-fish, or Meduse, bright colors of
some, 345.

Jenner, Dr., on the voice of the rook,
486; on the finding of new mates
by magpies, 526; on retardation of
the generative functions in birds,
529,

Jenyns, L., on the desertion of their
young by swallows, 147; on male
birds singing after the proper sea-
son, 529.

Jerdon, Dr., on birds dreaming, 106;
on the pugnacity of the male bulbul,
468; on the pugnacity of the male
Ortygornis gularis, 472; on the
spurs of Galloperdix, 473; on the
habits of Lobivanellus, 475; on
the spoonbill, 485; on the drum-
ming of the Kalij-pheasant, 487;
on Indian bustards, 489; on Otis
bengalensis, 493; on the ear-tufts
of Sypheotides auritus, 498; on the
double moults of certain birds, 505;
on the moulting of the honey-suck-
ers, 506; on the moulting of bus-
tards, plovers, and drongos, 507;
on the spring change of color in
some finches, 508; on display in
male birds, 509; on the display
of the under-tail coverts by the
male bulbul, 518; on the Indian
honey-buzzard, 547; on sexual dif-
ferences in the color of the eyes of
hornbills, 549; on the markings of
the Tragopan pheasant, 554; on the
nidification of the Orioles, 584; on
the nidification of the hornbills, 585;
on the Sultan yellow-tit, 590; on
Paleornis javanicus, 595; on the
immature plumage of birds, 600 e
seg.; on representative species of
birds, 604; on the habits of Tur-
nix, 613; on the continued increase
of beauty of the peacock, 626; on

833

eran in the genus Palzornis,

637.

Jevons, W. &., on the migrations of
man, 72.

Jews, ancient use of flint tools by the,
196; uniformity of, in various parts
of the world, 256; numerical pro-
portion of male and female births
among the, 320; ancient, tattooing
practiced by, 739.

Johnstone, Lieut., on the Indian ele-
phant, 288.

Jollofs, fine appearance of the, 755.

Jones, Albert, proportion of sexes of
Lepidoptera, reared by, 334.

Juan Fernandez, humming-birds of,
629. :
Junonia, sexual differences of coloring

in species of, 404.

Jupiter, comparison with Assyrian

effigies, 748.

K

Kaffir skull, occurrence of the diastema
in a, 63.

Kaffirs, their cruelty to animals, 160;
lice of the, 227; color of the, 746;
engrossment of the handsomest
women by the chiefs of the, 766;
marriage-customs of the, 770.

Kalij-pheasant, drumming of the male,
487; young of, 604.

Kallima, resemblance of, to a withered
leaf, 407.

Kalmucks, general beardlessness of,
421; aversion of, to hairs on the
face, 747; marriage-customs of the,
770.

Kangaroo, great red, sexual difference
in the color of, 689.

Kant, Immanuel, on duty, 134; on
self-restraint, 150; on the number
of species of man, 232.

Katydid, stridulation of the, 372.

Keen, Dr., on the mental powers of
snakes, 458.

Keller, Dr., on the difficulty of fash-
ioning stone implements, 174.

Kent, W. 8., elongation of dorsal fin
of Callionymus lyra, 438; courtship
of Labrus mixtus, 443; colors and
courtship of Cantharus lineatus, 443.

Kestrels, new mates found by, 527.

834

Kidney, one, doing double work in dis-
ease, 53-54,

King, W. R., on the vocal organs of
Tetrao cupido, 483; on the drum-
ming of grouse, 487-488; on the
reindeer, 650; on the attraction of
male deer by the voice of the female,
680.

King and Fitzroy, on the marriage-cus-
toms of the Fuegians, 770.

King-crows, nidification of, 584.

Kingfisher, harsh ery of, 482; spoon
or racket-shaped feathers in the tail
of a, 497.

Kingfishers, colors and nidification of
the, 587, 589, 591; immature plu-
mage of the, 602, 604; young of
the, 621.

King Lory, 590; immature plumage of
the, 602.

Kingsley, C., on the sounds produced
by Umbrina, 452.

Kirby and Spence, on sexual differ-
ences in the length of the snout
in Curculionide, 276; on the court-
ship of insects, 292; on the elytra
of Dytiscus, 364; on peculiarities in
the legs of male insects, 364; on the
relative size of the sexes in insects,
367; on the Fulgoride, 371; on the
habits of Termites, 482; on differ-
ence of color in the sexes of beetles,
386; on the horns of the male Jamel-
licorn beetles, 389; on hornlike proc-
esses in male Curculionide, 391; on
the pugnacity of the male stag-bee-
tle, 392.

Kite, killed by a game-cock, 471.

Knot, retention of winter plumage by
the, 505.

Knox, R., on the semilunar fold, 36;
on the occurrence of the supra-con-
dyloid foramen in the humerus of
man, 40; on the features of the
young Memnon, 225.

Koala, length of the cecum in, 40.

Kobus ellipsiprymnus, proportion of
the sexes in, 325,

Kélreuter, on the sterility of hybrid
plants, 229.

Koodoo, development of the horns of
the, 308; markings of the, 703.

Képpen, F. T., on the migratory locust,
372.

Koraks, marriage-customs of, 770.

INDEX

Kordofan, protuberances artificially
produced by natives of, 739.
Korte, on the proportion of sexes in
locusts, 336; Russian locusts, 372.
Kovalevsky, A., on the affinity of the
Ascidia to the Vertebrata, 213-214.
——, W., on the pugnacity of the male
eapercailzie, 472; on the pairing of

the capercailzie, 476.

Krause, on a convoluted body at the
extremity of the tail in a Macacus
and a cat, 43.

Kupffer, Prof., on the affinity of the
Ascidia to the Vertebrata, 214.

L

Labidocera Darwinii, prehensile organs
of the male, 352.

Labrus, splendid colors of the species
of, 445.

—— mixtus, sexual differences in, 439,
443,

— pavo, 445.

Lacertilia, sexual differences of, 460.

Lafresnaye, M. de, on birds of para-
dise, 500.

Lamarck, on the origin of man, 19.

Lamellibranchiata, 347.

Lamellicorn beetles, hornlike proc-
esses from the head and thorax of,
388, 391; influence of sexual selec-
tion on, 393.

Lamellicornia, stridulation of, 396.

Lamont, Mr., on the tusks of the wal-
rus, 648; on the use of its tusks by
the walrus, 663; on the bladder-nose
seal, 682.

Lampornis porphyrurus, colors of the
female, 585.

Lampyridz, distasteful to mammals,
365.

Lancelet, or amphioxus. 213, 220.

Landois, H., gnats attracted by sound,
369; on the production of sound by
the Cicads, 371; on the stridulating
organ of the crickets, 373; on Dec-
ticus, 375; on the stridulating or-
gans of the Acridiide, 376; stridu-
lating apparatus in Orthoptera, 378;
sounds produced by Atropus, 382;
on the stridulation of Necrophorus,
395; on the stridulant organ of Ce-
tambyx heros, 396; on the stridu-

INDEX

lant organ of Geotrupes, 396; on
the stridulating organs in the Cole-
optera, 399; on the ticking of Ano-
bium, 400.

Iandor, Dr., on remorse for not obey-
ing tribal custom, 156.

Language, an art, 121; articulate, ori-
gin of, 122; relation of the progress
of, to the development of the brain,
123; effects of inheritance in pro-
duction of, 124; complex structure
of, among barbarous nations, 128;
natural selection in, 128; gesture,
238; primeval, 240; of a lost tribe
preserved by a parrot, 241.

Languages, presence of rudiments in,
126; classification of, 126; variabil-
ity of, 126-127; crossing or blend-
ing of, 126; complexity of, no test
of perfection or proof of special crea-
tion, 128; resemblance of, evidence
of community of origin, 199.

and species, identity of evidence
of their gradual development, 126.

Lanius, 595; characters of young, 599.

-—— rufus, anomalous young of, 622.

Lankester, E. R., on comparative lon-
gevity, 180, 183; on the destructive
effects of intemperance, 185.

Ianugo, of the human foetus, 38,
772.

Lapponian language, highly artificial,

127,

Lark, proportion of the sexes in the,
327; female, singing of the, 480.

Larks, attracted by a mirror, 533.

Lartet, E., comparison of cranial ca-
pacities of skulls of recent and ter-
tiary mammals, 81; on the size of
the brain in mammals, 114; on Dryo-
pithecus, 208; on prehistoric flutes,
134.

Larus, seasonal change of plumage in,
636. :
Larva, luminous, of a Brazilian beetle,

366.

Larynx, muscles of the, in song-birds,
481.

Lasiocampa quercus, attraction of males
by the female, 333; sexual difference
of color in, 412.

Latham, R. G., on the migrations of
mau, 72. :
Latooka, perforation of the lower lip

by the women of, 741.

835

Laurillard, on the abnormal division of
the malar bone in man, 61.

Lawrence, W., on the superiority of
savages to Europeans in power of
sight, 65; on the color of negro in-
fants, 718; on the fondness of sav-
ages for ornaments, 742; on beard-
less races, 747-748; on the beauty
of the English aristocracy, 754.

Layard, EH. L., on an instance of ra-
tionality in a cobra, 458; on the
pugnacity of Gallus Stanleyi, 471.

Laycock, Dr., on vital periodicity, 24;
theroid nature of idiots, 58.

Leaves, autumn, tints useless, 346.

Lecky, Mr., on the sense of duty, 1853
on suicide, 159; on the practice of
celibacy, 161; his view of the crimes
of savages, 161; on the gradual rise
of morality, 169.

Leconte, J. L., on the stridulant organ
in the Corprini and Dynastini, 397.

Lee, H., on the numerical proportion
of the sexes in the trout, 329.

Leg, calf of the, artificially modified,
739-740.

Legitimate and illegitimate children,
proportion of the sexes in, 321.

Legs, variation of the length of the, in
man, 46; proportions of, in soldiers
and sailors, 54; front, atrophied in
some male butterflies, 365; peculiari-
ties of, in male insects, 365;

Leguay, on the occurrence of the
supra-condyloid foramen in the hu-

* merus of man, 41.

‘Lek’? of the black-cock and caper
cailzie, 523.

Lemoine, Albert, on the origin of lan-
guage, 122.

Lemur macaco, sexual difference of
color in, 693,

Lemuride, 204; ears of the, 33; vari-
ability of the muscles in the, 64-65;
position and derivation of the, 210;
their origin, 220.

Lemurs, uterus in the, 61.

Lenguas, disfigurement of the ears of
the, 741.

Leopards, black, 697.

Lepidoptera, 401; numerical propos-
tions of the sexes in the, 329; col-
oring of, 403; ocellated spots of,
552.

Lepidosiren, 213, 220.

B36

Leptalides, mimicry of, 423.

Leptorhynchus angustatus, pugnacity
of male, 392.

Leptura testacea, difference of color in
the sexes of, 386.

Leroy, on the wariness of young foxes
in hunting districts, 114; on the de-
see of their young by swallows,
147.

ae D., marriage-customs of Kaffira,

0

Lesse, valley of the, 41.

Lesson, on the birds of paradise, 289,
520; on the sea-elephant, 682.

Lessona, M., observations on Serranus,
216,

Lethrus cephalotes, pugnacity of the
males of, 389, 393.

Leuckart, R., on the vesicula pros-
tatica, 43; on the influence of the
age of parents on the sex of off-
spring, 322,

Levator clavicule, muscle, 65.

Libellula depressa, color of the male,
381.

Libellulide, relative size of the sexes
of, 367; difference in the sexes of,
380,

Lice of domestic animals and man,
227,

Licentiousness, a check upon popula-
tion, 71; prevalence of, among sav-
ages, 162.

Lichtenstein, on Chera progne or
widow-bird, 541.

Life, inheritance at corresponding peri-
ods of, 301, 306,

Light, effects on complexion, 53; in-
fluence of upon the colors of shells,
348.

Lilford, Lord, the ruff attracted by
bright objects, 533.

Limosa lapponica, 616.

Linaria, 595.

——— montana, 327.

Lindsay, Dr. W. L., diseases commu-
nicated from animals to man, 23;
madness in animals, 112; the dog
considers his master his god, 133.

Linnzus, views of, as to the position
of man, 200.

Linnet, numerical proportion of the
sexes in the, 327; crimson forehead
and breast of the, 509; courtship of
the, 517.

INDEX

Lion, polygamous, 288; mane cf the,
defensive, 672; roaring of the, 680,

Lions, stripes of young, 598.

Lips, piercing of the, by savages, 741,

Lithobius, prehensile appendages of
the female, 361.

Lithosia, coloration in, 410.

Littorina littorea, 347.

Livingstone, Dr., manner of sitting of
gorilla, 203; on the influence of
dampness and dryness on the color
of the skin, 266; on the liability of
negroes to tropical fevers after resi-
dence in a cold climate, 257; on the
spur-winged goose, 475; on weaver-
birds, 488; on an African night-jar,
497%, 519; on the battle-scars of
South African male mammals, 646;
on the removal of the upper incisors
by the Batokas, 740; on the perfora-
tion of the upper lip by the Makalolo,
741; on the Banyai, 745-746.

Livonia, numerical proportion of male
and female births in, 284, 320.

Lizards, relative size of the sexes of,
460; gular pouches of, 464,

Lloyd, L., on the polygamy of the
capercailzie and bustard, 289; on
the numerical proportion of the
sexes in the capercailzie and black-
cock, 326; on the salmon, 435; on
the colors of the sea-scorpion, 439;
on the pugnacity of male grouse,
474; on the capercailzie and black-
cock, 476, 481; on the call of the
capercailzie, 486; on assemblages of
grouse and snipes, 524; on the pair-
ing of a shield-drake with a common
duck, 535; on the battles of seals,
647; on the elk, 656.

Lobivanellus, wing-spurs in, 475.

Local influences, effect of, upon stat-
ure, 52.

Lockwood, Mr., on the development
of Hippocampus, 218,

. Rev. §., account of a musical
mouse by, 731.

Locust, bright-colored, rejected by liz-
ards and birds, 381.

—, migratory, 372; selection by fe-
male, 373.

Locusts, proportion of sexes in, 336;
stridulation of, 373.

Locustide, stridulation of the, 372-3753
descent of the, 275.

INDEX

Longicorn beetles, difference of the
sexes of, in color, 386; stridulation
of, 396.

Teasdale, Mr., on an example of per-
te attachment in Helix pomatia,

Lophobranchii, marsupial receptacles
of the males, 450.

Lophophorus, habits of, 542.

Lophorina atra, sexual difference in
coloration of, 634.

Lophornis ornatus, 502.

Lord, J. K., on Salmo lycacdon, 434—
435.

Lory, King, 590; immature plumage
of the, 602,

Love-antics and dances of birds, 492.

Lowne, B. T., on Musca vomitoria, 80,
80, 369.

Loxia, (cross-bills), characters of young
of, 599.

Lubbock, Sir J., on the antiquity of
man, 18; on the origin of man, 19;
on the mental capacity of savages,
93; on the origin of implements,
116; on the simplification of lan-
guages, 128; on the absence of the
idea of God among certain races of
men, 130; on the origin of the belief
in spiritual agencies, 132; on super-
stitions, 133-134; on the sense of
duty, 134-135; on the practice of
burying the old and sick among the
Fijians, 140; on the immorality of
savages, 162; on Mr. Wallace’s claim
to the origination of the idea of nat-
ural selection, 73; on the absence
of remorse among savages, 178; on
the former barbarism of civilized na-
tions, 193; on improvements in the
arts among savages, 194; on resem-
blances of the mental characters in
different races of men, 238; on the
arts practiced by savages, 238; on
the power of counting in primeval
man, 239; on the prehensile organs
of the male Labidocera Darwinii,
352; on Chloéon, 362; on Smyn-
thurus luteus, 368; tinding of new
mates by jays, 526; on strife for
women among the North American
Indians, 723; on music, 733; on the
ornamental practices of savages, 738 ;
on the estimation of the beard among
the Anglo-Saxons, 748; on artificial

837

deformation of the ekull, 750; on
‘communal > T56-157;
on exogamy, 758, 762; on the
Veddahs, 761; on polyandry, %63.

Lucanids, variability of the mandibles
in the male, 393.

Lucanus, large size of males of, 367.

cervus, numerical proportion of

sexes of, 335; weapons of the

male, 392.

elaphus, use of mandibles of,
393; large jaws of male, 363.

Lucas, Prosper, on pigeons, 640; on
sexual preference horses and
bulls, 677.

Luminosity in insects, 365.

Lunar periods, 24, 220.

Lund, Dr., on skulls found in Brazilian
caves, 225,

Lungs, enlargement of, in the Quichua
and Aymara Indians, 56; a modified
swim-bladder, 215; different capac-
ity of, in races of man, 224,

Luschka, Prof., on the termination of
the coccyx, 43.

Luxury, expectation of life uninfiu-
enced by, 183.

Lyczna, sexual differences of coloring
in species of, 405

Lyell, Sir O., on the antiquity of man,
18; on the origin of man, 19; on
the parallelism of the development
of species and languages, 126; on
the extinction of languages, 1263
on the Inquisition, 190; on the
fossil remains of vertebrata, 210;
on the fertility of mulattoes, 228,

Lynx, Canadian, throat-ruff of the,
672.

Lyre-bird, assemblies of, 524.

Macacus, ears of, 33; convoluted body
in the extremity of the tail of, 43;
variability of the tail in species of,
85; whiskers of species of, 686.

—— brunneus, 86-87.

—— cynomolgus, superciliary ridge of,
718; beard and whiskers of, becom-
ing white with age, 719.

—— ecaudatus, 87.

— lasiotus, facial spots of, 710.

—— radiatus, 202.

Deseent—Vou. IT.—18

838

Macacus, rhesus, sexuai difference in
the color of, 696, 711.

Macalister, Prof., on variations of the
palmaris accessorius muscle, 47; on
muscular abnormalities in man, 65-
66; on the greater variability of the
muscles in men than in women, 295.

Macaws, Mr. Buxton’s observations on,
140; screams of, 486.

McCann, J., on mental individuality,
118-119.

McClelland, J., on the Indian Cypri-
nide, 446.

Macculloch, Colonel, on an Indian vil-
lage without any female children,
762.

——, Dr., on tertian ague in a dog, 24.

Macgillivray, W., on the vocal organs
of birds, 125; on the Egyptian goose,
473; on the nabits of woodpeckers,
487; on the habits of the snipe, 289;
on the whitethroat, 493; on the
moulting of the snipes, 505; on
the moulting of the Anatide, 508;
on the finding of new mates by
magpies, 526; on the pairing of a
blackbird and thrush, 535; on pied
ravens, 547; on the guillemots, 548;
on the colors of the tits, 590; on
the immature plumage of birds,
601 et seg.

Machetes, sexes and young of, 626.

—— pugnax, supposed to be polyga-
mous, 290; numerical proportion of
the sexes in, 326; pugnacity of the
male, 469; double moult in, 505.

McIntosh, Dr., colors of the Nemer-
tians, 350.

McKennan, marriage-customs of Ko-
raks, 770.

Mackintosh, on the moral sense, 134.

MacLachlan, R., on Apatania muliebris
and Boreus hyemalis, 337; on the
anal appendages of male insects,
362; on the pairing of dragon-flies,
367; on dragon-flies, 381; on di-
morphism in Agrion, 382; on the
want of pugnacity in male dragon-
flies, 382; color of ghost moth in the
Shetland Islands, 413.

McLennan, Mr., on infanticide, 70,
161; on the origin of the belief in
spiritual agencies, 132; on the prev-
alence of licentiousness among sav-
ages, 162, 756; on the primitive

INDEX

barbarism of civilized nations, 193;
on traces of the custom of the for-
cible capture of wives, 194, 762; on
polyandry, 763.

Macnamara, Mr., susceptibility of An-
daman islanders and Nepdlese to
change, 249-250.

McNeill, Mr., on the use of the antlers
of deer, 659; on the Scotch deer-
hound, 667-668; on the long haira
on the throat of the stag, 673; on
the bellowing of stags, 679-680.

Macropus, courtship of, 444.

Macrorhinus proboscideus, structure of
the nose of, 682.

Magpie, power of speech of, 125; nup-
tial assemblies of, 525; new mates'
found by, 525-526; stealing bright
objects, 533; young of the, 621;
coloration of the, 637.

Magpies, vocal organs of the, 481.

Maillard, M., on the proportion of the
sexes in a species of Papilio from
Bourbon, 330.

Maine, Sir Henry, on the sheorpiicn of
one tribe by another, 173; a desire
for improvement not general, 179,

Major, Dr. C. Forsyth, on fossil Ital-
ian apes, 208; skull of Bos etruscus,
653; tusks of miocene pigs, 672,

Makalolo, perforation of the upper lip
by the, 741,

Malar bone, abnormal division of, in
man, 61-62.

Malay Archipelago, marriage-customs
of the savages of the, 770.

Malays, line of separation between the
Papuans and the, 226; general beard-
lessness of the, 721; staining of the
teeth among, 739; aversion of some,
to hairs on the face, 747.

—— and Papuans, contrasted charac-
ters of, 224.

Male animals, struggles of, for the
“possession of the females, 291-292;
eagerness of, in courtship, 292-293;
generally more modified than female,
291-293; differ in the, same way
from females and young, 306.

—— characters, developed in females,
300-301; transfer of, to female
birds, 608.

——. sedentary, of a ne ie
parasite, 292.

Malefavtors, “84.

INDEX

Males, presence of rudimentary female
organs in, 217,

—— and females, comparative numbers
of, 281, 284; comparative mortality
of, while young, 285,

Malherbe, on the woodpeckers, 590.

Mallotus peronii, 432.

villosus, 432.

Malthus, T., on the rate of increase of
population, 68-70.

Maluride, nidification of the, 586.

Malurus, young of, 626,

Mammez, 275; rudimentary, in male
Mammals, 28, 43, 216, 217, 218;
supernumerary, in women, 569; of
male human subject, 59.

Mammalia, Prof. Owen’s classification
of, 198; genealogy of the, 211.

Mammals, recent and tertiary, com-
parison of crania] capacity of, 80;
nipples of, 217; pursuit of female,
by the males, 291; secondary sexual
characters of, 646; weapons of, 647;
-relative size of the sexes of, 665-666 ;
parallelism of, with birds in second-
ary sexual characters, 699; voices
of, used especially during the breed-
ing season, 730.

Man, variability of, 46; erroneously
regarded as more domesticated than
other animals, 49; migrations of,
12; wide distribution of, 72; causes
of the nakedness of, 83; supposed
physical inferiority of, 91; a mem-
ber of the Catarrhine group, 208;
early progenitors of, 214; transi-
tion from ape indefinite, 240; nu-
merical proportions of the sexes in,
284; difference between the sexes,
295; proportion of sexes among the
illegitimate, 321; different complex-
ion of male and female negroes, 716-
717; secondary sexual characters of,
716; primeval condition of, 764.

Mandans, correlation of color and text-
ure of hair in the, 261.

Mandible, left, enlarged in the male of
Taphroderes distortus, 364-365.

Mandibles, use of the, in Ammophila,
363; large, of Corydalis cornutus,
363; large, of male Lucanus ela-
phus, 363.

Mandrill, number of caudal vertebree
in the, 86; colors of the male, 696,
698, 711.

839

Mantegazza, Prof., on last molar teeth
of man, 39; bright colors in male
animais, 296; on the ornaments of
savages, 738 e¢ seg.; on the beard
lessness of the New Zealanders,
748; on the exaggeration of nat-
ural characters by man, 749,

Mantell, W., on the engrossment of
pretty girls by the New Zealand
chiefs, 766.

Mantis, pugnacity of species of, 379.

Maories, mortality of, 245; infanticide
and proportion of sexes, 339-340;
distaste for hairiness among men,
(47.

Marcus Aurelius, on the origin of the
moral sense, 135; on the influence
of habitual thoughts, 167.

Mareca penelope, 535.

Marks, retained throughout groups of
birds, 551,

Marriage, restraints upon, among sav-
ages, 70; influence of, upon morals,
161; influence of, on mortality, 187=
188; development of, 759.

Marriages, early, 186-187; communal,
757

Marshall, Dr. W., protuberances on
birds’ heads, 310, 497; on the
moulting of birds, 507; advantage
to older birds of paradise, 626.

, Col., interbreeding among Todas,

251; infanticide and proportion of

sexes with Todas, 338; choice of

husbands among Todas, %63.

, Mr., on the brain of a Bush-
woman, 224,

Marsupials, 211; development of the
nictitating membrane in, 35; uterus
of, 61; possession of nipples by,
21%; their origin from Monotrema-
ta, 220; abdominal sacs of, 275;
relative size of the sexes of, 666;
colors of, 689.

Marsupium, rudimentary, in male mar-
supials, 216.

Martin, W. C. L., on alarm nianifested
by an orang at the sight of a turtle,
104; on the hair in Hylobates, 204;
on a female American deer, 664; on
the voice of Hylobates agilis, 681;
on Semnopithecus nemeeus, 712.

, on the beards of the inhabitants
of St. Kilda, 721.

Martins deserting their young, 147.

340

Martins, C., on death caused by inflam-
mation of the vermiform append-
age, 40.

Mastoid processes in man and apes,

9-8

Maudsley, Dr., on the indinenes of the
sense of smell in men, 36; on idiots
smelling their food, 58; on Laura
Bridgman, 123; on the development
of the vocal organs, 125; moral
sense failing in incipient madness,
167; change of mental faculties at
puberty in man, 727.

Mayers, W. F., on the domestication
of the goldfish in China, 446.

Mayhew, E., on the affection between
individuals of different sexes in the
dog, 675.

Maynard, C. J., on the sexes of Chry-
semys picta, 456.

Meckel, on correlated variation of the
muscles of the arm and leg, 67.
Medicines, effect produced by, the
same in man and in monkeys, 23.
Meduse, bright colors of some, 345.
Megalithic structures, prevalence of,

238.

Megapicus validus, sexual difference of
color in, 590.

Megasoma, large size of males of,
367.

Meigs, Dr. A., on variation in the
skulls of the natives of America,
46,

Meinecke, on the numerical proportion
of the sexes in butterflies, 330.

Melanesians, decrease of, 247.

Meldola, Mr., colors and marriage flight
of Colias and Pieris, 416.

Meliphagide, Australian, nidification
of, 586.

Melita, secondary sexual characters
of, 354.

Meloé, difference of color in the sexes
of a species of, 386.

Memory, manifestations of, in animals,
105-106.

Memnon, young, 225.

Mental characters, difference of, in
different races of men, 223.

—faculties, diversity of, in the same
race of men, 47; inheritance of, 48;
variation of, in the same species,
47-48, 95; similarity of the, in differ-
ent races of man, 237; of birds, 530.

INDEX

Mental powers, difference of, in the two
sexes in man, 725,

Menura Alberti; 524; song of, 481.

—— superba, 524; long tails of both
sexes of, 581.

Merganser, trachea of the male, 485.

—— serrator, male plumage of, 508.

Mergus cucullatus, speculum of, 311.

merganser, young of, 603.

Metallura, splendid tail-feathers of,
571.

Methoca ichneumonides, large male of,
368.

Meves, M., on the drumming of the
snipe, 488.

Mexicans, civilization of the, not for-
eign, 195.

Meyer, on a convoluted body at the
extremity of the tail in a Macacus
and a cat, 43,

——, Dr. A., on the copulation of
Phryganide of distinct species,
363.

—, Prof. L., on development of
helix of ear, 33-34; men’s ears
more variable than women’s, 295;
antennz serving as ears, 369.

Migrations of man, effects of, 72.

Migratory instinct of birds, 143; van-
quishing the maternal, 147, 154.

Mill, J. S., on the origin of the moral
sense, 135; on the ‘‘greatest lap-
piness principle,’’ 162-163; on the
difference of the mental powers in
the sexes of man, 727.

Millipedes, 361.

Milne-Edwards, H., on the use of the
enlarged chelz of the male Gelasi-
mus, 353.

Milvago leucurus, sexes and young of,
618.

Mimicry, 421.

Mimus polyglottus, 531.

Mind, difference of, in man and the
highest animals, 170; similarity of
the, in different races, 237.

Minnow, proportion of the sexes in
the, 329.

Mirror, larks attracted by, 533.

Mitchell, Dr., interbreeding in the
Hebrides, 251.

Mitford, selection of
Sparta, 50.

Mivart, St. George, on the reduction
of organs, 29; on the ears of the

children in

INDEX

lemuroidea, 33; on variability of the
muscles in lemuroidea, 64, 72; on
the caudal vertebra of monkeys,
85; on the classification of the
primates, 206; on the orang and on
man, 206-207; on differences in the
lemuroidea, 207; on the crest of the
male newt, 453.

Mobius, Prof., on reasoning powers in
a pike, 108.

Mocking-thrush, partial migration of,
531; young of the, 628,

Modifications, unserviceable, 90-91.

Moggridge, J. T., on habits of spiders,
99; on habits of ants, 198.

Moles, numerical proportion of the
sexes in, 325; battles of male,
646.

Mollienesia petenensis, sexual differ-
ence in, 439.

Mollusca, beautiful colors and shapes
of, 348; absence of secondary sex-
ual characters in the, 346.

Molluscoida, 213, 347.

Monacanthus scopas and M. Peronii,
432.

Mongolians, perfection of the senses
in, 56.

Monkey, protecting his keeper from a
baboon, 142, 151; bonnet-, 202;
rhesus-, sexual difference in color
of the, 696, 711; mustache-, colors
of the, 694.

Monkeys, liability of, to the same dis-
eages aS man, 23; male, recognition
of women by, 25; diversity of the
mental faculties in, 47; breaking
hard fruits with stones, 75; hands
of the, 76-76; basal caudal ver-
tebree of, imbedded in the body, 86;
revenge taken by, 100; maternal
affection in, 100-101; variability of
the faculty of attention in, 105;
American, manifestation of reason
jn, 110; using stones and sticks,
115; imitative faculties of, 122;
signal-cries of, 122; mutual kind-
nesses of, 139; sentinels posted by,
138; human charactera of, 201-
202; American, direction of the
hair on the arms of some, 303-203;
gradation of species of, 233; beards
of, 688; ornamental characters of,
707-708; analogy of sexual differ-
ences of, with those of man, 719;

841

different degrees of difference in
the sexes of, 722; expression of
emotions by, 736; generally monog-
amous habits of, 759; polygamous
habits of some, 760; naked surfaces
of, 772-773.

Monogamy, not primitive, 194,

Monogenists, 234.

Mononychus pseudacori, striduiation
of, 398.

Monotremata, 211; development of the
nictitating membrane in, 35; lactif-
erous glands of, 217; connecting
mammals with reptiles, 220.

Monstrosities, analogous, in man and
lower animals, 51; caused by ar-
rest of development, 58; correla-
tion of, 67; transmission of, 230,

Montagu, G., on the habits of the
black and red grouse, 289; on the
pugnacity of the ruff, 469; on the
singing of birds, 478; on the double
moult of the male pintail, 508.

Monteiro, Mr., on Bucorax abyssini-
cus, 496.

Montes de Oca, M., on the pugnacity
of maie humming-birds, 468.

Monticola cyanea, 588.

Monuments, as traces of extinct tribes,
241.

Moose, battles of, 647; horns of the,
an encumbrance, 665.

Moral and instinctive impulses, alli-
ance of, 161.

faculties, their influence on nat-

ural selection in man, 173.

rules, distinction between the
higher and lower, 165~166.

—— sense, so-called, derived from the
social instincts, 163-164; origin of
the, 168.

—— tendencies, inheritance of, 168,

Morality, supposed to be founded in
selfishness, 162; test of, the gen-
eral welfare of the community,
163-164; gradual rise of, 168-169;
influence of a high standard of,
178-179.

Morgan, L. H., on the beaver, 97; on
the reasoning powers of the beaver,
107; on the forcible capture of
wives, 194; on the castoreum of
the beaver, 683; marriage un-
known in primeval times, 757-758;
on polyandry, 763,

842

Morley, J., on the appreciation of
praise and fear of blame, 193.

Morris, F. O., on hawks feeding an
orphan nestling, 529.

Morse, Dr., colors of mollusea, 349.

Morselli, E., division of the malar
bone, 61.

Mortality, comparative, of females and
males, 285, 320.

Morton, on the number of species of
man, 233.

Moschkau, Dr. A., on a _ speaking
starling, 120,

Moschus moschiferus, odoriferous or-
gans of, 684.

Motacillze, Indian, young of, 604.

Moths, 409; absence of mouth in some
males, 275; apterous female, 276;
male, prehensile use of the tarsi
by, 277; male, attracted by fe-
males, 332; coloration of, 410;
sexual differences of color in, 411.

Motmot, inheritance of mutilation of
tail feathers, 87, 776; racket-shaped
feathers in the tail of a, 497.

Moult, double, 596; double annual, in
birds, 504,

Moulting of birds, 624.

Moults, partial, 506.

Mouse, song of, account of by Rev. 8.
Lockwood, 731.

Mud-turtle, long claws of the male,
456,

Mulattoes, persistent fertility of, 228;
immunity of, from yellow fever,
256, °

Mule, sterility and strong vitality of
the, 229.

Mules, rational, 111.

Miller, Ferd., on the Mexicans and
Peruvians, 195.

Fritz, on astomatous males of

Tanais, 275; on the disappearance

of spots and stripes in aduJt mam-

mals, 706; on the proportions of

the sexes in some Crustacea, 338;

on secondary sexual characters in

various Crustaceans, 350 ef seq.;

musical contest between male
Cicada, 371; mode of holding
wings in Castnia, 411; on birds

showing a preference for certain
colors, 413; on the sexual matu-
rity of young amphipod Crustacea,
625.

INDEX

Miller, Hermann, emergence of bees
from pupa, 282; pollen-gathering
of bees, 301; proportion of sexes
in bees, 336; courting of Eristalis,
369; color and sexual selection with
bees, 384.

—, J., on the nictitating membrane
and semilunar fold, 35-36.

—, Max, on the origin of language,
122; language implies power of
general conception, 124; struggle
for life among the words, etc., of
languages, 127.

, S., on the banteng, 693; on
the colors of Semnopithecus chryso-
melas, 694.

Muntjac-deer, weapons of the, 663.

Murie, J., on the reduction of organs,
29; on the ears of the Lemuroi-
dea, 33; on the variability of the
muscles in the Lemuroidea, 64, 72;
basal caudal vertebree of Macacus
brunneus imbedded in the body,
86; on the manner of sitting in
short-tailed apes, 87; on differ-
ences in the Lemuroidea, 207; on
the throat-pouch of the male bus-
tard, 483; on the mane of Otaria
jubata, 672; on the sub-orbital pits
of Ruminants, 684; on the colors
of the sexes in Otaria nigrescens,
691.

Murray, A., on the Pedicula of differ-
ent races of men, 227.

——, T. A., on the fertility of Austra-
lian women with white men, 228.

Mus coninga, 114.

— minutus, sexual difference in the
color of, 690.

Musca vomitoria, 80.

Muscicapa grisola, 586.

— luctuosa, 586.

—— ruticilla breeding in immature
plumage, 625.

Muscle, ischio-pubic, 64,

Muscles, rudimentary, the occurrence
of, in man, 30; variability of the,
46-47; effects of use and disuse
upon, 53; animal-like abnormalities
of, in man, 65; correlated variation
of, in the arm and leg, 67; variabil-
ity of, in the hands and feet, 72; of
the jaws, influence of, on the physi-
ognomy of the apes, 79-80; habitual
spasms of, causing modifications of

INDEX

the facial bones, 82; of the early
progenitors of man, 215; greater
variability of the, in men than in
women, 295,

Musculus sternalis, Prof. Turner on
the, 30.

Music, rude, 238; of birds, 478; dis-
cordant, love of savages for, 492;
reason of power of perception of
notes in animals, 731; power of
distinguishing notes, 732-733; of
the nations of Western Europe, 734;
connection of, with primeval speech,
735; different appreciation of, by
different peoples, 733-734; origin
of, 733, 737; effects of, 735.

Musical cadences, perception of, by
animals, 732; powers of man, 728
et seq.

Musk-deer, canine teeth of male, 648,
663, 664; male, odoriferous organs
of the, 684; winter change of the,
700.

Musk-duck, Australian, 466; large size
of male, 471; of Guiana, pugnacity
of the male, 469.

Musk-ox, horns of, 653.

Musk-rat, protective resemblance of
the, to a clod of earth, 700.

Musophagz, colors and nidification of
the, 587; both sexes of, equally
brilliant, 592-593.

Mussels, opened by monkeys, 75.

Mustaches, in monkeys, 202.

Mustache-monkey, color of the, 694,
712.

Mustela, winter change of two species
of, 700.

Musters, Captain, on Rhea Darwinii,
617; marriages among Patagonians,
769.

Mutilations, healing of, 24;
tance of, 87.

Mutilla europza, stridulation of, 385;
power possessed by other sexes, ac-
cording to Goureau, 385.

Mutillidz, absence of ocelli in female,
362.

Mycetes caraya, polygamous, 287;
vocal organs of, 681; beard of,
686; sexual differences of color in,
693; voice of, 730.

——seniculus, sexual differences of
color in, 694.

Myriapoda, 361.

inheri-

843

N

Nageli, on the influence of natural
selection on plants, 88; on the
gradation of species of plants, 233.

Nails, colored yellow or purple in part
of Africa, 739.

Narwhal, tusks of the, 648, 655.

Nasal cavities, large size of, in Ameri-
can aborigines, 56,

Nascent organs, 28.

Nathusius, H. von, on the een
breeds of pigs, 236; male domesti-
cated animals more variable than
females, 294; horns of castrated
sheep, 654; on the breeding of
domestic animals, 767.

Natural selection, its effects on the
early progenitors of mau, 72; in-
fluence of, on man, 86-90; limita-
tion of the principle, 89; influence
of, on social animals, 90; Mr. Wal-
lace on the limitation of, by the
influence of the mental faculties in
man, 172; influence of, in the prog-
ress of the United States, 191; in
relation to sex, 342.

Natural and sexual
trasted, 297-298.

Naulette, jaw from, large size of the
canines in, 63.

Neanderthal skull, capacity of the, 81.

Neck, proportion of, in soldiers and
sailors, 54.

Necrophorus, stridulation of, 696, 698,

Nectarinia, young of, 604.

Nectariniz, moulting of the, 506; nidi-
fication of, 586.

Negro, resemblance of a, to Europeans,
in mental characters, 237.

Negro-women, their kindness to Mungo
Park, 160.

Negroes, Caucasian features in, 223;
character of, 224; lice of, 227; fer-
tility of, when crossed with other
races, 228; blackness of, 230-231;
variability of, 232-233; immunity
of, from yellow fever, 256; differ-
ence of, from Americans, 261; dis-
figurements of the, 698; color of
new-born children of, 718; compar-
ative beardlessness of, 721; readily
become musicians, 734; apprecia-
tion of beauty of their women by,
143, 746; idea of beauty among,

selection con-

844

749; compression of the nose by
some, 750.

Nemertians, colors of, 350.

Neolithic period, 195.

Neomorpha, sexual difference of the
beak in, 467.

Nephila, size of male, 360.

Nests, made by fishes, 448; decora-
tion of, by hummiag-birds, 533.

Neumeister, on a change of color in
pigeons after several moultings,
313.

Neuration, difference of, in the two
sexes of some butterflies and hy-
menoptera, 364-365,

Neuroptera, 336, 380.

Neurothemis, dimorphism in, 381.

New Zealand, expectation by the na-
tives of, of their extinction, 254;
practice of tattooing in, 742; aver-
sion of natives of, to hairs on the
face, 747; pretty girls engrossed by
the chiefs in, 766.

Newton, A., on the throat-pouch of
the male bustard, 483; on the dif-
ference between the females of two
species of Oxynotus, 606; on the
habits of the Phalarope, dotterel,
and godwit, 616.

Newts, 452.

Nicholson, Dr., on the non-immunity
of dark Europeans from yellow
fever, 258,

Nictitating membrane, 35, 215.

Nidification, of fishes, 448; relation
of, to color, 583-584, 588-589; of
British birds, 586.

Night-heron, cries of the, 477.

Nightingale, arrival of the male be-
fore the female, 280; object of the
song of the, 478.

Nightingales, new mates found by,
527

Nightjar, selection of a mate by the
female, 537; Australian, sexes of,
618; coloration of the, 634,

- Nightjars, noise made by some male,
with their wings, 487; elongated
feathers in, 497, 519.

Nilghau, sexual differences of color in
the, 691.

Nilsson, Prof., on the resemblance of
stone arrow-heads from various
places, 238; on the development of
the horns in the reindeer, 308.

INDEX

Nipples, absence of, in Monotremata,
217,

Nitzche, Dr., ear of foetal orang, 35.

Nitzsch, C. oe on the down of birds,
504.

Noctuz, brightly colored beneath,
411-412.

Noctuidee, coloration of, 409.

Nomadic habits unfavorable to human
progress, 179.

Nordmann, A., on Tetrao urogalloides,
523,

Norfolk Island, half-breeds on, 253.

Norway, numerical proportion of male
and female births in, 319.

Nose, resemblance of, in man and the
apes, 205; piercing and ornamenta-
tion of the, 740; very flat, not ad-
mired in negroes, 749; flattening
of the, 750.

Nott and Gliddon, on the features of
Rameses II., 255; on the features
of Amunoph III., 255; on skulls
from Brazilian caves, 255; on the
immunity of negroes and mulattoes
from yellow fever, 256; on the
deformation of the skull among
American tribes, 750.

Novara, voyage of the, 159;
in New Zealand, 159.

Nudibranch Mollusca, bright colors of,
349,

Numerals,
194,

Nunemaya, natives of, bearded, 721-
722.

Nut-hatch of Japan, intelligence of,
530.

suicide

Roman, 194; origin of,

oe

Obedience, value of, 159, 176.

Observation, powers of, possessed by
birds, 531.

Occupations, sometimes a cause of
diminished stature, 62-53; effect
of, upon the proportions of the
body, 53.

Ocelli, absence of, in female Mutillidsx,
362.

—— of birds, formation and variability
of the, 552.

Ocelot, sexual differences in the color-
ing of the, 690.

Ocyphaps, lophotes, 519.

INDEX

Odonata, 336.

Odonestis potatoria, sexual difference
of color in, 412.

Odor, correlation of, with color of skin,
261-262; emitted by snakes in the
breeding-season, 457; of mammals,
683.

Ccanthus nivalis, difference of color in
the sexes of, 380.

—— pellucidus, 380.

Ogle, Dr. W., relation between color
and power of smell, 36.

Oidemia, 634.

Olivier, on sounds produced by Pimelia
striata, 400.

Omaloplia brunnea, stridulation of, 397.

Onitis furcifer, processes of anterior
femora of the male, and on the head
and thorax of the female, 390.

Onthophagus, 389.

rangifer, sexual differences of,
$88; variation in the horns of the
male, 389.

Ophidia, sexual differences of, 456.

Ophidium, 451.

Opossum, wide range of, in America,
226.

Optic nerve, atrophy of the, caused by
destruction of the eye, 53.

Orang-oulang, 722; Bischoff on the
agreement of the brain of the, with
that of man, 22; adult age of the,
25; ears of the, 32; vermiform ap-
pendage of, 40; hands of the, 75;
absence of mastoid processes in the,
48-19; platforms built by the, 96;
alarmed at the sight of a turtle,
103-104; using a stick as a lever,
115; covering itself with straw, 115;
using missiles, 115; using the leaves
of the Pandanus as a night cover-
ing, 117; direction of the hair on
the arms of the, 202-203; its aber-
rant characters, 206; supposed evo-
lution of the, 236; voice of the, 681;
monogamous habits of the, 1759;
male, beard of the, 686.

Oranges, wild, treatment of, by Amer-
ican monkeys, 75.

Orange-tip butterfly, 403, 408.

Orchestia Darwinii, dimorphism of
males of, 354,

Tucuratinga, limbs of, 353, 358.

Ordeal, trial by, 133.

Oreas canna, colors of, 692.

845

Oreas Derbianus, colors of, 692, 702.

Organs, prehensile, 277; utilized for
new purposes, 735.

Organic scale, von Baer’s definition of
progress in, 219,

Orioles, nidification of, 584.

Oriolus, species of, breeding in imma-
ture plumage, 625.

melanocephalus, coloration of the
sexes in, 594.

Ornaments, prevalence of similar, 238;
of male birds, 476; fondness of sav-.
ages for, 739.

Ornamental characters, equal transmis-
sion of, to both sexes, in mammals,
100; of monkeys, 707.

Ornithoptera crcesus, 331.

Ornithorhynchus, 209; reptilian ten-
dency of, 212; spur of the male,
649.

Orocetes erythrogastra, young of, 628.

Orrony, Grotto of, and the humeri of
the Bronze period, 41.

Orsodacna atra, difference of color in
the sexes of, 386.

Orthoptera, 372; metamorphosis of,
311; stridulating apparatus of, 372,
378; colors of, 380; rudimentary
stridulating organs in female, 378;
stridulation of the, and Homoptera,
discussed, 378.

Ortygornis gularis, pugnacity of the
male, 472. i

Oryctes, stridulation of, 397; sexual
differences in the stridulant organs
of, 399, 400.

Oryx leucoryx, use of the horns of,
657, 668.

Osphranter rufus, sexual difference in
the color of, 689.

Ostrich, African, sexes and incubation
of the, 617.

Ostriches, stripes of young, 599.

Otaria jubata, mane of the male, 672.

nigrescens, difference in the color-
ation of the sexes of, 691.

Otis bengalensis, love-antics of the
male, 493.

—— tarda, throat-pouch of the male,
483; polygamous, 290.

Ouzel, ring-, colors and nidification of
the, 587.

—., water-, colors and nidification of
the, 587.

Ovibos moschatus, horns of, 653.

.

846

Ovipositor of insects, 275.

Ovic cycloceros, mode of fighting of,
656, 662.

Ovule of man, 25-26.

Owen, Prof., on the Corpora wolfiana,
26-27; on the great toe in man, 28;
on the nictitating membrane and semi-
lunar fold, 35-36; on the develop-
ment of the posterior molars in dif-
ferent races of man, 39; on the
length of the cecum in the Koala,
39-40; on the coccygeal vertebre,
42; on rudimentary structures be-
longing to the reproductive system,
44; on abnormal conditions of the
human uterus, 61; on the number of
digits in the Ichthyopterygia, 60; on
the canine teeth in man, 63; on the
walking of the chimpanzee and orang,
75; on the mastoid processes in the
higher apes, 79; on the hairiness of
elephants in elevated districts, 83;
on the caudal vertebrae of monkeys,
85; classification of mammalia, 198;

on the hair in monkeys, 203-204; |

on the piscine affinities of the Ich-
thyosaurians, 212; on polygamy and
monogamy among the antelopes, 287 ;
on the horns of Antilocapra ameri-
cana, 308-309; on the musky odor
of crocodiles during the breeding sea-
son, 456; on the scent glands of
snakes, 457; on the Dugong, Cacha-
lot, and Ornithorhynchus, 649; on
the antlers of the red deer, 659; on
the dentition of the Camelide, 664;
on the horns of the Irish elk, 665;
on the voice in the giraffe, porcupine
and stag, 679; on the laryngeal sac
of the gorilla and orang, 681; on the
odoriferous glands of mammals, 683-
684; on the effects of emasculation
on the vocal organs of men, 729; on
the voice of Hylobates agilis, 730;
on American monogamous monkeys,
730.

Owls, white, new mates found by, 527.

Oxynotus, difference of the females of
two species of, 606.

P

Pachydermata, 288,
Pachytylus migratorius, 372.

INDEX

Paget, on the abnormal development of
hairs in man, 37; on the thickness
of the skin on the soles of the feet
of infants, 55.

Painting, pleasure of savages in, 238.

Palzemon, chelee of a species of, 354.

Paleeornis, sexual differences of coloi
in, 637,

—— javanicus, color of beak of, 595,

rosa, young of, 602.

ca cornuta, spurs on the wings,
474.

Paleolithic period, 195.

a aoe habits of the chaffinch in,
327.

Pallas, on the perfection of the senses
in the Mongolians, 56; on the want
of connection between climate and
the color of the skin, 255; on the
polygamous habits of Antilope Saiga,
287; on the lighter color of horses
and cattle in winter in Siberia, 302;
on the tusks of the musk deer, 663;
on the odoriferous glands of mam-
mals, 683; on the odoriferous glands
of the musk deer, 684; on winter
changes of color in mammals, 700;
on the ideal of female beauty in
North China, 744,

Palmeris accessorius, variations of the
muscle in the, 47.

Pampas, horses of the, 241. ;

Pangenesis, hypothesis of, 301-305.

Panniculus carnosus, 30.

Pansch, on the brain of a foetal Cebus
apella, 272.

Papilio, proportion of the sexes in
North American species of, 330;
sexual differences of coloring in
species of, 404; coloration of the
wings in species of, 407.

—— ascanius, 404.

—— Sesostris and Childrenz, variabil-
ity of, 417.

— Turnus, 330.

Papilionide, "variability 4 in the, 41%,

Papuans, line of separation between
the, and the Malays, 226; beards of
the, 721; hair of, 740.

— and Malays, contrast in charac-
ters of, 224,

Paradise, Birds of, 523, 596; supposed
by Lesson to be polygamous, 289;
rattling of their quills by, 4863
racket-shaped feathers in, 497; sex-

INDEX

ual differences in color of, 500; de-
composed feathers in, 500, 520; dis-
play of plumage by the male, 511,

Paradisea apoda, barbless feathers in
the tail of, 498; plumage of, 498;
and P, papuana, 498; divergence of
the females of, 606; increase of
beauty with age, 626.

Paraguay, Indians of, eradication of
eyebrows and eyelashes by, 747.

Parallelism of development of species
and languages, 126.

Parasites on man and animals, 24; as
evidence of specific identity or dis-
tinctness, 227; immunity from, cor-
related with color, 256,

Parental feeling in earwigs, starfishes,
and spiders, 145; affection, partly a
result of natural selection, 145.

Parents, age of, influence upon sex of
offspring, 321-322, ©

Paring, sexual difference of color in,
590.

Park, Mungo, negro women teaching
their children to love the truth, 160;
his treatment by the negro women,
160, 725; on negro opinions of the
appearance of white men, 745.

Parker, Mr., no bird or reptile in line
of mammalian descent, 211.

Paroquet, Australian, variation in the
color of the thighs of a male, 547.

Parrot, racket-shaped feathers in the
tail of a, 497; instance of benevo-
lence in a, 531.

Parrots, change of color in, 88; imita-
tive faculties of, 104; living in trip-
lets, 528; affection of, 530; colors
and nidification of the, 58%, 590,
591; immature plumage of the, 602;
colors of, 632; sexual differences of
color in, 637; musical powers of,
135.

Parthenogenesis in the Tenthredina,
335; in Cynipide, 335; in Crustacea,
337.

Partridge, monogamous, 290; propor-
tion of the sexes in the, 326; female,
608.

«*_— -dances,’’ 492, 523.

Partridges, living in triplets,
spring coveys of male, 529;
tinguishing persons, 531.

Parus coeruleus, 590.

Passer, sexes and young of, 623.

528;
dis-

B47

Passer brachydactylus, 623.

—— domesticus, 586, 623.

—— montanus, 586, 623.

Patagonians, self-sacrifice by,
marriages of, 769.

Patterson, Mr., on the Agrionide, 381.

Patteson, Bishop, decrease of Melane-
sians, 2417.

Paulistas of Brazil, 231.

Pavo cristatus, 310, 556.

muticus, 310, 556; possession of
spurs by the female, 473, 580,

—— nigripennis, 541.

Payaguas Indians, thin legs and thick
arms of the, 54,

Payan, Mr., on the proportion of the
sexes in sheep, 324.

Peacock, polygamous, 290; sexual
characters of, 310; pugnacity of the,
473; rattling of the quills by, 486;
elongated tail-coverts of the, 491,
519; love of display of the, 509,
544; ocellated spots of the, 556;
inconvenience of long tail of the, to
the female, 572, 581-582; continued
increase of beauty of -the, 626,

-butterfly, 407.

Peafowl, preference of females for a
particular male, 540; first advances
made by the female, 540.

Pediculi of domestic animals and man,
227.

Pedigree of man, 221.

Pedionomus torquatus, sexes of, 614.

Peel, J., on horned sheep, 652.

Peewit, wing-tubercles of the male,
475.

Pelagic animals, transparency of, 346-
347.

Pelecanus erythrorhynchus, horny
crest on the beak of the male, dur-
ing the breeding season, 503.

—— onocrotalus, spring plumage of,
508.

Pelelé, an African ornament worn in
the upper lip, 742.

Pelican, blind, fed by his companions,
141; young, guided by old birds,
141; pugnacity of the male, 469.

Pelicans, fishing in coucert, 139.

Pelobius Hermanni, stridulation of, 396,
398.

Pelvis, alteration of, to suit the erect
attitude of man, 65; differences of
the, in the sexes of man, 71°.

161;

848

Penelope nigra, sound produced by the
male, 489,

Pennant, on the battles of seals, 647;
on the bladder-nose seal, 682.

Penthe, antennal cushions of the male,
364.

Perch, brightness of male, during breed-
ing season, 442,

Peregrine falcon, new mate found by,
527,

Periodicity, vital, Dr. Laycock on, 24.
Period of variability, relation of, to
sexual selection, 315.

Periods, lunar, followed by functions
in man and animals, 24, 220-221.
—— of life, inheritance at correspond-

ing, 301-307.
Perisoreus canadensis, young of, 621:
Peritrichia, difference of color in the
sexes of a species of, 386.
Periwinkle, 347.
Pernis cristata, 547.

Perrier, M., on sexual selection, 207;

on bees, 384.

Perseverance, a characteristic of man,
726.

Persians, said to be improved by inter-
mixture with Georgians and Circas-
sians, 755,

Personnat, M., on Bombyx Yamamai,
331.

Peruvians, civilization of the, not for-
eign, 195.

Petrels, colors of, 637.

Petrocincla cyanea, young of, 628.

Petrocossyphus, 595.

Petronia, 623.

Pfeiffer, Ida, on Javan ideas of beauty,
746.

Phacocherus ethiopicus, tusks and
pads of, 670.

Phalanger, Vulpine, black varieties of
the, 697.

Phalaropus fulicarius, 616.

hyperboreus, 616.

Phaneus, 391.

— caruifex, variation of the horns of
the male, 389,

— faunus, sexual differences of, 388.

—— lancifer, 388.

Phaseolarctus cinereus, taste for rum
and tobacco, 24.

Phasgonura viridissima, stridulation of,
375.

Phasianus Scemmerringii, 574.

INDEX

Phasianus versicolor, 532.

—— Wallichii, 516, 609.

Pheasant, polygamous, 290; and blacks
grouse, hybrids of, 635; production
of hybrids with the common fowl,
ole immature plumage of the, 601~
602.

——, Amherst, display of, 521.

—-, Argus, 560, 596; display of plu-
mage by the male, 513; ocellated
spots of the, 554, 561; gradation of
characters in the, 560-561.

—, Blood-, 473.

——, Cheer, 516, 609.

—-, Eared, 310, 516, 609; length of
the tail in the, 582; sexes alike in
the, 593.

. Golden, display of plumage by

the male, 611; age of mature plu-

mage in the, 624; sex of young
ascertained by pulling out head-

feathers, 624,

, Kalij, drumming of the male, 487.

——, Reeve’s, length of the tail in,
583,

——, Silver, triumphant male, deposed
on account of spoiled plumage, 541;
sexual coloration of the, 635.

——, Soemmerring’s, 574, 583.

——, Tragopan, 496; display of plu-
mage by the male, 513; markings
of the sexes of the, 554,

Pheasants, period of acquisition of male
characters in the family of the, 310;
proportion of sexes in chicks of, 326;
length of the tail in, 574, 581-582.

Philters, worn by women, 743.

Phoca groenlandia, sexual difference in
the coloration of, 691.

Phoenicura ruticilla, 527.

Phosphorescence of insects, 365.

Phryganidz, copulation of distinct spe-
cies of, 363.

Phryniscus nigricans, 454.

Physical inferiority, supposed, of man,
91-92.

Pickering, on the number of species of
man, 232.

Picton, J. A., on the soul of man, 789.

Picus auratus, 469.

major, 519.

Pieris, 407, 416.

Pigeon, female, deserting a weskened
mate, 283; carrier, late development
of the wattle in, 313; pouter, late

INDEX

development of the crop in, 313;
domestic, breeds and sub-breeds of,
593. : :

Pigeons, nestling, fed by the secretion
of the crop of both parents, 218;
changes of plumage in, 302; trans-
mission of sexual peculiarities in,
303; Belgian, with black-streaked
males, 305, 313, 675; changing
color after several moultings, 313;
numerical proportion of the sexes
in, 325; cooing of, 486; variations
in plumage of, 498; display of plu-
mage by male, 519; local memory of,
530; antipathy of female, to certain
males, 539; pairing of, 539; profli-
gate male and female, 540; wing-
bars and tail-feathers of, 551; sup-
posititious breed of, 573; pouter and
carrier, peculiarities of, predominant
in males, 576; nidification of, 584;
Australian, 591; immature plumage
of the, 602.

Pigs, origin of the improved breeds of,
236; numerical proportion of the
sexes in, 324; stripes of young, 599,
705; tusks of miocene, 672; sexual
preference shown by, 677.

Pike, American, brilliant colors of the
male, during the breeding season,
442,

—,, reasoning powers of, 108; male,
devoured by females, 328.

Pike, L. 0., on the psychical elements
of religion, 133.

Pimelia striata, sounds produced by the
female, 400.

Pinel, striking case of hairiness in an
idiot, 59.

Pintail, drake, plumage of, 508; pair-
ing with a wild duck, 536.

—— duck, pairing with a widgeon,
535.

Pipe-fish, filamentous, 447; marsupial
receptacles of the male, 450.

Pipits, moulting of the, 506.

Pipra, modified secondary wing-feath-
ers of male, 490. >

deliciosa, 490.

Pirates stridulus, stridulation of, 370.

Pitcairn Island, half-breeds on, 253.

Pithecia leucocephala, sexual differ-
enees of color in, 694.

— Satanas, beard of, 687; resem-
blance of, to a negro, 777.

849

Pits, suborbital, of Ruminante, 684.
Pittides, nidification of, 584.
Placentata, 211.

-Plagiostomous fishes, 431.

Plain-wanderer, Australian, 614.

Planarise, bright colors of some, 345.

Plantain-eaters, colors and nidification
of the, 587; both sexes of, equally
brilliant, 593.

Plants, cultivated, more fertile than
wild, 69; Nageli, on natural selec-
tion in, 88; male flowers of, mature
before the female, 281; phenomena
of fertilization in, 293.

Platalea, 485; change of plumage in,
595.

Platyblemnus, 380.

Platycercus, young of, 621.

Platyphyllum concavum, 372, 376.

Platyrrhine monkeys, 205.

Platysma myoides, 30.

Plecostomus, head-tentacles of the
males of a species of, 440.

barbatus, peculiar beard of the
male, 441.

Plectropterus gambensis, spurred wings
of, 473.

Ploceus, 480, 487, 523.

Plovers, wing-spurs of, 475; double
moult in, 506.

Plumage, changes of, inheritance of,
by fowls, 301-302; tendency to anal-
ogous variation in, 498; display of,
by male birds, 509, 519; changes
of, in relation to season, 594; imma-
ture, of birds, 599-600; color of, in
relation to protection, 631.

Plumes on the head in birds, difference
of, in the sexes, 581.

Pneumora, structure of, 377.

Podica, sexual difference in the color
of the irides of, 549.

Poeppig, on the contact of civilized and
savage races, 240.

Poison, avoidance of, by animals, 113.

Poisonous fruits and herbs avoided by
animals, 96.

Poisons, immunity from,
with color, 256.

Polish fowls, origin of the crest in,
304.

Pollen and van Dam, on the colors of
Lemur macaco, 693.

Polyandry, 763; in certain Cyprinids,
329; among the Elaterids, 335.

correlated

850

Polydactylism, in man, 60.

Polygamy, influence of, upon sexual
selection, 286; superinduced by do-
mestication, 290; supposed increase
of female births by, 321; in the
stickleback, 432.

Polygenists, 234.

Polynesia, prevalence of infanticide in,

Polynesians, wide geographical range
of, 50; difference of stature among
the, 52; crosses of, 231; variability
of, 232; heterogeneity of the, 255;
aversion of, to hairs on the face,
W47,

Polyplectron, number of spurs in, 473;
display of plumage by the male, 512;
gradation of characters in, 557; fe-
male of, 607.

— chinquis, 512, 557.

Hardwickii, 557.

— malaccense, 558-559,

Napoleonis, 557, 559.

Polyzoa, 347.

Pontoporeia affinis, 351.

Porcupine, mute, except in the rutting
season, 679,

Pores, excretory, numerical relation of,
to the hairs in sheep, 262.

Porpite, bright colors of some, 345.

Portax picta, dorsal crest and throat-
tuft of, 686; sexual differences of
color in, 692, 701.

Portunus puber, pugnacity of, 355.

Potamocheerus penicillatus, tusks and
facial knobs of the, 671.

Pouchet, G., the relation of instinct to
intelligence, 96-97; on the instincts
of ants, 198; on the caves of Abou-
Simbel, 225; on the immunity of
negroes from yellow. fever, 256;
change of color in fishes, 447.

Pouter pigeon, late development of the
large crop in, 313.

Powell, Dr., on stridulation, 371.

Power, Dr., on the different colors of
the sexes in a species of Squilla,
357. y

Powys, Mr., on the habits of the chaf-
finch in Corfu, 327.

Pre-eminence of man, 73.

Preference for males by female birds,
534, 543; shown by mammals in
pairing, 674.

Prehensile organs, 275.

INDEX

ee entellus, fighting of the male,
23,

Preyer, Dr., on function of shell of ear,
32; on supernumerary mamme in
women, 59.

Prichard, on the difference of stature
among the Polynesians, 52; on the
connection between the breadth of
the skull in the Mongolians, and the
perfection of their senses, 56; on
the capacity of British skulls of dif-
ferent ages, 81; on the flattened
heads of the Colombian savages,
740; on Siamese notions of beauty,
744; on the beardlessness of the
Siamese, 721; on the deformation of
the head among American tribes and
the natives of Arakhan, 750. -

Primary sexual organs, 274,

Primates, 200, 271; sexual differences
of color in, 693.

Primogeniture, evils of, 182-183.

Prionid, difference of the sexes in
color, 386.

Proctotretus multimaculatus, 464,

tenuis, sexual difference in the
color of, 464.

Profligacy, 185.

Progenitors, early, of man, covered
with hair, 214-216.

Progress, not the normal rule in human
society, 179; dependent on favorable
conditions, 179; elements of, 191.

Prong-horn antelope, horns of, 309.

Proportions, difference of, in distinct
races, 223,

Protective coloring in butterflies, 407;
in lizards, 465; in birds, 610, 632;
iu mammals, 700.

nature of the dull coloring of

female Lepidoptera, 419, 421, 423.

resemblances in fishes, 447.

Protozoa, absence of secondary sexual
characters in, 344.

Pruner-Bey, on the occurrence of the
supra-condyloid foramen in the hu-
merus of man, 42; on the color of
negro infants, 718.

Prussia, numerical proportion of male
and female births in, 320.

Psocus, proportions of the sexes in,
336,

Ptarmigan, monogamous, 290; summer
and winter plumage of the, 505-506;
nuptial assemblages of, 524; triple

INDEX

moult of the, 596; protective colora-
tion of, 611.

Puff-birds, colors and nidification of
the, 587.

Pugnacity of fine-plumaged male birds,
516.

Pumas, stripes of young, 599.

Puppies learning from cats to clean
their faces, 104.

Pyenonotus hemorrhous, pugnacity of
the male, 468; display of under tail
coverts by the male, 518,

Pyranga estiva, male aiding in incuba-
tion, 584.

Pyrodes, difference of the sexes in
color, 386,

Q@

Quadrumana, hands of, 75; differences
between man and the, 200; sexual
differences of color in, 693; orna-
mental characters of, 707; analogy
of sexual differences of, with those
of man, 718-719; fighting of males
for the females, 723; monogamous
habits of, 759; beards of the, 775,

Quain, R., on the variation of the mus-
cles in man, 47.

Quatrefages, A. de, on the occurrence
of a rudimentary tail in man, 42; on
variability, 50; on the moral sense
as a distinction between man and
animals, 134; civilized men stronger
than savages, 183; on the fertility
of Australian women with white
men, 228; on the Paulistas of Bra-
zil, 231; on the evolution of the
breeds of cattle, 236; on the Jews,
256; on the liability of negroes to
tropical fevers after residence in a
cold climate, 257; on the difference
between field- and house-slaves, 260;
on the influence of climate on color,
259-260; colors of annelids, 350; on
the Ainos, 721; on the women of San
Giuliano, 755.

Querquedula acuta, 535.

Quetelet, proportion of sexes in man,
319; relative size in man and woman,
320. .

Quichua Indians, 56; local variation of
eolor in the, 260; no gray hair
among the, 719; hairlessness of
the, 722; long hair of the, 747.

851

Quiscalus major, 297; proportions of
the sexes of, in Florida and Hon-
duras, 227-228,

Rabbit, white tail of the, 700.

Rabbits, domestic, elongation of the
skull in, 82; modification of the
skull in, by the lopping of the ear,
82; danger-signals of, 138; numeri-
cal proportion of the sexes in, 324-
325.

Races, distinctive characters of, 224—
225; or species of man, 225; crossed,
fertility or sterility of, 227-228; of
man, variability of the, 232; of man,
resemblance of, in mental characters,
237; formation of, 240; of man, ex-
tinction of, 241; effects of the cross-
ing of, 254; of man, formation of
the, 254; of man, children of the,
717-718; beardless, aversion of, to
hairs on the face, 747.

Raffles, Sir S., on the banteng, 693.

Rafts, use of, 73, 139,

Rage, manifested by animals, 100.

Raia batis, teeth of, 436.

—— clavata, female spined on the
back, 432; sexual difference in the
teeth of, 436.

maculata, teeth of, 436.

Rails, spur-winged, 475.

Ram, mode of fighting of the, 656;
African, mane of an, 688; fat-tailed,
688.

Rameses IJI., features of, 225.

Ramsay, Mr., on the Australian musk-
duck, 466; on the regent-bird, 534;
on the incubation of Menura superba,
581,

Rana esculenta, vocal sacs of, 455.

Rat, common, general dispersion of, a
consequence of superior cunning,
114; supplantation of the native,
in New Zealand by the European
rat, 254; common, said to be polyga-
mous, 288; numerical proportion of
the sexes in, 325.

Rats, enticed by essential oils, 685.

Rationality of birds, 530.

Rattlesnakes, difference of the sexes in
the, 456-457; rattles as a call,
459,

852

Raven, vocal organs of the, 481; steal-
ing bright objects, 533; pied, of the
Feroe Islands, 547.

Rays, prehensile organs of male, 521.

Razor-bill, young of the, 627.

Reade, Winwood, suicide among sav-
ages in Africa, 159; mulattoes not
prolific, 228; effect of castration of
horned-sheep, 654; on the Guinea
sheep, 309; on the occurrence of a
Mane in an African ram, 688; on the
negroes’ appreciation of the beauty
of their women, 743; on the admira-
tion of negroes for a black skin, 745;
on the idea of beauty among negroes,
748-749; on the Jollofs, a tribe on
the west coast of Africa, 755; on
the marriage customs of the negroes,
T71,.

Reason, in animals, 107.

Redstart, American, breeding in imma-
ture plumage, 625.

Redstarts, new mates found by, 5217.

Reduvide, stridulation of, 370.

Reed-bunting, head-feathers of the
male, 518; attacked by a bull-finch,
532.

Reefs, fishes frequenting, 446.

Reeks, H., retention of horns by breed-
ing deer, 650; cow rejected by a
bull, 677; destruction of piebald rab-
bits by cats, 701.

Regeneration, partial, of lost parts in
man, 24.

Regent-bird, 534.

Reindeer, horns of the, 308; battles
of, 647; horns of the female, 650;
antlers of, with numerous points,
659; winter change of the, 700;
sexual preferences shown by, 714.

Relationship, terms of, 759.

Religion, deficiency of, among certain
races, 130; physical elements of,

_ 182-133.

Remorse, 155; deficiency of, among
savages, 177-178.

Rengger, on the diseases of Cebus
azare, 23; on the diversity of the
mental faculties of monkeys, 48; on
the thin legs and thick arms of the
Payaguas Indians, 54; on the in-
feriority of Europeans to savages in
their senses, 55; on revenge taken
by monkeys, 100; on maternal af-

fection in a Cebus, 100; on the rea-

INDEX

soning powers of American mon-
keys, 110; on the use of stones by
monkeys for cracking hard nuts,
114-115; on the sounds uttered by
Cebus azar, 119; on the signal-
cries of monkeys, 122; on the po-
lygamous habits of Mycetes caraya,
287; on the voice of the howling
monkeys, 682; on the odor of Cervus
campestris, 684; on the beards of
Mycetes caraya and Pithecia Sa-
tanas, 686; on the colors of Felis
mitis, 690; on the colors of Cervus
paludosus, 693; on sexual differences
of color in Mycetes, 694; on the color
of the infant Guaranys, 718; on the
early maturity of the female of Cebus
azar, 718; on the beards of the
Guaranys, 722; on the emotional
notes employed by monkeys, 736;
on American polygamous monkeys,
760.

Representative species, of birds, 604.

Reproduction, unity of phenomena of,
throughout the mammalia, 24; period
of, in birds, 624,

Reproductive system,
structures in the,
parts of, 216.

Reptiles, 455.

—— and birds, alliance of, 220,

Resemblances, small, between man and
the apes, 201-202,

Retrievers, exercise of reasoning facul-
ties by, 111.

Revenge, manifested by animals, 100.

Reversion, 59; perhaps the cause of
some bad dispositions, 185,

Rhagium, difference of color in the
sexes of a species of, 386.

Rhamphastos carinatus, 635.

Rhea darwinii, 617.

Rhinoceros, nakedness of, 83; horns
of, 653; horns of, used defensively,
669; attacking white or gray horses,
698.

rudimentary
43; accessory

Rhynchea, sexes and young of, 614.

australis, 614.

— bengalensis, 615.

—— capensis, 615.

Rhythm, perception of, by animals,
732-733,

Richard, M., on rudimentary muscles
in man, 30.

Richardson, Sir J., ow the pairing of

INDEX

Tetrao umbellus, 476; on Tetrao uro-
phasianus, 483; on the drumming
of grouse, 488; on the dances of
Tetrao phasianellus, 492-493; on
assemblages of grouse, 624; on the
battles of male deer, 647; on the
reindeer, 650; on the horns of the
musk-ox, 653; on antlers of the rein-
deer with numerous points, 659; on
the moose, 665; on the Scotch deer-
hound, 667.

Richter, Jean Paul, on imagination,
106.

Riedel, on profligate female pigeons,
540.

Riley, Mr., on mimicry in butterflies,
422; birds’ disgust at taste of cer-
tain caterpillars, 425.

Ring-ouzel, colors and nidification of
the, 587.

Ripa, Father, on the difficulty of dis-
tinguishing the races of the Chinese,
223,

Rivalry, in singing, between male birds,
479,

River-hog, African, tusks and knobs of
the, 671.

Rivers, analogy of, to islands, 213.

Roach, brightness of male during breed-
ing-season, 442.

Robbery, of strangers, considered hon-
orable, 159.

Robertson, Mr., remarks on the devel-
opment of the horns in the roebuck
and red-deer, 308.

Robin, pugnacity of the male, 468;
autumn song of the, 480; female
singing of the, 480; attacking other
birds with red in their plumage, 533;
young of the, 620.

Robinet, on the difference of size of
the male and female cocoons of the
silk-moth, 366.

Rodents, uterus in the, 60; absence of
secondary sexual characters in, 288;
sexual differences in the colors of,
689.

Roe, winter change of the, 700.

Roblfs, Dr., Caucasian features in
negro, 223; fertility of mixed races
in Sahara, 228; colors of birds in
Sahara, 632; ideas of beauty among
the Bornuans and the Pullo tribes,
749.

Rolle, F., on the origin of man, 19; on

858

a change in German families settled
in Georgia, 260.

Roller, harsh cry of, 482.

Romans, ancient, gladiatorial exhibi-
tions of the, 166.

Ronjou, M. A., coincidence of arrested
development with polydactylism, 60.

Rook, voice of the, 486,

Rossler, Dr., on the resemblance of the
lower surface of butterflies to the
bark of trees, 407.

Rostrum, sexual difference in the length
of, in some weevils, 276.

Royer, Mdile., mammals giving suck,
218.

Rudimentary organs, 28; origin of, 43.

Rudiments, presence of, in languages,
126.

BRudolphi, on the want of connection
between climate and the color of the
skin, 255,

Ruff, supposed to be polygamous, 290;
proportion of the sexes in the, 326;
pugnacity of the, 469; double moult
in, 505, 507; duration of dances of,
523; attraction of the, to bright ob-
jects, 533.

Ruminants, male, disappearance of ca-
nine teeth in, and its relation to the
development of horns, 79, 724; gen-
erally polygamous, 287; suborbital
pits of, 684; sexual differences of
color in, 691.

Rupicola crocea, display of plumage by
the male, 510.

Ruppell, on canine teeth in deer and
antelopes, 664.

Russia, numerical proportion of male
and female births in, 284, 319.

Ruticilla, 595.

Ritimeyer, Prof., on the physiognomy
of the apes, 79-80; on the sexual
differences of monkeys, 722.

Rutlandshire, numerical proportion of
male and female births in, 319.

s

Sachs, Prof., on the behavior of the
male and female elements in fertili-
zation, 293,

Sacrifices, human, 194,

Sagittal crest on the cranium in adult
male apes and Australians, 718-719.

854

Sahara, fertility of mixed races in, 228;
birds of the, 588; animal inhabitants
of the, 632.

Sailors, growth of, delayed by condi-
tions of life, 52; long-sighted, 55.
and soldiers, difference in the pro-

portions of, 54.

St. John, Mr., on the attachment of
mated birds, 530.

St. Kilda, beards of the inhabitants of,
583.

Salmo eriox, and 8. umbla, coloring of
the male, during the breeding sea-
son, 442.

— lycaodon, 434.

salar, 434, 7

Salmon, leaping out of fresh water,
147; male, ready to breed before
the female, 281; proportion of the
sexes in, 328; male, pugnacity of
the, 433; male, characters of, dur-
ing the breeding season, 434-436;
spawning of the, 448; breeding of
immature male, 625.

Salvin, O., inheritance of mutilated
feathers, by mot-mots, 87, 498, 776;
on the humming-birds, 289, 585;
on the numerical proportion of the
sexes in humming-birds, 327, 629;
on Chameepetes and Penelope, 489;
on Selasphorus platycercus, 489;
on Pipra deliciosa, 490; on Chas-
morhynchus, 501.

Samoan Islands, beardlessness of the
natives of the, 721, 748.

Sand-skipper, 356,

Sandwich Islands, variation in the
skulls of the natives of the, 46;
decrease of native population, 247;
population of, 340; superiority of
the nobles in the, 754-765.

— Islanders, lice of, 227.

San Giuliano, women of, 755.

Santali or hill-tribes of India, recent
rapid increase of the, 69; Mr, Hunter
on the, 255.

Saphirina, characters of the males of,
357.

Sarkidiornis melanonotus, characters of
the young, 600.

Sars, O., on Pontoporeia affinis, 351.

Saturnia carpini, attraction of males by
the female, 333.

—— Io, difference of coloration in the
sexes of, 412.

INDEX

Saturniidse, coloration of the, 410-412,

Savage, Dr., on the fighting of the
male gorilla, 723; on the habits of
the gorilla, 760.

Savage and Wyman, on the polygamous
habits of the gorilla, 287-288.

Savages, uniformity of, exaggerated,
49; long-sighted, -65; rate of in-
crease among, usually small, 70;
retention of the prehensile power
of the feet by, 77; imitative facul-
ties of, 123, 174; causes of low mo-
rality of, 161; tribes of, supplanting
one another, 174; improvements in
the arts among, 194; arts of, 239;
fondness of, for rough music, 492;
altention paid by, to personal ap-
pearance, 738-742; reiation of the
sexes among, 760-761; infanticide,
and the capturing of wives among,
161-762.

Saviotti, Dr., on division of the malar
bone, 61.

Saw-fly, pugnacity of a male, 383.

Saw-flies, proportions of the sexes in,
335.

Saxicola Rubicola, young of, 629.

Scalp, motion of the, 30; curious in-
stances of, 31.

Scent-glands in snakes, 457.

Schaaffhausen, Prof., on the develop-
ment of the posterior molars in dif-
ferent races of man, 39; on the jaw
from La Naulette, 63; on the cor-
relation between muscularity and
prominent supra-orbital ridges, char-
acteristic of the lower races of man,
67; on the mastoid processes of the
human skull, 78-79; on modifica-
tions of the cranial bones, 82; on
human sacrifices, 194; on the prob-
able speedy extermination of the an-
thropomorphous apes, 210; on the
ancient inhabitants of Europe, 242;
on the effects of use and disuse of
parts, 261; on the superciliary ridge
being more .narked in man than in
woman, 716; on the absence of race
differences in the infant skull in man,
718; on ugliness, 752.

Schaum, H., on the elytra of Dytiscus
and Hydroporus, 364.

Schelver, on dragon-flies, 381.

Schiodte, on the stridulation of Hetero-
cerus, 396.

INDEX

Schlegel, F. von, on the complexity of
the languages of uncivilized peoples,
127.

, Prof., on Tanysiptera, 604.

Schleicher, Prof., on the origin of lan-
guage, 122,

Schomburgk, Sir R., on the pugnacity
of the male musk-duck of Guiana,
469; on the courtship of Rupicola
crocea, 510.

Schoolcraft, Mr., on the difficulty of
fashioning stone implements, 74.
a complexion of negroes,

16.

Scizena aquila, 452.

Sclater, P. L., on modified secondary
wing-feathers in the males of Pipra,
490; on elongated feathers in night-
jars, 497; on the species of Chasmo-
rhynchus, 601; on the plumage of
Pelecanus onocrotalus, 508; on the
plantain-eaters, 593; on the sexes
and young of Tadorna variegata,
618; on the colors of Lemur macaco,
693; on the stripes in asses, 707.

Scolecida, absence of secondary sexual
characters in, 344.

Scolopax frenata, tail-feathers of, 489.

—— gallinago, drumming of, 488.

javensis, tail-feathers of, 489.

—— major, assemblies of, 523.

Wilsonii, sound produced by, 489.

Scolytus, stridulation of, 395.

Scoter-duck, black, sexual difference
in coloration of the, 634; bright
beak of male, 634.

Scott, Dr., on idiots smelling their food,
58.

——, J., on the difference in color be- |

tween the hair of the head and the
beard in man, 719.

Scrope, on the pugnacity of the male
salmon, 433; on the battles of stags,
647.

Scudder, 8. H., imitation of the stridu-
lation of the Orthoptera, 373; on the
stridulation of the Acridiide, 376;
on a Devonian insect, 379; on strid-
ulation, 729.

Sculpture, expression of the ideal of
beauty by, 748.

Sea-anemones, bright colors of, 345.

Sea-bear, polygamous, 289.

Sea-elephant, male, structure of the
nose of the, 682; polygamous, 289.

855

Sea-lion, polygamous, 289,

Seal, bladder-nose, 682.

Seals, their sentinels generally females,
138; evidence furnished by, on class-
ification, 201; polygamous habits of,
289; battles of male, 646; canine
teeth of male, 648; sexual differ-
ences, 666; pairing of, 675; sexual
peculiarities of, 682; in the colora-
tion of, 690; appreciation of music
by, 732.

Sea-seorpion, sexual differences in, 438,

Season, changes of color im birds, in
accordance with the, 503; changes
of plumage of birds in relation to,

5

Seasons, inheritance at corresponding,
302,

Sebituani, African chief, trying to alter
a fashion, 740.

Sebright Bantam, 314.

Secondary sexual characters, 274; re-
lations of polygamy to, 286; trans-
mitted through both sexes, 297;
gradation of, in birds, 554,

Sedgwick, W., on hereditary tendency
to produce twins, 69,

Seemann, Dr., on the different appre-
ciation of music by different peoples,
133-134; on the effects of music, 735,

Seidlitz, on horns of reindeer, 653.

Selasphorus platycercus, acuminate first
primary of the male, 489-490.

Selby, P. J., on the habits of the black
and red grouse, 289.

Selection, double, 297.

— of male by female birds, 522, 543,

——, methodical, of Prussian grena-
diers, 49.

—, sexual, explanation of, 276, 281,
291; influence of, on the coloring of
Lepidoptera, 418.

——, sexual and natural, contrasted,
297-299,

Self-command, habit of, inherited, 1575;
estimation of, 161.

Self-consciousness, in animals, 117.

Self-preservation, instinct of, 152.

Self-sacrifice, by savages, 151; estima-
tion of, 161.

Semilunar fold, 36.

Semnopithecus, 206; long hair on the
heads of species of, 202, 777.

chrysomelas, sexual differences of

color in, 694,

856

Semnopithecus comatus, ornamental
hair on the head of, 709,

—— frontatus, beard, etc., of, 710.

—— nasica, nose of, 202.

—— nemeus, coloring of, 711.

— rubicundus, ornamental hair on
the head of, 708.

Senses, inferiority of Europeans to sav-
ages in the, 55,

Sentinels, among animals, 138, 146.

Serpents, instinctively dreaded by apes
and monkeys, 103.

Serranus, hermaphroditism in, 216,

Sex, inheritance limited by, 303.

Sexes, relative proportions of, in man,
318-319; differences between, %17~
718; probable relation of the, in
primeval man, 760-761.

Sexual characters, secondary, 274; re-
lations of polygamy to, 286; trans-
mitted through both sexes, 297;
gradation of, in birds, 554,

and natural selection, contrasted,
297-299.

—— characters, effects of the loss of,
304; limitation of, 304.

—— differences in man, 25,.

—— selection, explanation of, 276, 281,
291; influence of, on the coloring of
Lepidoptera, 415; objections to, 639;
manner of action with mankind, 765.

similarity, 338,

Shaler, Prof., sizes of sexes in whales,
666.

Sharks, prehensile organs of male, 431.

Sharpe, Dr., Europeans in the tropics,
259,

—, R. B., on Tanysiptera sylvia,
582; on Ceryle, 589; on the young
male of Dacelo Gaudichaudi, 602.

Shaw, Mr., on the pugnacity of the
male salmon, 433.

——, J., on the decorations of birds,
495.

Sheep, danger signals of, 138; sexual
differences in the horns of, 303;
horns of, 309, 652; domestic, sexual
differences of, late developed, 312;
numerical proportion of the sexes
in, 324; inheritance of horns by one
sex, 652; effect of castration, 654;
mode of fighting of, 656; arched
foreheads of some, 688.

— Merino, loss of horns in females
of, 304; horns of 309.

INDEX

Shells, difference in form of, in malg
and female Gasteropoda, 341; beau-
tiful colors and shapes of, 348-349.

Shield-drake, pairing with a common
duck, 535; New Zealand, sexes and
young of, 618.

Shooter, J on the Kaffirs, 146; on
the marriage-customs of the Kafiira,
770.

Shrew-mice, odor of, 683,

Shrike, Drongo, 594,

Shrikes, characters of young, 599.
Shuckard, W. E., on sexual differences
in the wings of Hymenoptera, 365.

Shyness of adorned male birds, 520.

Siagonium, proportions of the sexes in,
335; dimorphism in males of, 391.

Siam, proportion of male and female
births in, 322.

Siamese, general beardlessness of the,
721; notions of beauty of the, 744;
hairy family of, 774.

Sidgwick, H., on morality in hypotheti-
ca] bee community, 137; our actions
not entirely directed by pain and
pleasure, 163.

Siebold, C. T. von, on the proportion
of sexes in the Apus, 337; on the
auditory apparatus of the stridulant
Orthoptera, 373.

Sight, inheritance of long and short, 55,

Signal cries of monkeys, 122.

Silk-moth, proportion of the sexes in,
330-331; Ailanthus, Prof. Canestrini,
on the destruction of its larve by
wasps, 332; difference of size of the
male and female cocoons of the, 366;
pairing of the, 415.

Simiade, 204; their origin and divi-
sions, 220-221.

Similarity, sexual, 297-298,

Singing of the Cicadee and Fulgorida,
371; of tree-frogs, 455; of birds,
object of the, 478.

Sirenia, nakedness of, 83,

Sirex juvencus, 383.

Siricide, difference of the sexes in, 383.

Siskin, 508; pairing with a canary, 536.

Sitana, throat-pouch of the males of,
460, 464.

Size, relative, of the sexes of insects.
366.

Skin, movement of the, 30-31; naked-
ness of, in man, 83-84; color of the,
255.

INDEX

Skin and hair, correlation of color of,
261,

Skull, variation of, in man, 46; cubic
contents of, no absolute test of in-
tellect, 80; Neanderthal, capacity of
the, 81; causes of modification of
the, 81; difference of, in form and
capacity, in different races of men,
225; variability of the shape of the,
232; differences of, in the sexes in
man, 717-718; artificial modification
of the shape of, 740.

Skunk, odor emitted by the, 683; white
tail of, protective, 701.

Slavery, prevalence of, 159; of women,
163-764.

Slaves, difference between field- and
house-, 260.

Sloth, ornaments of male, 690.

Smell, sense of, in man and animals,
36-37.

Smith, Adam, on the basis of sympa-
thy, 145.

—, Sir Andrew, on the recognition
of women by male Cynocephali, 25;
on revenge by a baboon, 100; on
an instance of memory in a baboon,
105; on the retention of their color
by the Dutch in South Africa, 256;
on the polygamy of the South Afri-
can antelopes, 287; on the polygamy
of the lion, 288; on the proportion of
the sexes in Kobus ellipsiprymuus,
325; on Bucephalus capensis, 457;
on South African lizards, 463; on
fighting gnus, 647; on the horns of
rhinoceroses, 653; on the fighting of
lions, 672; on the colors of the Cape
eland, 692; on the colors of the gnu,
692; on Hottentot notions of beauty,
445; disbelief in communistic mar-
riages, 757.

—, F., on the Cynipide, and Ten-
thredinide, 335; on the relative
size of the sexes of Aculeate Hy-
menoptera, 367; on the difference
between the sexes of ants and bees,
383-384; on the stridulation of Trox
sabulosus, 396; on the stridulation
of Mononychus pseudacori, 398.

Smynthurus luteus, courtship of, 368.

Snakes, sexual differences of, 456-457 ;
mental powers of, 457; male, ardency
of, 457.

*Snarling muscles,’’ 64.

857

Snipe, drumming of the, 488; colora-
tion of the, 634,

, painted, sexes and young of,

614-615,

, Solitary, assemblies of, 523,

Snipes, arrival of male before the fe-
male, 280; pugnacity of male, 469;
double moult in, 504.

Snow-goose, whiteness of the, 636.

Social animals, affection of, for each
other, 140; defence of, by the
males, 146.

Sociability, the sense of duty connected
with, 135-136; impulse to, in ani-
mals, 144; manifestations of, in
man, 148; instinct of, in animals,
150.

Sociality, probable, of primeval men,
91; influence of, on the development
of the intellectual faculties, 173; ori-
gin of, in man, 174,

Soldiers, American, measurements of,
52,

and sailors, difference in the stat-
ures of, 52; difference in the propor-
tions of, 54.

Solenostoma, bright colors and marsu-
pial sac of the females of, 450.

Song of male birds appreciated by their
females, 129; want of, in brilliant-
plumaged birds, 517; of birds, 580-
581.

Sorex, odor of, 683.

Sounds, admired alike by man and ani-
mals, 129; produced by fishes, 451;
produced by male frogs and toads,
455; instrumentally produced by
birds, 488 e¢ seq.

Spain, decadence of, 190.

Sparassus smaragdulus, difference of
color in the sexes of, 359,

Sparrow, pugnacity of the male, 468;
acquisition of the linnet’s song by
a, 480, 734; coloration of the, 611;
immature plumage of the, 601-602.

——, white-crowned, young of the,
6277,

Sparrows, house- and tree-, 586.

, new mates found by, 527.

——, sexes and young of, 623; learn-
ing to sing, 734.

Spathura Underwoodi, 500.

Spawning of fishes, 444, 448.

Spear, used before dispersion of man,
239.

858

Species, causes of the advancement
of, 183; distinctive characters of,
222; or races of man, 224; sterility
and fertility of, when crossed, 228;
supposed, of man, 232; gradation
of, 232; difficulty of defining, 233;
representative, of birds, 604; of
birds, comparative differences be-
tween the sexes of distinct, 605.

Spectrum femoratum, difference of color
in the sexes of, 380,

Speech, counection between the brain
and the faculty of, 123; connection
of intonation with music, 736-737.

“Spel”? of the black-cock, 486.

Spencer, Herbert, on the influence of
food on the size of the jaws, 55; on
the dawn of intelligence, 97; on the
origin of the belief in spiritual agen-
cies, 132; on the origin of the moral
sense, 167; on music, 737,

Spengel, disagrees with explanation of
man’s hairlessness, 775.

Sperm-whales, battles of male, 64%.

Sphingide, coloration of the, 410.

Sphinx, Humming-bird, 413.

—, Mr. Bates on the caterpillar of
a, 424,

—— moth, musky odor of, 402.

Spiders, 358; parental feeling in, 145;
male, more active than female, 292;
proportion of the sexes in, 337; sec-
ondary sexual characters of, 359;
courtship of male, 359; attracted by
music, 361; male, small size of, 360.

Spilosoma menthastri, rejected by tur-
keys, 412.

Spine, alteration of, to suit the erect
attitude of man, 78,

Spirits, fondness of monkeys for, 24.

Spiritual agencies, belief in, almost uni-
versal, 131.

Spiza cyanea and civis, 532.

Spoonbill, 485; Chinese, change of
plumage in, 594.

Spots, retained throughout groups of
birds, 503; disappearance of, in adult
mammals, 705,

Sprengel, C. K., on the sexuality of
plants, 281.

Spring-boe, horns of the, 657.

Sproat, Mr., on the extinction of sav-
ages in Vancouver Island, 240; on
the eradication of facial hair by the
natives of Vancouver Island, 747;

INDEX

on the eradication of the beard by
oe Indians of Vancouver island,
6.

Spurs, occurrence of, in female fowls,
300, 304; development of, in vari-
ous species of Phasianide, 310; of
Gallinaceous birds, 471-472; devel-
opment of, in female Gallinacere, 579.

Squilla, different colors of the sexes of
a species of, 357.

Squirrels, battles of males, 646; Afri-
can, sexual differences in the color-
ing of, 689; black, 697.

Stag, long hairs of the throat of, 673;
horns of the, 299-302; battles of,
647; horns of the, with numerous
branches, 659; bellowing of the,
679; crest of the, 686.

-beetle, numerical proportion of
sexes of, 335; large size of male,
367; weapons of the male, 392.

Stainton, H. T., on the numerical pro-
portion of the sexes in the smaller
moths, 331; habits of Elachista ru-
focinerea, 332; on the coloration of
moths, 410; on the rejection of Spi-
losoma menthastri, by turkeys, 412;
on the sexes of Agrotis exclama-
tionis, 413.

Staley, Bishop,
Maories, 248.

Stallion, mane of the, 673.

Stallions, two, attacking a third, 139;
fighting, 647; small canine teeth of,

664.

mortality of infant

Stansbury, Capt., observations on peii-
cans, 141.

Staphylinide, horn-like processes in
male, 391.

Starfishes, parental feeling in, 1465;
bright colors of some, 345.

Stark, Dr., on the death-rate in towns
and rural districts, 187; on the in-
fluence of marriage on mortality,
187-188; on the higher mortality
of males in Scotland, 320.

Starling, American field-, pugnacity of
male, 477.

——, red-winged, selection of a mate
by the female, 537.

Starlings, three, frequenting the same
nest, 289, 528; new mates found
by, 528.

Statues, Greek, Egyptian, Assyrian,
etc., contrasted, 748.

INDEX

Stature, dependence of, upon local in-
fluences, 52-53.

Staudinger, Dr., on breeding Lepidop-
tera, 332; his list of Lepidoptera,
333,

Staunton, Sir G., hatred of indecency
a modern virtue, 161.

Stealing of bright objects by birds, 533.

Stebbing, T. R., on the nakedness of
the human body, 772.

Stemmatopus, 683.

Stendhal, see Bombet.

Stenobothrus pratorum, stridulation,
376.

Stephen, Mr. Leslie, on the difference
in the minds of men and the lower
animals, 111; on general concepts
in animals, 125; distinction between
material and formal morality, 15I.

Sterility, general, of sole daughters,
183; when crossed, a distinctive
character of species, 222; under
changed conditions, 252-253.

Sterna, seasonal change of plumage
in, 636.

Stickleback, polygamous, 291; male,
courtship of the, 432; male, bril-
liant coloring of, during the breed-
ing season, 443; nidification of the,
448.

Sticks, used as implements and weap-
ons by monkeys, 115-116.

Sting in bees, 275.

Stokes, Captain, on the habits of the
great bower-bird, 495.

Stoliezka, Dr., on colors in snakes, 457.

Stonechat, young of the, 629.

Stone implements, difficulty of making,
74-15; as traces of extinct tribes,
241,

Stones, used by monkeys for breaking
hard fruits, and as missiles, 75-76,
114; piles of, 238.

Stork, black, sexual differences in the
bronchi of the, 485; red beak of
the, 634.

Storks, 634, 637; sexual difference in
the color of the eyes of, 549.

Strange, Mr., on the satin bower-bird,
493.

Stretch, Mr., on the numerical propor-
tion in the sexes of chickens, 325.
Strepsiceros kudu, horns of, 661; mark-
ings of, 703. ao
Stridulation, by males of Theridion,

859

361; of the Orthoptera and Homop-
tera discussed, 378; of beetles, 394,

Stripes, retained throughout groups of
birds, 549; disappearance of, in
adult mammals, 705.

Strix flammea, 527.

Structure, existence of unserviceable
modifications of, 88-89.

Struggle for existence, in man, 191-
193,

Struthers, Dr., on the occurrence of
the supra-condyloid foramen in the
humerus of man, 40.

Sturnella ludoviciana, pugnacity of the
male, 477.

Sturnus vulgaris, 528.

Sub-species, 233; propriety of using
the term, 234.

Suffering, in strangers, indifference of
savages to, 160.

Suicide, 185; formerly not regarded as
a crime, 159; rarely practiced among
the lowest savages, 159.

Suidz, stripes of young, 599.

Sulivan, Sir B. J., on speaking of par-
rots, 120; on two stallions attacking
a third, 647.

Sumatra, compression of the nose by
the Malays of, 750.

Summer, Archbishop, man alone capa-
ble of progressive improvement, 113.

Sun-birds, nidification of, 586.

Superstitions, 194; prevalence of, 165.

Superstitious customs, 133.

Superciliary ridge, in man more marked
than in woman, 716; in male and
female monkeys, 718.

Supernumerary digits, more frequent
in men than in women, 295; in-
heritance of, 305-306; early devel-
opment of, 312.

Supra-condyloid foramen in the early
progenitors of man, 215.

Suspicion, prevalence of, among ani-
mals, 99,

Swallow-tail butterfly, 407.

Swallows deserting their young, 147,
154-155.

Swan, black, wild, trachea of the, 485;
white, young of, 623; red beak of
the, 634; black-necked, 637.

Swans, 634, 637; young, 620.

Swaysland, Mr., on the arrival of mié-
gratory birds, 280.

Swifts, migration of, 147.

860

Swinhoe, B., on the common rat in
Formosa and China, 114; behavior
of lizards when caught, 461; on the
sounds produced by the male hoopoe,
487; on Dicrurus macrocerus and the
spoonbill, 594; on the young of Ar-
deola, 604; on the habits of Turnix,
616; on the habits of Rhynchea
bengalensis, 615; on Orioles breed-
ing in immature plumage, 626.

Sylvia atricapilla, young of, 628.

cinerea, aérial love-dance of the
male, 493.

Sympathy, 181; among animals, 141;
its supposed basis, 145,

Sympathies, gradual widening of, 166.

Syngnathous fishes, abdominal pouch
in male, 217-218. ;

Sypheotides auritus, acuminated pri-
maries of the male, 489; ear-tufts
of, 498,

T

Tabanide, habits of, 275.

Tadorna variegata, sexes and young of,
618.

—— vulpanser, 537.

Tahilians, 195; compression of the
nose by the, 750. S

Tail, rudimentary, occurrence of, in
man, 42; convoluted body in the
extremity of the, 43; absence of,
in man and the higher apes, 84-85;
variability of, in species of Macacus
and in baboons, 85; presence of, in
the early progenitors of man, 212;
length of, in pheasants, 474, 581—
582; difference of length of the, in
the two sexes of birds, 581.
Tait, Lawson, on the effects of natural
selection on civilized nations, 180.
Tanager, scarlet, variation in the male,
547, ”

Tanagra estiva, age of mature plumage
in, 624,

—— rubra, 547; young of, 629.

Tanais, absence of mouth in the males
of some species of, 275; relations of
the sexes in, 237; dimorphic males
of a species of, 351.

Tankerville, Earl, on the battles of wild
bulls, 647.

Tanysiptera, races of, determined from
adult males, 604,

INDEX

Tanysiptera sylvia, long tail-feathers
of, 582,

Taphroderes distortus, enlarged left
mandible of the male, 364—365.

Tapirs, longitudinal stripes of young,
599, 705.

Tarsi, dilatation of front, in male bee-
tles, 363-364,

Tarsius, 209.

Tasmania, half-castes killed by the
natives of, 228.

Tasmanians, extinction of, 244-245,

Taste, in the Quadrumana, 698.

Tattooing, 238; universality of, 739.

Taylor, G., on Quiscalus major, 32%=
328.

Tea, fondness of monkeys for, 24,

Tear-sacs, of Ruminants, 684,

Teebay, Mr., on changes of plumage in
spangled Hamburg fowls, 302.

Teeth, rudimentary incisor, in Rumi-
nants, 28; posterior molar, in man,
39; wisdom, 39; diversity of, 4%;
canine, in the early progenitors of
man, 215; canine, of male mammals,
648; in man, reduced by correlation,
(24; staining of the, 739; front,
knocked out or filed by some sav-
ages, 740.

Tegetmeier, Mr., on the transmission
of colors in pigeons by one sex
alone, 305; numerical proportion of
male and female births in dogs, 322=
323; on the abundance of male pig-
eons, 325; on the wattles of game-
cocks, 520; on the courtship of
fowls, 538; on the loves of pigeons,
539; on dyed pigeons, 539; blue
dragon pigeons, 575.

Tembeta, South American ornament,
441.

Temper in dogs and horses, inherited,
99

Tench, proportions of the sexes in
the, 329; brightness of male, dur-
ing breeding season, 442.

Tenebrionide, stridulation of, 395.

Tennent, Sir J. E., on the tusks of the
Ceylon elephant, 654, 664; on the
frequent absence of beard in the na-
tives of Ceylon, 721; on the Chinese
opinion of the aspect of the Cinga-
lese, 744,

Tennyson, Alfred, on the control of
thought, 166.

INDEX

Tenthredinide, proportions of the sexes
in, 336; fighting habits of male, 383;
difference of the sexes in, 383.

Tephrodornis, young of, 604.

Terai, in India, 242.

Termites, habits of, 382.

Terns, white, 636; and black, 637.

, seasonal change of plumage in,

6

Terror, common action of, upon the
lower animals and man, 99.

Testudo elegans, 456.

—— nigra, 456.

Tetrao cupido, battles of, 477; sexual
difference in the vocal organs of,
483.

—— phasianellus, dances of, 492; du-
ration of dances of, 623.

—— scoticus, 587, 600, 608.

tetrix, 587, 600, 608; pugnacity
of the male, 412. -

—— umbellus, pairing of, 477; battles
of, 477; drumming of the male, 487.

urogalloides, dances of, 523.

urogallus, pugnacity of the male,

412
~—— urophasianus, inflation of the
cesophagus in the male, 483.

Thamnobia, young of, 604.

Thaumalea picta, display of plumage
by the male, 512.

Thecla, sexual differences of coloring
in species of, 405.

rubi, protective coloring of, 407.

Thecophora fovea, 402.

Theognis, Grecian poet, on selection in
mankind, 50.

Theridion, stridulation of males of, 361.

—— lineatum, 360.

Thomisus citreus, and T. floricolens,
difference of color in the sexes of,
359.

Thompson, J. H., on the battles of
sperm-whales, 647.

—— W., on the coloring of the male
char during the breeding season,
442; on the pugnacity of the males
of Gallinula chloropus, 468; on the
finding of new mates by magpies,
526; on the finding of new mates
by Peregrine falcons, 5627. __

Thorax, processes of, in male beetles,
387,

Thorell, f., on the proportion of the
sexes in spiders, 337.

861

4

Thornback, difference in the teeth of
the two sexes of the, 436,

Thoughts, control of, 166.

Thrush, pairing with a blackbird, 635;
colors and nidification of the, 587.

ae characters of young, 587,

99,

Thug, remorse of a, 159.

Thumb, absence of, in Ateles, Colobus,
and Hylobates, 76,

Thury, M., on the numerical propor-
tion of male and female births
among the Jews, 320.

Thylacinus, possession of the margiipial
sac by the male, 216.

Thysaoura, 368.

Tibia, dilated, of the male Orabo cri-
brarius, 364.

and femur, proportions of, in the
Aymara Indians, 56.

aes del Fuego, marriage-customs of,

69,

Tiger, colors and markings of the, 704.

Tigers, depopulation of distriets by. in
India, 70.

Tillus elongatus, difference of color in
the sexes of, 386.

Timidity, variability of, in the same
species, 99.

Tineina, proportion of the sexes in,
829.

Tipula, pugnacity of male, 369.

Tits, sexual difference of color in, 590.

Toads, protective colors of, 453; male,
treatment of ova by some, 218; male,
ready to breed before the female,
281,

Todas, infanticide and proportion of
sexes among the, 338; practice poly-
andry, 338, 763; choice of husbands
among the, 763.

Toe, great, condition of, in the human
embryo, 28.

Tomicus villosus, proportion of the
sexes in, 335.

Tomtit, blue, sexual difference of color
in the, 590.

Tonga Islands, beardlessness of the
natives of, 721, 748.

Tooke, Horne, on language as an art,
120-121.

Tools, flint, art of grinding rough, 195;
use of, universal, 195; used by mon-
keys, 114-115; use and manufacture
of, 74-75.

Descent—Vou. I.—19

862

Topknots in birds, 498,

Tortoise, voice of the male, during the
season of love, 730.

Tortures, submitted to by American
savages, 161.

Totanus, double moult in, 504.
Toucans, colors and nidification of the,
587; beaks and ceres of the, 635.
Towns, residence in, a cause of dimin-

ished stature, 53.

Toynbee, J., on the external shell of
the ear in man, 32.

Trachea, convoluted and imbedded in
the sternum, in some birds, 485;
structure of the, in Rhynchea,
614,

Trades, affecting the form of the skull,
82.

Tragelaphus, sexual differences of color
in, 692.

scriptus, dorsal crest of, 686;
markings of, 701-702.

Tragopan, 290; swelling of the wattles
of the male, during courtship, 496;
display of plumage by the male, 513;
markings of the sexes of the, 554.

Tragops dispar, sexual difference in the
eolor of, 457.

Training, effect of, on the mental dif-
ference between the sexes of man,
727-728.

Transfer of male characters to female
birds, 606.

Transmission, equal, of ornamental
characters, to both sexes in mam-
mals, 699,

Traps, avoidance of, by animals, 113;
use of, 73. .

Treachery, to comrades, avoidance of,
by savages, 161.

Tremex columbe, 383.

Tribes, extinct, 173-174; extinction of,
242-248.

Trichius, difference of color in the sexes
of a species of, 386.

Trigla, 451.

Trimen, R., on the proportion of the
sexes in South African butterflies,
330-331; on the attraction of males
by the female of Lasiocampa quercus,
333; on Pneumora, 377; 0n differ-
ence of color in the sexes of beetles,
386; on moths brilliantly colored be-
neath, 411; on mimicry in butter-
flies, 423; on Gynanisa Isis, and on

INDEX

the ocellated spots of Lepidoptera,
552; on Cyllo Leda, 552.

Tringa, sexes and young of, 626.

— cornuta, 505.

Tripheena, coloration of the species of,
409.

Tristram, H. B., on unhealthy districts
in North Africa, 25%; on the habits
of the chaffinch in Palestine, 327;
on the birds of the Sahara, 588; on
the animals inhabiting the Sahara,
632.

Triton cristatus, 453.

—— palmipes, 453.

punctatus, 453,

Troglodyte skulls, greater than those
of modern Frenchmen, 81.

Troglodytes vulgaris, 611.

Trogons, colors and nidification of the,
587-588.

Tropic birds, white only when mature,
635.

Tropics, fresh-water fishes of the, 447.

Trout, proportion of the sexes in, 328-
329; male, pugnacity of the, 433.

‘| Trox sabulosus, stridulation of, 396,

Truth, not rare between members of
the same tribe, 160; more highly
appreciated by certain tribes, 165.

Tulloch, Major, on the immunity of the
negro from certain fevers, 257-258.

Tumbler, almond, change of plumage
in the, 313.

Turdus merula, 586; young of, 628.

migratorius, 599.

—— musicus, 587.

— polyglottus, young of, 628.

torquatus, 58.

Turkey, wild, pugnacity of young male,
476; wild notes of the, 486; swell-
ing of the wattles of the male, 495;
variety of, with a topknot, 498; rec-
ognition of a dog by a, 532; male,
wild, acceptable to domesticated fe-
males, 540; wild, first advances made
by older females, 542; wild, breast-
tuft of bristles of the, 595.

Turkey-cock, scraping of the wings of,
upon the ground, 486; wild, display
of plumage by, 510; fighting habits
of, 521.

Turner, Prof. W. on muscular faciculi
in man referabfe to the panniculus
carnosus, 30; on the occurrence of
the supra-condyloid foramen in the

INDEX

863

human humerus, 41; on the filum | Urosticte Benjamini, sexual differences

terminale in man, 42; on muscles
attached to the coccyx in man, 43;
on the variability of the muscles,
47; on abnormal conditions of the
human uterus, 61; on the develop-
ment of the mammary glands, 217;
on male fishes hatching ova in their
mouths, 218, 449; on the external
perpendicular fissure of the brain,
265; on the bridging convolutions
in the brain of a chimpanzee, 265-
266.

Turnix, sexes of some species of, 613-
614, 619.

Turtle-dove, cooing of the, 486.

Tuttle, H., on the number of species
of man, 233.

Tylor, E. B., on emotional cries, ges-
tures, etc., of man, 120; on the ori-
gin of the belief in spiritual agen-
cies, 131; remorse for violation of
tribal usage in marrying, 157; on
the primitive barbarism of civilized
nations, 193; on the origin of count-
ing, 193-194; inventions of savages,
194; on resemblances of the mental
characters in different races of man,
238,

Type of structure, prevalence of, 219.

Typheeus, stridulating organs of, 395;
stridulation of, 396.

Tyranga zstiva, 595.

Twins, tendency to produce, heredi-
tary, 69.

Twite, proportions of the sexes in the,
327.

U

Ugliness, said to consist in an approach
to the lower animals, 752.

Umbrella-bird, 484,

Umbrina, sounds produced by, 452.

United States, rate of increase in, 68;
influence of natural selection on the
progress of, 191; change undergone
by Europeans in the, 260.

Upupa epops, sounds produced by the
male, 487.

Uraniide, coloration of the, 410.

Dria troile, variety of (=U. lacrymans),
548.

Urodela, 452.

in, 570.

Use and disuse of parts, effects of ine
creased, 53; influence of, on ths
races of man, 261.

Uterus, reversion in the, 61; more or
less divided, in the human subject,
61, 67; double, in the early progeni-
tors of man, 216,

Vv

Vaccination, influence of, in preserving
from smallpox, 180-181.

Vancouver Island, Mr. Sproat on the
savages of, 243; natives of, eradica-
tion of facial hair by the, 747.

Vanellus cristatus, w.nag tubercles of
the male, 475. -

Vanesse, 403; resemblance of lower
surface of, to bark of trees, 407.
Variability, causes of, 48; im man,
analogous to that in the lower ani-
mals, 50; of the races of man, 232=
233; greater in men than in women,
294-295; period of, relation of
the, to sexual selection, 314-315;
of birds, 545; of secondary sexual

characters in man, 720.

Variation, laws of, 50; correlated, 67;
in man, 196-197; analogous, 204-
205; analogous, in plumage of birds,
498.

Variations, spontaneous, 67-68.

Varieties, absence of, between two spe-
cies, evidence of their distinctness,
223-224,

Variety, an object in nature, 637.

Variola, communicable between man
and the lower animals, 23.

Vauréal, human bones from, 42.

Veddahs, monogamous habits of, 761.

Veitch, Mr., on the aversion of Japa-
nese ladies to whiskers, 747.

Vengeance, satisfying the instinct of,
154.

Venus Erycina, priestesses of, 755.

Vermes, 350.

Vermiform appendage, 39.

Verreaux, M., on the attraction of nu-
merous males by the female of an
Australian Bombyx, 333.

Vertebra, caudal, number of, in ma-
caques and baboons, 85; of mon-

864

bays partly imbedded in the body,

Vertsbeste, 431; common origin of the,
211-212; most ancient progenitors
of, 214-215; origin of the voice in
air-breathing, 729-730, _

Vesicula prostatica, the homologue of
the uterus, 43, 216.

Vibrissee, represented by long hairs in
the eyebrows, 37.

Vidua, 520, 596.

axillaris, 289.

Villerme, M., on the influence of plenty
upon stature, 52-53,

Vinson, Aug., courtship of male spider,
360; on the male of Epeira nigra,
360.

Viper, difference of the sexes in the,
456, :

Virey, on the number of species of
man, 232.

Virtues, originally social only, 158-
159; gradual appreciation of, 176—
177.

Viscera, variability of, in man, 47.

Vlacovich, Prof., on the ischio-pubic
muscle, 64,

Vocal music of birds, 477-478,

organs of man, 122-123; of birds,
125-126, 580; of frogs, 455; of the
Insessores, 481; difference of, in the
sexes of birds,‘ 481; primarily used
in relation to the propagation of the
species, 729.

Vogt, Karl, on tka origin of species,
17; on the origin of man, 19; on
the semilunar fold in man, 36; on
microcephalous idiots, 58; on the
imitative faculties of microcephalous
idiots, 122; on skulls from Brazilian
caves, 225; on the evolution of the
races of man, 235-237; on the for-
mation of the skull in women, 717;
on the Ainos and negroes, 721; on
the increased cranial difference of
the sexes in man with race devel-
opment, 128; on the obliquity of
the eye in the Chinese and Japa-
nese, 744,

Voice in mammals, 679; in monkeys
and man, 719; in man, 729; origin
of, in air-breathing vertebrates, 29-
730.

Von Baer, definition of advancement in
the organic scale, 219.

INDEX

Vulpian, Prof., on the resemblance te-
tween the brains of man and of the
higher apes, 22-23.

Vultures, selection of a mate by the
female, 537; colors of, 637,

w

Waders, young of, 627.

Wagner, R., on the occurrence of the
diastema in a Kaffir skull, 63; on
the bronchi of the black stork, 485.

Wagtail, Ray’s, arrival of the male be-
fore the female, 280.

Wagtails, Indian, young of, 604.

Waist, proportions of, in soldiers and
sailors, 54.

Waitz, Prof., on the number of species
of man, 233; on the liability of ne-
groes to tropical fevers after resi-
dence in a cold climate, 25%; on
the color of Australian infants, 718;
on the beardlessness of negroes, 721;
on the fondness of mankind for or-
naments, 738; on negro ideas of
female beauty, 745; on Javan and
Cochin Chinese ideas of beauty,
746,

Walckenaer and Gervais, spider at-
tracted by music, 361; on the Myri-
apoda, 361.

Waldeyer, M., on the hermaphroditism
of the vertebrate embryo, 216.

Wales, North, numerical proportion of
male and female births in, 319.

Walker, Alex., on the large size of the
hands of laborers’ children, 55.

——, F., on sexual differences in the
Diptera, 368-369.

Wallace, Dr. A., on the prehensile use
of the tarsi in male moths, 277; on
the rearing of the Ailanthus silk-
moth, 332; on breeding Lepidoptera,
332; proportion of sexes of Bombyx
cynthia, B, yamamai, and B. Pernyi
reared by, 334; on the development
of Bombyx cynthia and B. yamamai,
366; on the pairing of Bombyx cyn-
thia, 615.

Wallace, A. R., on the origin of man,
19; on the power of imitation in
man, 98-99; on the use of missiles
by the orang, 115; on the varying
appreciation of truth among differ-

INDEX

ent tribes, 165; on the limits of
natural selection in man, %3-174,
172; on the occurrence of remorse
among savages, 177-178; on the
effects of natural selection on civ-
ilized nations, 180; on the use of
the convergence of the hair at the
elbow in the orang, 203; on the
contrast in the characters of the Ma-
lays and Papuans, 224; on the line
of separation between the Papuans
and Malays, 226; on the birds of
paradise, 289; on the sexes of Or-
nithoptera Croesus, 230-231; on pro-
tective resemblances, 245; on the
relative sizes of the sexes of in-
sects, 366; on Hlaphomyia, 368-369 ;
on the pugnacity of the males of
Leptorhynchus angustatus, 392; on
sounds produced by Euchirus longi-
manus, 397; on the colors of Dia-
dema, 403; on Kallima, 407; on the
protective coloring of moths, 409;
on bright coloration as protective in
butterflies, 409; on variability in the
Papilionide, 417; on male and fe-
male butterflies inhabiting different
stations, 418; on the protective na-
ture of the dull coloring .of female
butterflies, 419-420, 423; on mimi-
ery in butterflies, 422; on the bright
colors of caterpillars, 424; on brightly
eolored fishes frequenting reefs, 446;
on the coral snakes, 458; on Para-
disea apoda, 500; on the display of
plumage by male birds of paradise,
511; on assemblies of birds of para-
dise, 523; on the instability of the
ocellated spots in Hipparchia Janira,
652; on sexually limited inheritance,
573; on the sexual coloration of
birds, 583, 609-610, 613, 619; on
the relation between the colors and
nidification of birds, 584, 587; on
the coloration of the Cotingide, 593;
on the females of Paradisea apoda
and papuana, 606; on the incuba-
tion of the cassowary, 616; on pro-
tective coloration in birds, 631; on
the Babirusa, 670; on the markings
of the tiger, 704; on the beards of
the Papuans, 721; on the hair of
the Papuans, 740; on the distribu-
tion of hair oa the human body,
772.

865

Walrus, development of the nictitating
membrane in the, 36; tusks of the,
ee 655; use of the tusks by the,

63.

Walsh, B. D., on the proportion of the

sexes in Papilio Turnus, 330; on the
Cynipide: and Cecidomyids, 335; on
the jaws of Ammophila, 363; on
Corydalis cornutus, 363; on the pre-
hensile organs of male insects, 363;
on the antennss of Penthe, 364; on
the caudal appendages of dragon-
flies, 364; on Platyphyllum con-
cavum, 376; on the sexes of the
Ephemeride, 380; on the differ-
ence of color in the sexes of Spec-
trum femoratum, 380; on sexes of
dragon-flies, 381; on the difference
of the sexes in the Ichneumonide,
383; on the sexes of Orsodacna atra,
386; on the variation of the horns
of the male Phanzeus carnifex, 388;
on the coloration of the species of
Anthocharis, 407.

Wapiti, battles of, 647; traces of horns

in the female, 651; attacking a man,
660; crest of the male, 686; sexual
difference in the color of the, 693.

Warbler, hedge-, 611; young of the,

621
Warblers, superb, nidification of, 586,

Wariness, acquired by animals, 114.
Warington, R., on the habits of the

sticklebacks, 432, 449; on the bril-
liant colors of the male stickleback
during the breeding season, 443.

Wart-hog, tusks and pads of the, 670.
Watchmakers, short-sighted, 55.
Water-hen, 468,

Waterhouse, C. O., on blind beetles,

386; on difference of color in the
sexes of beetles, 386.

, G. B., on the voice of Hylobates
agilis, 730.

Water-ouzel, 587; autumn song of the,

480.

Waterton, C., on the Bell-bird, 501; on

the pairing of a Canada goose with @
Bernicle gander, 535; on hares fight-
ing, 646.

Wattles, disadvantageous to male birds
in fighting, 520.

Weale, J. Mansel, on a South African
caterpillar, 424.

Wealth, influence of, 182.

866

Weapons, used by man, 73; employed
by monkeys, 115; offensive, of males,
278; of mammals, 646 e¢ seg.

Weaver-bird, 480.

Weaver-birds, rattling of the wings of,
487; assemblies of, 423.

Webb, Dr., on the wisdom teeth,

39.

Wedderburn, Mr., assembly of black
game, 525,

Wedgwood, Hensleigh, on the origin
of language, 122.

Weevils, sexual difference in length of
snout in some, 276.

Weir, Harrison, on the numerical pro-
portion of the sexes in pigs and rab-
bits, 324-325; on the sexes of young
pigeons, 326; on the songs of birds,
478; on pigeons, 531; on the dislike
of blue pigeons to other colored: va-
rieties, 540; on the desertion of their
mates by female pigeons, 540.

-——, J. Jenner, on the nightingale
and blackcap, 280; on the relative
sexual maturity of male birds, 282;
on female pigeons deserting a feeble
mate, 283; on three starlings fre-
quenting the same nest, 289; on
the proportion of the sexes in Ma-
chetes pugnax and other birds, 326;
on the coloration of the Triphzne,
409; on the rejection of certain
caterpillars by birds, 524; on sex-
ual differences of the beak in the
goldfinch, 467; on a piping bull-
finch, 478; on the object of the
vightingale’s song, 478; on song-
birds, 479; on the puguacity of
male fine-plumaged birds, 516; on
the courtship of birds, 617; on
the finding of new mates by Pere-
grine-falconas and Kestrels, 527; on
the bullfinch and starling, 527-528;

on the cause of birds remaining un- |

paired, 529; on starlings and parrots
living in triplets, 528; on recogni-
tion of color by birds, 532; on hy-
brid birds, 535; on the selection of
a greenfinch by-~a female canary,
536; on a case of rivalry of female
bullfinches, 542; on the maturity of
the golden-pheasant, 624.

Weisbach, Dr., measurement of men
of different races, 224; on the
greater variability of men than of

INDEX

women, 294-295; on the relative
proportions of the body in the
= of different races of man,
20.

Weismann, Prof., colors of Lycans,
408.

Welcker, M., on brachycephaly and
dolichocephaly, 83; on sexual dif-
ferences in the skull in man, 71%,

Wells, Dr., on the immunity of colored
races from certain poisons, 256.

Westring, on the stridulation of males
of Theridion, 361; on the stridula-
tion of Reduvius personatus, 370;
on the stridulation of beetles, 395;
on the stridulation of Omaloplia
brunnea, 397; on the stridulating
organs of the Coleoptera, 399; on
sounds produced by Cychrus, 398,

Westropp, H. M., on reason in a bear,
109; on the prevalence of certain
forms of ornamentation, 238.

Westwood, J. O., on the classification
of the Hymenoptera, 199; on the
Culicidee and Tabanide, 275; on a
Hymenopterous parasite with a sed-
entary male, 292; on the propor-
tions of the sexes in Lucanus cervus
and Siagonium, 335; on the absence
of ocelli in female mutillide, 362; on
the jaws of Ammophila, 363; on the
copulation of insects of distinct spe-
cies, 364; on the male of Crabro
cribrarius, 364; on the pugnacity
of male Tipulz, 369; on the stridu-
lation of Pirates stridulus, 370; on
the Cicade, 371; on the stridulat-
ing organs of the crickets, 373;
on Ephippiger vitium, 375, 378; on
Pneumora, 376-377; on the pug-
nacity of the Mantides, 379; on
Platyblemnus, 380; on difference
in the sexes of the Agrionide,
380; on the pugnacity of the
males of a species of Tenthre-
-dinz, 383; on the pugnacity of
the male stag-beetle, 392; on Ble-
dius taurus, and Siagonium, 391-
392; on lamellicorn beetles, 394;
on the coloration of Lithosia, 410.

Whale, Sperm-, battles of male, 646.

Whales, nakedness of, 83.

Whately, Archbishop, language not pe-
culiar to man, 119; on the primitive
civilization of man, 193.

INDEX

Whewell, Prof., on maternal affection,
100.

Whiskers, in monkeys, 202.

White, F. B., noise produced by Hy-
lophila, 402.

. Gilbert, on the proportion of the
sexes in the partridge, 326; on the
house-cricket, 372; on the object of
the song of birds, 479; on the find-
ing of new mates by white owls,
527; on spring coveys of male par-
tridges, 529.

Whiteness, a sexual ornament in some
birds, 638; of mammals inhabiting
snowy countries, 700.

White-throat, aérial love-dance of the
male, 493.

Whitney, Prof., on the development of
language, 121; language not indis-
pensable for thought, 124.

Widgeon, pairing with a pintail duck,
535.

Widow-bird, polygamous, 289; breed-
ing plumage of the male, 507, 520;
female, rejecting the unadorned male,
541.

Widows and widowers, mortality of,
188.

Wilckens, Dr., on the modification of
domestic animals in mountainous
regions, 57; on a numerical rela-
tion between the hairs aud excre-
tory pores in sheep, 262.

‘Wilder, Dr. Burt, on the greater fre-
quency of supernumerary digits in
men than in women, 295.

Wilhams, on the marriage customs of
the Fijians, 770.

Wilson, Dr., on the conical heads of
the natives of Northwestern Amer-
ica, 750; on the Fijians, 750; on
the persistence of the fashion of
compressing the skull, 751.

Wing-spurs, 579.

Wings, dfferences of, in the two sexes
of butterflies and Hymenoptera, 365 ;
play of, in the courtship of birds, 517.

Winter, change of color of mammal
in, 700. :

Witcheraft, 133-134.

Wives, traces of the forcible capture
of, 194.

Wolf, winter change of the, 700.

Wolff, on the variability of the viscera
in man, 47.

867

Wollaston, T, V., on Eurygnathus,
365; on musical Curculionids, 396;
on the stridulation of Acalles, 400.

Wolves, learning to bark from dogs,
104; hunting in packs, 139.

——, black, 697.

Wombat, black varieties of the, 697.

Women, distinguished from men by
male monkeys, 25; preponderance
of, in numbers, 321-322; selection
of, for beauty, 752; effects of selec-
tion of, in accordance with different
standards of beauty, 752; practice
of capturing, 759-762; early be-
trothals and slavery of, 763; free-
dom of selection by, in savage tribes,
70.

Wonder, manifestations of, by animals,
102.

| Wonfor, Mr., on sexual peculiarities in

the wings of butterflies, 365.

Wood, J., on muscular variations in
man, 47, 64-66; on the greater va-
riability of the muscles in men than
in women, 294-295.

, T. W., on the coloring of the
orange-tip butterfly, 408; on the
habits of the Saturniidz, 412; quar-
rels of chameleons, 463; on the
habits of Menura Alberti, 481; on
Tetrao cupido, 483-484; on the dis-
play of plumage by male pheasants,
510; on the ocellated spots of the
Argus pheasant, 568; on the habits
of the female cassowary, 617.

Woodcock, coloration of the, 634.

Woodpecker, selection of a mate by
the female, 537.

Woodpeckers, harsh cry of, 482; tap-
ping of, 487; colors and nidification
of the, 587, 590, 632; characters of
young, 600, 612, 621.

Woolner, Mr., observations on the ear
in man, 33.

Wormald, Mr., on the coloration of
Hypopyra, 411.

Wounds, healing of, 24.

Wren, 611; young of the, 621.
Wright, C. A., on the young of Oro-
eetes and Petrocincla, 628-629.
—, Chauncey, great brain power

requisite for language, 73; on cor-
relative acquisition, 735; on the en-
largement of the brain in man, 786.
—, Mr., on the Scotch deerhound,

868

667; on sexual preference in dogs,
676; on the rejection of a horse by
amare, 677.

Wright, W. von, on the protective plu-
mage of the Ptarmigan, 505.

Writing, 194.

Wyman, Prof., on the prolongation of
the coccyx in the human embryo,
26; on the condition of the great
toe in the human embryo, 28; on
the occurrence of the supra-condyloid
foramen in the humerus of man, 41;
on variation in the skulls of the na-
tives of the Sandwich Islands, 46;
on the hatching of the eggs in the
mouths and branchial cavities of
male fishes, 218, 449.

x

Xenarchus, on the Cicade, 370,

Xenophon, selection in mankind advo-
eated by, 50.

Xenorhynchus, sexual difference in the
color of the eyes in, 549.

Xiphophorus Hellerii, peculiar anal fin
of the male, 439-440.

Xylocopa, difference of the sexes in,
384,

Y

Yarrell, W., on the habits of the Cy-
prinidee, 329; on Raia clavata, 432;

INDEX

on the characters of the male salmon
during the breeding season, 434; on
the characters of the rays, 436; on
the gemmeous dragonet, 437; on the
spawning of the salmon, 448; on
the incubation of the Lophobranchii,
450; on rivalry in song-birds, 479;
on the trachea of the swan, 485; on
the moulting of the Anatide, 506;
on the young of the waders, 627.

Yellow fever, immunity of negroes and
moulattoes from, 256,

Youatt, Mr., on the development of
the horns in cattle, 309.

Yuracaras, their notions of beauty, 746.

Zebra, rejection of an ass by a female,
698; stripes of the, 704,

Zebus, humps of, 688.

Zigzags, prevalence of, as ornaments,
238,

Zincke, Mr., on European emigration
to America, 191.

Zootoca vivipara, sexual difference in
the color of, 464.

Zouteveen, Dr., polydactylism, 60; pro-
portion of sexes at Cape of Good
Hope, 319; spiders attracted by
music, 361; on sounds produced
by fish, 451-452.

Zygeenide, coloration of the, 410.

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