Fireworks, determinants and ids compared to, 7. "Fits," 6 footnote. Fluctuations of development, 74-75. Formative laws, 17 et seq., 23. Frog, 14. Functional adaptation, 29. Functionless parts, 64. Galton, 36. Germs, 7 et seq., 40 et seq. {86} Germinal selection, 3, 39, 44, 50-53, 59, 63, 66-68. Germinal substance, 55 et seq. Germ-plasm, 9, 44, 57. Haase, Eric, 70. Heliconids, 19, 20, 51 footnote. Henslow, G., 70, 82. Heredity, 4 et seq. Hertwig, O., 54 footnote, 58, 59. Hertz, 5, 6. Histonal selection, 66. Huxley, Thomas, 12. Hypna, 22. Hypotheses, nature of, 5 et seq. Ids, their theoretical character, 7. Imagination, its function in science, 4. "Imperfect" formations, 81. Individual variations, 73 et seq. Inertia, law of organic, 15. Internal forces of evolution, 16, 23, 24, 31, 60, 82-4. Intrabiontic selection, 29. Ishikawa, Professor, 34. Japanese cocks, long-tailed, 34, 44, 78. Kallima, 22, 23, 50. Katagramma, 22. Knowledge, its character, 5. Lamarckian principles, 24, 29 et seq., 31 et seq., 38, 63-64, 68, 84. Leaves, imitated by butterflies, 20 et seq. Locomotive, simile of, 11. Malthusian principle, 65, 67. Markings, butterflies', 16 et seq. Maxwell, 4, 5. Mean of variation, 78-79. Meristic, 18. Mimicry, 19, 51 et seq. Minot, S., 54 footnote. Models, mental, 4 et seq. Molecules, 58. Morgan, Prof. C. Lloyd, 32, 71, 83. Mueller, Fritz, 77-79. Mueller, Hermann, 77. Mussels, 28. Mutations, 31 footnote, 72-76. Naegeli, 4, 11, 24, 60, 82. Neumayr, 72. Newton, 5. Nutrition of determinants, 36, 37, 41, 47. Nymphalidae, 21. Ontogenesis, 8. Orr, Henry B., 69. Osborn, Prof. H. F., 33. Owen, Richard, 11. Paleontology, 31, 73, 75, 76. Palms from Cordilleras, 82. Pangenes, 40. Panmixia, 15, 39, 42, 43, 64. Papilio, 16, 52. Parallecta, 23. Parts, struggling of the, 29, 39, 66-67. Passively functioning parts, 30 et seq., 64. Personal selection, 30, 41, 42, 45, 52, 64-86, 80. Phyletic variation, 31-32 footnote. Phylogenesis, 8. Phylogenetic variations, 31-32, 73. Plasomes, 40. Plus and minus variations, 35, 42, 46, 50, 79-80. Polymorphism, 58. Poulton, 64 footnote. Predestined variation, 4. Pre-established harmony, 25. Preformation, 53. Protective colorings, 14 et seq. Protogonius, 22. Pseudocraea, 52. Qualitative modifications, 46. Quantitative changes, 46-47. Retrogressive development, 38. Round-worms, eggs of, 28. Roux, Wilhelm, 29, 39, 65, 66. Salamis, 22. Scott, Prof. W. B., 31 footnote, 72-74. Segmentation, 10. {87} Selection, natural, 10, 25 et seq., 50, 51, 67, 69-73, 81, 82. Selective value of variations, 60. Semper, 69. Siderone, 22. Snails, 28. Spencer, 14, 28, 29, 40, 53, 56, 80. Struggle for existence, 65. Survival of the fit, 52. Symphaedra, 22.