INDEX 



687 



Retina, 110; /// 



Reversion, 316 



Rhizoids, 197, 261, 608, 610; 594 



Rhizome, 198, 611, 618 



Rhodesian man, 500, 505; 485, 502 



Rhodopsin, 59, 111 



Riboflavin, 61 



Rickets, 59 



Rocks and strata, 388-391 



Rodents, 376-377, 667; 875 



Rods of retina, 110-112 



Root cap, 143; 144 



Root hairs, 143, 144 



Root nodules, 202, 569; 570 



Root pressure, 162 



Root systems, 142-143 



Roots, of plants, 141-151, 198; 138, 594 



of spinal nerve, 106; 119 

 Rotifers 640; 552, 641 

 Roundworms 629, 639-640 

 Rudimentary structures, 359-361 

 Ruling reptiles, 444-453, 631 



S 



Sacculus, 114; 113 



Salamanders, amphibians, 631, 661 



rodents, 376n. 

 Saprophytes, 200-202, 603; 408, 604, 606 

 Sapwood, 157 



Saurischian dinosaurs, 447-451, 631 

 Sauropod dinosaurs, 449-450 

 Scale trees, 412, 614; 411, 616 

 Scales, of fishes, 428; 430 



of reptiles, 661 

 Scaly reptiles, 443-444, 631, 661; 662 

 Schleiden and Schwann cell hypothesis, 7 

 Science and scientific method, 4 

 Sclerenchyma, 160; 154 

 Sclerotic coat, 110; 111 

 Scorpions, 425, 630, 651 

 Scouring rushes, 410, 597, 611-612 

 Scurvy, 62 



Sea lilies, 435, 629, 642; 426, 643 

 Sea squirts, tunicates, 656; 4%4 

 Seal trees (see Sigillaria) 

 Secretin, 69, 125-126 

 Secretion, 22, 65, 66, 70, 125-128, 253 

 Seed ferns, 410-411, 598, 617-618; 594 

 Seed plants, 135n., 139, 596, 616; 594 



life history of, 268-276; 262 



origin and evolution of, 413-418 

 Seeds, 139-140, 273-276; 594 



dispersal of, 382; 383 

 Segregation of genes, 282, 289 

 Selection, artificial, 341 



and culture, 529 



effectiveness of, 348-349 



Selection, and evolution, 347-349 



inter- and intragroup, 349 



limitations to, 348 



in man, 319-321, 506 



natural, 342-343, 347-349 



sexual, 342 

 Selaginella, 612-613; 614 

 Self-pollination, 272; 271 

 Semicircular canals, 114; 118 

 Semipermeable membrane, 148 

 Sensation and senses, 109-115 

 Sense organs, receptors, 50, 109-115 

 Sepals, 265; 263 

 Sere, 583 

 Serum, 97 



Sewall Wright effect, 351-352 

 Sex, in animals, 211, 212, 214-224 



in plants, 254-257 

 Sex chromosomes, 291-292 

 Sex determination, 290-292 

 Sex linkage, 290-292, 316 

 Sexual reproduction (see Reproduction, 



sexual) 

 Seymouria, 437-438, 631 

 Sharks, 427, 630, 657-658; 429 

 Shoulder girdle (see Pectoral girdle) 

 Sieve tubes, 160-161; 154 

 Sight, 109-112, 472 

 Sigillaria, 412, 614; 411, 484, 615 

 Silurian period, 395, 421; 4®0, 423, 425 

 Skeleton, homologies in, 357-359; 483 



of man, 27-40; 80 



appendicular, 34-40; 30 

 axial, 29-34 

 Skin, 24, 48-54 



appendages of, 50-53 



and disease, 54, 100, 102 



excretion by, 78, 80 



respiration by, 188, 548-549 

 Skin color, inheritance of, 307, 310 



as racial trait, 513; 512 

 Skull, changes in, ape to man, 494-505 

 fish to reptile, 438 

 in primates, 472-473 

 reptile to mammal, 457-459 



human, 31, 494; 483, 484, 495, 505 

 racial traits in, 513; 512 

 Smell, 110, 472 

 Snakes, 443, 631, 661; 356, 662 



leg rudiments in, 360, 443 

 Social behavior, 463, 570-571 

 Soil bacteria, 199-201, 570, 603 

 Soils, classification of, 559-561 



dynamic processes in, 557-559 



in energy cycle, 544 



as environment of roots, 146-147 



as environmental complex, 557-561 



