that such great men only appear at
certain stages of human development, and that two or more of the special
talents are not unfrequently combined in one individual, he concludes
thus--

"Upon this subject I only wish to add that, in my opinion,
talents do not appear to depend upon the improvement of any
special mental quality by continued practice, but they are the
expression, and to a certain extent the bye-product, of the
human mind, which is so highly developed in all directions."

It will, I think, be admitted that this view hardly accounts for the
existence of the highly peculiar human faculties in question.]

[Footnote 237: For an earlier discussion of this subject, with some
wider applications, see the author's _Contributions to the Theory of
Natural Selection_, chap. x.]

INDEX

=A=

Abbott, Dr. C.C., instability of habits of birds, 76
on American water-thrushes (Seiurus), 117
Mr., drawings of caterpillars and their food plants, 203

Accessory plumes, development and display of, 293

Acclimatisation, 94

Achatinellidae, Gulick on variations in, 147

Acquired characters, non-heredity of, 440

Acraeidae, mimicry of, 247

Adaptation to conditions at various periods of life, 112

Adolias dirtea, sexual diversity of, 271

Aegeriidae, mimicry by, 240

Agaristidae, mimicry of, 246

Agassiz, on species, 5
on North American weeds, 15.

Agelaeus phoeniceus, diagram showing variations of, 56;
proportionate numbers which vary, 64

Albatross, courtship of great, 287

Allen, Mr. Grant, on forms of leaves, 133
on degradation of wind-fertilised from insect-fertilised flowers,
325 (note)
on insects and flowers, 332
on production of colour through the agency of the colour sense, 334
Mr. J.A., on the variability of birds, 50

Allen, Mr. J.A., on colour as influenced by climate, 228

Alluring coloration, 210

American school of evolutionists, 420

Anemone nemorosa, variability of, 78

Animal coloration, a theory of, 288
general laws of, 296
intelligence, supposed action of, 425
characteristics of man, 454

Animals, the struggle among, 18
wild, their enjoyment of life, 39
usually die painless deaths, 38
constitutional variation of, 94
uses of colours of, 134
supposed effects of disuse in wild, 415
most allied to man, 450

Antelopes, recognition marks of, 219

Anthrocera filipendula inedible, 235

Apples, variations