436 



Index 



PAGE 



Spelerpes 237, 374 



spermaries 138 



sperm nuclei 151 



Sphaerella 103, 104 



Sphaeriidae 181 



sphagnum 89, 94, 117, 146, 147, 149, 

 284, 348, 349, 350, 351, 352, 



353, 355, 359 



Sphenophorus 346 



spicules 164, 266 



spiders 183, 192, 346 



spiracles 270, 275, 276 



Spirillum 140 



Spirodela 149, 334 



Spirogyra 119, 120, 216, 223, 263, 322 

 336 



Spirotaema 119 



Spirulina 133 



sponge fishers 30 



sponges. 165, 266, 269, 332, 335, 341 

 sponges, fresh- water 164, 265, 266, 



325 



sponges, marine 266 



spongilla flies 214, 280 



sporangia 143 



spore development 310 



spores 140, 142, 296 



springs 53, 57, 59, 64, 84, 152 



springtails 195, 338 



stagnation 35, 39 



starches 244 



statoblasts 164, 165, 169, 247, 265, 

 266, 269, 325 



Staurastrum 51, 119, 299 



Stauroneis in 



Stenostomum 170 



Stentor 160, 332 



Stephanoceros 178, 299 



Stephanodiscus . . . . in, 112, 114, 297 



Steuer 27 



Sticklebacks 234, 235 



Stokes, Alfred C 19 



stomates 151, 270, 271 



stoneflies 195, 203, 259, 278, 280, 345, 



36o, 368, 374 



stoneworts 50, 52, 101, 137, 138, 139, 

 251,263,319,334 



strainers 252, 253, 365 



strata, soluble 68 



stratification, horizontal 307 



thermal 31, 34, 35, 39, 



46, 54, 7i 

 Stratiomyia 338 



PAGE 



stream-line form 249, 250, 251, 259, 

 273, 274, 313, 366 



streams 59, 77, 141, 231, 319, 406 



streams, pollution of 80, 130 



Streptothrix 142 



Strodtmann 305 



sturgeon, shovel-nosed 235 



sturgeon 291,333,356 



Stylaria 173 



suckers 232, 233, 234, 259 



sulfur 53 



sundew 156, 283, 351 



sunfish 232, 233, 234, 388 



Surber 289 



surface film 181, 327, 328, 337 



swale-flies 230, 277, 329, 346 



swales 56, 64 



Swammerdam 16, 202 



Swamp, Dismal 90 



Okefenokee 93 



swamps, coniferous 152 



marine 90 



sweet flag 157, 343 



swimmerets 192 



symbiosis 282 



Symphynota 287 



Synchaeta 178, 299, 300, 303 



Synedra in, 112, 297 



Synura 103, 107, 303 



Syrphidae 229 



syrphus flies 339, 380 



Tabelaria in, 114, 115, 245, 297, 303, 



305 



Tabanidae 227 



tadpoles 236 



tailfin 251 



Tanypus 225 



Tanytarsus 257, 371, 372 



tardigrade 164 



tear-thumb 343, 344 



teeth, raptorial 235, 313 



temperature 25, 37, 244, 248, 304, 



306, 307, 308 

 temperature, at different depths 



32, 34, 35, 36, 38 



changes of 40 



conditions of. .32, 36, 46 



fluctuations of 345 



levels of 39 



optimum 131 



range of 33, 34 



yearly cycle of 34 



