INDEX 



Spermatozoon, 57, 122, 129, 134, 137, 140, 

 143, 192 



Spcrmio^enesis, 137, 143; in guinea pig, 137 



Sphaenum, yil; S. slnalinum, blastula of, 134 



Sphenodon, 567, 571 



Sphyramirn, 328 



Spicules, of sea cucumbers, 529; of sponges, 

 273, 276, 277, 528 



Spider crab, 441 



Spiders, 423, 480, 482, 485; as food of wasps, 

 470; nervous integration in, 525 



Spinal column, 92 



Spinal cord, 87, 96, 98, 101, 154 



Spinal nerves, 90 



Spindle fibers, 39 



Spiny anteater, 566, 581, 582 



Spiny lobster, 440 



Spnobolus, 479 



Spirostomum, 257 



Spleen, 48, 64 



Splint bones, 625, 633 



Sponge structure, asconoid, 276; comparative, 

 278 



Sponges, 272, 273-283, 490; fossil, 274; skele- 

 ton, 528 



Spongia, 274 



Spongin, 528 



Spongocoel, 275, 276, 278 



Spontaneous generation, 618 



Spores, 244; of Monocystts, 245 



Sporocyst, 330, 331 



Sporosacs, 302 



Sporozoa, 216, 229, 244-248 



Sporozoites, 247; of Monocyslis, 245 



Sporulation, 141 



Spring peeper, 566 



Squamata, 567 



Squamous epithelium, 59; simple, 59, 70; 

 stratified, 59 



Squash bug, 462 



Squid, 270, 388-392; as food for whales, 589; 

 circulatory system of, 514; nervous integra- 

 tion in, 525; skeletal structures of, 528 



Sqmlla, 440 



Squirrel, 580 



Stable fly, 476 



Staining, of cells, 13 



Starches, see Polysaccharides 



Starfish, 486, 488, 489-497; digestive glands 

 in, 513 



Starling, 1 17 



Statoblasts, 361 



Statocysts, of crayfish, 433; of jelly fishes, 304; 

 of pelecypods, 374 



Statoliths, 434 



Steapsin, see Lipase 



Steenstrup, J. J., 305 



Stegocephalia, 562 



Stellate ganglia, 390 



Stem reptiles, 566 



Stenopelmntus, 482 



Sknostomwn, 325 



Stenotele, 290 



Slentor, 257 



Sternum, 92; of birds, 576 



Steroids, 26, 31, 121 



Stevens, Nettie M., 185 



Stigma, in Chlarnydomtmas, 265; in Euolena, 



.241 

 Stimulus, 13, 95, 105, 111 

 Sting ray, 557 



Stolon, of entoprocts, 356, 357 

 Stomach, 48, 71, 75; of ruminants, 48 

 Stomochord, 542, 543 

 Stomodeum, 154 

 Strata, geologic, 623 

 Stratified epithelium, 59 

 Storage, of food, 76-79 

 Striated muscle, 54, 68, 155 

 Strobila, 333 



Strobilization, 141; in Scyphomedusae, 305 

 Strombidwm, 258 

 Struggle for existence, 648 

 Strulhw, 577 

 Struthiomimus, 577 

 Sturgeon, 558 

 Styela, 545 

 Slylonychia, 258 



Subcutaneous fat, in mammals, 598 

 Subdermal spaces, 277 

 Subepidermal nerve plexus, in annelids, 524; 



in Saccoglossus, 542; in starfish, 494 

 Submucosa, 61, 69 

 Substrate, of enzyme, 28 

 Succession, ecological, 614; geologic, 623 

 Sucker, 159, 169 

 Sucrase, 72 

 Sucrose, 26 



Suctoria, 216, 229, 258-259 

 Sugar-active compounds, 121 

 Sulfonamides, 33 

 Superfemales, 211 

 Supermales, 21 1 



Supporting lamella, 284, 287, 288 

 Survival of the fittest, 649 

 Sustentative tissue, 61-63 

 Sutton, W. S., 185 

 Sweat glands, 82, 125 

 Swim bladder, 558 

 Swimmerets, 428 

 Swimming plates, 310 

 Swine, 580 



Syconoid sponges, 276 

 Symbiosis, 291 

 Symmetry, 222; bilateral, 222; radial, 222; of 



Anthozoa, 307; of echinoderms, 486; of Echi- 



noidea, 502; of sea cucumber, 503; of 



sponges, 278 

 Sympathetic nerves, 90, 115, 121 

 Sympathetic trunk, 115 



705 



