612 



INDEX 



Spherical symmetry, 51 



Sphincters, 131, 461 



Spicules, 128, 130, 131, 175 



Spider crabs, 261 



Spiders, 296-299, 440, 442, 473, 485, 510, 514 



Spinal cord, 307, 317, 327, 328, 336 



Spinal curvature, 423 



Spinal nerves, 327, 328 



Spindle, 46, 47 



Spines, 53, 191-193, 195, 202, 203 



Spinnerets, 296, 297 



Spinning, 29S, 470 



Spiny-headed worms, 181 



Spiracle, 272, 275, 296, 297, 300, 338, ,362, 373 



Spiral cleavage, 121 



Spiral valve, 338, 339 



Spireme, 46, 47 



Spiritus, 553 



Spirobolus, 270 



Spirochaetes, 87 



Splanchnic mesoderm, 123, 307, 376 



Splanchnopleure, 376 



Spleen, 317, 322, 324, 339, 366 



Sponges, 127-133, 261, 436-438, 440, 441, 443, 



449, 461, 466, 468, 469, 495, 512, 513 

 Spongilla lacustris, 127 

 Spongin, 130, 463 

 Spongoblasts, 130 

 Spontaneous generation, 25, 516 

 Sporoblast, 88 

 Sporocyst, 171, 172 

 Sporozoa, 78, 82, 83, 87 

 Sporozoites, 86 

 Sports, 522 



Sporulation, 67, 08, 88 

 Squalus, 338 



Squalus acanthias, 338, 339, 342, 347 

 Squamata, 379, 380 



Squamous epithelium {see Pavement epithelium) 

 Squash bug, 284 

 Squids, 217, 222, 224-226, 43S 

 Squirrels, 414, 481, 509 

 Stag mo mantis Carolina, 274 

 Stapes, 330, 331, 362, 410 

 Starfishes, 112, 191-199, 201, 206, 207, 513 

 Statoblast, 189 



Statocysts, 149, 154, 155, 213, 219, 222, 256 

 Statoliths, 213, 256 

 Steapsin, 323 

 Stegocephala, 515 

 Stegodon, 524 

 Stegomastodon, 524 

 Stentor, 83 



Stentor polijmorphus, 84 

 Stercoral pocket, 297 

 Sternal artery, 252, 253 

 Sternum, 319 

 Sterols, 19 

 Stigma, 79 

 Stimuli, 54, 56, 101, 131, 139, 2.38, 328, 444, 445 



467-471 

 Sting ray, 341 



Stomach, 184, 186, 188, 190, 195, 196, 197, 204, 

 210, 212, 222, 246, 253, 254, 276, 277, 297, 

 311, 312, 317, 322-323, 339, 350, 393,416, 

 431, 430, 461 

 Stomodeum, 144-146, 154, 371, 372, 438 

 Stone canal, 194 

 Storage, food, 38 

 Strainer, 254 

 Stratification, 479 

 Stratified epithelium, 96, 97 

 Stream fauna, 484 

 Strobila, 149, 150, 167 

 StrobilatiOn, 149 



Strongylocentrotus drobachiensis, 202 

 Struggle for existence, 517, 521 

 Sturgeons, 345, 349 



tail, 358 

 Stylonychia, 83 

 Styloni/rhia viytihis, 84 

 Subclavian artery, 339, 360, 379, 409 

 Subclavian vein, 339, 409 

 Subdermal cavity, 130 

 Subesophageal ganglion, 254, 276, 277 

 Subimago, 281 

 Subneural gland, 311 

 Subperitoneal rib, 317 

 Subpharyngeal ganglia, 233 

 Subspecies, 58, 543 

 Subterranean fauna, 484 

 Succession, 480, 481 

 Suckers, flukes, 166, 171 



leeches, 245 



tapeworm, 168 



tube feet, 194 

 Sucking, 468 



discs, 221 



fish, 495 



flies, 498 



lice, 283 

 Suctoria, 79, 83 

 Suctorial insects, 273, 289 

 Sugar, 34, 461 

 Sulphur, 18 



Summation of stimuli, 74 

 Sunbirds, 507 

 Sunfish, mouth, 352 



Superficial cleavage, 117, 119, 258, 264, 278, 449 

 Supporting lamella, 136 

 Supporting tissues, 98, 99 

 Suprabranchial chambers, 210-212 

 Supraesophageal ganglion, 253, 254, 276, 277 

 Suprapharyngeal ganglia, 232, 233 

 Surface films, 10 

 Surinam toad, 366 

 Survival of fittest, 516 

 Suspensions, 11 

 Suspensory ligament, 333 

 Swallowing, 468 

 Swammerdam, 552 

 Swamp sparrow, 481 

 Swans, 403 

 Swarming, 293 

 Sweat glands, 318, 406, 456 

 Swim bladder, 348 

 Swimmerets, 251-253, 258 



