PLANTS, NAMES OF:--AEgilops, 58 _n._; Artichoke (Jerusalem), 79; Ash, weeping, seeds of, 61; Asparagus, 79; Azalea, 13, 59, 97; Cabbage, 109, 135, 204; Calceolaria, 11, 99; Cardoon, 153; Carrot, variation of, 58 _n._; Chrysanthemum, 59; Crinum, 11, 99; Crocus, 96, 99 _n._; Cucubalus, crossing, 232; Dahlia, 21, 59, 63, 69, 74, 110; Foxglove, 82; Gentian, colour of flower, 107 _n._; Geranium, 102; Gladiolus, crossed, ancestry of, 11; Grass, abortive flowers, 233; Heath, sterility, 96; Hyacinth, colours of, 106; --feather-hyacinth, 229; Juniperus, hybridised, 97; Laburnum, peculiar hybrid, 108; Lilac, sterility of, 13, 100; Marigold, style of, 47, 233, 237; Mistletoe, 6, 86, 87, 90 _n._; Nectarines on peach trees, 59; Oxalis, colour of flowers of, 107 _n._; Phaseolus, cultivated form suffers from frost, 109; Pine-apple, 207; Poppy, Mexican, 154; Potato, 69, 74, 110; Rhododendron, 97, 99; Rose, moss, 59; --Scotch, 69; Seakale, 79; Sweet-william, 59; Syringa, persica and chinensis, _see_ Lilac; Teazle, 129; Thuja, hybridised, 97; Tulips, "breaking" of, 58; Turnip, Swedish and common, 205; Vine, peculiar hybrid, 108; Yew, weeping, seeds of, 61 Plasticity, produced by domestication, 1, 63 Plesiosaurus, loss of unity of type in, 41, 217 Pteropods, embryology, 218 Quadrupeds, extinction of large, 147 Quinary System, 202 Race, the word used as equivalent to variety, 94 Races, domestic, classification of, 204 Rarity, 28, 148; and extinction, 28, 149, 210 Recapitulation theory, 42, 219, 230, 239 Record, geological, imperfection of, 26, 140 Regions, geographical, of the world, 29, 152, 174; formerly less distinct as judged by fossils, 177 Resemblance, analogical, 36, 199 Reversion, 3, 64, 69, 74 "Roguing," 65 Rudimentary organs, _see_ Organs Savages, domestic animals of, 67, 68, 96 Selection, human, 3, 63; references to the practice of, in past times, 67; great effect produced by, 3, 91; necessary for the formation of breeds, 64; methodical, effects of, 3, 65; unconscious, 3, 67 Selection, natural, xvi, 7, 87; natural compared to human, 85, 94, 224; of instincts, 19, 120; difficulty of believing, 15, 121, 128 Selection, sexual, two types of, 10, 92 Silk-worms, variation in larval state, 44 _n._, 223 Skull, morphology of, 39, 215 Species, representative, seen in going from N. to S. in a continent, 31 _n._, 156; representative in archipelagoes, 187; wide-ranging, 34 _n._, 146; and varieties, difficulty of distinguishing, 4, 81, 197; sterility of crosses between, supposed to be criterion, 11, 134; gradual appearance and disappearance of, 23, 144; survival of a few among many extinct, 146