724 Index 



Siphonophora, 393 



Siputiculoidea, 348, 462-465 



Sipunculus, 465 



Siren, 596, 598 



Sirenia, 630, 639 



Sirenidae, 596 



Sistrurus, 609 



Six-hooked embryo (see oncosphere), 



418 

 Skate, 568 

 Skeletal muscle, 58, 116, 122-126, 190 



system, 40, 55, 58,92-113 

 Skeleton, appendicular, 58, 109-110 

 arthropod, 487 

 axial, 55-57, 100-108 

 frog, 55-58 

 perch, 583, 585 

 Squalus, 577 

 starfish, 542, 545 

 vertebrate, 92-113 

 visceral, 56, 108, 130 

 Skin, 47-74 

 frog, 54-55, 62-63 

 inheritance of color, 306 

 Skink, 607 



Skull, 55, 56, 57, 100-104 

 Skunk, 76, 82, 129, 134-135, 630, 638 

 Slave-making ants, 534 

 Sleep, 211 



Sleeping sickness, 358 

 Slider, 605, 606 



Slipper animalcule (see Paramecium) 

 Sloth, 630, 635 

 Slug, 468, 471 



Small intestine, 61, 134-135, 138 

 Smell, 214 



Smooth muscle, 58, 115-116, 124 

 Snail, 45, 92, 253, 348, 466, 468, 470- 

 471 

 as intermediate host, 410, 413, 414, 

 415 

 Snake, 46, 75, 131, 195. 220, 254, 567, 



603, 606, 608-610, 612, 613 

 Snapdragons, inheritance in, 300 

 Snapper, 605, 606 

 Sneeze, 157 

 Snore, 157 



Social insects, 532-535 

 Sodium, 26, 29, 186, 236, 269 

 bicarbonate, 160 

 chloride, 235 

 level in blood, 235, 250 

 Soft-shelled turtle, 605, 606 

 Soil, 229 

 Sol, 33, 359 

 Soldiers, 532, 533, 535 

 Sole, 590 



Solenichthyes, 590 

 Solenogastres, 469 



Solpugida, 514, 515 

 Solute, 32 

 Solution, 32-33, 35 

 Solvent, 32 

 Somatic cells, 279 



mesoderm, 282, 288 

 Somatopleure, 290 

 Somite, 288 

 Song, 241 

 Sorex, 630, 634 

 Soricidae, 633 

 Space, intercostal, 107 

 Spadefoot toad (see Scaphiopus), 596, 



599 

 Sparrow, 617, 671 

 Species, 42, 43, 44 

 Speech, 130 

 Sperm, 38, 189, 240, 252, 253, 255, 257, 



258-259, 275, 276, 293, 297 

 Sperm whale, 632, 637 

 Spermatic cord, 258 

 Spermatid, 257, 275 

 Spermatocyte, 257, 273, 275 

 Spermatogenesis, 273-275 

 Spermatogonium, 257, 273 

 Spermatophore, 480, 491, 597 

 Spermatozoan (see Sperm) 

 Sphenethmoid bone, 56 

 Sphenisciformes, 625 

 Sphenodon, 600, 603, 604, 611, 612, 614 

 Sphenoidal bone, 243 



complex, 102, 103 

 Spherical symmetry, 345 

 Sphincter muscle, 59, 119, 132, 142, 



143, 189 

 Sphyrna, 576, 580 

 Spicule, 376, 377, 426 

 Spider, 45, 489, 509, 511-513 

 Spider monkey, 635 

 Spinal column, 101, 204, 206 

 cord, 69, 70. 202-203 

 ganglion, 195 

 nerves. 71, 203-204 

 Spindle fibers, 270, 271 



of mitosis, 271 

 Spine, neural, 105, 106, 107 

 of scapula. 109 

 of sea urchin, 550 

 Spinneret, 512 

 Spiny anteater, 629, 631 

 Spiracle, 512, 523 

 Spiral valve, 63, 571, 577 

 Spirobolus, 489 

 Spirostomum, 372 

 Splanchnic mesoderm, 282, 288 

 Spanchnopleure, 290 

 Spleen, 61, 177, 178 

 Splenic artery, 167 

 Sponge, 45, 147, 252, 253, 255, 346, 650 



