BIRGUS, a species of land crab, or crustaceous animal, that can live either on land or under water, having respiratory organs fitted for both modes of existence. The most remarkable is B. latro, that climbs cocoa trees to prey on the fruit, a native of Amboyna. This species is described by Cumming as inhabiting the islands in the Pacific, and we know that B. laticauda is found in Mauritius.