Index 883 



Monozygotic, 844 



Morphogenesis, 241, 242, 442-456, 576, 

 580 



Morula, 444, 451,* 452, 710,* 711 

 Mosquito, 364,* 366, 569* {see also 

 Insects) 



mouth parts, 411,* 569* 

 Moss, club, 110, 112, 134, 135, 135,* 

 191-194, 256 



Irish, 119,* 249 



peat (bog), 133, 134,* 187 



Polytrichum, 133, 133,* 186 



Sphagnum, 133, 134,* 187 



Mother cell, 202, 203 

 Mother-of-pearl, 541 

 Moths, 319, 549, 567,* 568* {see also 

 Insects) 



Motor root, 844 



Mouh, 393 



Mouth, 278,* 286,* 288,* 290,* 293- 

 297, 296,* 299,* 300,* 304, 

 305,* 309, 310,* 312*-316,* 

 321,* 326,* 327, 332,* 350,* 

 358,* 368-374 

 parts, 394-404, 409, 410,* 411,* 414- 

 418 



Mucus, 293, 368, 387* 

 Mud puppy, 335* 

 Muller, Johannes, 803 

 Mulatto, 692 



Multiceps, 537, 538,* 661, 788 

 Musci (moss), 109, 132, 133,* 134,* 

 186 



Muscle, 312,* 425, 426,* 467-472, 

 467,* 468,* 497,* 498-499, 

 505 {see also Tissues, muscu- 

 lar) 

 spindle, 505 



Mushroom (Psalliota [Agaricus]), 128,* 



129, 177-179, l78* 

 Mussel (Anodonta, Lampsillis), 311 

 Mutation, 93, 624, 695, 722, 724 {see 



also Heredity) 

 Mycelium, 124,* 125, 126, 127,* 173, 



178* 



Mycorrhiza, 664 

 Myelin, 54 

 Myocardium, 478 

 Myofibril, 53 

 Myogenic theory, 844 

 Myoneme, 279,* 359 

 Myotome, 328* 

 Myriapoda, 318 

 Myxamoeba, 124, 167, 172 

 Myxedema, 511 



Myxomycophyta (slime mold), 109, 

 122-124, 123,* 167, 172-173 

 Myxophyta, 114, 151 



N 

 Nacre, 541 

 Naiad, 411, 412* 

 Nails, 459, 461 

 Nares, 332,* 427,* 434, 439 

 Nasal {see Nostril) 

 Natural selection, 844 

 Nautilus, 311 

 Nearctic region, 597 

 Necator (hookworm), 295, 296,* 539 

 Nectar and nectary, 208, 223,* 404 

 547, 785 



Necturus, 335* 



Needham, 732 



Negro, inheritance, 692 



Nemalion, 119, 154, 163,* 164 



Nemathelminthes, 295-298, 374-382, 



538, 539 

 Nematocyst, 286, 286,* 287*-291* 

 Nematoda, 295, 298 

 Neoplasm, 583, 845 

 Neoteny, 845 

 Neotropical region, 598 

 Nephridia, 318, 375,* 385,* 386, 387,* 



390 



Nephridiopore, 390 

 Nephrostome, 390, 435 

 Nereis (sandworm), 307,* 308 

 Nerve cells, 54, 55* 



cord, 54, 55,* 308,* 314, 321,* 322,* 

 325-343, 327,* 329, 370,* 

 371,* 378,* 387,* 391, 397 

 cranial, 54, 438, 496,* 502-504 

 ending, 437 

 fiber, 459, 498* 

 impulse, 498-502, 498* 

 motor, 844 



olfactory {see Olfactory) 

 optic, 497,* 498,* 505 

 peripheral, 54, 435 

 radial, 302* 



ring, 296,* 308,* 376, 381 

 sensory, 502, 503 

 ^ spinal, 54, 55,* 502 

 Nervous equipment {see also specific 

 organisms) 

 system {see also specific organisms) 

 autonomic, 502, 506 

 central, 54, 435, 502 

 enteric, 502, 506 

 parasympathetic, 502, 506 

 peripheral, 54, 435 

 sympathetic, 54, 397, 435, 437, 

 502, 506 

 Neural arch, 424 



groove, 445,* 446, 449,* 455 

 plate, 449* 

 spine, 424 

 tube, 447, 449* 



