On its western side the North Atlantic is connected with the Polar Seas by Davis and Hudson's Straits; the former opening directly into Baifin Bay, the latter into Hud son Bay. The Gulf of St. Lawrence communicates with the Atlantic on the north by Belleisle Strait, on the south by the Gut of Canso, and on the east by a wider channel between Cape North (Cape Breton L) and Cape Ray (Newfoundland). The Mexican Gulf sends out a vast current into the Atlantic through the Straits of Florida, having admitted the inflow through the Channel of Yucatan. The Caribbean Sea com municates with the ocean by a number of channels between the various West Indian Islands—the principal being the Windward Pass, between Cuba and Hayti ; Mona Pass, between San Domingo and Porto Rico, thence to Trinidad by numerous straits and " passes " between the Lesser Antilles.
The Pacific Ocean, unlike the Atlantic, which has a comparatively free communication with the Arctic Sea, is almost entirely landlocked on the north—the extreme eastern part of Asia approaching so closely to the extreme western part of North America that they are separated only by a narrow channel, Behring's Strait. On the contrary, on the south it is perfectly open from Australia to South America, its waters merging broadly into those of the Antarctic Ocean. Direct communication with the Atlantic is possible in the south through the channel between Tierra del Fuego and South Shetland, or by the Straits of Magellan,—the indirect com munication to the north, through Behring's Strait, by the " North-west Passage," has been already noticed, as also the probable artificial communication by the Panama CanaL The Indian Ocean communicates directly with the Pacific by a wide expanse of perfectly open water, stretching from Tasmania to the Antarctic Circle, the imaginary boundary line being the meridian of South-West Cape of Tasmania In directly, communication between these two oceans is possible by the numerous channels and seas of the Malay Archipelago, the principal being by (1) Torres Strait and Arafura Sea, between North Australia and New Guinea; (2) Gilolo Pass and Molucca Pass, Banda Sea, Flores Sea, and the straits between Timor, Ombay, and Flores; (3) Celebes Sea, Strait of Macassar, Java Sea, and Lombok, Sunda and other straits ; (4) Channel of Formosa or Sulu Sea, China Sea, and Straits of Malacca.
Of minor ramifications the principal are the Sea of Okhotsk or Kurile Sea, prevented from uniting broadly with the ocean by a chain of islands stretching from Japan to Kamschatka. The Sea of Japan communicates with the ocean by the Straits of Corea, Bungo Channel, Straits of Sanger and Le Perouse, and by the Gulf of Tartary on the north, uniting its waters with those of the Kurile Sea. The Yellow Sea unites directly with the ocean, while the China Sea communicates with it by the Strait and Channel of Formosa. On the north the Sea of Kamschatka or Behring's S ea is, like the Kurile Sea, separated from the open ocean by a chain of islands, the Aleutian Islands.
The northern portion of the Indian Ocean is land locked on all sides except towards the south, where it opens out broadly into the Antarctic Ocean, from which it is only partially separated by natural limits, such as Enderby Land, Kemp Land, and Clarie Land. The only considerable inland expanses belonging to the Indian Ocean are the Red Sea, con nected with it by the Strait of Bab-el-mandeb and the Gulf of Aden ; the Persian Gulf, connected by the Strait of Ormuz and the Gulf of Oman, the Arabian Sea, and the Bay of BengaL It communicates freely with the South Atlantic, the limiting line south of Cape Agulhas being the meridian of 20° E. long., and with the South Pacific between Tasmania and the Antarctic coasts. Indirect communication with the Pacific is also maintained by numerous straits and channels between the various islands of the Malay Archipelago, the principal being the Straits of Malacca, Sunda, Lombok, and Torres. The direct communication between the Mediterranean and the Red Sea by means of the Suez Canal has been already observed.
Of the Arctic Ocean it will suffice to notice that— with the exception of Behring's Strait, leading into the Pacific, and Davis Strait, East Greenland Channel, and the wider ex panse between Iceland and the Norwegian coasts leading into the Atlantic—it is almost entirely land-locked, the northern limits of the surrounding land following very nearly the parallel of 72° N. lat. The Antarctic Ocean is limited only in a few places by natural boundaries, its waters com municating freely with those of the South Atlantic, Indian, and Pacific Oceans.