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wattles, &c., &c.) have been developed in many cases where sexual selection has certainly not acted, renders it probable, à priori, that the unknown cause which has operated in these numerous cases has operated in those instances also which seem to favour the hypothesis supported by Mr. Darwin. Still he contends that the greater part of the beauty and melody of the organic world is due exclusively to this selective process, by which, through countless generations, the tail of the peacock, the throat of the humming-bird, the song of the nightingale, and the chirp of the grasshopper have been developed by females, age after age, selecting for their mates males possessing in a more and more perfect degree characters which must thus have been continually and constantly preferred.
Yet, after all, Mr. Darwin concedes in principle the very point in dispute, and yields all for which his opponents need argue, when he allows that beautiful and harmonious variations may occur spontaneously and at once, as in the dark or spangled bars on the feathers of Hamburgh fowls (* Descent of Man,' vol. i. p. 281). For what difference is there, other than mere difference of degree, between the spontaneous appearance of a few beautiful new feathers with harmonious markings and the spontaneous appearance of a whole beautiful clothing like that of the Tragopans ?
Again, on Mr. Darwin's own showing, it is manifest that male sexual characters, such as he would fain attribute to sexual selection, may arise without any such action whatever. Thus he tells us, “There are breeds of the sheep and goat, in which the horns of the male differ greatly in shape from those of the female;' and with tortoise-shell cats, the females alone, as a general rule, are thus coloured, the males being rusty-red' (vol. i. p. 283). Now, if these cats were only known in a wild state, Mr. Darwin would certainly bring them forward amongst his other instances of alleged sexual selection, though we now know the phenomenon is not due to any such cause. A more striking instance, however, is the following :—With the pigeon, the sexes of the parent species do not differ in any external character; nevertheless, in certain domesticated breeds the male is differently coloured from the female. The wattle in the English carrier-pigeon and the crop in the pouter are more highly developed in the male than in the female ;' and this has arisen, not from, but rather in opposition to, the wishes of the breeder; which amounts to a positive demonstration that sexual characters may arise spontaneously, and, be it noted, in the class of birds.
The uncertainty which besets these speculations of Mr. Darwin is evident at every turn. What at first could be thought a
better instance of sexual selection than the light of the glowworm, exhibited to attract her mate? Yet the discovery of luminous larvæ, which of course have no sexual action, leads Mr. Darwin to observe: 'It is very doubtful whether the primary use of the light is to guide the male to the female' (vol. i. p. 345). Again, as to certain British field-bugs, he says: 'If in any species the males had differed from the females in an analogous manner, we might have been justified in attributing such conspicuous colours to sexual selection with transference to both sexes' (vol. i. p. 350). As to the stridulating noises of insects (which is assumed to be the result of sexual selection), Mr. Darwin remarks of certain Neuroptera :- It is rather surprising that both sexes should have the power of stridulating, as the male is winged and the female wingless' (vol. i. p. 366); and he is again surprised to find that this power is not a sexual character in many Coleoptera (vol. i. p. 382).
Moths and butterflies, however, are the insects which Mr. Darwin treats of at the greatest length in support of sexual selection. Yet even here he supplies us with positive evidence that in certain cases beauty does not charm the female. He tells us :
Some facts, however, are opposed to the belief that female butterflies prefer the more beautiful males; thus, as I have been assured by several observers, fresh females may frequently be seen paired with battered, faded, or dingy males.'-vol. i. p. 400.
As to the Bombycidae he adds :
• The females lie in an almost torpid state, and appear not to evince the least choice in regard to their partners. This is the case with the common silk-moth (B. mori). Dr. Wallace, who has had such immense experience in breeding Bombyx cynthia, is convinced that the females evince no choice or preference. He has kept above 300 of these moths living together, and has often found the most vigorous females mated with stunted males.'
Nevertheless, we do not find, for all this, any defect of colour or markings, for, as Mr. Alfred Wallace observes (Nature, March 15th, 1871, p. 182), “the Bombyces are amongst the most elegantly coloured of all moths.' .
Mr. Darwin gives a number of instances of sexual characters, such as horns, spines, &c., in beetles and other insects; but there is no fragment of evidence that such structures are in any way due to feminine caprice. Other structures are described and figured which doubtless do aid the sexual act, as the claws of certain Crustacea; but these are often of such size and strength (e. g. in Callianassa and Orchestia) as to render any power of
Siers, we havcities, buection.
commence to femrities, buptions an
choice on the part of the female in the highest degree incredible.
Similarly with the higher classes, i.e. Fishes, Reptiles, and Beasts, we have descriptions and representations of a number of sexual peculiarities, but no evidence whatever that such characters are due to female selection. Often we have statements which conflict strongly with a belief in any such action. Thus, e.g., Mr. Darwin quotes Mr. R. Buist, Superintendent of Fisheries, as saying that male salmon
*Are constantly fighting and tearing cach other on the spawningbeds, 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.' ...The keeper of Stormonifield found in the northern Tyne about 300 dead salmon, all of which with one exception were males; and he was convinced that they had lost their lives by fighting.'—vol. ii. p. 3.
The female's choice must here be much limited, and the only kind of sexual selection which can operate is that first kind, determined by combat, which, we before observed, must rather be ranked as a kind of natural selection. Even with regard to this, however, we may well hesitate, when Mr. Darwin tells us, as he does, that seeing the habitual contests of the males, “it is surprising that they have not generally become, through the effects of sexual selection, larger and stronger than the females ;' and this the more as 'the males suffer from their small size,' being liable to be devoured by the females of their own species' (vol. ii. p. 7). The cases cited by our Author with regard to fishes, do not even tend to prove the existence of sexual selection, and the same may be said as to the numerous details given by him about Reptiles and Amphibians. Nay, rather the facts are hostile to his views. Thus, he says himself, It is surprising that frogs and toads should not have acquired more strongly-marked sexual differences; for though cold blooded, their passions are strong' (vol. ii. p. 26). But he cites a fact, than which it would be difficult to find one less favourable to his cause. He adds: •Dr. Günther 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. If female selection was difficult in the case of the female salmon, it must be admitted to have been singularly infelicitous to the female toad.
We will now notice some facts brought forward by Mr. Darwin with regard to beasts. And first, as to the existence of choice on the part of the females, it may be noted that Mr. Bienkiron, the greatest breeder of race-horses in the world, says that stallions are so frequently capricious in their choice, rejecting one mare and without any apparent cause taking to another, that various artifices have to be habitually used. He has never known a mare to reject a horse ;' though this has occurred in Mr. Wright's stable.
Some of the most marked sexual characters found amongst mammals, are those which exist in apes. These are abundantly noticed by Mr. Darwin, but his treatment of them seems to show his inability to bring them within the scope of his theory.
It is well known that certain apes are distinguished by the lively colours or peculiarities as to hair possessed by the males, while it is also notorious that their vastly superior strength of body and length of fang, would render resistance on the part of the female difficult and perilous, even were we to adopt the utterly gratuitous supposition, that at seasons of sexual excitement the female shows any disposition to coyness. Mr. Darwin has no facts to bring forward to prove the exercise of any choice on the part of female apes, but gives in support of his views the following remarkable passage:
Must we attribute to mere purposeless variability in the male all these appendages of hair and skin? It cannot be denied that this is possible; for, with many domesticated quadrupeds, certain characters, apparently not derived through reversion from any wild parent-form, have appeared in, and are confined to, the males, or are more largely developed in them than in the females, for instance, the hump in the male zebu-cattle of India, the tail in fat-tailed rams, the arched outline of the forehead in the males of several breeds of sheep, the mane in the ram of an African breed, and, lastly, the mane, long hairs on the hinder legs, and the dewlap in the male alone of the Berbura goat. — vol. ii. p. 284.
If these are due, as is probable, to simple variability, then, he adds,
• It would appear reasonable to extend the same view to the many analogous characters occurring in animals under a state of nature. Nevertheless I cannot persuade myself that this view is applicable in many cases, as in that of the extraordinary development of hair on the throat and fore-legs of the male Ammotragus, or of the immense beard of the Pithecia (monkey).'—vol. ii. p. 285.
But one naturally asks, Why not? Mr. Darwin gives no reason (if such it may be called) beyond that implied in the gratuitous use of the epithet ' purposeless' in the passage cited, and to wbich we shall return.
In the Rhesus monkey the female appears to be more vividly coloured than the male ; therefore Mr. Darwin infers (grounding
his inference on alleged phenomena in birds) that sexual selection is reversed, and that in this case the male selects. This hypothetical reversion of a hypothetical process to meet an exceptional case will appear to many rash indeed, when they reflect that as to teeth, whiskers, general size, and superciliary ridges this monkey follows the common rule of the male excelling the female' (vol. ii. p. 294).
To turn now to the class on which Mr. Darwin especially relies, we shall find that even Birds supply us with numerous instances which conflict with his hypothesis. Thus, speaking of the battling of male waders, our author tells us:--Two were seen to be thus engaged for half an hour, until one got hold of the head of the other, which would have been killed had not the observer interfered; the female all the time looking on as a quiet spectator' (vol. ii. p. 41). As these battles must take place generally in the absence of spectators, their doubtless frequently fatal termination must limit greatly the power of selection Mr. Darwin attributes to the females. The same limit is certainly imposed in the majority of Gallinaceous birds, the cocks of which fight violently; and there can be little doubt but that, as an almost invariable rule, the victorious birds mate with the comparatively passive bens.
Again, how can we explain, on Mr. Darwin's hypothesis, the existence of distinguishing male sexual marks, where it is the male and not the female bird which selects? Yet the wild turkey-cock, a distinguished bird enough, is said by Mr. Darwin (vol. ii. p. 207) to be courted by the females; and he quotes (vol. ii. p. 120) Sir R. Heron as saying, that with peafowl, the first advances are always made by the female. And of the capercailzie he says, "the females flit round the male while he is parading, and solicit his attention.'
But though, of course, the sexual instinct always seeks its gratification, does the female ever select a particular plumage? The strongest instance given by Mr. Darwin is as follows:
Sir R. Heron during many years kept an account of the habits of the peafowl, which he bred in large numbers. He states that the hens have frequently great preference for 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 assembled close to the trellice-walls of his prison, and would not suffer a japanned peacock to touch them. On his being let out in the autumn, the oldest of the hens instantly courted him, and was successful in her courtship. The next year he was shut up in a stable, and then the hens all courted his rival. This rival was a japanned or black-winged peacock, which to our eyes is a more beautiful bird than the common kind.'-vol. ii. p. 119.