The forked bone formed by the union of the collarbones in many birds, such as the common Fowl.

An order of birds of which the common Fowl, Turkey, and Pheasant, are well-known examples.

The genus of birds which includes the common Fowl.

A swelling or knot from which nerves are given off as from a centre.

Fishes covered with peculiar enamelled bony scales. Most of them are extinct.

A minute vesicle in the eggs of animals, from which the development of the embryo proceeds.

A period of great cold and of enormous extension of ice upon the surface of the earth. It is believed that glacial periods have occurred repeatedly during the geological history of the earth, but the term is generally applied to the close of the Tertiary epoch, when nearly the whole of Europe was subjected to an arctic climate.