648 



ANIMAL BIOLOGY 



Vagus nerves, 459 

 Valves, blood vessels, 236, 259, 581 

 oral, 358, 359 

 spiral, 344, 345 

 Vampire bats, 534, 545 

 Vane, 406 

 Variation, 546 

 Varieties, 59, 573 

 Vas deferens, 162, 163, 168, 170, 217, 240, 267, 



258, 339 

 Vasa efferentia, 162, 163, 168, 240, 331 

 Vascular systems, air-vascular (see Tracheae) 

 blood-vascular (see Circulatory system) 

 gastrovascular (see Gastrovascular cavity) 

 water-vascular (see Water-vascular system) 

 Vegetal pole, 120, 378 

 Vegetation regions, 535-537 

 Veins, 279, 304, 330, 580, 581 

 Velum, 145, 162, 230, 317, 319, 320 

 Velvet mites, 308 

 Vena cava, 214, 217, 428 

 Venomous snakes, 396-398 

 Ventral aorta, 347 

 Ventral fins, 354 

 Ventral line, 179 

 Ventral nerve cord, 179, 236, 238, 257, 259, 281, 



282 

 Ventral root, 333, 334 

 Ventral sucker, 378, 379 

 Ventral vessel, 236 



Ventricle, 214, 345, 346, 367, 386, 388 

 Ventriculus, 282 

 Venus' flower basket, 131 

 Venus' girdle, 157 

 Vermes, 186 



Vermiform appendix, 328, 427, 647 

 Vertebrae, 322, 326, 451 

 Vertebral column, 312, 322, 324, 326, 326, 451, 



466, 548 

 Vertebral discs, 425 

 Vertebrata, 314, 322-340, 576 

 Vertebrates, 322-454, 468-470, 472, 491, 494, 

 546, 548 

 diagrammatic longitudinal section, 323 

 parallel stages in development, 648 

 skeleton, 324 

 Vertical distribution, 531 

 Vertical life zones, 630, 531 

 Vertical migration, 269, 531 

 Vesalius, 679, 580 

 Vestigial structures, 546, 647 

 Villi, 36, 329, 467 

 Villi, placental, 444 

 Vipers, 398 

 Virchow, 50 

 Virus, 517 



Visceral ganglion, 214, 217 

 Visceral mass, 215, 223 

 Visceral muscle, 102 

 Visceral pain, 473 

 Visceral part of skull, 326 

 Visceral sensations, 473 

 Viscosity, 9 

 Vision (see Sight) 



Vital activities, 22 

 Vital force, 25, 582 

 Vitalism, 25 

 Vitamins, 34, 38, 483 

 Vitelline membrane, 383 

 Vitrella, 260 

 Vitreous body, 338 

 Vitreous retina, 227 

 Viviparity, 108 

 Voluntary muscles, 326, 327 

 Volvox, 81, 95 

 Volvox aureus, 80 

 Vomiting, 496 

 Von Baer, 270, 583 



law, 583 

 Von Mohl, 19, 583 

 Vorticella, 83, 84 



W 



Wading birds, 413, 414 

 Walking legs, 251, 253, 255, 413 

 Walking sticks, 279, 288, 613 

 Wallace, 545, 549 

 Walruses, 437, 448 

 Wandering cells, 133 



(See also Leucocytes) 

 Warbler, beak, 412 

 Warm-blooded animals, 484 

 Warm-bloodedness, 427, 484 

 Warning coloration, 514 

 Warts, 372 



Wasps, 296, 300, 613 ^ 



Water, 21, 39, 482, 483, 488, 507, 528 



beetle, 279, 283 



birds, 420 



boatmen, 279, 289 



fleas, 108, 268 



moccasin, 396 



striders, 10, 289, 609 



tubes, 215, 216 



vacuoles, 64 

 Water-vascular system, 197-198, 204, 575 

 Wax, 287, 491 

 Weasels, 436 

 Webs, spiders, 305 

 Webworm, 290 

 Weevils, 290 

 Weismann, 96, 479, 545 

 Whale sharks, 441 

 Whalebone, 443, 448 

 Whales, 4, 424, 429, 441, 443, 448 

 White ants, 457 

 White body, 227 

 White corpuscles, 330 

 White fibers, 101 

 White matter, 333, 334 

 Wilson, H. v., 132 

 Wind, 507, 528 



Wings, 63, 64, 278-280, 392, 403, 410-415, 432. 

 473 



bones, 404 



deciduous, 286 

 Winking, 496 



