INDEX 



473 



Sexual characters, secondary, 206 



Shark, 164, 416 



Sheep, 263 



Shoot, 65, 76, 81 



Simplex group, 234 



Sinus venosus, 165, 166 



Skeleton, appendicular, 143; axial, 

 143; Bat's wing, 352; Bird's 

 wing, 352; Cat, 145; Fish, 141; 

 Gorilla, 354; Horse's leg, 352; 

 Man, 354; Man's arm, 352; 

 Ox's leg, 352; Vertebrate, 140- 

 146; Vertebrate limbs, 352; 

 Whale's flipper, 352 



Skin, 138, 175; human, 139 



Skull, 141, 143; bones, ^/'evo- 

 lution, in Camel, 363; evolution, 

 in Horse, 362 



Sloth, 317 



Smell, sense of, 196 



'Smilax,' 70 



Snake, 416; hind limbs, 355 



'Social heredity,' 297 



Sociology, 4 



Sol, 8 



Somatic cells, 229, 246 (see 

 Germ plasm and Germinal 

 continuity) 



Somatoplasm, 265 



Somite (see Metamere) 



Sorus, 104 



Spallanzani, 395 



Special creation, 210, 346 



Species, 262, 345; classification, 

 391, 392; concept, 390; muta- 

 bility, 410 



Specific form, 11 



Spencer, 15, 114, 115, 375 



Sperm, 101, 104, 106, 112, 236; 

 discovery, 388; human, 239; 

 Snake, 25 



Spermatic fluid, 152, 207 



Spermatid, 231 



Spermatocytes, primary, second- 

 ary, 231 



Spermatogenesis, 230-232; dia- 

 gram of, 231 



Spermatogonia, 224 



Spermatophytes, 61, 112, 414 



Sphaerella, 30-38, 52, 169, 413 



Spider, 129, 415 



Spinal cord, 137, 142, 152, 153; 

 paths of nervous impulses, 193 



Spinal nerves, 188, 190, 193 



Spines, 72 



Spireme, 225 



Spirogyra, 61 



Spleen, 137, 148, 149, 150, 152 



Splint bones, 355, 361, 362 



Spondylomorum, 55 



Sponges, 115, 117, 414 



Spontaneous generation, 209, 210, 

 388 



Sporangium, 65, 74, 112 



Spore, 31, 101-113; formation, 92, 

 93, 312, 332 



Sporogony, 335 



Sporophyll, 65, 74, 106, 112 



Sporophyte, 64, 101, 104, 105 



Sporulation, 213, 335 



Squeteague, food of, 330 



Squid, 330, 415 



Squirrel, 349; classification, 350; 

 dissection, 152 



Stamen, 107, 108, 112 



Staminate flower, 355 



Stapes, 198 



Starch, 13, 36 



Starfish, 221, 415 



Statolith, 131 



Stele, 76 



Stem, 60, 65, 69-71, 81, 103, 112 



Sternum, 145, 151, 153 



Stigma, 108 



Stimulus, 18 



Stipule, 71 



