INDEX 



457 



Schoetensack, 202 



Schuchert, 120, 248 



Scientific methods, development of, 

 8 



Sciuropterus volucella, 231 



Scott, 172, 182 



Sea anemone, 214; and hermit crab, 

 241 



Sea urchins, artificial parthenogenesis 

 in, 330; cytoplasmic differentiation 

 in ovum of, 302 



Secondary sexual characters, 22, 314, 

 334 



Secretions, repellent, 237 



Sedum, 226 



Seeds, dispersal of, 260 



Segregation, of unit characters, 279; 

 and chromosomes, 303; and natural 

 selection, 387; of defectives, 382 



Selection, 271, 274; practical value 

 and methods of, 351; in pure lines, 

 356, 357; limits of, 357; pheno- 

 typic, 350; natural, 385; sexual, 

 394; germinal, 401, 406; coincident, 

 408; in bees, 397; results of, in 

 horses, 352 



Semon, 424 



Serosa, Ji.5 



Sex, chromosomes, 298; determina- 

 tion of, 298, 325; reversal, 327, 335, 

 338; reversal in fowl, 336; control 

 in Arisaema, 337; and the heritage, 

 327; purpose of, 331 



Sexes, differentiation of, 331; con- 

 tributions to heritage, 300 



Sex-linkage, in Drosophila, 312, 313, 

 315; in man, 314, 364, 365 



Sexual colors, 244 



Sexual forms, 22 



Sexual selection, 10, 394 



Shale, 120 



Sheep, Ancon, 404; selection in, 351 



Shepherd's purse, 316; inheritance in, 

 317 



Shore bugs, 254 



Shrews, 253 



Shull, 316, 342, 380 



Sierra Nevada mountains, 257 



Silurian, 123, 150; lung-fishes of, 130; 

 change of climate during, 248 



Simla, 189 



Simiidae, 188 



Siwalik Hills, 198 



Skeleton, appendicular, 77; of lower 

 fishes, 51; of higher fishes, 55; 

 above fishes, 55; visceral, 73, 74; of 

 man and gorilla, 192; of Neander- 

 thal man, 205 



Skull, ganoid stage, 68, 69; dermal 

 bones of, 69; of Cryptobranchus, 58; 

 in Amphibia, 70; above Amphibia, 

 71; human, 71; of elephants, 167; 

 of Moeritheriuiu, 168; of Probos- 

 cidea, 174; diagram of mammalian, 

 59; of horse, 177; of Smilodon, 391; 

 of Felis, 391; of Java ape-man, 199; 

 of Piltdown man, 203; of Neander- 

 thal man, 205 



Sloth, two-toed, 223 



Sloths, 222 



Smilodon, skull of, 391 



Smith, E., 421 



Social animals, 22 



Sociology, 376 



Soma, 306 



Somatoplasm, 305 



Song sparrows, distribution of, 4IO 



Sparrow, English, 251; song, distri- 

 bution of, 410 



Specialization, 93; limitations of, 252 



Species, 19, 25 



Spencer, Herbert, 15, 417 



Spermatids, 294 



Spermatocyte, 292; of Proteus, 290 



Spermatogenesis, 292; in Ascaris, 295 



Spermatophyta, 28 



Spermatozoa, 292; human, 296 



Sphaerella, 91; life history, 326 



Spinal column, 72 



Spirula, 133 



Spondylomorum, 34 



Sponges, 214 



Spontaneous generation, 6 



Spores, 325; of Sphaerella, 326 



Sporophyte, 24 



Spy, 203 



Squids, 132 



Squirrels, as arboreal animals, 229; 

 flying, 229; in adaptive radiation, 

 253 



Starfishes, artificial parthenogenesis 

 in, 330 



Stegocephalia, 151, 152 



Stegodon, 172; tooth of, 174 



Steinmetz, 380 



Stenodiclya lobata, I40 



