INDEX. 
Organs of Sense (see Sensation , Organs 
of). 
Ornithorhyncus, 186, 664. 
Otolithes, 513. 
Ovarium, 732 ; of Bird, 754. 
Ovum, structure of, 732, 733. 
Oxygen, carried by blood-corpuscles, 
235 ; by liquor sanguinis, 241 ; ab¬ 
sorbed in respiration, 300—306, 343, 
346; consumption of, dependent on 
muscular action, 307—309. 
Oyster, 113, 316, 437. 
P. 
Palates of Gasteropods, 189. 
Palpi of Insects, 172, 503. 
Palsy of muscles, 586—588. 
Paludina, 112. 
Pancreatic fluid, use of in digestion, 213. 
Papillae of skin, 37, 490; of tongue, 500. 
Parotid gland, 356. 
Paxy-waxy, 29. 
Pecten, nervous system of, 110, 437. 
Pectinibranchiata, development of, 752. 
Pedal ganglia, of Mollusks, 437, 438; of 
Articulata, 446. 
Pelvis, 645. 
Penguin, 667. 
Pentacrinoid-larva of Comatula, 741. 
Perch, skeleton of, 666. 
Pericardium, 43. 
Peristaltic movement of intestines, 215, 
579. 
Peritoneum, 43. 
Perspiration, 371—374. 
Pharyngeal ganglia, of Mollusks, 438; 
of Articulata, 446. 
Pharnyx, 192. 
Phosphorescence of the sea, 394, 395. 
Phosphorus in animal bodies, 166; 
sources of, 167; light produced by, 
402. 
Pia mater, 458. 
Pigment, black, of eye, 533; use of, 545 
Pigment-cells, 533. 
Pitch of sound, dependent on number 
of vibrations, 523, 682. 
Placenta of Mammals, 761. 
Planaria, reparative power of, 389. 
Plants, general comparison of with 
Animals, 6—12 ; afford food to Ani¬ 
mals, M4—147 ; resemblance of their 
life to organic life in Animals, 425, 
426. 
Plastron, of Turtles, 83. 
Plethoric state of body, 233. 
Pleura, 328. 
Pneumogastric nerve, 459, 470. 
Podura, leaping power of, 662. 
Poisonous gases, 344. 
Polycystina, 132. 
Polype, fresh-water (see Hydra). 
Polypifera, 121—125 (see Zoophytes). 
Polyzoa, 115; gizzard of, 202; circula- 
601 
tion of, 295; gemmation of, 728 ; de¬ 
velopment of, 752. 
Pompilus, nest of, 703. 
Porifera, 136, 137; circulation in, 296. 
Portal system of blood-vessels, 267, 366. 
Poulp, 316, 448. 
Primitive trace, 757. 
Prehension, act of, 171—173, 643, 674. 
Projection, idea of, to what due, 560—562. 
Proteus, blood-discs of, 230, 231. 
Protozoa, 128; movements of, 577. 
Pseudopodia, 130, 131. 
Pterodactylus, 669. 
Pteropoda, 122. 
Pulmonary circulation, 268. 
Pulse, 276; influence of posture on, 655. 
Pupa, of insect, 97. 
Pupil, 553; dilatation and contraction 
of, 534. 
Pus, 393. 
Q. 
Quadrumana, extremities of, 643, 648, 
674. 
Queen-bee, 712, 714, 716, 747. 
R. 
Rabbit, teeth of, 177; movements of, 661. 
Radiata, general characters of, 116, 
117; stomach of, 203; nervous system 
of, 434. 
Radius, 63g. 
Ray, peculiar swimming of, 666. 
— electric, 419. 
Red Corpuscles of blood (see Blood- 
Corpuscles). 
Reflex actions, 195, 340, 430, 692; in 
Mollusca, 436, 439 ; in Articulata, 442 
—445, 693; in Vertebrata, 451; the 
spinal cord their instrument, 464— 
474; dependent on stimuli, 466; not 
dependent on sensation, 467—469. 
Refraction of light, 527—532. 
Relief, perception of, 560—562. 
Rennet, action of, 15; nature of, 199. 
Repair of injuries, 389—393. 
Reproduction (see Development, Gemma¬ 
tion, and Generation). 
Reptiles, general characters of, 81— 
87; teeth of, 187; blood-discs in, 430; 
circulation in, 284, 285; respiration in, 
325 ; importance'of skin, as respiratory 
organ in, 325; heat of, 406; nervous 
system of, 454; vertebral column of, 
629 ; reproduction of, 75’6—760. 
Republican Grosbeak, 710. 
Resistance, sense of, 496. 
Respiration, 299; use of blood-cor¬ 
puscles in, 235 ; necessity for, 297 ; in 
aquatic animals, 298 ; changes pro¬ 
duced by, in air, 300—302, 334—336; 
in blood, 303—306; related to nervo- 
muscular activity, 307; energy of, in 
