O Oates, 255, 379 Obliterative colouration, 184-7 _Ocydromus_, 365 _Œnis_, 205 _Œnopopelia tranquebarica_, 122, 123, 324, 333 _Œnothera lamarckiana_, 84, 85, 87, 88 _Ononis repens_, 23 _O. spinosa_, 22 Opossum, 243 Orchid, 268, 269, 270, 272 _Orgyia antiqua_, 215 “Origin of Species, The,” 7, 9, 11, 31, 53, 57, 63, 114, 170, 194, 347, 348, 356, 367 Oriole, 244, 249, 284, 304 _Oriolus galbula_, 282 _O. kundoo_, 282 _O. melanocephalus_, 244, 284 “Ornithological and Other Oddities,” 255 _Orohippus_, 41 Orr, 15-7 Orthogenesis, 15, 16, 34 _Ossifraga gigantea_, 99, 362 _Otidiphaps insularis_, 244 _Ovis ammon_, 120 _O. vignei_, 120 Owen, Sir Richard, 7 Owl, 247, 277, 289 —— little, 97, 98 —— scops, 101 —— snowy, 190 Ox, 146, 352 Oxygen, 152, 153, 263 P Paddy bird, 254 Paint-root, 357 _Palæornis torquatus_, 102, 325 Pallas, 115 Pansy, 260 Panther, 360 _Papilio_, 228, 246 _P. aristolochiæ_, 179, 216, 220, 221 _P. polites_, 179 Paradise, bird of, 62, 249 Paradise flycatcher, 47, 202, 298, 303, 316, 324, 338 _Paradisea apoda_, 249 Paraguay cattle, 94 _Parnassius apollo_, 155 Paroquet, 102, 121, 325 Parrot, 103 Parthenogenesis, 135, 138 Partridge, 185, 315, 337 _Parus leucopterus_, 245 _Passer domesticus_, 289, 342 _P. montanus_, 342 _P. swainsoni_, 342 Pasteur, 5 _Pavo nigripennis_, 96 _Pavoncella pugnax_, 343 Pea, sweet, 74, 75, 81, 141 Pear, 72 Pearson, Karl, 309, 310 Peckham, 308 Pekin robin, 179 Pelagic animals, 173, 192-4 Penguin, 191 Pennant’s parakeet, 121 _Petaurus breviceps_, 243 Petrel, 44, 190, 191, 277, 337 Pfeffer, 33 _Phalacrocorax carbo_, 381 Phalanger, 243 Phalarope, 327 _Phasianidæ_, 125, 330 _Phasianus colchicus_, 114, 123 _P. torquatus_, 114, 123 _P. versicolor_, 114, 123, 124 Pheasant, 97, 104, 114, 121, 123, 128-30, 141, 315, 336, 338 Pictet, 155, 156 _Pieris napi_, 155 _Piezorhynchus_, 285 Pig, 57, 283, 357, 365 Pigeon, 61, 62, 65, 68, 71, 72, 91, 92, 93, 98, 101, 109, 126, 127, 244, 277, 282, 353, 357, 364, 365 Pigment, massing of, 256 Pike, 102, 222 Pimpernel, 261 Pintail duck, 130, 132, 293, 337 Pintailed nonpareil finch, 102 “Plant Breeding,” 87 Plasomes, 151 Plastidules, 151 _Platycercus elegans_, 121 _P. erythropeplus_, 121 _P. eximius_, 121 _Pliohippus_, 41 Plover, 207 Plumage, decorative, 40 Pochard, 126, 337 Pœcilomeres, 288-95 _Poëephila mirabilis_, 99 Polar bear, 119, 130 Polar bodies, 135 Polecat, 119 Polytypic evolution, 367 Poppy, 82, 261 _Porzana bailloni_, 251 _P. pusilla_, 251 Post-nuptial display, 316 _Potentilla tormentilla_, 263 Poulton, 11, 25, 26, 171, 173, 177, 181, 184, 210, 213, 217, 221, 223-5, 229-35, 238-42 _Precis artexia_, 203, 204, 212 Preferential mating among human beings, 309, 310