Page:The Zoologist, 4th series, vol 2 (1898).djvu/505

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ASSIMILATIVE COLOURATION.
473

were a genius loci, whose subtle and pervading essence spread itself around, penetrating and impregnating the denizens of the place with its facies,—possibly only affecting some, the conditions of whose entry on existence render them more liable to receive its impression than others; more probably affecting all, some more and some less," &c.[1] It may, however, be suggested that this adaptive colouration was due to an assimilative process in early times,[2] and that the "genius loci" is a pseudonym of that operation. It is at least probable that where we have protective resemblance in a unicolorous condition, it is a survival of original assimilative colouration, and is not a direct product of "natural selection"; but is ratified and perpetuated by that agency as agreeing altogether with its conditions. Unchanged it has survived as the fittest.[3] It must have been in the original head-quarters or centre of evolution before migration took place, and a uni- or concolorous hue prevailed. Such a centre for Anthropoids, palaeontology proves to have once existed in India. In the words of Mr. Lydekker:—"We have decisive proof that at a former epoch of the earth's history such an assembly of Primates was gathered together on the plains of India at a time when the Himalaya did not exist as has been seen nowhere else beyond the walls of a menagerie. Side by side with Langurs and Macaques closely resembling those now found in that region were Chimpanzees and Baboons as nearly related to those of modern Africa, whilst the extinct Indian Orang recalls the existing species of Borneo and Sumatra. India, therefore, in the Pliocene period, seems to have been the central point whence the main groups of Old World Primates dispersed themselves to their far distant homes."

  1. "Disguises in Nature," vide 'Edinburgh New Philosoph. Journ.,' January, 1860.
  2. Eimer proposes a theory of colour-photography: "The colours of the environment of an animal may be reflected in the colours of its skin" ('Organic Evolution,' Eng. transl. p. 145).
  3. A different argument, propounded on somewhat similar grounds, was advanced by Agassiz in his "Natural Relations between Animals and the Elements in which they live," to prove that marine animals were less specialised in structure than those inhabiting the land areas (vide Silliman's 'Amer. Journ. Sci. and Arts,' May, 1850).