The first forms we shall consider are the Swans (Subfamily Cygninae), which may be characterized by the very long neck, this being as long as or even longer than the body. The number of vertebre entering into the neck are from twenty-three to twenty-five, whereas in the remainder of the Anseres the number is less than twenty. They are large, markedly aquatic birds and their compact bodies and gracefully curved necks make them models of grace and beauty on the water. They number about eight species, disposed in two genera, though upon this latter point authorities differ. The true Swans may be referred for convenience to the genus Cygnus, notwithstanding the fact that it is sometimes divided into two or more. With two exceptions the plumage is pure white throughout, although the head is often stained with rusty. They are mainly natives of the Northern Hemisphere, North America laying claim to two of the finest species.