INDEX 



237 



Races, prepotent, 180 



Racial characters, blending of, 117-8, 



179, 185, 189 

 definition of. 103 



mode of transmission of, 184-9, 213 

 permanency of, 103 

 not represented by chromosomes, 



23 



stability of, 121 

 transition of individual to, 103-8, 



213-4 



variations of race, 103 

 Rats, effect of inoculation with try- 



panosomes upon, 140 

 growth of teeth in, 1(50 

 Reaction to injury, 47 

 Recapitulation, Archdall Reid on, 113, 

 as explanation of reversion, 114, 



11(5 

 and Niigeli's idioplasm theory, 114, 



122 



reversion implies incomplete, 116 

 sometimes absent in plants, 111 

 theory of, 110-22 

 Recessive characters, 168, 170 

 Reducing division, 20-44 



results of, 22 



Reduction in number of chromo- 

 somes, 20 

 Regeneration of crystalline lens in 



Salamander, 69 

 in Hydra after injury, 68 

 of nerve-cells, 32 

 in plants, 68-9 

 of tissue in vertebrates, 68 

 in unicellular animals after injury, 



32 

 Regressive variations, 109 



at all stages of development, 111 

 Reid, Archdall, on bi-parental repro- 

 duction, 128 

 letter to, on malaria among troops, 



104 



on Mendelian characters, 202-3 

 on recapitulation, 113 

 theory of immunity to disease, 103 

 Reproduction in multicellular organ- 

 isms, 3, 27 



in unicellular organisms, 2, 29 

 Reversion to ancestral characters, 



113-18 



to ancestral characters in domesti- 

 cated races, 115 

 implies incomplete recapitulation, 



116 

 recapitulation as explanation of, 



114, 116 

 Roach, hybrids, 118 



Rothschild and Jordan on continuity 

 between species, 74 



Rotifers, experimental determination 

 of sex in, 192 



Roux, experiments on germinal local- 

 isation, 10 



Roux-Weismann theory of an heredi- 

 tary substance, 9, 11 



Royal Commission on the care and 

 control of the feeble-minded, 154 



Rudd, hybrids, 118 



Salmofario hybrids, 117, 118 

 SaJmo salar hybrids, S. fario, 118 

 Sulrdinus dipinus hybrid, 118 

 Sdtvelinus fontiiialis hybrid, 117 

 Scorpiurus, adaptation in seeds of, 88 

 Seasonal changes in colours of ani- 

 mals, 84 



Secondary sexual characters depen- 

 dent upon primary, 209, 211 

 experiments upon, 2U5-6 

 potentiality of, present in all indi- 

 viduals, 205-7 

 are racial, 209-1 1 

 Segregration of gametes, theory of, 



169-70 



imperfect, 176-7 

 most perfect in self - fertilising 



organisms, 184-5 

 Selection of variability, 71 

 Sex alternative in Myxine glutinosa 



(hag-fish) 191 

 nature of, 203, 210 

 Sex, blending of, prevented by 



natural selection, 207-8, 210 

 a comparatively late product of 



evolution, 190 

 definition of, 191 

 determination of, Wilson's theory, 



195-7, 201-2 



of eggs determined before segmen- 

 tation, 193 



function, production and deter- 

 mination of, 190-21 1 

 an individual character, 204-5, 



207-8, 210 



influenced by environment, 191-3 

 Mendelian experiments upon de- 

 termination of, 199, 209-10 

 Mendelian interpretation of, 197- 



202 



theory of inheritance of, 203-11 

 Sheep, blended characters in, 185 

 Sheik-el-Beled, village sheik, 120 

 Silk-moths, Meudelian experiments 



with, 186 

 Sitaris humeralis, adaptations in, 77. 



