832 



Species, 621, 622, 623, 625- 

 630, 676, 683, 684, 685, 

 686, 687, 711, 729. See 

 also Races, Subspecies, 

 Taxonomic categories. 

 aUopatric, 608, 612, 616, 



659 

 asexual, 606, 628, 629, 630 

 binding, in communities, 



466 

 dominant, of trees, 575 

 extinct, 328, 399, 400, 634, 



638, 680 

 formation, convergent, 625 

 geminate, in Central Ameri- 

 can seas, 597 

 hybrid origin, 624, 644, 



674 

 mendelian characters, 624 

 polyploid, sex and, 677 

 polyvalent, 567 

 potential, birth rate and, 



273 

 recognition, 621, 645, 689, 



691, 710 

 relict, 661, 662, 663, 679, 



680, 682 

 sexual, 630 

 shade, 448, 449, 500. See 



also Ecophene. 

 survival of, 684 

 sympatric, 610, 612, 616, 

 621, 622, 659, 660, 710 

 Specific gravity, animals, 132, 



133 

 Spectra, Raunkiaer frequency, 



518 

 Spectral change, diurnal, 90 

 Spectrum, electromagnetic, 88 



toleration, 539 

 Spencer, Herbert, 30, 672, 



684 

 Spermatozoa, competitive co- 

 operation, 395, 411 

 Spiders, 134, 148, 234, 365, 

 485, 487, 513, 533, 534, 

 537, 618, 632, 673, 690, 

 697 

 sea, 632 

 Spitzbergen, insects, air trans- 

 port, 148 

 Sponge(s), 102, 253, 341, 

 397, 436, 459, 537, 712 

 gemmules, 102 

 regeneration, 397 

 silicon and, 167, 204 

 Sporozoa. See Malaria, Pro- 

 tozoa. 

 Spring pulse, fresh-water 

 algae, 503, 504 

 marine diatoms, 502 

 Spruce, 699 



Squirrels, 546, 547, 705, 723 

 ground, 103, 106, 215 



SUBJECT INDEX 



Stability, ecological, 283, 

 315-318, 332, 639, 655, 

 656, 659, 671, 672, 681, 

 682, 683, 696, 710, 721. 

 See also Balance, Equilib- 

 rium, Homeostasis. 

 evolutionary, 629, 655, 



680-683, 688 

 gene, 600, 655, 681 

 organismic, 694. See also 

 Homeostasis. 

 Staphylinidae, 422, 465, 472, 

 484, 534, 615, 665, 718, 

 719, 720, 721 

 Stark, 22 



Statistical methods, historical 

 aspects, 46, 54, 55 

 in population studies, 287 

 Stenohaline organisms, 341 

 Stenoky, 213, 214, 215 

 Stenophagy, 373 

 Stenothermal, 213 

 Steppe, artificial, 475 



biota, 467, 692 

 Sterihty, hybrid, 606, 618, 

 623, 626 

 individual, 690, 692, 693. 



See also Castes. 

 interspecific, 605, 617, 623, 

 676, 677. See also Infer- 

 tility. 

 Stoneflies, 102, 618 

 Stones, habitat under, 697 

 Storm(s), dust, 475, 516, 

 579, 580 

 mortahty and, 339, 340 

 wind, 146 

 wands, 578 

 Strains, 628, 629, 653, 657, 

 680, 685, 708, 709, 711. 

 See also Bacteria, Races. 

 Strand of lakes, 452 

 Stratal equivalents in forests, 

 492, 493 

 in grassland, 470, 471, 

 473 

 indices, 479 

 Stratification, 442 

 atmospheric, 131 

 community, 441-495 

 correlation with maturity, 



462, 484 

 eflFects of vertical migra- 

 tion on, 554-557 

 of environment, 131 

 of fishes, 450, 457, 460, 



466 

 in forest communities, 478 

 in grassland communities, 



466 

 horizontal, in aquatic com- 

 munities, 451 

 marine, 454 

 of Hymenoptera, 494 



Stratification, principle of, 

 442, 484, 507 

 in lakes, 192, 193, 194, 



196, 202, 203, 204 

 in terrestrial communities, 



461 

 thermal, 93, 94 

 air, 97 

 land, 96 

 ocean, 96 

 rivers, 155 

 tropical forest, 482, 483, 



489 

 vertical, in African forest, 

 483 

 in aquatic communities, 



443 

 in forests, 481-495 

 Stratosphere, 142 

 Stratum, abyssal, 137, 542 

 epipatomic, 489, 490 

 herbaceous, in forests, 481, 

 488-495 

 in grassland, 472-476 

 profundal, bacterial action 

 in, 500 

 succession in, 570, 571 

 subterranean, 465, 466, 

 537, 633, 674 

 of ecotone, 477 

 in forests, 481, 484, 485 

 in grassland, 466, 467 

 Stream, 652, 696 

 bed load, 154 



community, phytoplankton 

 of, 505 

 pollution in, 516 

 succession, 155, 156, 572 

 Streamlined form, 156, 157. 



662, 671 

 Streamlining, eflFect on resist- 

 ance to flowing water, 157 

 Structural inductions by tem- 

 perature, 118, 119, 120 

 Structure, animal, eflFect of 

 gravity on, 131. See also 

 Adaptation, Morphology, 

 Nests. 

 group modification of, 408 

 Struggle, evolutionary, 29 

 for existence, 31, 304, 

 640, 647, 657, 658, 699, 

 700. See also Competi- 

 tion, Drive, Survival. 

 Struve, Otto, 74 

 Subclimax, 574 

 Sublittoral zone in lakes, 451, 

 452, 453 

 marine, 458 

 Subordinance, social, signs of, 



414, 415 

 Subseres, 578 

 Subsidence theory, 40, 598 



