INDEX 



581 



Sea squirt, 304, 305 

 Sea urchins, 295 

 Sea walnut, 264 

 Seals, 440, 546 

 Segmented worms, 169 

 Semicircular canals, 328, 368 

 Sense organs, crayfish, 191 



frog, 326 



man, 326 



planaria, 135 

 Sensory nerves, 141, 174 

 Sensory reactions, 68 

 Sepia, 282 

 Serai stages, 473 

 Serology, 559 

 Seventeen-year locust, 251 

 Sex chromosomes, 519 

 Sex control in bees, 235 

 Sex determination, 517 

 Sex hormones, 517, 362 

 Sex-linked inheritance, 521 

 Sexual reproduction, 70, 111, 122 

 Sexual selection, 545 

 Sharks, 367 

 Shellfish, 271 

 Shrew, 433 

 Shrimp, 194 

 Sight, 326 

 Silver fish, 211, 240 

 Siphonaptera, 259 

 Sirenia, 446 

 Skeletal system, arthropods, 183 



embryology, 532 



frog, 308 ' 



man, 308 



starfish, 290 

 Skin-color inheritance, 515 

 Skin, embryology, 531 

 Skippers, 255 

 Skunk, 438 

 Sloths, 449 

 Slugs, 280 

 Smell, 326 



Smooth muscle, 319, 533 

 Snails, 279 



Snake superstitions, 401 

 Snake-bite treatment, 400 

 Snakes, 390 

 Social insects, 227 



Sol, 45 



Solution, 43 



Somatoplasm, 491 



Somites, 529 



Spemann, Hans, 538 



Sperm, 111 



Spermatogenesis, 493 



Sphenodon, 460 



Spicules, 109 



Spider web, 199 



Spiders, 198 



Spindle figure, 26 



Spiracles, 213 



Sponges, 109 



Spontaneous generation, 14 



Sporozoa, 96 



Springtails, 240 



Squash bug, 251 



Squid, 281 



Squirrels, 447 



Starfish, 289 



Starlings, 459 



Sticktights, 259 



Stink bugs, 251 



Sting rays, 369 



Stone flies, 243 



Stork, 422, 424 



Strand, 469 



Striated muscle, 315, 533 



Sturgeon, 374 



Succession, ecological, 473 



Suctoria, 106 



Surface-volume ratio, 62 



Suspension, 43 



Swallowtail butterflies, 255 



Swarming of bees, 233 



Swim bladder, 371 



Symbiosis, 126, 166 



Symmetry, 134, 289 



Syrinx, 407 



Tachina flies, 257 

 Tactile sense, 328 

 Taenia saginata, 150 

 Taenia solium, 149 

 Tail, 300 

 Tapeworms, 147 

 Tapirs, 441 

 Tarantula, 203 

 Taste, 327 



