604 
INDEX. 
V. 
w, 
Valves of heart, 272, 273; of veins, 279. 
Vascular area, 758. 
Vegetative repetition of parts, 2. 
Veins, 246; structure of, 248; pressure 
of blood in, 249; arrangement of, 250, 
266; flow of blood through, 277, 278; 
valves in, 279. 
Vena cava, 266. 
Vena portae, 267, 366. 
Ventilation, importance of, 336, 337. 
Ventricles of brain, 458. 
- of heart, 257; action of, 270. 
Ventriloquism, 525. 
Vertebrae, structure of, 71, 628; classifi¬ 
cation of, 626; number of, 627 ; con¬ 
nexion of, in Reptiles and Fishes, 
629; in Man, 630; in Birds, 630. 
Vertebral column. 70, 71, 626—632; first 
development of, 757. 
Vertebrata, general characters of, 70 
—76; nervous system of, 449—452; 
skeleton of, 599; gemmation in, 729; 
embryonic development of, 757—762. 
Vessels, origin of, 393. 
Vestibule of ear, 518, 521. 
Vibrations, sonorous, 510—512; pitch 
determined by number of, 523, 682. 
Villi of mucous membrane, 41; absorp¬ 
tion performed through, 41, 217. 
Vision, dependent on light, 526, 542; 
adaptation of eye to distinct, 543—553 ; 
influence of attention on, 555; infe¬ 
rences drawn from, 556—566; duration 
of impressions, 567; distinction of 
colours by, 568—570; erect, though 
picture inverted, 558; single, with two 
-eyes; 559; double, 559. 
Vitality, independent, of parts of organ¬ 
ism, 65. 
Vitreous humour, 536. 
Vocal cords, 681. 
Voice , confined to Vertebrata, 680 ; how 
produced in larynx, 682; differences in 
pitch and quality of, 683, 684. 
Voltaic electricity, discovery of, 583, 584. 
Voluntary movements, 589, 590. 
Vorticella, reproduction of, 725. 
Vowel sounds, 689, 690. 
Vulture, skeleton of, 668. 
Walking, act of, 657. 
Warm-blooded animals, 407—409. 
Wasps, nest of, 711. 
Waste of the system, 160, 307, 345. 
Water, passed off* by kidneys, 369; ex¬ 
haled from lungs, 343, 344; from skin, 
370—374. 
Water-Newt, 87. 
Wax formed from sugar only, 155. 
Webs of Spiders, 698. 
Whale, mouth of, 185; peculiar arterial 
distribution in, 265; sensibility of 
surface in, 491; blow-holes of, 509; 
propulsion of, in water, 665, 666. 
Whalebone, 185. 
Wheel-animalcules, (see Rotifer a). ) 
White fibrous tissue, 23—29. 
White of egg, 14, 755. 
Wings, of Birds, 78, 668; of Bat, 669; 
of Pterodactylus, 669; of Insects, 670; 
action of, 667—672. 
Winter eggs of Hydra and Rotifera, 735. 
Wounds, healing of, 391—393; of ar¬ 
teries, treatment of, 277. 
Wren, intelligence of, 717. 
X. 
Xylocopa, nest of, 703. 
Y. 
Yawning, 341. 
Yellow Fibrous tissue, 23—29. 
Yellow spot of retina, 554. 
Yolk of egg, 733, 736, 754. 
Yolk-bag, 733, 754. 
Young animals, heat of, 408, 409. 
Z. 
Zoea, larva of Crab, 101. 
Zoophytes, 117, 121; tissues of, 64, 577 ; 
circulation in, 296; gemmiparous pro¬ 
duction of, 726; development of Me¬ 
dusae from, 738, 740; generation of, 
738, 739. 
THE END. 
■ 9 $ 
\ i- 
R. CLAY, PRINTER, BREAD STREET HILL. 
