What, then, is the conclusion at which we must arrive with respect to brute animals-even those the most Conclusion. like us or the most seemingly intelligent? What

is the lesson which nature seems to teach us in their regard? We may, it is here contended, learn from it and the evidence here adduced two lessons. The first is that in accepting testimony respecting the psychical characters of brutes, we should be especially on our guard against a certain common form of credulity and tendency to exaggerationBiological Anthropomorphism. The second lesson is, that while we have abundant evidence of the sensitive and imaginative powers of brutes, we have both negative and positive evidence that the form, or force, which energizes in the dog, the bee, the elephant, the ant, or the gorilla, is one which is sentient but not rational-that it feels both pleasures and pains, but neither knows nor reflects upon the one or the other. Finally, we may conclude that the instinctive qualities of the brute may be more or less imperfectly understood by means of those lower powers of the human soul hereinbefore enumerated, which may be performed without deliberation and reflex self-consciousness, while all the efforts of the best-informed naturalists who desire to confound the nature of the brute with that of man but serve to bring out more forcibly the profound gulf which separates psychically man and the brute.

CHAPTER VIII.

LIKENESSES IN ANIMALS AND PLANTS.

"The facts of mimicry and of the various kinds of homology as exhibited in comparative anatomy, teratology and pathology, reveal an internal force and dynamic agency, the soul, in each animal, which forms one indissoluble unity with its material frame."

IN considering the form and structure of animals and plants, Two kinds of amongst the different resemblances presented to our considered. view there are two orders of likeness which it is intended here to notice.

likeness to be

The first of these orders of resemblance is one which is merely external; namely, the likenesses borne by different animals to others of more or less different nature, to plants or to inanimate objects, and likenesses borne by plants to others of more or less different nature or to animals. This kind of resemblance is termed MIMICRY.

The second of the two orders of resemblance extends to internal structure, and relates to likenesses of the kind borne by parts of one animal or plant to parts of other animals or plants, and it also relates to likenesses borne by one part of any animal or plant to other parts of the same individual. First as to Mimicry: "Mimicry" is a close and striking, yet superficial resemblance borne by some animal Mimicry. or plant to some perhaps very different object. A familiar example of mimicry is seen in the bee and spider orchis, and in clear-winged moths, which may be mistaken for bees. One of the most perfect examples of mimicry is afforded by an insect (of the grasshopper and cricket order) which is called, on account of the appearance it presents, the

"walking leaf;" since both in form and colour its body so closely resembles a leaf that it is most difficult of detection when found amongst real leaves.

Mr. Bates was the first to call attention to the phenomenon as it exists amongst butterflies, and he may be called the discoverer of what he named "mimicry." Mr. Wallace, in his work on Natural Selections,' has brought forward* most interesting examples, serving to show not only the existence of these strange likenesses but the protecting influence which they, in many instances, exercise in favour of the creatures which exhibit them. One of the most complete instances is that afforded by an Indian butterfly, as to which he remarks: t

"But the most wonderful and undoubted case of protective resemblance which I have ever seen, is that of the common Indian Kallima inachis, and its Malayan ally Kallima paralecta. The upper surface of these is very striking and showy, as they are of a large size, and are adorned with a broad band of rich orange on a deep bluish ground. The under-side is very variable in colour, so that out of fifty specimens no two can be found exactly alike, but every one of them will be of some shade of ash, or brown, or ochre, such as are found among dead, dry, or decaying leaves. The apex of the upper wings is produced into an acute point, a very common form in the leaves of tropical shrubs and trees, and the lower wings are also produced into a short, narrow tail. Between these two points runs a dark curved line exactly representing the midrib of a leaf, and from this radiate on each side a few oblique lines, which serve to indicate the lateral veins of a leaf. These marks are more clearly seen on the outer portion of the base of the wings, and on the inner side towards the middle and apex; and it is very curious to observe how the usual marginal and transverse striæ of the group are here modified and strengthened so as to become adapted for an imitation of the variation of a leaf. . . . . But this resemblance, close as it is, would be of little use if the habits of the insect did not accord with it. If the butterfly sat upon leaves as upon flowers, or opened its wings so as to expose the upper surface, or exposed and moved its head and antennæ as many other butterflies do, its disguise would be of little avail. We might be sure, however, from the analogy of many other cases, that the habits of the insect are such as still further to aid its deceptive garb; but we are not obliged to make any such supposition, since I myself had the good fortune to

* Chap. iii.

p.

45.

† Op. cit. p. 59.

observe scores of Kallima paralecta in Sumatra, and to capture many of them, and can vouch for the accuracy of the following details. These butterflies frequent dry forests, and fly very swiftly. They were seen to settle on a flower or a green leaf, but were many times lost sight of in a bush or tree of dead leaves. On such occasions they were generally searched for in vain; for while gazing intently at the very spot where one had disappeared, it would often suddenly dart out, and again vanish twenty or fifty yards further on. On one or two occasions the insect was detected reposing, and it could then be seen how completely it assimilates itself to the surrounding leaves. It sits on a nearly upright twig, the wings fitting closely back to back, concealing the antennæ and head, which are drawn up between their bases. The little tails of the hind wing touch the branch and form a perfect stalk to the leaf, which is supported in its place by the claws of the middle pair of feet, which are slender and inconspicuous. The irregular outline of the wings gives exactly the perspective effect of a shrivelled leaf. We thus have size, colour, form, markings, and habits, all combining together to produce a disguise which may be said to be absolutely perfect; and the protection which it affords is sufficiently indicated by the abundance of the individuals that possess it."

Not only moths, but also beetles imitate bees. Wasps and objects the most strange are also mimicked by beetles, such, e.g., as dung and drops of dew. There are also creatures called bamboo or walking-stick insects, which present a most striking resemblance to twigs of bamboo. Concerning these Mr. Wallace tells us: "Some of these are a foot long and as thick as one's finger, and their whole colouring, form, rugosity, and the arrangement of the head, legs and antennæ are such as to render them absolutely identical in appearance with dry sticks. They hang loosely about shrubs in the forest, and have the extraordinary habit of stretching out their legs unsymmetrically, so as to render the deception more complete."

But there are facts yet more extraordinary. Some insects which mimic leaves, mimic even the marks made upon leaves by the ravages of other insects or by mould. As to this Mr. Wallace further informs us:† "One of these creatures obtained by myself in Borneo (Ceroxylus laceratus)

was covered over with foliaceous excrescences of a clear olive-green colour, so as exactly to resemble a stick grown over by a creeping moss or jungermannia. The Dyak who brought it me assured me it was grown over with moss although alive, and it was only after a most minute examination that I could convince myself it was not." In speaking of a leaf-butterfly he tells us that: "We come to a still more extraordinary part of the imitation, for we find representations of leaves in every stage of decay, variously blotched, and mildewed, and pierced with holes, and in many cases irregularly covered with powdery black dots, gathered into patches and spots, so closely resembling the various kinds of minute fungi that grow on dead leaves, that it is impossible to avoid thinking at first sight that the butterflies themselves have been attacked by real fungi."

Not to be ex

lined by

accidental

These facts appeared to me some years ago to be of a nature which no amount of accidental minute indefinite variations acted on by the destroying agencies of nature (inducing the "survival of the fittest") variations. could possibly account. I then saidt (opposing the Darwinian hypotheses of the origin of species by natural selection): "Now let us suppose that the ancestors of these various animals were all destitute of the very special protections they at present possess, as on the Darwinian hypothesis we must do. Let it also be conceded that small deviations from the antecedent colouring or form would tend to make some of their ancestors escape destruction by causing them more or less frequently to be passed over, or mistaken by their persecutors. Yet the deviation must, as the event has shown, in each case be in some definite direction, whether it be towards some other animal or plant, or towards some dead organic matter. But as, according to Mr. Darwin's theory, there is a constant tendency to indefinite variation, and as the minute incipient variations will be in all directions,

* Op. cit. p. 60.

Genesis of Species' (Macmillan), 2nd edition, p 38.