722 



INDEX 



Mendel's law, 513-525; experimental 

 evidence on, 516-521 ; experiments 

 with mice, 524. 



Mendel's law and gametic purity, 521. 



Merinos in New Zealand, 223. 



Merism, 33. 



Meristic variation, 33-74 ; cervical fis- 

 tulae and auricular appendages, 44- 

 46; doubling of complicated parts, 

 64-69; due to cell division, 72, 158; 

 homoeosis in, 37 ; in digits, 53-64 ; 

 in eyes, 51; in generative parts, 44; 

 in head, 67, 68; in horns, 52, 53; in 

 legs, 64 ; in mammae, 46, 47 ; in radial 

 series, 70-73 ; in spinal nerves, 42 ; 

 in teeth, 48-51 ; in vertebrae and ribs, 

 39-42; in wings, 51. 



Mice, acclimatization of, to ricin, 309 ; 

 variation in digits of, 58. 



Microsomes, 146. 



Mid-parent, Gallon's, 481 ; Pearson's, 



529- 



Mid-parent deviation, formula for, 531. 



Mid-parent variability, formula for, 531. 



Milk production, variation in, 78-80, 

 92, 93 ; transmitted by males, 360. 



Milk secretion by males, 105, 107. 



Minnesota station, system of planting 

 at, 644. 



Mitosis, as a cause of variation, 155- 

 181 ; details of, 145-152; irregular- 

 ities in, 150-152; pathological, 150, 



IS 1 -' 



Mixed breeding, purity in, 507. 

 Modal coefficient, 422, 423. 

 Mode, the, 421, 422; empirical and 

 theoretical, 422 ; practical value of, 



423- 



Modifications due to external influences, 

 transmission of, 348-417. 



Moisture, effect of, upon development, 

 230-233; effect of, upon spiny 

 growth, 231. 



Monte Carlo and roulette, 365. 



Morgan, observations on acclimatiza- 

 tion to heat, 311 ; on fear in chicks, 



403- 



Morgan horse, 296. 

 Morning-glory, Darwin's experiments 



in inbreeding, 621-624. 

 Morphological variation, 25-29 ; causes 



of, 27 ; in mulberry leaves, 26. 

 Moss roses, a bud variety, 181. 

 Moths, flight of, determinedby light, 250. 

 Movement induced by contact, 234. 

 Mulberry leaves, polymorphism in, 26. 

 Multiplying plots, 650. 

 Multipolar mitosis, 151. 



Mumford, experiments in feeding, 82 ; 

 on pork production, 228. 



Muscle fiber, effect of light upon, 247. 



Mutability of species, 298-305. 



Mutants, 21; origin of, in toadflax, 

 115-118. 



Mutation, biological significance of, 1 36, 

 137; distinguished from ordinary va- 

 riation, no; economic significance 

 of, 135, 136; in chrysanthemum, 1 19- 

 121 ; in primrose, 121-129; ^ aws f> 

 127-129; in toadflax, 115-118; in 

 American native fruits, 129-135; in 

 general, 110-138; relation of, to re- 

 duction and fertilization, 180. 



Mutation and elementary species, 128. 



Mutation and parthenogenesis, 179. 



Mutilations, are they transmitted ? 363- 

 368 ; experiments upon transmission 

 of, 367 ; resemblance of, to natural 

 deformity, 366. 



Nageli, experiments with copper, 268. 

 Narwhal, meristic variation in tusk of, 



70. 



Natural selection always at work, 588. 

 Nectarine, mutant of the peach, 112. 

 Neo-Darwinians, 354. 

 Neo-Lamarckians, 354. 

 Nerves, meristic variation in, 42. 

 Neugebauer, studies in mammas, 47. 

 Nucleus, 145-152. 



Odors, attraction of, 275. 



Oil content of corn, 83-85 ; effect of 

 selection upon, 445, 446 ; progression 

 in breeding for, 496-498. 



Old Granny, example of longevity and 

 extreme fertility, 89, 90. 



Oocyte, 165. 



Oogonia, 165. 



Orientation, 247. 



Origin of characters, 413-415. 



Orthogenesis, 204-208 ; explained by 

 germinal selection, 215. 



Osborn, researches on evolution of the 

 horse, 302. 



Ossification, 99. 



Otocyon, teeth of, 50. 



Overfeeding, evil effects of, 227. 



Ovum, r.6 1, 165; polarity of, 341-343; 

 promorphology of, 341 ; segmenta- 

 tion of, without fertilization, 177- 

 180. 



Oxygen, effect of, upon protoplasm, 265. 



Panmixia, 288. 



Parry, originator of blackberry, 132. 



