ation of the, 221
Seebohm, Mr., on _Parus palustris_, 65
on _Emberiza schoeniclus_, 66
on snow in Siberia, 166
on birds of Japan, 396
Seeds, dispersal of, 257
carried by birds, 258
_Senecio australis_, on burnt ground, 513
Sericinus, Palaearctic, 42
Seychelles Archipelago, 429
birds of, 430
reptiles and amphibia of, 430
fresh-water fishes of, 433
land-shells of, 434
Sharp, Dr. D., on beetles of the Sandwich Islands, 319
on peculiar British beetles, 345
Shells, peculiar to Britain, 356
Shetland Isles, peculiar beetle of, 354
Shore deposits, 85, 211
proving the permanence of continents, 97
distance from coast of, 221
_Sialia sialis_, variation of, 58
Siberia, amount of snow and its sudden disappearance in, 166
Silurian boulder-beds, 201
warm Arctic climate, 202
Simiidae, 27
_Sisyrinchium bermudianum_, 272
Skertchley, Mr., on four distinct boulder-clays, 118
on Tertiary deposits in Egypt and Nubia, 191
on climatic stability of present epoch, 233
Slug peculiar to Ireland, 356
Snake peculiar to Round Island, 438
Snakes of the Galapagos, 280
of the Seychelles, 431
Snow and ice, properties of, in relation to climate, 131
Snow, effects of, on climate, 133
Snow, quantity of heat required to melt, 134
often of small amount in high latitudes, 135
never perpetual on lowlands, 136
conditions determining perpetual, 137
maintains cold by reflecting the solar heat, 144
Snow-line, alterations of, causing migration of plants, 516
Sollas, Mr. J. W., on greater intensity of telluric action in past time,
223
South Africa, recent glaciation of, 163
many northern genera of plants in, 524
its supposed connection with Australia, 525
South American plants in New Zealand, 521
South Temperate America, poor in species, 53
climate of, 146
Southern flora, comparative tenderness of, 528
Southern plants, why absent in the Northern Hemisphere, 527
Space, temperature of, 129
Specialisation antagonistic to diffusion of _species_, 505
Species, origin of new, 56
extinction of, 63
rise and decay of, 64
epoch of exceptional stability of, 232
dying out and replacement of, 409
preservation of, in islands, 410
Specific areas, 14; discontinuous, 64
_Spiranthes romanzoviana_, 364
Spitzbergen, Miocene flora of, 184
absence of boulder-beds in, 187
Spruce