Index 



377 



in Protenor, 750 

 in Tenebrio, 160 

 chromosomal determination, 158 

 XO type, 158 

 XY type, 1 60 



Environmental influence, 166 

 alteration of sex ratios, 166 



hermaphrodites and inter- 

 sexes, 168 

 McCLUNG on, 159 

 WILSON on, 160, 161 

 STEVENS on, 160 

 Sex glands, effects on development, 



232 



Sex hormones, 173 

 SEX-LIMITED INHERITANCE, 73, 170 

 SEX-LINKED INHERITANCE, 73, 119, 



185-189 



Sex ratio, modification of, 166-168 

 Sexual reproduction, value of, 174 

 Share of egg and sperm in heredity, 



198-203 



Share of chromosomes and cyto- 

 plasm, 203 

 SHULL, A. F., sex determination in 



Rotifers, 168 



SHULL, G. H., leaf colors, 113 

 heterosis, 274 

 Oenothera mutants, 277 

 Significance of cleavage, 144, 148, 206 



of mitosis, 131, 145, 150 

 Simplex character, 98 

 Skin color, 109 



mulatto, 109, no 

 influence of light on, 214 

 Slow breeding of man, 116, 315 

 SOBOTTA, fertilization of mouse, 139 

 Social inheritance vs. germinal, 254 

 Social institutions, deal only with en- 

 vironment, 254 



Society, highest grade of organiza- 

 tion, 339 

 power of, 295 

 responsibility of, 339 

 supreme duty of, 340-342 

 Soil, poor, induction effect on plants, 

 246 



SOMAT'C DISCONTINUITY, 125 



Somatoplasm, in cell body, 127 

 SPARTA, destruction of unfit, 292 

 Special senses, origin of, 38 



Specialized types, 209 



SPECIFICITY OF GERM CELLS, 171, 177 



of protoplasm, 172 

 SPENCER, physiological units, 129 

 Sperm centrosome, 136 

 Sperm nucleus, II, 21 

 Spermatocytes, 148 

 Spermatogenesis of Ancyracanthus, 



154 



Spermatogonia, 148 

 Spermatozoon, p, //, 12 



formation of, 157 

 Spina bifida, 228 

 Spinal cord, development, 23 

 Spindle, mitotic, 17, 18, 138 

 SPIRILLA, reactions to chemicals, 30 

 "Sports," 74 



Star-fish, isolated cleavage cells, 224 

 Star-fish, isolated cleavage cells, 222 

 Statistical methods vs. Physiological, 



80, 8 1 

 STATISTICAL STUDY OF INHERITANCE. 



76-81 

 Stature, inheritance of, 66, 78, 80 



tendency to mediocrity, 78 



influence of food on, 216 

 STENTOR, modifiable behavior, 50 

 Sterile insects, 315 

 Sterility, 292, 311, 313 

 Sterilization, 303 



STEVENS, on sex determination, 160 

 Stimuli, chemical and physical, 217 



331 



conflicting, 50 

 definition, 50, 216 

 DEVELOPMENTAL, 216 

 non-specific, 217 

 external and internal, 50, 330 

 range of, 331 



rational, social, ethical, 330 

 summation of, 43 

 STOCKARD, alcohol on guinea-pigs, 



218, 219, 220 

 experimental cyclopia, 172, 229, 



230 



STRASBURGER, phototropism of seed- 

 ling, 41 

 Structures and functions, reciprocal 



relations, 31, 35, 68 

 STYELA. anterior half -embryos, 226 

 dislocated organs, 228 

 egg substances, 140 



