Marsupials, 104.

Mastodon, 97.

Mechanism,
  organic, 14;
  living, 110.

Melanesia, 103.

Mendel, Gregor, 145;
  his law, 146; 147, 148.

Mentality, human, 233.

Metazoa, 254.

Mice, 41, 134;
  field, 139.

Miller, 293.

Mind,
  anatomy of, 202;
  human, differs only in degree, 203; 210, 211;
  embryology of, 214;
  palaeontology of, 217;
  and matter inseparable, 234-237.

Missing links, 77.

Moeritherium, a significant fossil, 97.

Molecule, protein, 22, 23, 24.

Mollusks, 81, 82;
  connecting widely separated ages, 95.

Monkeys, 158.

Morgan, Lloyd, 148.

Morphology, 32.

Moths, 67.

Mueller, 293.

Mutation theory, 146.

Naegeli, 143, 148.

Natural Selection,
  doctrine of, 116, 117, 118;
  the struggle for existence, 124, 125;
  simply trial and error, 131;
  Darwin recognized it as incomplete, 142;
  germ-plasm theory supplements, 145.

Nebula, gaseous, 84.

Nervous systems, 201, 202, 205, 206, 211;
  of worker-bee, 232.

Niagara, 85, 86, 89.

Ontogeny, recapitulates phylogeny, 63.

Orang-outang, 163, 164.

Orders, 32.

Organic, 15;
  systems, 17;
  transformation, analogies of, 43,
  a real and natural process, 55, 56, 76;
  mechanism, alteration of, 55.

Organisms,
  living, 14;
  analysis of, 16; 17, 18, 19, 26, 28, 29, 31, 32;
  characteristic early stages, 55;
  are they adapted by circumstances? 109;
  environment, 111;
  physical heritage of, 113;
  variation of, 119;
  difference, 121;
  universal conflict of, 127;
  change, 130;
  human, 32, 156, 159, 165-171;
  nervous system of, 201;
  psychical characteristics of, 202;
  many-celled, 257.

Organs, 16, 17, 28;
  of human body, 156.

Origin of Species, 136, 149.

Origination of new parts, 109.

Osborn, 148.

Ostrich, 44.

Over production, 122-124, 129.

Owls, horned, of Arizona, 45; 139.

Palaeontology, 32, 34, 73, 74, 76;
  evidence of, not complete, 80, 81;
  table of facts of, 91; 94;
  second division of evidence, 95;
  does it throw light on antiquity of man? 155;
  of mind, 202, 203, 217.

Paludina, 95.

Partulae, 103.

Pearson, Karl, 6, 7, 142, 147;
  heredity of mental qualities, 232.

Penguin, a counterpart of the seal, 44.

Peoples,
  fusion of, 178, 179;
  Mexicans, 178, 181;
  Anglo-Saxon, 179;
  American, 179;
  Indians, 181, 183, 185, 191, 192;
  Patagonian, 180, 192;
  Polynesian, 181, 182, 187;
  Moor, 181;
  Zulu, 181, 183;