279.
Rengger on flies destroying cattle, 72.
Reproduction, rate of, 63.
Resemblance to parents in mongrels and hybrids, 273.
Reversion, law of inheritance, 14.
---- in pigeons to blue colour, 160.
Rhododendron, sterility of, 251.
Richard, Prof., on Aspicarpa, 417.
Richardson, Sir J., on structure of squirrels, 180.
----, on fishes of the southern hemisphere, 376.
Robinia, grafts of, 262.
{500}
Rodents, blind, 137.
Rudimentary organs, 450.
Rudiments important for classification, 416.

S.

Sagaret on grafts, 262.
Salmons, males fighting, and hooked jaws of, 88.
Salt-water, how far injurious to seeds, 358.
Saurophagus sulphuratus, 183.
Schioedte on blind insects, 138.
Schlegel on snakes, 144.
Sea-water, how far injurious to seeds, 358.
Sebright, Sir J., on crossed animals, 20.
----, on selection of pigeons, 31.
Sedgwick, Prof., on groups of species suddenly appearing, 302.
Seedlings destroyed by insects, 67.
Seeds, nutriment in, 77.
----, winged, 146.
----, power of resisting salt-water, 358.
---- in crops and intestines of birds, 361.
---- eaten by fish, 362, 387.
---- in mud, 386.
----, hooked, on islands, 392.
Selection of domestic products, 29.
----, principle not of recent origin, 33.
----, unconscious, 34.
----, natural, 80.
----, sexual, 87.
----, natural, circumstances favourable to, 102.
Sexes, relations of, 87.
Sexual characters variable, 156.
---- selection, 87.
Sheep, Merino, their selection, 31.
----, two sub-breeds unintentionally produced, 36.
----, mountain, varieties of, 76.
Shells, colours of, 132.
----, littoral, seldom embedded, 288.
----, fresh-water, dispersal of, 385
---- of Madeira, 391.
----, land, distribution of, 397.
Silene, fertility of crosses, 257.
Silliman, Prof., on blind rat, 137.
Skulls of young mammals, 197, 436.
Slave-making instinct, 219.
Smith, Col. Hamilton, on striped horses, 164.
----, Mr. Fred., on slave-making ants, 219.
----, on neuter ants, 239.
----, Mr., of Jordan Hill, on the degradation of coast-rocks, 283.
Snap-dragon, 161.
Somerville, Lord, on selection of sheep, 31.
Sorbus, grafts of, 262.
Spaniel, King Charles's breed, 35.
Species, polymorphic, 46.
----, common, variable, 53.
---- in large genera variable, 54.
----, groups of, suddenly appearing, 302, 307.
---- beneath Silurian formations, 307.
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