Page:The Zoologist, 4th series, vol 2 (1898).djvu/504

472 ment, and "when skulking through the dark shade, either of corinda or jungle, it would be almost impossible to make out his huge cat-like carcass creeping along like a silent shadow." Eimer also observes:—"I have permitted myself to express the supposition (Varüren, &c.) that the fact of the original prevalence of longitudinal striping might be connected with the original predominance of the monocotyledonous plants whose linear organs and linear shadows would have corresponded with the linear stripes of the animals; and further, that the conversion of the striping into a spot-marking might be connected with the development of a vegetation which cast spotted shadows. It is a fact that several indications exist that in earlier periods the animal kingdom contained many more striped forms than is the case to-day." To even fancy the appearance of animal and plant life in past geologic epochs, apart from structure as revealed by palaeontology, is left to sober scientific imagination. We know there was a flowerless age, but even then animal life existed. Is it to be argued that such animal life had reached its development in colouration? Can we not more easily imagine that animals assimilated in colour with the monotonous and semi-sombre hues of their then environment; but as they multiplied and the struggle for existence caused migration, the same inherent tendency to assimilative colouration prompted assimilative variation in response to the difference in surrounding conditions, and when this variation became adaptive and protective, the process of natural selection accentuated and perpetuated whatever was advantageous to the creature's existence.

The late Andrew Murray, in a paper read before the British Association in 1859, and just before or coincident with the appearance of Darwin's 'Origin of Species,' appears to have held a similar impression, though not reaching the explanation of "natural selection." His words well serve to conclude this discursive suggestion of original and universal assimilative colouration:—"We have seen that in all the instances to which I have referred, the external appearance of the animal bears definite relation to the appearance of the soil on which it lives, or the objects which surround it. It would appear as if there