INDEX 
491 
Rook and crow, 2 
Roses, Mr. Baker on varieties of, 77 
Rubus, Bentliam and Babington on 
species and varieties of, 77 
Rudiments and variations in man, 
446 
Runts, 91 
Rutaceae, variation of structure in, 
79 
S 
St. Helena, destruction of forests by 
goats, 17 
St. Hilaire, M. Aug., variability of 
Gomphia oleaefolia, 79 
Saxicola, divergence of character in 
species of, 108 
recognition marks of, 222 
Scientific opinion before Darwin, 4 
Scolopax, figures of tails of, 225 
Scudder, Mr. S. H., on inedibility of 
Danais archippus, 238 
on fossil insects, 403 
Seebokm, Mr., on swamping effects of 
intercrossing, 143 
Seeds, how dispersed, 306 
how protected, 307 
floating great distances, 361 
dispersal of, by wind, 362 
weight and dimensions of, 364 
importance of wind-carriage of, 
372 
remarkable case of wind-carriage 
of, 373 
Seiurus carolineusis, diagram of varia¬ 
tion, 67 
sp., habits of, 117 
Selection, artificial, 84 
by man, circumstances favour¬ 
able to, 96 
unconscious, 96 
Selective association, isolation by, 
171 
Self-fertilisation of flowers, 321 
Semper, Professor, on casting hairs of 
ieptiles and Crustacea, 137 
(note) 
on direct influence of environ¬ 
ment, 426 
Sesikbe, mimicry by, 240 
Sex colour and nests of birds, 277 
Sex, colours characteristic of, 269 
Sexual colours of insects, probable 
causes of, 273 
of birds, 275 
characters due to natural selec¬ 
tion, 283 
diversity the cause of variation, 
439 
Sexual selection and colour, 274 
by struggles of males, 282 
neutralised by natural selection, 
294-296 
restricted to male struggles, 296 
Shetland Islands, variety of ghost- 
moth in, 270 
Shrews and field-mice, internal varia¬ 
tions of, 69 
Shrikes, recognition marks of, 222 
Similarity of forms of life not due to 
similarity of conditions, 339 
Singing of male birds, use of, 284 
Skull of wolf, diagram of variations 
of, 70 
of Ursus labiatus, diagram of 
variations of, 72 
of Sus cristatus, diagram of 
variations of, 73 
Skunk an illustration of warning 
colour, 233 
Slack, Baron von, on protective 
markings of sloths, 201 
Sloth, protective colour and marking 
of, 201 
Snakes, mimicry of poisonous, 261 
Snipe, tails of two species (figs.), 
225 
Sounds and odours peculiar to male, 
how useful, 284 
produced by peculiar feathers, 
284 
South America, fossil and recent 
mammals of, 393 
Species,'definition of, 1, 2 
origin of, 2, 6 
Lyell on, 4 
Agassiz on, 5 
transmutation of, 6 
Geoffroy St. Hilaire on, 6 
Dean Herbert on, 6 
Professor Grant on, 6 
Von Buch on, 6 
allied, found in distinct areas, 
36 
