INDEX 



531 



Significance of cleavage, 122, 

 123, 126 



of mitosis, 122, 123, 126 

 Simplex character, 249 

 Skin color, 197, S89, 291, 292 



mulatto, 282-285 



influence of light on, 303 

 . Slow breeding of man, 290, 438 

 SoBOTTA, fertilization of mouse, 



114 

 Social inheritance vs. germinal, 



360-363 

 Social institutions, deal only 



with environment, 360 

 Society, highest grade of or- 

 ganization, 482 



power of, 410 



responsibility of, 482 



supreme duty of, 487, 488, 

 491 

 Soil, poor, induction effect on 



plants, 349 

 Somatic DiscoifTiirtjiTT, 92, 97 

 Somatoplasm, in cell body, 125 

 Somites, 27, 29 



Sparta, destruction of unfit, 404 

 Special senses, origin of, 52 

 Specializea types, 413, 415 

 Specificity of Gekm Cells, 151- 



161 

 Spencer, physiological units, 



100, 495 

 Sperm centrosome, 16 

 Sperm nucleus, 16, 24 

 Spermatocytes, 129 

 Spermatogenesis of Ancyracan- 



thus, ISS 

 Spermatogonia, 128 

 Spermatozoon, 15, 17 



formation of, 138 

 Spina bifida, 325 

 Spinal cord, development, 28 

 Spindle, mitotic, 110, 111 

 Spireme, 111 

 Spirilla, reactions to chemicals 



51 



"Sports," 210 



Stakdftjss, mutations of insects, 



348 

 Star-fish, isolated cleavage cells, 



314 

 Statistical methods, strength 



and weakness of, 219, 221 

 Statistical Study of Inheri- 

 tance, 214-223 

 Stature, inheritance of, 196, 218, 

 219, 220 

 tendency to mediocrity, 218, 



220 

 influence of food on, 303 

 Stentor, modifiable behavior, 68 

 Sterile insects, 440 

 Sterility, 409, 435, 439 

 Sterilization, 419, 421, 422, 439 

 Stevens, on sex determination, 



141, 143, 166, 500 

 Stimuli, chemical and physical, 

 467 

 conflicting, 68, 464 

 definition, 308 

 Developmental, 307, 310 

 chemical, 308 

 non-specific, 309 

 physical, 308 

 external and internal, 67, 



457, 464, 465 

 range of, 468 



rational, social ethical, 467 

 summation of, 57 

 Stockard, alcohol on spermato- 

 zoa, 311, SIB, 500 

 experimental cyclopia, 153, 



ssd 



structures and functions, recip- 

 rocal relations, 38, 45 

 Sttela, anterior half-embry- 

 os, 319 

 dislocated organs, S« 

 egg substances, 117-119 

 gastrulation and larva, 124 

 half and three-quarter em- 

 bryos, 317 



