INDEX 



873 



Spermatogenesis, 1 1 9 

 Spermatogonia, 119 

 Spermatophore, 1 24, 264, 300, 449 

 Spermatozoan, 119 

 Spliaeroeca, 832 

 Sphaeroeca volvox, 156, 157 

 Sphenisciformes, 841 

 Sphenodon, 458, 840 

 Spicules, sponge, 175 

 Spinal cord, 596 

 Spinal ner\es, 591 



rami of, 593 



roots of, 593 

 Spinal reflexes, 419 

 Spindle, 42 

 Spindle fibers, 38 

 Spinnerets, 322 

 Spiny anteater, 491 

 Spiny-headed worms, 232, 806 

 Spiny shark, 432 



Spiracle, 89, 309, 311, 422, 435, 437, 518 

 Spiral cleavage, 239-241 

 Spiral vahe, 435 

 Spirotricha, 164, 832 

 Splanchnic nerves, 417, 595 

 Spleen, 409 

 Sponges, 172 



evolutionary relationships of, 236 



reproduction of, 178 



types of, 173 

 Sponiiiidae, 832 

 Spongillidae, 832 

 Spongin, 176 

 Spongocoel, l 74 

 Spontaneous evisceration, 373 

 Spontaneous generation. 114 

 Spontaneous mutation. 706 

 Spontaneous origin of living things, 711 

 Spores, 116 

 Sporocyst, 215 

 Sporozoa, 149, 832 

 Squalus acanthias, 434 

 Squamata, 459, 840 

 Squamosal, 466, 511 

 Squid, 260 



anatomy of, 262 



reproduction of. 264 

 Squirrels, 500 

 Stanley, W. M., 684 

 Stapes, 397, 415, 511, 565, 583 

 Starfish, 364 



Starling, Ernest H., 11, 525, 605 

 Starling's "law of the heart." 554 

 Statistical analysis, 6 

 Statocyst, 109, 183, 201, 297 

 Stegosaurus, 462, 840 

 Stem reptiles, 456 

 Stenothermic, 761 

 Sternum, 308, 401, 474, 508 

 Steroid hormones, 619 



Steroids, 27, 618 



biosynthesis of, 619 

 Stimulus, intensity of, 588 

 Stinger, 318 

 Stinging cells, 184 

 Stomach, 519 



cow, 518 

 Stomochord, 360, 363, 382 

 Stomodeum, 197 

 Stone ages, 751 

 Stone canal, 368 

 Stratum compactum, 396 

 Stratum corneimi. 395, 502 

 Stratum germinativum, 395, 502 

 Stratum granulosum, 630 

 Stratum spongiosum, 396 

 Stream pollution, 826 

 Strepsiptera, 837 

 Stress, 635 

 Strigiformes, 841 

 Strix, 841 

 Strobila, 194, 195 

 Strongyloidea, 834 

 Structural formula, 25 

 Struggle for survival, 699 

 Struthio, 841 

 Sturgeon, 440 

 Stylasterina, 833 

 Styloid process, 511 

 Subclavian artery, 549 

 Subesophageal ganglion, 310 

 Sublingual glands, 516 

 Submaxillary glands, 516 

 Submucosa, 405, 521 

 Subphylum, 141 

 Subumbrellar surface, 182 

 Subungulates, 499 

 Sucrase, 81 

 Sucrose, 26, 524 

 Suctoria, 149. 165, 832 

 Sugars, 25 

 Sulcus, 601 



Sulcus of Rolando, 602 

 Superfemale, 661 

 Superior colliculi, 597 

 Supermale, 661 

 Supplementary genes, 671 

 Supracoracoid, 475 

 Suprascapula, 400 

 Survival curve, 771 

 Survival of the fittest, 699 

 Sus, 842 

 Suspension, 30 

 Sutton, W. S., 650 

 Swallowing, 518 

 Swallows, 482 

 Swammerdam, Jan, 10 

 Swanscombe man, 749 

 Swartkrans man ape, 744 

 Sweat glands, 487, 506 



