., on varieties of melons, 87

Nectarinea amethystina, protective colouring of, 201

Nestor notabilis, variation of habits of, 75

Nests of birds influence the colour of females, 278

New species, conditions favourable to origin of, 115

Newton, Professor A., on fertile hybrid ducks, 162

New Zealand, European plants in, 15
spread of white clover in, 28
effects of introduced plants in, 29
native rat and fly exterminated by European species, 34
many plants of, incapable of self-fertilisation, 321
fauna of, 348
few spiny plants in, 433

Nocturnal animals, colours of, 193

Non-adaptive characters, instability of, 138

Normandy pigs, fleshy appendages to jaws of, 139

North America, Miocene fossils of, 378

Northern plants in southern hemisphere, 368

Nostus Borbonicus, variability of, 80

Number of individuals which vary, 62

Nutmeg, how dispersed, 307

Nuts, not meant to be eaten, 305

=O=

Oaks, great variability of, 78

Objections to Darwin's theory, 126

Ocean floor, deposits on, 343

Oceanic animals, colours of, 193
and continental areas, 346
islands have no mammals or batrachia, 342

Oceans, the permanence of, 341

Oedicnemus, figures of wings of, 223

Opthalmis lincea and Artaxa simulans (figs.), 247

Orang-utans, variations of skull of, 69

Orchideae, why scarce on oceanic islands, 367

Orchis pyramidalis, mode of fertilisation of, 314
figures illustrating fertilisation of, 315

Organic development, three stages of, involving new cause or power, 474
world, the development of, implies a spiritual world, 476

Organisation, advance of, by natural selection, 120
degradation in, 121

Origin of species, objections, 7
of accessory plumes, 291

Orioles mimicking honey-suckers, 263

Ornamental plumes and vitality, 293

=P=

Pachyrhynchi subjects of mimicry, 261

Pampas, effects of drought in, 23

Papaver bracteatum, variability of, 79

Papilio, use of forked tentacle of larva of, 210
protected groups of, 235
mimicry of, 247

Paraguay, absence of wild cattle and horses, 19

Parnassia palustris, sham nectaries of, 317

Parrot, change of habits of New Zealand, 75

Parus, species of, illustrate divergence, of character, 107

Passenger-pigeon, account of its breeding-places and numbers, 31

Pelagic animals, colours of, 193

Phasmidae, resemblance of, to sticks and leaves, 203

Physiological selection, 180

Pickard-Cambridge, Rev. O