Two of the commonest British hydroids belong to this family, Obelia and Clytia.
While stone is the material used in the construction of the majority of great buildings of London, some modern examples (notably the Westminster Roman Catholic cathedral) are of red brick with stone dressings; and brick is in commonest use for general domestic building.
The oldest and commonest method of shunting is that known as " push-and-pull," or in America as " link-and-pin " or " tail " shunting.
The commonest land-snails are those species which constitute the family Helicidae, order Pulmonata, sub-order Stylommatophora.
The oxidizing agent in commonest use is copper oxide, which must be freshly ignited before use on account of its hygroscopic nature.