9.

Proteolepas, 148.

Proteus, 139.

Psychology, future progress of, 488.

Quagga, striped, 165.

Quince, grafts of, 261.

Rabbit, disposition of young, 215.

Races, domestic, characters of, 16.

Race-horses:
Arab, 35.
English, 356.

Ramond on plants of Pyrenees, 368.

Ramsay, Professor:
on thickness of the British formations, 284.
on faults, 285.

Ratio of increase, 63.

Rats:
supplanting each other, 76.
acclimatisation of, 141.
blind in cave, 137.

Rattle-snake, 201.

Reason and instinct, 208.

Recapitulation, general, 459.

Reciprocity of crosses, 258.

Record, geological, imperfect, 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, Professor, on Aspicarpa, 417.

Richardson, Sir J.:
on structure of squirrels, 180.
on fishes of the southern hemisphere, 376.

Robinia, grafts of, 262.

Rodents, blind, 137.

Rudimentary organs, 450.

Rudiments important for classification, 416.

Sageret on grafts, 262.

Salmons, males fighting, and hooked jaws of, 88.

Salt-water, how far injurious to seeds, 358.

Saurophagus sulphuratus, 183.

Schiodte 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, Professor, 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, 101,

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