Cope, Dr. E.D., on non-adaptive characters, 131
on fundamental laws of growth, 420
on bathmism or growth-force, 421
on use producing structural change, 422
on law of centrifugal growth, 422
on origin of the feet of ungulates, 423
on action of animal intelligence, 425
Correlations in pigeons, horses, etc., 140
Corvus frugilegus, 2
corone, 2
Coursers, figures of secondary quills, 224
Cowslip, two forms of, 157
Crab, sexual diversity of colour of, 269
Cretaceous period, dicotyledons of, 400
Crisp, Dr., on variations of gall bladder and alimentary canal, 69
Crosses, a cause of variation, 99
reciprocal, 155
Cross-fertilisation, modes of securing, 310
difference in, 155
Crossing and changed conditions, parallelism of, 166
Cruciferæ, variations of structure in, 80
Cuckoo, eggs of, 216
Cuckoos mimick hawks, 263
Cultivated plants, origin of useful, 97
Curculionidæ mimicked by various insects (figs.), 260
Curves of variation, 64
D
Dana, Professor, on the permanence of continents, 342
Danaidæ little attacked by mites, 235
mimicry of, 246
Darwin, change of opinion effected by, 8
the Newton of Natural History, 9
his view of his own work, 10
on the enemies of plants, 16
on fir-trees destroyed by cattle, 17
on change of plants and animals caused by planting, 18
on absence of wild cattle in Paraguay, 19
on cats and red clover, 20
on variety of plants in old turf, 35
on the beneficent action of the struggle for existence, 40
on variability of wild geraniums, 79
on variability of common species, 80
his non-recognition of extreme variability of wild species, 82
on races of domestic pigeon, 90
on constitutional variation in plants, 95
on unconscious selection, 96
on a case of divergence, 105
on advantage of diversification of structure in inhabitants of one region, 110
on species of plants in turf, 110
on isolation, 119
on origin of mammary glands, 129
on eyes of flatfish, 129
on origin of the eye, 130
on useless characters, 131
on use of ears and tails, 136
on disappearance of sports, 140
on tendency to vary in one direction, 141
on rare perpetuation of sports, 142
on utility of specific characters, 142 (note)
on importance of biological environment, 148
on variable fertility of plants, 155
on fertile hybrids among plants, 164
