410 



INDEX 



Eltringham, species-recognition in 

 butterflies, 148 



Elysia, influence of food on size, 79 



Emberiza, close resemblance of Cuckoo's 

 eggs to eggs of, 267 



Emberiza schoeniclus, unusual nesting- 

 site, 54 



Ena, correlation of characters, 163 



Engrams, 346 



Ennea, elaborate oral denticles, 322, 334 



Environment, deterioration, 355 



■ — , fluctuations of, 355 



— , methods of protection against, 360 



— , selection of, by animals, 305, 



354-55 

 Enzymes, genes as, 29 

 Ephemerella, adaptation to water-flow, 



266 

 Ephestia, continuous variation with 



discontinuous genetic basis, 87 

 — , non-heritable variants, 20 

 Epiblema, species with similar genitalia, 



J 54 



Epigamic characters, relation to isola- 

 tion, 144 

 Epinephelus, polymorphism, 101 

 Erebia, colour-convergence in the Alps, 



260 

 Eristalis, mimicry of bees, 252 

 Eumenes maxillosa, variation, 67 



, varietal intergradation, 89 



Euphausiacea, lack of geographical 



variation, 1 10 

 Eupithicia, isolation of species, 143 

 Euschistus, segregation of characters in 



genitalia, 156 

 Euxanthis, local form of, 1 72 

 Evolution, as a unitary process, 368-69 

 — , dimensions of steps in, 369 

 — , irreversibility of, 365 

 Ewing, experiments on pure lines, 191 

 Exotype, 72 



Extra-nuclear factors, 23 

 Eye-colours, mutations in, 28, 222 

 Eyes, loss of, in relation to dispersal, 

 147-48 



Faber, specific songs in Orthoptera, 150 

 Feeding-habits, evolution of, 302-4 

 Feltia, range in U.S.S.R., 357 

 Fenton, determinate evolution, 325 

 — , racial senescence, 330 

 — , redefinition of ' subspecies ' and 



' form,' 64 

 Fernald, polymorphism in Chlorion, 103 

 Ferroniere, experiments on Tubifex, 36 

 Ferry and others, failure to modify 



mutation-rate, 29 

 Fertilisation, prevention of, 156-57 

 Ferton, habits of Aporus, 278 



Feuerborn, species-recognition in Psy- 



chodidae, 148 

 Filipjev, distribution of Feltia, 357 

 Finger-prints, human, 61 

 Finlay, experiments on Cavia, 36 

 Fireflies, specific light-signals, 150 

 Fischer, experiments on Arctia, 36 

 Fish, adaptive specific differences, 283 

 — , albinism, 92 



— , effects of temperature on, 160 

 — , inhabiting corals, significance of 



colours, 240-41 

 — , specific differences in copulatory 



fins, 297 

 — , study of shoals, 92 

 Fisher, blending and particulate inheri- 

 tance, 184 

 — , choice of food by young birds, 253 

 — , definition of adaptation, 351-52 

 — , deterioration of environment, 355 

 — , difficulty of demonstrating Natural 



Selection, 196 

 — , difficulty of spread of non-adaptive 



characters, 306 

 — , effect of pre-adult mortality on 



selection, 195 

 — , evolution of complex organs, 307-8 

 — , evolution of warning colours, 



245-46 

 — , fission of species, 298 

 — , impetus due to selection carried 



beyond adaptive needs, 332 

 — , influence on mutation-rate on 



evolution, 221 

 — , infrequency of mutations, 6 

 — , mathematical treatment of Natural 



Selection, 218 

 • — ■, nature of species, 171 

 — , permutations of genes, 24 

 — , rich store of variation in most 



species, 226 

 — , sexual selection, 292 

 — , significance of polymorphism, 282 

 — , viability of mutants, 219, 223 

 Fisher and Ford, abundant species. 



vary most, 139 

 Fleas, see Ctenophthalmus 

 Flounder, local races, 69 

 Fluctuations, difficulty of recognition 



of, 19, 78 

 — , extrinsic and intrinsic causation, 



21-2 

 ■ — , frequency of, 19 

 Fluctuations in populations, 359 



, effects on spread of mutants, 



224 

 Fcetalisation in man, 365 

 Foot and Strobell, genetic analysis of 



characters in genitalia, 150 

 Ford, E. B., abundant species vary 

 most, 139 



