414 



SUBJECT INDEX. 



larvae, 198; effect of, in pro- 

 ducing variations, 224; effect 

 of, on development of frog, 

 225, 226, 227; optimum, 227; 

 maximum, 228; effect of, on 

 plant growth, 228; on size of 

 Echinoid larvae, 229; on Lepi- 

 doptera, 230, 233, 239, 242; on 

 Mollusca, 231; on lemming, 

 243; on hare, 244; adaptation 

 to high, in Flagellata, 379 



Temperatures, death, of develop- 

 ing larvae, 198 



Torilis anthriscus, variation in, 

 15,46 



Toxin, diphtheria, acclimatisa- 

 tion to, 387 



Transplantation of rabbits' ova, 

 119 



Trotting horses, prepotency in, 

 149 



Twins, identical, 115; measure- 

 ments upon, 117 



Type forms, fertility of, 90; 

 replacement of, by variety, 91 



Typha, measurements upon, 42 



Umbelliferae, variation in, 48 

 Undifferentiated like organs, 135 

 Unpigmented cave animals, 254 

 Urea, effect of, on larvae, 300 

 Uric acid, effect of, on larvae, 300 

 Urmi, Lake, Artemia present in, 



274 

 Use and disuse, inheritance of 



effects of, 360 



Vanessa cardui, production of 

 sports of, 175; effect of tem- 

 perature on, 237 



Vanessa io, production of sports 

 of, 175; effect of temperature 

 on, 237, 238 



Vanessa levana, seasonal di- 

 morphism in, 233 



Vanessa prorsa, seasonal di- 

 morphism in, 233 



Vanessa urtic, effect of temper- 

 ature on, 237; protective re- 

 semblance in, 258 



Variable protective resemblance, 

 255, 260 



Variability, diagrammatically 

 represented, 5; method of 

 estimation of, 17; Law of 

 Equable, 96; in parthenogene- 

 tic forms, 177, 180; in poppies, 

 181, 182; individual, in relation 

 to racial, 181; racial and spe- 

 cific, 182; small, of a sexually 

 reproduced forms, 184, 185; 

 relations of, to external condi- 

 tions, 199; of growing guinea- 

 pigs, 204; diminution of, with 

 growth, 204; of growing man, 

 205; of crabs, 206; of peri- 

 winkle, 206, 215; of embryos, 

 207; diminution of , with evolu- 

 tion, 210; diminution of, with 

 selection, 210; of offspring and 

 parents, 210; relation of, to 

 homotyposis, 211; relation of, 

 to intensity of heredity, 211; 

 effect on, of artificial selection, 

 211; effect on, of Natural Se- 

 lection, 211; effect of fertility 

 of type forms on, 212; of Eng- 

 lish and American sparrow, 

 212; of environment and of or- 

 ganisms subjected to it, 219; in 

 relation to Domestication, 221; 

 of otter, 221 ; produced by food , 

 281; produced by season, 285; 

 of sparrow, 342; increased by 

 somatic variations, 368 



Variants, defined, 4 



Variation, defined, 1; numerical 

 treatment of, 3; universally 

 present, 6; obeys Laws of 

 Chance, 11; importance of 

 numerical treatment of, 98; 

 hereditary cause of, 102; due 

 to amphimixis, 103, 114, 126; 

 of organisms, chiefly blasto- 

 genic, 121 ; produced by cross- 

 ing, 161; Laws of, 189; in 

 periwinkle, 215, in birds, 

 219 



