INDEX 



645 



Spermaries, hydra, 137, 142, 143 



Spermatids, 109, 110 



Spermatocytes, 109, 110, 567 



Spermatogenesis, 109, 110, 112, 475 



Spermatogonia, 109, 110, 142 



Spermatophores, 163, 251 



Spermatozoon, 109 



Sphenodon, 533, 534 



Sphenodon punctatum, 398, 399 



Sphenoidal sinus, 336 



Spherical symmetry, 52 



Sphincters, 133, 329, 489 



Spicules, 130, 132, 133, 178, 222 



Spider crabs, 266 



Spiders, 302, 303-305, 502, 513, 538, 542 



Latrodectus mactans, black widow, 306 

 Spinal cord, 313, 323, 333, 334, 342 

 Spinal curvature, 451 

 Spinal nerves, 333, 334 

 Spindle, 47, 48 



Spines, 54, 194-196, 198, 206, 207 

 Spinnerets, 302, 303 

 Spinning, 304, 498-499 

 Spiny-headed worms, 185 

 Spiracle, 277, 280, 302, 303, 306, 344, 379 

 Spiral cleavage, 123 

 Spiral valve, 344, 345 

 Spireme, 47, 48 

 Spiritus, 582 

 Spirobolus, 276 

 Spirochaetes, 88 



Splanchnic mesoderm, 125, 313, 383 

 Splanchnopleure, 384 

 Spleen, 323, 328, 330, 345, 373 

 Sponges, 129-135, 464-466, 468, 469, 523, 541 

 Spongilla lacustris, 129 

 Spongin, 132, 491 

 Spongoblasts, 132 

 Spontaneous generation, 26, 544 

 Sporoblast, 89 

 Sporocyst, 173, 174 

 Sporozoa, 78, 82, 83, 88 

 Sporozoites, 87 

 Sports, 550 



Sporulation, 67, 68, 89 

 Spotted fever, 448 

 Sgualus, 344 



Squalus acanthias, 344, 345, 348, 353 

 Squamata, 386, 389 



Squamous epithelium (see Pavement epithelium) 

 Squash bug, 289 

 Squids, 221, 226, 226, 466 

 Squirrels, 433, 509, 537 

 Staghorn coral, 153 

 Stagmomantis Carolina, 279 

 Stalked eyes, 256 

 Stapes, 336, 337, 368, 428 

 Starches, 20 



Starfishes, 114, 194-202, 204, 210, 211, 541 

 Statoblast, 192 



Statocysts, 151, 156, 157, 217, 226, 261 

 Statoliths, 217, 261 

 Steapsin, 329 

 Stegocephala, 543 

 Stegodon, 662 



Stegomastodon, 552 

 Stentor, 83 



Stentor polymorphus, 84 

 Steps, in embryogeny, 122 



in fertilization, 115 

 Stercoral pocket, 303 

 Sternal artery, 258, 259 

 Sternum, 326 

 Sterols, 20 

 Stigma, 79 

 Stimuli, 55, 57, 103, 133, 141, 243, 334, 472, 473, 



495-499 

 Sting ray, 347 



Stomach, 187, 189, 191, 198, 199, 200, 208, 214, 

 216, 226, 251, 253, 281, 282, 303, 317, 318, 

 323, 328-329, 346, 406, 438, 459, 467, 489 

 Stomodeum, 146, 156, 379, 380, 466 

 Stone canal, 197 

 Storage, food, 39 

 Strainer, 259 

 Stratification, 507 

 Stratified epithelium, 98, 99 

 Stream fauna, 512 

 Strobila, 161, 152, 169 

 Strobilation, 151 



StTongylocentrotus drobachiensis, 206 

 Structural characteristics (see Internal anatomy) 

 Structure of organisms, 463-474 

 Struggle for existence, 545, 549 

 Sturgeons, 351, 364 



tail, 355 

 Stylonychia, 83 

 Stylonychia mytilus, 84 

 Subclavian artery, 345, 366, 386, 428 

 Subclavian vein, 345, 428 

 Subdermal cavity, 132 

 Subesophageal ganglion, 259, 281, 282 

 Subimago, 286 

 Subneural gland, 317 

 Subperitoneal rib, 323 

 Subpharyngeal ganglia, 238 

 Subspecies, 59, 573 

 Subterranean fauna, 512 

 Succession, 508, 509 

 Suckers, flukes, 168, 173 



leecTies, 250 



tapeworm, 170, 171 



tube feet, 195, 196, 197 

 Sucking, 496 



discs, 225 



fish, 523 



flies, 526 



lice, 288 

 Suctoria, 79, 83 

 Suctorial insects, 278, 294 

 Suctorial mouth parts, 278 

 Sugar, 20, 35, 489 

 Sulphur, 19 



Summation of stimuli, 74 

 Sunbirds, 535 

 Sunfish, mouth, 358 

 Sunflower star fish, 204 



Superficial cleavage, 119. 120, 263. 269, 283, 477 

 Supporting lamella, 138 

 Supporting tissues, 100, 101 



