sea pen, long, slender colonial organism of the same phylum as the jellyfish. Sea pen colonies are formed by several genera of the order Pennatulacea. The colony consists of a stalk formed by an organism called a primary polyp (see polyp and medusa) and short branches formed by secondary polyps. The stalk, embedded in sand or mud, holds the colony upright. Sea pens differ from the closely related sea pansies and sea feathers by the form of the colony. Sea pens are marine organisms; they are found on Atlantic and Pacific coasts in shallow to moderately deep water. Some reach a length of 2 ft (61 cm) or more. They belong in the phylum Cnidaria, class Anthozoa, order Pennatulacea.

pen-based computer, computer that uses pattern-recognition software to enable it to accept handwriting as a form of input. A stylus, which may contain special electronic circuitry, is used to write on the computer display or on a separate tablet. The earliest devices were limited to recognizing geometric shapes for computer graphics applications and neatly printed alphabetic characters. Pattern recognition has improved to the level where cursive input is now acceptable, especially in personal digital assistants, although such input is not always accurately interpreted by the software. Some software requires the use of a specially modified alphabet to enter data.

pen, pointed implement used in writing or drawing to apply ink or a similar colored fluid to any surface, such as paper. Various kinds of pens have been used since ancient times. Reeds that were slit or frayed at the end were used in antiquity; similar pens, usually made of bamboo, are commonly employed in Asia today. In ancient Greece and Rome much writing was done by scratching the wax coating of a tablet with a stylus, or style—a pointed implement whose blunt end was used to make erasures by smoothing the wax. Quills were introduced early in the Middle Ages and continued to be the main writing device until the mid-19th cent. Plucked from live birds (usually geese), the quills were treated with heat and shaped with a penknife, and they required frequent sharpening. Although metal pens were known to the Romans, and a few had been made in Europe in the 18th cent., a cheap, efficient slip-in nib did not come into common use until Josiah Mason improved existing models and began large-scale production in 1828 at Birmingham, England. The fountain pen, which feeds ink to the pen point from a reservoir, was first successfully produced on a commercial scale in the 1880s. The ball-point pen, introduced c.1944, offered several advantages over the fountain pen. Tipped with a ball bearing that rolls a gelatinous instant-drying ink onto paper, the ball-point pen contains a longer-lasting supply of ink than the fountain pen and is less likely to leak. Although soft-tip pens had been used in ancient times (the Egyptians made soft-tip pens from rushes c.4000 B.C., and the Chinese later used hair-tip pens), it was not until the 1950s that felt-tip markers came into fairly common use in the United States. By the 1960s felt-tip markers had been largely replaced by fiber-tip markers. These are made of such materials as nylon and plastic, are available in a wide variety of colors, and are capable of marking any surface, including plastic and glass.

Yen Li-pen, d. 673, Chinese painter, foremost master of the T'ang dynasty. He became the most celebrated court painter of the 7th cent. and held several high public offices. Although probably none of his original works survives today, records tell us that he was most renowned for his paintings of Buddhist and Taoist themes and also as the painter of historical personages and events. The superb scroll painting Portraits of Thirteen Emperors in the Museum of Fine Arts, Boston, has been attributed to him but may be a copy. It represents the peak of early T'ang art.

Pen-ch'i: see Benxi, China.

Le Pen, Jean-Marie, 1928-, French politician. He graduated from law school, was elected (1956) a parliamentary deputy, and criticized President de Gaulle's Algerian policy. Since 1972 he has led the extremely right-wing National Front. His views against immigration and his support for national defense have aroused strong feelings in France, and he has been convicted and fined for remarks that minimized aspects of the Holocaust and the Nazi occupation of France. Although his party won a number of seats in the National Assembly during the late 1980s, the party was unsuccessful in the 1988 elections. Still, his presidential campaign in 1988 was supported by four million voters. He became a member of the European parliament in 1984. He was stripped of his seat in 2000 as a result of his 1998 conviction for assaulting a rival politician, but it was later restored by the courts pending an appeal, which he lost in 2003. In the first round of the 2002 presidential election Le Pen edged out Premier Lionel Jospin to finish second behind President Jacques Chirac, but in the subsequent runoff Le Pen garnered only 18% of the vote. Le Pen placed fourth in the 2007 presidential election.

Artwork executed wholly or in part with pen and ink, usually on paper. It is fundamentally a linear method of making images. Artists who wish to suggest three-dimensional forms use hatching and cross-hatching or washes of colour laid onto the drawing with a brush. The three most common types of ink are black carbon ink, the finest type being Chinese ink or the modern India ink; brown ink, which was popular with the Old Masters; and iron gall, a chemical ink. The three pen types are quill, reed, and metal. Quill pens were most popular for their flexibility and ability to be sharpened to extreme fineness. Steel became the predominant pen type by the 20th century.

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(born June 20, 1928, La Trinité, France) French nationalist politician. He was elected in 1956 to the National Assembly as its youngest member. Le Pen helped to found the National Front in 1972, becoming the party's leader later that year. The party emphasized the threat to France posed by immigration, particularly of Arabs from France's former North African colonies. The party also opposed European integration, favoured the reintroduction of capital punishment, and sought prohibitions on the building of additional mosques in France. Le Pen ran several times for the presidency; though he captured less than 1percnt of the vote in 1974, in 1988 and 1995 he won some 15percnt. In the presidential election of 2002 Le Pen finished second in the first round of voting, winning 18percnt, though he was easily defeated in the second round by Jacques Chirac. In the 2007 election he failed to reach the second round. Le Pen was widely regarded as the leader of French neofascism, and his National Front party constituted the main right-wing opposition to the country's mainstream conservative parties from the 1970s through the early 21st century.

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(born June 20, 1928, La Trinité, France) French nationalist politician. He was elected in 1956 to the National Assembly as its youngest member. Le Pen helped to found the National Front in 1972, becoming the party's leader later that year. The party emphasized the threat to France posed by immigration, particularly of Arabs from France's former North African colonies. The party also opposed European integration, favoured the reintroduction of capital punishment, and sought prohibitions on the building of additional mosques in France. Le Pen ran several times for the presidency; though he captured less than 1percnt of the vote in 1974, in 1988 and 1995 he won some 15percnt. In the presidential election of 2002 Le Pen finished second in the first round of voting, winning 18percnt, though he was easily defeated in the second round by Jacques Chirac. In the 2007 election he failed to reach the second round. Le Pen was widely regarded as the leader of French neofascism, and his National Front party constituted the main right-wing opposition to the country's mainstream conservative parties from the 1970s through the early 21st century.

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