SUBJECT INDEX. 



411 



Physiological characters, subject 

 to variation, 71 



Physiological Selection, 66 



Pieris napi, effect of temperature 

 on, 239, 241 



Pigeons, correlation in, 85; re- 

 version in, 140; effect of meat 

 on, 295; effect of domestication 

 on, 333 



Pigment cells in skin, of Proteus, 

 251; of flounder, 251; of frog, 

 256; of Octopus, 257 



Pigments in larvae, derived from 

 food, 291 



Pigmentation, effect of light on, 

 249, 251, 252; in man, inherit- 

 ance of, 361 



Pisum sativum, varieties of, 

 155; cross-fertilisation of, 155, 

 159 



Plants, variations in, do not agree 

 with Law of Error, 15; de- 

 termination of variations in, 

 46; hybrids among, 161; 

 diminishing effect of environ- 

 ment on developing, 199; 

 desert, 263; aerial and aquatic, 

 265; adaptation of, to changed 

 environment, 267 



Plant structures, origin of, 265 



Pleuronectes flems, measurements 

 of, 14; variability in fin-rays 

 of, 27, 34; correlation in, 84; 

 effect of lighten, 251 



Plymouth Sound, changing con- 

 ditions in, 338 



Polygon of Variation, 17 



Polyommatus phlceas, reaction of, 

 to temperature, 234, 241 



Poppies, variation in seed cap- 

 sules of, 89 



Porto Santo rabbit, 330 



Portunus depurator, variation 

 of, 9 



Position of organic stability, as 

 regards sports, 170 



Potato, asexual propagation of, 

 184 



Prawns, measurements of, 14 



Pregnancy, condition of mother 

 during, 209 



Prepotency, in dog, 148; in bull, 

 148; in horse, 148, 149; in 

 man, 150; in Basset hounds, 

 151; in relation to sex, 151; 

 produced by inbreeding, 152; 

 conforms to Law of 'Heredity, 

 154 



Primrose, variation in, 48; hy- 

 brids of, 164 



Primula officinalis, variation in, 

 48 



Probability curve, 10 



Probability, Laws of, govern 

 variations, 12 



Probable Error, 17; determina- 

 tion of, 19 



Products of metabolism, effect of, 

 on growth, 296, 298, 302, 303, 

 307, 308 



Protective resemblance, 255, 260 



Proteus anguineus, effect of light 

 on, 251 



Protophyta, adaptation of, to 

 high temperature, 380 



Pseudoclytia pentata, variation 

 in, 90 



Pupae, effect of temperature on, 

 240; effect of lighten, 257 



Pupal stage, in relation to tem- 

 perature, 240; in relation to 

 light, 257 



R 



Rabbits, effect of nutrition of 

 sex-cells in, 113; transplanta- 

 tion of ova in, 119; local race 

 of, 330 



Race, variability of, compared 

 with that of species, 182; local, 

 of mice, 350 



Races, local, of Chrysanthemum 

 segetum, 50; constant correla- 

 tion in, 79, 80; of Lepidoptera, 

 237; the result of environment, 

 310; in trees, 311; in Alpine 

 plants, 311; in shrimps, 318; 

 in mackerel, 319; in herring, 

 322; in fish, 324; in birds, 325; 

 in mammals, 327; in rabbit, 330 



Ranunculus repens, variation in, 

 16,30 



