Of forms with much stouter bills than _Sterna_, _Seena aurantia_, of India, the Burmese countries and Yunnan, has the bill and feet orange; _Hydroprocne caspia_, the Caspian Tern–largest of the Sub-family–has a very short tail, red bill, and black feet. The latter occupies most of the world, except tropical South America and the Pacific Islands, visiting Britain, and breeding as near to it as Sylt. _Gelochelidon anglica_, the Gull-billed Tern, with a long metatarsus, reddish-black beak and feet, occurs in Britain and is found through the temperate and tropical parts of the Old and New Worlds, but not in South Africa, and rarely in Western America. _Phaëthusa magnirostris_, of the warmer portions of North America, has a short tail, yellow bill, and olive-yellow feet. The genus _Hydrochelidon_, or Marsh Tern, is distinguished by a short tail, a comparatively small bill, and feet with much indented webs. The note is shrill; the food consists of aquatic insects, varied by frogs, newts, and small fish: the nests, placed in close proximity on swamps or pools, are formed of water plants and are sometimes mere floating masses of them; the three eggs are often very dark olive or brown. _H. nigra_, the Black Tern or Blue Darr, ranges from Europe south of lat. 60° N. and the Mediterranean to Turkestan, wintering as far as Loango and Abyssinia. It bred in the east of England up to 1858, since which date a nest is quite exceptional, while its two congeners are only chance visitors. The colour is lead-grey, with blacker head, black bill and reddish-brown feet. The darker race _H. surinamensis_ inhabits temperate America from Alaska and Canada southwards, migrating to Chili and Brazil. _H. leucoptera_, the White-winged Black Tern, is found in Central and Southern Europe, temperate Asia and North Africa; reaching accidentally to America, and in winter from Cape Colony to Australia and New Zealand. It is chiefly black, with white carpal region, rump, tail, and vent, the bill and feet being red. _H. hybrida_, the Whiskered Tern, has a similar range, but breeds also from India to Australia. The main colour is slate-grey, the head and nape being black, the bill {315}and feet red, and a white streak marking each cheek. In the winter and immature plumage the under parts are entirely, and the head partially white, throughout the genus. Of fossil Laridae _Halcyornis_ occurs in the Lower Eocene of England, _Aegialornis_[203] in the Upper Eocene of France; while the Lower Miocene of the latter country, the Middle Miocene of Germany, and the Pliocene of Oregon furnish _Larus_.