INDEX. 



403 



conclusions on species-form- 

 ing, 309, 394 



Ultra-Darwinism, reaction 



against, 130 

 Utility, many species characters 



of no, 38 . 



Variation according to the law 

 of chance, 32, 59; causes of, and 

 means of segregation the chief 

 factors in species-forming, 

 377 ; determinate, apparent 

 cases of, 319; determinate, as 

 a species-forming factor, 33 ; 

 determinate, produced by 

 germinal selection, 198 ; de- 

 terminate, Whitman's belief 

 in, 325; discontinuous, 33, 

 328; favourable, swamped by 

 inter-breeding, 44; fluctuating, 

 as a basis for species-forming, 

 35 ; fluctuating, insignificance 

 of, 36; fluctuating, of linear 

 and quantitative value only, 

 139; fluctuating, too slight to 

 be of selective value, 138; gen- 

 eral, Delage's theory of, 289 ; 

 how cumulated, 379 ; in in- 

 sects, 62 ; in parthenogenetic 

 insects, 58 ; natural selection 

 based on, 30 ; necessity for co- 

 incident appearance of other, 

 to make a certain one effect- 

 ive, 46; non-correlated in bi- 

 laterally repeated organs, 65 ; 

 occurrence of needed coin- 

 cident, 45 ; qrthogenetic, in 

 palaeontology, 319; parallelism 

 in, 279 ; references for, 57 ; 

 suggestion concerning the 

 cause of, 384 



Vejodoysky, example of pro- 

 gressive degeneration not ex- 

 plicable by natural selection, 

 100 



Vernon, H. M., theory of repro- 

 ductive divergence, 248; theory 

 of the ultimate structure of 

 protoplasm, 225 



Vestigial structures, explanation 



of, by panmixia, 190 ; La- 

 marckian explanation of, 192 

 Von Kolliker, R., proposal of a 

 theory of heterogenesis, 330 



Waagen, use of term mutation, 



324 



Wagner, M., formulation of 

 Separations -theorie, 236 ; 

 founder of theory of species- 

 forming by geographic isola- 

 tion, 234 



Wallace, A. R., criticism of Ro- 

 manes's theory, 247; suggested 

 explanation of secondary 

 sexual characters, 354 



Weismann, A., admission of ob- 

 jections to selection, 45; at- 

 tack on Lamarckism, 266; dis- 

 cussion of degeneration, 77 ; 

 principle of amphimixis, 180 ; 

 references to evolution writ- 

 ings of, 212; theory of germi- 

 nal selection, 188, 193; theories 

 of neo-Darwinism and neo- 

 Lamarckism, 133 ; theory of 

 panmixia, 188 



Weldon, selection experiments 

 on Carcinus, 158 



Whitman, C. O., belief in deter- 

 minate variation, 325 ; favour- 

 ing orthogenesis, 288 



Wolff, G., attack on the assump- 

 tion by selectionists of the ap- 

 pearance at the right time of 

 the needed variation, 64; 

 criticism of panmixia by, 98 ; 

 criticism of sexual selection, 

 126; discussion of selection, co- 

 efficient, 101 ; objections to ex- 

 planation by selection of com- 

 plex related body-parts, 51 ; 

 objection to natural selection, 

 based upon its dependence on 

 sexual selection theory, 125 ; 

 objections to sexual selection 

 theory, 126; objection that 

 selection can concern only 

 quantitative changes, 70 ; ob- 

 jection to the assumption by 

 selectionists of identical and 

 coincident variation, 67 



