Coupling, 110 Crab, extra claws, 74 Crustacean appendages and Serial Homology, 63 Crystals, analogy with, 78 Cyclopian monsters, artificial, 50 Daphnia, changed by environment, 216 Dasypus, polyembryony, 42 Dianthoecia, fixed and variable species, 25 Disease-resistance, 87 Division, power of, a fundamental attribute of living things, 38 Genetics of, 46,50 Dogger Bank, large varieties on, 125 Dogs, hybrid, 241 Dominance, nature of, 95 Dominants, origin of new, 88,90,95 Double monsters, 42 Draba, experiments with, 242 Drosophila, 91 Payne's experiments on, 228 Earthworm, regeneration, 77 Elephant, tusk segmented, 38 Entelechy, 80 Environmental treatment, effects of, 188 et seq. Enzymes and genetic factors, 86 Epilepsy, inheritance of traumatic, 197 Equidae, sterility of hybrid, 241 Erophila, experiments with, 242 species, 249 Exacum, right and left, 57 Euphonia elegantissima, local forms, 120 Eupithecia rectangulata, melanic form, 137