INDEX 



683 



Medium, influences of, 545-553 

 Medulla, of adrenal gland, 130, 131 



of brain, 104, 120-121 

 Megaspore, megasporophyll, 264, 269- 



271, 613; 263, 614, 617, 618 

 Meiosis, 215-219 



Melanesian Negro race, 523-524; 512, 525 

 Men (see Homo; Man; Mankind) 

 Mendel's laws of inheritance, 282, 284- 

 287 



limitations to second law, 292-301 

 Menstrual cycle, 246-247 

 Meristem, 139 

 Merychippus, 468-469; 467 

 Mesoderm, 183, 236-237, 362, 627; 238 

 Mesohippus, 468; 467 

 Mesolithic cultural period, 504; 502 

 Mesozoic era, 394, 414-416, 437, 453 



tetrapod life of, 437-455, 458-462, 470 

 Metabolism, 13; 25, 186 



anaerobic, in muscle, 44 

 Metagenesis, 215, 255, 635 

 Metamere, 237, 362, 628; 234, 238 

 Metamorphosis in insects, 230, 435 

 Metaphase, 19, 219; 18, 217 

 Metazoa, 179, 627, 629 



reproduction in, 213-230 

 Micro- vs. macroevolution, 353 

 Microspore, microsporophyll, 264, 269, 



613; 263, 270, 614, 618 

 Midbrain, 104, 122 

 Migration, 382-383 



and length of day, 555 

 Milankovitch glacial theory, 492; 502 

 Milk secretion, 253, 457 

 Mineral requirements, human, 62-64 



of plants, 147-148 

 Mitochondria, 17; 16 

 Mitosis, 17-22 



Modifications, adaptive, 377; 378, 462 

 Mole and molar concentration, 149n. 

 Moles, analogies in, 360; 361 

 Mollusks, 630, 643-646; 547, 594 



bivalve, 420, 643, 645; 549 

 Mongol race, 520; 519 

 Mongoloids, 505, 511, 514, 518-522, 536, 



537; 485, 502, 512 

 Monkeys, 475-477, 666; 478, 485 

 Monocots, 135n., 598, 621-624 



compared with dicots, 622 



flowers of, 263, 622 



stems of, 153, 158-159 

 Monoecious condition, 268 



(See also Hermaphroditism) 

 Monohybrid cross, 278-283 

 Monosaccharide, 56 

 Mosasaurs, 442-443 

 Moss animals, 640-641; 642 



Mosses, 196-197, 409, 597, 610 



life history of, 257-259 

 Mouth, digestion in, 65, 68 

 Mucin, 66 

 Mucosa, 65; 71 



Multiple-factor hypothesis, 307-310 

 Muscles, 40-48, 65, 84; 20, 42 



antagonistic, 45 



cardiac (heart), 84-85; 20 



cells and fibers, 41; 20, 42 



ciliary, 110; 111 



contraction of, 42-44 



fasciculi of, 41; 42 



fibrils of, 41 



functioning of, 40-48 



involuntary or smooth, 65; 20 



as organs, 22-23, 41 



origin and insertion of, 41 ; 4& 



skeletal, 40-48; 20 



visceral, 65 n 



voluntary or striated, 40-41; 20 

 Mutation rate, 345, 346 

 Mutations, 312-316, 345-346 



causes of, 316, 345-346 



in Drosophila, 314-316 



induced, 345-346 

 Mycelium, 603; 604 

 Mycorrhiza, 202, 603, 605 

 Myelin, 107 



N 



Nails, 51, 471-474, 476 

 Naming, of human races, 514 



of organisms, 373-374 

 Natural selection, 340-344, 347-349, 352- 



353 

 Nature and nurture, 318-322 

 Neanderthal man, 496-498, 505; 485, 



502 

 Neanderthaloids, 494-500, 507, 539; 502 

 Negrito (Pygmy) race, 524; 485, 512, 526 

 Negroids, 503, 505, 511, 514, 523-524; 



502, 512, 525, 526 

 distribution of, 536, 538 

 earliest known, 503 

 Nekton, 419 



Nemathelminthes, 629, 639-640 

 Neolithic cultural era, 533-536; 530, 590 

 Neolithic peoples, 536-538; 590 

 Nephridium, 189-190; 183 

 Nerve cell (see Neuron) 

 Nerve center, 109, 120 

 Nerve cord, 191; 182, 1 83 

 Nerve fiber, 107 

 Nerve impulse, 108-109 

 Nerve net, 191; 181 

 Nerve plexus, 105 



