Elimination, climatic, 125. Elimination, by enemies, 126. Elimination, physical, 125. Elimination, through competition, 126. Elms, 216. Embryo, coral, 123. Embryo, instability of, 167. Embryology, 33. Endoderm, 32, 230, 231. Endoplasm, 11. Enteron, 231. Enteropneusta, 233. Environment, 54, 55, 64, 72, 73, 74, 75, 76, 77, 90, 127, 223. Environment, complexity of, 90. Environment and coloration, 126, 127. Environment, unstable, 81. Eohippus, 113. Epencephalon, 199. Epiblast, 32. Epoch, Champlain, 85, 89. Epoch, Eocene, 85. Epoch, Glacial, 85, 89. Epoch, Miocene, 85. Epoch, Pliocene, 85. Epoch, Terrace, 85, 89. Equatorial-plate, 27. Equus, 113. Era, Archæan, 85, 94. Era, Cenozoic, 85. Era, Mesozoic, 85, 110. Era, Palæozoic, 85, 86. Era, Psychozoic, 85, 114. Erythrolamprus, 149. Eucalyptus, 132. Evolution, 108. Evolution, factors of, xiii. Evolution, definition of, xiii. Evolution, psychic, 215. Evolution, social, 215, 225. Evolution, goal of, 226. Falcon, 127. Fantail, 120. Ferns, 100, 102, 244. Fertilization, 29, 42. Fertilization, cross, 162. Fertilization, by humming birds, 161. Fertilization, by insects, 161. Fertilization, by the wind, 161. Fertilization, of flowers, 161. Fertilization, of frog’s eggs, 173. Fertilization, of ovum, 29. Fetichism, 209. Finches, 157. Fishes, 96, 101, 103, 104, 106, 109, 127, 152. Fishes, Age of, 101. Fishes, generalized, 102. Fishes, with Amphibian characters, 101. Flagellum, 19, 29. Flies, 142. Flower, simile of the, 213. Flowers, 105, 144. Flowers, conspicuous, 162. Flowers, female, 161. Flowers, fertilization of, 151. Flowers, male, 160, 161. Flowers, parts of, 160. Flowers, primitive, 161. Food, 58, 61. Foraminifera, 12, 97, 102, 230. Forest of Dean, 169. Fossils, 94. Friar Birds, 148. Frog, development of, 173, 177. Frogs, 135, 136, 137, 138, 146, 238. Fuegians, 187. Fungi, 244. Game-cock, 157, 159. Ganglia, 232, 233. Ganoidei, 101, 103, 105, 106, 107, 109, 110, 237. Garpikes, 105, 237. Gasteropoda, 234. Gastrula, 32. Gastrulation, 32. Gemmæ, 6. Gemmules, 6. Generations, alternations of, 231. Geometer Moth, caterpillar of, 140. Gephyrea, 2, 3. Germ-cells, 45, 54, 57, 161. Germ-cells, continuity of, 67, 70, 71. Germ-cells, insulated, 65, 68, 70. Gibbons, 243, 244. Giraffe, 129, 130. Globigerina, 13, 23. Goat-sucker, 134. Goniatites, 100, 102, 105. Gorillas, 243, 244. Graptolites, 96, 97, 99. Grasses, 245. Gregarina, 230. Gregarinida, 230. Gromia oviformis, 20. Grouse, 159. Gymnophiona, 238. Gymnospermæ, 244. Habitat, 54, 60. Hair, 194. Hapale, 242. Hapalidæ, 241, 242. Hares, 157, 160. Hare, Polar, 127. Hawk, 132. Hearing, 195. Heliconidæ, 145, 147, 148.