h natural selection

St. Helena, productions of

St. Hilaire, Aug., on variability of certain plants
--on classification

St. John, Mr., on habits of cats

Sting of bee

Stocks, aboriginal, of domestic animals

Strata, thickness of, in Britain

Stripes on horses

Structure, degrees of utility of

Struggle for existence

Succession, geological
--of types in same areas

Swallow, one species supplanting another

Swaysland, Mr., on earth adhering to the feet of migratory birds

Swifts, nests of

Swim-bladder

Switzerland, lake inhabitants of

System, natural

Tail of giraffe
--of aquatic animals
--prehensile
--rudimentary

Tanais, dimorphic

Tarsi deficient

Tausch, Dr., on umbelliferae

Teeth and hair correlated
--rudimentary, in embryonic calf

Tegetmeier, Mr., on cells of bees

Temminck, on distribution aiding classification

Tendrils, their development

Thompson, Sir W., on the age of the habitable world
--on the consolidation of the crust of the earth

Thouin, on grafts

Thrush, aquatic species of
--mocking, of the Galapagos
--young of, spotted
--nest of

Thuret, M., on crossed fuci

Thwaites, Mr., on acclimatisation

Thylacinus

Tierra del Fuego, dogs of
--plants of

Timber-drift

Time, lapse of
--by itself not causing modification

Titmouse

Toads on islands

Tobacco, crossed varieties of

Tomes, Mr., on the distribution of bats

Transitions in varieties rare

Traquair, Dr., on flat-fish

Trautschold, on intermediate varieties

Trees on islands belong to peculiar orders
--with separated sexes

Trifolium pratense
--incarnatum

Trigonia

Trilobites
--sudden extinction of

Trimen, Mr., on imitating-insects

Trimorphism in plants

Troglodytes

Tuco-tuco, blind

Tumbler pigeons, habits of, hereditary
--young of

Turkey-cock, tuft of hair on breast

Turkey, naked skin on head
--young of, instinctively wild

Turnip and cabbage, analogous variations of

Type, unity of

Types, succession of, in same areas

Typotherium

Udders enlarged by use
--rudimentary

Ulex, young leaves of

Umbelliferae, flowers and seeds of
--outer and inner florets of

Unity of type

Uria lacrymans

Use, effects of
--under domestication
--in a state of nature

Utility, how far important in the constructi