872 



INDEX 



Sea anemones, 197 



Sea cows, 500 



Sea cucumbers, 372 



Sea fan, 197 



Sea horses, 442 



Sea lilies, 370 



Sea lions, 497 



Sea slugs, 251 



Sea turtles. 456 



Sea urchins, 373 



Seals, 497 



Sebaceous glands, 506 



Secondary oocyte, 120 



Secondary spermatocytes, 119 



Secretin, 525, 605 



Sedentaria, 834 



Segmentation, 285, 514 



Segments, 267 



Selachii. 436, 839 



Selective accumulation, 53 



Selye, Hans, 635 



Semicircular canals, 581 



Semilunar fold, 579 



Semilunar valves, 553 



Seminal fluid, 123 



Seminal receptacle, 300 



Seminal vesicle, 123, 414, 569 



Seminiferous tubules, 413, 566, 02/ 



Semipermeable membrane, 51 



Senescence, 226 



Sense organs, 107, 414 

 birds, 477 



Sensory cilia, 379 



Sensory fields, 428 



Sensory neuron, 418 



Sensory vesicle, 386 



Sepioidea, 834 



Septa, 268 



.Septibranchiata, 834 



Sere, 777 



Serosa, 404 



Serratus anterior, 514 



Serum, 541 



Serum proteins, evolution of, 729 



Sex chromosomes, 660 



Sex, genetic determination of, 660 



Sex-influenced trait, 663 



Sex-linked characteristic, 662 



Sexual reproduction, 116, 566-573 



Shaft, 471 



Shag, 763 



Shallow sea, 795 



Sham operation, 35 



Sharks, 436 



Sheep, 499 



Shell gland, 250, 302 



Shellfrsh, 828 



Shrews, 492 



Siamese twins, 135, 648 



Sickle cell anemia, 693 



Silk glands, 323 



Silkworm, 111 



Silurian period, 721 



Sinaiillnopus pekinensis, 746 



Single twitch, loi 



Sinoatrial node, 553 



Sinus gland, 112, 328 



Sinus venosus, 411, 545, 549, 553 



Siphon, 248 



Siphonaptera, 802, 837 



Siphonophora, 190, 833 



Sipunculoidea, 353, 835 



Sireiiia, 500, 842 



Skates, 436 



Skeleton, 96 

 bird, 472 

 fish, 507 

 frog, 397 

 mammalian, 508 

 man, 509 



subdivisions of vertebrate, 507 

 vertebrate, 506 



Skimmer, 482 



Skin, 95, 449, 502, 559 

 reptiles, 453 



Skin color, inheritance of, 674 



Skull, 397, 473, 510 



Slime glands, 204 



Slugs, 252 



Small intestine, 521 



Smallpox, 543 



Snakes, 460 



evolution of, 461 

 feeding of, 460 

 tongue of, 461 

 Snowshoe hare, 773 

 Snowy owls, 774 

 Social parasites, 820 

 Sodium, 23 



Soil, effect of worms on, 280 

 Sol, 17, 31 

 Soles, 442 

 Solifugae, 836 

 Solo man, 748 

 Solute, 30 

 Solution, 30 

 Solvent, 30 

 Somatic skeleton, 397 

 Somites, 130, 285, 643 

 Sonar, 493 

 Song birds, 481 

 Sonneborn, T. M., 116, 162 

 Sparrow, 482 



Species, 140, 142, 146, 726 

 Species specificity, 28 

 Specific linkage, 666 

 Sperm, 61, 114, 119, 566 

 Sperm reservoirs, 278 

 Spermatids, 119 

 Spermatocytes, primary, 119 



