The Divers, _Colymbus_, are distinguished from other Brachypteres by their beak being longer than the head, straight, robust, and nearly cylindrical, slightly compressed on the sides, acute, the upper mandible longer than the lower; their toes, in place of being each furnished with marginal membranes, have the three united by a single membrane; their feet being placed far backward and on the same perpendicular line with the tibia--an arrangement very unfavourable for walking, compelling the birds to take a vertical position, rendering their movements on land both painful and difficult. They are, however, intrepid swimmers, and they dive with such alertness that it requires a quick eye and hand to shoot them. They are inhabitants of northern seas; there they build their nests in some solitary islet or desert promontory, where they lay two eggs, oblong in shape, and more or less shaded of an Isabella white. Fish, particularly the herring, form their principal food; crustaceans and marine vegetables are also eaten by them. Their flesh is tough and leathery, and tastes disagreeable. In the winter they migrate to temperate countries, where they frequent the rivers and lakes, returning to the northern regions when the ice has broken up. There are three species described: the Great Northern Diver, _Colymbus glacialis_; the Arctic Diver; and the Imber Diver. But there is considerable doubt on this subject, the young of _C. glacialis_ of the first and second year being so unlike the parent birds as to have been long supposed a distinct species. THE GREAT NORTHERN DIVER (_Colymbus glacialis_). ENGLISH SYNONYMS.--Northern Diver: Montagu, Selby. Speckled Diver, Ember Goose: Gunner. Ring-necked Loon. LATIN SYNONYMS.--_Colymbus glacialis_: Linn., Adult, Latham, Jenyns, Brien. _Colymbus Immer_: Young, Linn., Latham. FRENCH SYNONYM.--_Plongeon Imbrim_: Temminck. [Illustration: Fig. 80.--Great Northern Divers (_Colymbus glacialis_).]