Page:The Zoologist, 4th series, vol 4 (1900).djvu/361

Rh It must be particularly pointed out that in Mr. Distant's general discussion of the subject he has most clearly suggested that the present day colouring, which is classed by him as assimilative (in opposition to adaptive) was only developed in the earliest geological epochs, and prior to the first appearance of natural selection as an efficient factor—according to his conception of that first appearance. Fortunately we are able to obtain, from certain passages, some idea as to this conception, for with regard to the Lias formation of the Jurassic Period (Mesozoic), when the gigantic Enaliosaurians abounded, it is freely admitted that "Here we see natural selection, with its iron and implacable rule, a real factor"; and, further, in the later essays on "Mimicry," good cause is shown for the recognition of the occurrence of natural selection so far back as the Carboniferous Period in Palæozoic times.

But when we come to consider the examples adduced in support of the above suggestion, we at once find that the fundamental proposition is practically disregarded. A single instance will suffice. Referring to the colouring of primitive man, it is remarked that: "Their colour would have been uniform, either derived from their more brutish ancestors, or, possibly, a more assimilative colouration may have ensued to the soil on which they walked." It will be thus seen that the vast majority of