Thus we have the wonderful birds of Paradise,[72] which agree in developing plumage unequalled in beauty, but a beauty which, as to details, is of different kinds, and produced in different ways in different species.

To develop "beauty and singularity of plumage" is a character of the group, but not of any one definite kind, to be explained merely by inheritance.
{92} [Illustration] Again, we have the very curious horned flies,[73] which agree indeed in a common peculiarity, but in one singularly different in detail, in different species and not known to have any protecting effect.
Amongst plants, also, we meet with the same peculiarity.

The great group of Orchids presents a number of species which offer strange and bizarre {93} approximations to different animal forms, and which have often the appearance of cases of mimicry, as it were in an incipient stage.
[Illustration: HORNED FLIES.] [Illustration: THE MAGNIFICENT BIRD OF PARADISE.] The number of similar instances which could be brought forward from amongst animals and plants is very great, but the examples given are, it is {94} hoped, amply sufficient to point towards the conclusion which other facts will, it is thought, establish, viz.

that there are causes operating (in the evocation of these harmonious diverging resemblances) other than "Natural Selection," or heredity, and other even than merely geographical, climatal, or any simply external conditions.
Many cases have been adduced of striking likenesses between different animals, not due to inheritance; but this should be the less surprising, in that the very same individual presents us with likenesses between different parts of its body (_e.g._, between the several joints of the backbone), which are certainly not so explicable.

This, however, leads to a rather large subject, which will be spoken of in the eighth chapter of the present work.