sea scorpion See sculpin sea slug See nudibranch
sea snake Any of some 50 species (family Hydrophiidae) of venom¬ ous, marine snakes with an oarlike tail and flattened body. Most are found along coasts and in estuaries of Australia and Asia, sometimes basking on the surface in a large group, though the yellow-bellied, or pelagic, sea snake ranges throughout the Pacific. The nostrils, usually on top of the snout, have valvelike closings. The body of several species is much thicker than the head and neck. Most species are 3-4 ft (1—1.2 m) long; Laticauda semifasciata, a Japanese delicacy, may be twice as long. Though generally slow to strike, their venom may be lethal.
sea squirt Any tunicate in the class Ascidiacea; found in seas world¬ wide. Resembling potatoes more than animals, they are permanently fixed to a surface. A forceful contraction of the adult’s vaselike body shoots a jet of seawater when it is disturbed. They filter-feed near the shore on debris from dead plants and animals and, in deeper water, on plankton. Adults, from less than 1 in. to 1 ft (2-30 cm) long, have functional male and female reproductive organs. The free-swimming, tadpolelike larvae hatch from eggs shed by one individual and fertilized by another. Some species live individually, others in colonies.
sea star See starfish sea trout See weakfish
sea urchin Any of about 700 species (class Echinoidea) of echinoderms found worldwide. Sea urchins have a globular body covered with mov¬ able, sometimes poisonous, spines up to 12 in. (30 cm) long. Pores along the internal skeleton accommodate slender, extensible, often sucker- tipped tube feet. Sea urchins live on the seafloor and use their tube feet or spines to move about. The mouth is on the body’s underside; teeth are
extruded to scrape algae and other food from rocks. Some species exca¬ vate hiding places in coral, rock, or even steel. Roe of some species is eaten in certain countries.
Seaborg Yse-.borgV, Glenn (Theodore) (b. April 19,1912, Ish- peming, Mich., U.S.—d. Feb. 25,
1999, Lafayette, Calif.) U.S. nuclear chemist. Seaborg pursued graduate study at the University of California at Berkeley. Working with John Liv- ingood, Emilio Segre, and others, he discovered some 100 isotopes, including many that would prove to be of major importance, such as iodine-131 and technetium-99. How¬ ever, his best-known work involved the isolation and identification of tran¬ suranium elements. In 1941 he and his colleagues discovered plutonium. He went on to discover and isolate the elements americum, curium, berkelium, californium, einsteinium, fermium, mendelevium, and nobelium (atomic numbers 95-102). He joined the Manhattan Project in 1942 and was instru¬ mental in the development of the atomic bomb, although he pleaded, unsuc¬ cessfully, with Pres. Truman not to use the bomb on civilian targets. He shared a 1951 Nobel Prize with Edwin Mattison McMillan (1907-91). Pre¬ diction of new elements’ chemical properties and placement in the periodic table was helped greatly by an important organizing principle enunciated by Seaborg, the actinide concept. He served as head of the Atomic Energy Commission (1961-71). A strong advocate of nuclear disarmament, he led the negotiations that eventuated in the Limited Nuclear Test-Ban Treaty (1963) and later played a leading role in the passage of the Nuclear Non¬ proliferation Treaty. In 1997 his name was given to the new element seaborgium, the first time a living person had been so honoured.
seafloor spreading Theory that oceanic crust forms along subma¬ rine mountain zones, known collectively as the oceanic ridge system, and spreads out laterally away from them. This idea, proposed by U.S. geo¬ physicist Harry H. Hess (1906-1969) in 1960, was pivotal in the devel¬ opment of the theory of plate tectonics.
seafood Edible aquatic animals excluding mammals, but including both freshwater and ocean creatures. Seafood includes bony and cartilaginous FISHeS, CRUSTACEANS, MOLLUSKS, edible JELLYFISH, Sea TURTLES, FROGS, SEA URCHINS, and sea cucumbers. The roe, or eggs, of some species are eaten as caviar. After cereals, seafood may be mankind’s most important food, furnish¬ ing about 15% of the world’s protein intake. Lean fish is equivalent to beef or poultry in its protein yield (18-25% by weight), but it is much lower in calories. Much seafood is eaten uncooked, either raw, dried, smoked, salted, pickled, or fermented. Otherwise it is cooked whole or cut into steaks, filets, or chunks. It is often used in stews or soups.
Seagram Building High-rise office building in New York City (1958). Designed by Ludwig Mies van der Rohe and Philip Johnson, this sleek Park Avenue skyscraper is a pure example of a rectilinear prism sheathed in glass and bronze; it took the International Style to its zenith. Despite its austere and forthright use of the most modem materials, it demonstrates Mies’s exceptional sense of proportion and concern for detail.
Seagram Company Ltd. Formerly the world’s largest producer and marketer of distilled spirits. The company began when Distillers Corp., Ltd., a Montreal distillery owned by Samuel Bronfman, acquired Joseph E. Seagram & Sons in 1928. The new company, Distillers Corp.-Seagrams Ltd., grew rapidly. Originally a maker of blended whiskies, the firm diver¬ sified in the 1950s and ’60s into scotch, bourbon, rum, vodka, gin, and wines, which were sold around the world. In the 1990s it entered the field of music and entertainment, purchasing Universal Studios, media firm MCA, and the Dutch music giant Polygram NV. The company was acquired by French media conglomerate Vivendi in 2000 to form Vivendi Universal. The beverage businesses were later sold to Diageo and Pernod Ricard. See also Seagram Building.
seal Aquatic carnivore with webbed flippers and a streamlined body. Ear¬ less (true, or hair) seals (of the family Phocidae, with 18 species) lack exter¬ nal ears. In water, they propel themselves by side-to-side strokes of the hind limbs and maneuver with their forelimbs. On land, they wriggle on their belly or pull themselves with their forelimbs. Earless species include the
Slate -pencil urchin (Heterocentrotus mammillatus)
DOUGLAS FAULKNER
© 2006 Encyclopaedia Britannica, Inc.
Sealyham terrier ► season I 1711
elephant seal, harbour seal, harp seal, and leopard seal. The eared seals (family Otariidae, with five species of sea lion and nine of fur seal) have external ears and longer flippers. In water, they propel themselves by a rowing motion of their forelimbs; on land, they use all four limbs to move about.
Sealyham terrier Breed of terrier developed in the late 19th century by Capt. John Edwardes for hunting foxes, otters, and badgers on his Welsh estate, Sealyham. A small, short-legged, sturdy dog, it was bred for courage, stamina, and hunting ability. It has a double coat, soft under¬ neath and wiry on top, and may be solid white or white with darker mark¬ ings on its head and drooping ears. It stands about 10 in. (25.5 cm) and weighs about 20 lbs (9 kg).
Seami See Zeami
seamount Large submarine volcanic mountain rising at least 3,000 ft (1,000 m) above the surrounding seafloor; smaller submarine volcanoes are called sea knolls, and flat-topped seamounts are called guyots. Sea¬ mounts are abundant and occur in all major ocean basins. By the late 1970s more than 10,000 seamounts had been reported in the Pacific Ocean basin alone. Virtually every oceanographic expedition discovers new sea¬ mounts, and it is estimated that about 20,000 exist worldwide.