FONSECA, BAY or GULF OF, an arm of the Pacific ocean extending into Central America and bounded on the south by Nicaragua, on the east and north-east by Honduras and on the north and north-west by Salvador. It is about 5om. long and 3om. wide, and forms one of the finest natural harbours in the world. Surrounded by volcanic shores, with high sugar-loaf islands be speckling its surface, it suggests to the observer that it is itself the crater of a vast volcano, the surroundings and the island dotted surface of the bay forming a setting of unsurpassed natural beauty. The islands are green and some of them cultivated, and the distant volcanoes include Conchagua (3,800ft.) and Conse guina (3,000f t.) at the entrance of the strait 18m. in width which connects the bay with the Pacific ocean. The islands at Concha quita, Mianguiri and the rocky "Farellones" guard the entrance and help to protect the harbour from the winds and waves of the Pacific. The largest islands in the bay itself are Sacate Grande, 7x4m., and El Tigre, on which the Pacific port of Honduras, Amapala (q.v.) is situated, and which rises to a height of 2,5ooft. in a volcanic cone. The bay is bounded by a shore cut into in numerable inlets, some on the south and east, with volcanic lava shores, but north and north-eastward with sloping plains leading to the mountains, some miles distant. Fonseca bay was discovered in 1522 by Gil Gonzales de Avila and was named by him after his patron, that Archbishop Juan Fonseca who was the persecutor of Columbus. The bay is also known, locally, as the Gulf of Ama pala or the Bay of Conchagua. Under the Bryan-Chamorro treaty of 1916, between the United States and Nicaragua, by the terms of which the United States acquired a perpetual option to the site of an interoceanic canal in Nicaraguan territory, Nicaragua also granted the United States the right to establish a naval base in Nicaraguan territory on Fonseca bay. This provision brought a prompt protest from Salvador, whose government held that such a naval base would constitute a threat against her sovereignty, and that the waters of Fonseca bay were not open sea but were the joint property of Salvador, Honduras and Nicaragua. This protest, inspired, it is now certain, by President Carranza of Mexico as a part of his Latin American activities against the United States during the World War, was carried to the Central American Court of Justice at San Jose, Costa Rica, and was one of the causes which led to the dissolution of the court (see CENTRAL AMERICA). (W. TH0.)