snakes

Schobl, Dr., on the ears of mice

Scott, Mr. J., on the self-sterility of orchids
--on the crossing of varieties of verbascum

Sea-water, how far injurious to seeds
--not destructive to land-shells

Sebright, Sir J., on crossed animals

Sedgwick, Prof., on groups of species suddenly appearing

Seedlings destroyed by insects

Seeds, nutriment in
--winged
--means of dissemination
--power of resisting salt-water
--in crops and intestines of birds
--eaten by fish
--in mud
--hooked, on islands

Selection of domestic products
--principle not of recent origin
--unconscious
--natural
--sexual
--objections to term
--natural, has not induced sterility

Sexes, relations of

Sexual characters variable
--selection

Sheep, Merino, their selection
--two sub-breeds, unintentionally produced
--mountain, varieties of

Shells, colours of, littoral
--hinges of
--seldom embedded

Shells, fresh-water, long retain the same forms
--fresh-water, dispersal of
--of Madeira
--land, distribution of
--land, resisting salt water

Shrew-mouse

Silene, infertility of crosses

Silliman, Prof., on blind rat

Sirenia, their affinities

Sitaris, metamorphosis of

Skulls of young mammals

Slave-making instinct

Smith, Col. Hamilton, on striped horses

Smith, Dr., on the Polyzoa

Smith, Mr. Fred., on slave-making ants
--on neuter ants

Snake with tooth for cutting through egg-shell

Somerville, Lord, on selection of sheep

Sorbus, grafts of

Sorex

Spaniel, King Charles' breed

Specialisation of organs

Species, polymorphic
--dominant
--common, variable
--in large genera variable
--groups of, suddenly appearing
--beneath Silurian formations
--successively appearing
--changing simultaneously throughout the world

Spencer, Lord, on increase in size of cattle

Spencer, Mr. Herbert, on the first steps in differentiation
--on the tendency to an equilibrium in all forces

Sphex, parasitic

Spiders, development of

Sports in plants

Sprengel, C.C., on crossing
--on ray-florets

Squalodon

Squirrels, gradations in structure

Staffordshire, heath, changes in

Stag-beetles, fighting

Star fishes, eyes of
--their pedicellariae

Sterility from changed conditions of life
--of hybrids
--laws of
--causes of
--from unfavourable conditions
--not induced throug