INDEX. 599 
Intelligence of Vertebrata, 73, 483—485* 
694; examples of, 695, 717; corre¬ 
spondence of, with development of the 
Cerebrum, 452, 692, 718—720. 
Intervertebral substance, 631. 
Intestinal juice, 213. 
- tube, motion of aliment 
through, 215 ; digestion continued in, 
213, 214; relative length of, 213. 
- Worms, 105 ; development of, 
742, 743. 
Invertebrata , 92 ; absorption in, 225 ; 
nature of circulating fluid in, 225, 235 ; 
heat of, 404 ; skeletons of, 598, 599. 
Involuntary movements, 589, 590. 
Iris, 533, 534. 
Iron, a constituent of animal bodies, 166, 
167; of red corpuscles of blood, 232. 
Ivory, structure and composition of, 54. 
lulus, 103. 
J. 
Jaw, motion of, in Quadrupeds, 138; in 
Man, 189; articulation of, 623. 
Jelly-fish, 120. 
Joints, 603; dislocation of, 604. 
K. 
Kangaroo, leaping powders of, 661; skele¬ 
ton of, 661. 
Kidneys, structure of, 357, 358, 368, 369 ; 
purposes of their excretion, 346—348, 
367. 
L. 
Labyrinth of ear, 519. 
Lachrymal apparatus, 540. 
- gland, 540. 
- sac, 540. 
Lacteals, 217, 218. 
Lactic acid, 349, 367. 
Lacunae of bone, 50. 
Lamprey, 317; chorda dorsalis of, 53, 
757. 
Lampyridae, 397—399. 
Land-crabs, 315. 
Lantern-flies, 400. 
Larva, of Cirrhipeds, 749; of Crab, 101; 
of Fchinodermata, 741; of Entozoa, 
742 ; of Insects,97,141,745 ; of Medusae, 
740. 
Larynx, 192; structure of, 680, 681; 
action of, 682—684 ; in Birds, 685. 
Laughing, act of, 341. 
Leaping, 661, 662. 
Leech, 104, 105. 
Leg, bones and muscles of, 647. 
Lepidosiren, 81; blood-discs of, 230; 
respiration of, 324. 
Leverage of bones, 612—615. 
Life, maintained by continual change, 
68 . 
Ligaments, structure of, 29. 
- vocal, 681—684. 
Light, emitted by living animals, 394— 
402; by dead bodies, 402. 
—— propagation of, 526; refraction of 
527—532. 
Lime, amount of, in bones, 49; in teeth, 
54; in egg-shell, 169; in shells of 
Mollusks, 169; in shells of Crustacea, 
170. 
- sources of, in animal bodies, 166— 
170. 
Limulus, 100. 
Lingual nerve, 500. 
Liquids, reception of, 173. 
Liquor sanguinis, 229, 232, 236—241, 385, 
387, 391. 
Lithic acid, 346, 348, 367. 
Liver, structure of, 356, 358, 363; circu¬ 
lation in, 267, 363 ; assimilating action 
of, 224; secreting action of, 364—366; 
formation of sugar by, 366. 
— objects of its excretion, 346, 350. 
Living beings, distinctive characters of, 
1—5. 
Lizard tribe, 84; reparative powers of, 
390. 
Lobster, 100; circulation in, 292. 
Lock-jaw, 473. 
Locomotion, reflex movements of, 471 ; 
organs of, 596. 
Locusts, voracity of, 148; multiplication 
of prevented, 149. 
Long-sighted eyes, 552, 553. 
Luminousness, animal, 394-400 ; uses of, 
401; from decomposition, 402. 
Lungs, rudimentary in Fishes, 324; in 
Reptiles, 325; in Birds, 326, 327; in 
Mammals, 326—333* 
Lymnseus, parasites of, 743. 
Lymph, coagulable, 391. 
Lymphatics, 219, 220. 
M. 
Mactra, 113. 
Madrepore, 127. 
Malapterurus, electric, 419, 422. 
Malpighian bodies of kidney, 369. 
Mammals, general structure of, 77; di¬ 
gestive apparatus in, 197—199; blood- 
discs in, 229; circulation in, 281, 282; 
respiration in, 328—333; heat of, 407; 
nervous system of, 456 ; reproduction 
in, 756, 761. 
Mammary glands, structure of, 376. 
Man, food of, 163; stomach of, 197; 
heart of, 256, 257; arterial system of, 
258; quantity of air required by, 334 
—337 ; reproduction of lost parts in, 
390; repair of injuries in, 391—393; 
heat of, 407; nervous system of, 456— 
462; peculiar characters of soul of, 
721, 722. 
Mantis, actions of, 444. 
Mantle of Mollusca, 107. 
Marmot, hybernation of, 309. 
Marrow of bones, 49. 
- Spinal (see Spinal Cord). 
