Machetes pugnax, polymorphism of male, 28 Maize, Blaringhem's experiments on, 229 Maize, cumulative factors in, 116 Malformations, dominants, arising de novo, 89 Manx Cat, heredity, 46 Matthiola, 84,104,113 Melanic varieties, 135 et seq. Memory, analogy with heredity, 190 Meristic variation, 69,83,86 Mirabilis, striped, 57 Models of segmentation, 59,60 "Modes," Coutagne's conception of, 126 Mödling, peculiar race of _Pieris napi_ at, 178 Mole, albino, 27,28 Mule, Linnaeus on, 8 Mutation, Matthioli on, 4 in Mercurialis, 5 in Kales, 5 alleged in bulbs, 5 Theory, 97 periods of, 114 in Bacteria, 214 Mutilation, consequences of, 71 alleged effect of, on offspring, 229 Myxococcus, variation in, 213 Narwhal, asymmetry of tusks, 44 Nemesia strumosa, 91 Neuration, a basis for classification, 13 Nicotiana, sterility of hybrid, 242 Nightjars, varying, 150 Noctuidae, fixity and variability, 25 Noctua, polymorphic and fixed species, 25 Noctua castanea, local forms of, 122 Nomenclature, future of, 94,245 Notonecta, variations of, 130