forms like that of languages, 32;
single characters in relation to, 37;
aggregates of characters in relation to, 35-37;
adaptive and non-adaptive characters in relation to, 34, 35, 38, 39;
chains of affinities in relation to, 39-40;
biological differs from astronomical, 43.

Cockerell, on vegetable galls, 447, 448.

Colours, of plants and animals in relation to the theory of natural
selection, 317-332;
in relation to the theory of sexual selection, 391, 392, 394-396,
408-410, 448-450.

Colouring, _see_ Recognition marks, Protective, Seasonal, Warning, and
Mimicry.

Congenital characters, _see_ Characters.

Conjugation, of Protozoa, 115-117.

Continuity, principle of, in nature, 15-21.

Contrivance, Darwin's use of the word, 281.

Co-operation, mutual, of species alleged, 445-448.

Co-operative instincts, due to natural selection, 267, 269.

Cope, Professor, his table of geological formations, 163, 164;
his table of palaeontological development of feet, vertebral column, and
brain, 197.

Correlation of growth, 357-362.

_Cossonidae_, 233.

Courtship, _see_ Sexual Selection.

Crabs, 62-65, 139.

Cuttle-fish, 317.

Cuvier, on method in natural history, 3-4;
on monkeys, 429.

Cyst, _see_ Encystation.

D.

Darwin, Charles, his influence on ideas of method, 1-9;
on classification, 35, 36, 39, 40;
on vestigial characters in man, 77, 86, 87, 92;
on imperfection of geological record, 165, and Appendix;
on means of dispersal, 216, 218;
on geographical distribution, 218, 219;
on fauna of the Galapagos Archipelago, 227, 228;
on natural selection, 252, 253, 255, 256, 286, 375, 376;
his use of such words as 'accident,' 'fortuitous,' 'purpose,'
'contrivance,' &c., 281, 334-340;
on sexual selection, 379-400.

Darwin, Erasmus, his theory of evolution, 253.

De Blainville, on the theory of descent, 258.

De Candolle, on classification, 34.

Deer, 98, 99, 167-169, 187, 191, 196, 198, 199.

Degeneration, 269, 270, 342.

Delamination, 139.

_Diadema euryta_, 330.

Diaster, 129-133.

Dingo, _see_ Dog.

_Dinornis_, 60, 61.

_Diptera_ mimicking _Hymenoptera_, 329.

Dog, dentition of, 39;
Dingo, 304;
domesticated varieties of, 305, 307;
hairless, 307;
skulls of, 307.

Duck, logger-headed, 68.

Dugong, eye of, 75.

E.

Eagle, eye of, 75.

Ear, of whales, 65;
vestigial features of human, 76, 86-89;
of man a