INDEX 



417 



Mimicry, analysis of the problem, 252 

 — , Berg's view, 258 

 — , between species of one genus, 256 

 — , between species not living together, 



255-56 

 — , cases difficult to explain by Natural 



Selection, 259-60 

 — , geographical range of mimic and 



model, 256 

 — , indirect evidence as to survival of 



specific characters, 261-63 

 — , role of climatic ' trends,' 258-59 

 — , role of parallel variation, 255-59 

 — , size of steps in evolution, 255 

 — , snakes, 243 

 Mnemic principles, 346 

 Modification, 353 



Modifications, definition, 4, 64, 71 

 — , induced, 28 



Mollusca, changes in populations, 216 

 — , colour-polymorphism, 282 

 — , darts, 293, 297 

 — , fluctuations, 20 

 — , influence of chemical factors, 81 

 — , insular forms, 137 

 — , lack of protective resemblances, 234 

 — , local races, 69, 108, 323 

 — , marine, larval death-rates, 194 

 — , sporadic variation, 93 

 — , subspecific variation, 67 

 — , variation in size, 157 

 Momentum, 325, 330, 372 

 Morgan, A., and Lestage, adaptation of 



Ephemerella to water-flow, 266 

 Morgan, T. H., genetic basis of 



characters, 178 

 — , mutations and progressive changes 



in evolution, 319 

 Morgan, T. H., and others, chromo- 

 somal abnormalities in 

 Drosophila, 24 



, intersexes in Drosophila, 23 



, variation in Drosophila, 20 



Morrison, L., preferential mating in 



Tipula, 143 

 Moss, experiments on pupae of Pieris, 



203 

 Moths, see Lepidoptera 

 Moulting, in winter, in arctic mammals, 



241 

 Mouse-deer, races of, 137 

 Muir, effect of pre-adult mortality on 



selection of adults, 194-95 

 Muller, alteration of mutation-rates, 29 

 Muller and Mott Smith, effect of 



natural radiations, 30 

 Multiple effects of single genes, 1 78, 279 

 Murella, local races, 108 

 Murray and Hjort, modification of 



eyes in deep-sea forms, 270 

 Alus, see Mice 



Mutation, types of, 3, 24 



Mutation-rate, 220 



— , acceleration of, 27 



— , influence of, on evolution, 221 



Mutations, induced, 28 



— , parallel, 257 



— , also see Gene-mutations 



Myers, food of Coati, 255 



— , habitat-differences in Cicadas, 146 



— , song of Cicadas, 1 2 1 



Myriapoda, insular forms, 135 



Nabours, linkage in Grouse-locusts, 



I72_ 



— , mutation in Grouse-locusts, 220 

 — , stability of colour in Grouse- 

 locusts, 19 

 von Nageli, ' Vervollkommnungs- 



prinzip,' 324 

 JVatio, 64, 70 



Natural population, definition, 10 

 Natural Selection, analogy with arti- 

 ficial selection, 190 

 and correlation, 168, 170 

 arrangement of evidence for, 1 88 

 as an explanation of group- 

 formation and organisation, 



373 



conflicting views on theory, 

 185-86 



confused by Darwin with evolu- 

 tion, 182 



Darwin's original statement, 

 181-84 



difficulties raised by theory, 271- 



309 

 difficulty of proof of theory, 187, 



196 

 direct evidence, 192-213, 247 

 direct evidence, classification of, 



.196-97 . 

 direct evidence, summary of 



results, 212 

 effect of random death-rates, 



.194-95 



evidence from abyssal and cave 

 animals, 269 



evidence from adaptation to life 

 in torrents, 265-66 



evidence from complex organs 

 and co-adaptations, 306 



evidence from Cuckoo's eggs, 

 266-69 



evidence from mimicry, 251-65 



evidence from protective re- 

 semblance, 232-43 



evidence from specific differ- 

 ences, 274-306 



evidence from warning colora- 

 tion, 243-47 



2 E 



