Pafnuty Chebyshev was the founder of the St. Petersburg mathematical school (sometimes called the Chebyshev school), who is remembered primarily for his work on the theory of prime numbers and on the approximation of functions. Chebyshev became assistant professor of mathematics at the University

Erg Chech, sandy region of the Sahara in western Algeria and northern Mali. It consists largely of shifting

Chefchaouene, town, northern Morocco, situated in the Rif mountain range. Founded as a holy city in 1471 by the warrior Abū Youma and later moved by Sīdī ʿAlī ibn Rashīd to its present site at the base of Mount El-Chaouene, it became a refuge for Moors expelled from Spain. A site long closed to

Chefchaouene, town, northern Morocco, situated in the Rif mountain range. Founded as a holy city in 1471 by the warrior Abū Youma and later moved by Sīdī ʿAlī ibn Rashīd to its present site at the base of Mount El-Chaouene, it became a refuge for Moors expelled from Spain. A site long closed to

Caspian Sea: Physical features: The largest are Chechen, Tyuleny, Morskoy, Kulaly, Zhiloy, and Ogurchin.

Chechnya: People: …main ethnic group is the Chechens, with minorities of Russians and Ingush. The Chechens and the Ingush are both Muslim and are two of the many Caucasian mountain peoples whose language belongs to the Nakh group. Fiercely independent, the Chechens and other Caucasian tribes mounted a prolonged resistance to Russian…

Caucasian languages: Nakho-Dagestanian languages: The Nakh languages consist of Chechen (890,000 speakers), Ingush (210,000), and Bats (or Tsova-Tushian, about 3,000 speakers). The Chechens and Ingush live in Chechnya and Ingushetiya; the Bats dwell in the village Zemo-Alvani in the Akhmeta district of northeastern Georgia. Both Chechen and Ingush, which are fairly similar to one…

Chechnya, republic in southwestern Russia, situated on the northern flank of the Greater Caucasus range. Chechnya is bordered by Russia proper on the north, Dagestan republic on the east and southeast, the country of Georgia on the southwest, and Ingushetiya republic on the west. In the early 21st

Chechnya, republic in southwestern Russia, situated on the northern flank of the Greater Caucasus range. Chechnya is bordered by Russia proper on the north, Dagestan republic on the east and southeast, the country of Georgia on the southwest, and Ingushetiya republic on the west. In the early 21st

Chechnya, republic in southwestern Russia, situated on the northern flank of the Greater Caucasus range. Chechnya is bordered by Russia proper on the north, Dagestan republic on the east and southeast, the country of Georgia on the southwest, and Ingushetiya republic on the west. In the early 21st

Chechnya, republic in southwestern Russia, situated on the northern flank of the Greater Caucasus range. Chechnya is bordered by Russia proper on the north, Dagestan republic on the east and southeast, the country of Georgia on the southwest, and Ingushetiya republic on the west. In the early 21st

Chechnya, republic in southwestern Russia, situated on the northern flank of the Greater Caucasus range. Chechnya is bordered by Russia proper on the north, Dagestan republic on the east and southeast, the country of Georgia on the southwest, and Ingushetiya republic on the west. In the early 21st

Chechnya, republic in southwestern Russia, situated on the northern flank of the Greater Caucasus range. Chechnya is bordered by Russia proper on the north, Dagestan republic on the east and southeast, the country of Georgia on the southwest, and Ingushetiya republic on the west. In the early 21st

chess: Object of the game: …is said to be in check. The game is won when one king is in check and cannot avoid capture on the next move; this is called checkmate. A game also can end when a player, believing the situation to be hopeless, acknowledges defeat by resigning.

keyboard instrument: Invention: Cristofori provided a check (a pad rising from the back of the key) to catch and hold the falling hammer. At the end of the key he included a separate slip of wood, resembling a harpsichord jack, to carry the dampers that silence the string when the key…

check, bill of exchange drawn on a bank and payable on demand; it has become the chief form of money in the domestic commerce of developed countries. As a written order to pay money, it may be transferred from one person to another by endorsement and delivery or, in certain cases, by delivery

information theory: Error-correcting and error-detecting codes: …of error-detecting code is the parity code, which adds one bit to a block of bits so that the ones in the block always add up to either an odd or even number. For example, an odd parity code might replace the two-bit code words 00, 01, 10, and 11…

check kiting, fraud committed against a banking institution in which access is gained to deposited funds in one account before they can be collected from another account upon which they are drawn. The scheme usually involves several checking accounts at several different banks. In effect, a bank

Beastie Boys: Check Your Head (1992), the Beastie Boys’ first release on Grand Royal, featured a collection of radio-friendly rhymes that layered pop culture references over distorted funk instrumentation. The group’s next album, Ill Communication (1994), had a similar sound, and the music video for the hit…

Hank Ballard: …covered by American Bandstand stalwart Chubby Checker, Ballard’s popularity was confined primarily to a wildly appreciative Black audience that made the Midnighters a hit on the Chitlin Circuit (music venues that attracted African American audiences). “Work with Me Annie”—which prompted a raft of answer songs, most notably “Roll with Me…

partridgeberry, (Mitchella repens), North American plant of the madder family (Rubiaceae), growing in dry woods from southwestern Newfoundland westward to Minnesota and southward to Florida and Texas. Partridgeberry is a good wild-garden plant for shady places and is popular in winter terrariums

Gaultheria: Major species: Wintergreen (G. procumbens), also called checkerberry or teaberry, is a creeping shrub with white bell-shaped flowers, spicy red fruits, and aromatic shiny leaves.

Buddy Guy: …renowned blues clubs in Chicago—the Checkerboard Lounge (1972–85) and (since 1989) Buddy Guy’s Legends. In 2012 he published the autobiography When I Left Home: My Story (written with David Ritz).

checkered beetle, any of the approximately 3,000 species of the insect family Cleridae (order Coleoptera). Checkered beetles occur throughout the world, mainly in the tropics; the common name derives from their markings and coloration (orange, red, yellow, green, and blue). They range between 3 and

elephant shrew: Checkered elephant shrews (Rhynchocyon cirnei) weigh about half a kilogram (1.1 pounds), with a body 23 to 31 cm (9 to 12 inches) long and a slightly shorter tail (18 to 25 cm). The fur is short, stiff, and glossy. Upperparts may be patterned with…

checkers, board game, one of the world’s oldest games. Checkers is played by two persons who oppose each other across a board of 64 light and dark squares, the same as a chessboard. The 24 playing pieces are disk-shaped and of contrasting colours (whatever their colours, they are identified as

Richard Nixon: Vice presidency: …televised address, the so-called “Checkers” speech, in which he acknowledged the existence of the fund but denied that any of it had been used improperly. To demonstrate that he had not enriched himself in office, he listed his family’s financial assets and liabilities in embarrassing detail, noting that his…

conservation: Surviving but threatened small populations: …long-term study of the Bay checkerspot butterfly (Euphydryas editha bayensis) in the grasslands above Stanford University in Palo Alto, California. In 1960 scientists began following the fate of several local populations of the butterfly at a time when grasslands around San Francisco Bay were being lost to housing developments. The…

checkerwork, in architecture, masonry built of two materials, usually stone and flint or stone and brick, so arranged as to make a checkerboard pattern and to give variety in texture and colour. Stone and flint checkerwork is common in the parish churches and smaller houses of East Anglia, England;

ice hockey: Rules and principles of play: Checking—body contact to take an opponent out of play—is permitted anywhere on the ice. In most leagues, including the NHL, players may not make or take a pass that has traveled across the two blue lines; if this occurs, the play is ruled offside. A…

Whether you’ve started your first job or your first well-paying one, now that you’ve begun making money, you need someplace to keep it. A reputable bank backed by the federal government is a solid choice. Next, you’ll have to decide what type of account to open: checking or savings—or maybe both.

chess: Object of the game: …next move; this is called checkmate. A game also can end when a player, believing the situation to be hopeless, acknowledges defeat by resigning.

Juan Manuel Santos: Four months later Santos supervised Operation Checkmate, an intelligence operation that led to the dramatic rescue of 15 hostages held by the FARC, including Colombian politician Ingrid Betancourt. Those two events, along with the death by heart attack of FARC founder Manuel Marulanda Vélez in March 2008, dealt a devastating…

Checkpoint Charlie, the best known official crossing point between East Berlin and West Berlin during the Cold War. It is located on the corner of Friedrichstrasse and Zimmerstrasse and was the designated crossing point for foreign tourists and dignitaries and for members of the Allied armed

checks and balances, principle of government under which separate branches are empowered to prevent actions by other branches and are induced to share power. Checks and balances are applied primarily in constitutional governments. They are of fundamental importance in tripartite governments, such

heraldry: Ordinaries: Checky, or chequy, describes the field or charge divided into squares of two tinctures, like a checkerboard. Billets are oblong figures. If their number exceeds 10 and they are irregularly placed, the field is described as billetté. The pall, or shakefork, is the upper half…

checkers, board game, one of the world’s oldest games. Checkers is played by two persons who oppose each other across a board of 64 light and dark squares, the same as a chessboard. The 24 playing pieces are disk-shaped and of contrasting colours (whatever their colours, they are identified as

Cheddar, village (parish), Sedgemoor district, administrative and historic county of Somerset, southwestern England. It is situated at the mouth of a spectacular limestone gorge in the Mendip Hills. The gorge (now owned by the National Trust) and caverns, in which human remains and artifacts dating

cheddar, hard cow’s-milk cheese named for the district of its origin in the southwestern county of Somerset, England. Cheddar is one of England’s oldest cheeses. The original so-called farmhouse variety remains in limited production in modern times. In the traditional method of cheddar manufacture,

Ayutthaya: The Chedi Si Suriyothai (Queen Suriyothai Memorial) is a monument to a famous queen who died in battle saving her husband, and Phra Mongkhon Bophit sanctuary contains one of the world’s largest seated images of the Buddha. Ayutthaya also has a massive elephant kraal (walled enclosure),…

Chédiak-Higashi syndrome, a rare inherited childhood disease characterized by the inability of white blood cells called phagocytes to destroy invading microorganisms. Persons with Chédiak-Higashi syndrome experience persistent or recurrent infections. Other symptoms associated with the disease

kabaddi, game played between two teams on opposite halves of a field or court. Individual players take turns crossing onto the other team’s side, repeating “kabaddi, kabaddi” (or an alternate chant); points are scored by tagging as many opponents as possible without being caught or taking a breath

Cheduba Island, island in the Bay of Bengal, southwestern Myanmar (Burma). It lies about 30 miles (50 km) west of Taungup on the Arakan Coast and is separated from Ramree Island to the north by the Cheduba Strait. It is 20 miles (32 km) long and 17 miles (27 km) wide and has an area of 202 square

Kenny Rogers: …actor Jason Robards; and comedians Cheech and Chong.

human digestive system: The lips and cheeks: The lips, two fleshy folds that surround the mouth, are composed externally of skin and internally of mucous membrane, or mucosa. The mucosa is rich in mucus-secreting glands, which together with saliva ensure adequate lubrication for the purposes of speech and mastication.

orangutan: Reproduction: …particularly the flat and prominent cheek pads that develop along the sides of the face. The pads enhance the size of the head and are linked with increased levels of testosterone. Adult males also have a throat pouch that serves as a resonating chamber for the “long call,” a sequence…

golden hamster: …furry ears and huge internal cheek pouches that open inside the lips and extend to behind the shoulders. The tail is stubby and can be either white or pink.

Tony Bennett: Cross-generational collaborations: His next significant release was Cheek to Cheek (2014), an album of jazz standards from the Great American Songbook recorded with pop artist Lady Gaga, who had previously appeared on Duets II. That record also won a Grammy for best traditional pop vocal album as did The Silver Lining: The…

Sir John Cheke was an English humanist and supporter of the Protestant Reformation who, as the poet John Milton said, “taught Cambridge and King Edward Greek” and who, with his friend Sir Thomas Smith, discovered the proper pronunciation of ancient Greek. Through his teaching he made the University

zygomatic bone, diamond-shaped bone below and lateral to the orbit, or eye socket, at the widest part of the cheek. It adjoins the frontal bone at the outer edge of the orbit and the sphenoid and maxilla within the orbit. It forms the central part of the zygomatic arch by its attachments to the

Cheektowaga, town (township), Erie county, western New York, U.S. It lies immediately east of Buffalo, on Ellicott, Scajaquada, and Cayuga creeks, near Lake Erie. Originally part of the Holland Land Purchase and the town of Amherst, the site was first settled in 1808 by Appollos Hitchcock, who was

one-horse shay, open two-wheeled vehicle that was the American adaptation of the French chaise. Its chairlike body, seating the passengers on one seat above the axle, was hung by leather braces from a pair of square wooden springs attached to the shafts. Early one-horse shays had fixed standing

Otto Ludwig: …Heiteretei und ihr Widerspiel (1851; The Cheerful Ones and Their Opposites) and Zwischen Himmel und Erde (1855; Between Heaven and Earth). His Shakespeare-Studien (1891) showed him to be a discriminating critic, but his preoccupation with literary theory proved something of a hindrance to his success as a creative writer.

General Mills, Inc.: Familiar products include Wheaties and Cheerios (originally introduced as Cheerioats in 1941; renamed Cheerios four years later) breakfast cereals, Gold Medal flour, Yoplait yogurt, and Bisquick baking mix. During those early years, the company also created the personage of Betty Crocker, who became of one of the most widely known…

General Mills, Inc.: Familiar products include Wheaties and Cheerios (originally introduced as Cheerioats in 1941; renamed Cheerios four years later) breakfast cereals, Gold Medal flour, Yoplait yogurt, and Bisquick baking mix. During those early years, the company also created the personage of Betty Crocker, who became of one of the most widely known…

cheerleading, team activity in which elements of dance and acrobatics are combined with shouted slogans in order to entertain spectators at sporting events and to encourage louder and more enthusiastic cheering. Once exclusively a sideline activity geared toward supporting school sports,

Although thought of as primarily the purview of girls and women today, cheerleading originated with college men. The first organized cheers, according to USA Cheer, were shouted at Ivy League football games in the 1860s. What do you think? Explore the ProCon debate The first cheer erupted at

Cheers, popular American television comedy series that appeared on NBC for 11 seasons (1982–93), ranking in the top 10 of the year-end Nielsen ratings seven times. A mixture of comedy and soap-opera romance, it followed the lives of the staff and patrons of Cheers, a fictional bar in Boston.

Tay Garnett: Films of the 1940s: Cheers for Miss Bishop (1941) was a departure for Garnett; the sentimental piece centres on a schoolteacher (Martha Scott) who devotes herself to her students to make up for the emptiness of her personal life. He turned to World War II for Bataan (1943), a…

cheese, nutritious food consisting primarily of the curd, the semisolid substance formed when milk curdles, or coagulates. Curdling occurs naturally if milk is not used promptly: it sours, forming an acid curd, which releases whey, a watery fluid containing the soluble constituents; and it leaves

historiography: Social and cultural history: …famous examples are Carlo Ginzburg’s The Cheese and the Worms (1980), about the unorthodox cosmological and theological beliefs of a 16th-century Italian miller, and Natalie Zemon Davis’s The Return of Martin Guerre (1983), a scholarly treatment of a famous true story about an imposter who took over the farm (and…

cheese making, process by which milk is transformed into cheese. With the variety of milks, bacterial cultures, enzymes, molds, environmental conditions, and technical processes, literally hundreds of varieties of cheese are made throughout the world. See also list of cheeses. Primitive forms of

casein painting, painting executed with colours ground in a solution of casein, a phosphoprotein of milk precipitated by heating with an acid or by lactic acid in souring. In the form of homemade curd made from soured skim milk, it has been a traditional adhesive and binder for more than eight

skipper, (family Piophilidae), any member of a family of insects in the fly order, Diptera, in which the larvae are known for jumping or skipping when alarmed. The family name means “fat-loving,” and many species breed in fatty materials such as cheese and meat, where they can become serious pests.

casu marzu: …a cheese fly known as Piophila casei are introduced to the cheese. The grubs are allowed to grow inside the cheese paste to encourage an advanced level of fermentation, one that most people would describe as decomposition. The developing grubs produce a spicy cream inside the cheese with a very…

hamburger: …the variation known as the cheeseburger, a slice of cheese is melted over the patty; bacon burgers are laden with strips of bacon. The patty itself is often seasoned or augmented with chopped onions, spices, or bread crumbs before cooking.

cheesecake, a dessert consisting of a thick, creamy filling of cheese, eggs, and sugar over a thinner crust and topped with sweet or sometimes salty items. North American variations of cheesecake, including the type known as New York style, use cream cheese in the filling and a crispy crust made

gauze: Similar fabrics include cheesecloth, made of cotton, originally used as a wrapping for pressed cheese and now used in bookbinding, as reinforcing in paper where high strength is desired, and for dustcloths and the like; bunting, made of cotton or wool, dyed and used for flags and decorations;…

cheese making, process by which milk is transformed into cheese. With the variety of milks, bacterial cultures, enzymes, molds, environmental conditions, and technical processes, literally hundreds of varieties of cheese are made throughout the world. See also list of cheeses. Primitive forms of

cheesesteak, a sandwich made with sliced or chopped steak and melted cheese on a long sandwich roll. While its origins are subject to debate, brothers Pat and Harry Olivieri are often credited with coming up with the idea in South Philadelphia in the 1930s. The sandwich soon gained popularity, and

chimpanzee: Natural history: For example, Cheetah the chimpanzee, an animal actor from the Tarzan movies of the 1930s and ’40s, was reported to have lived approximately 80 years.

cheetah, (Acinonyx jubatus), one of the world’s most-recognizable cats, known especially for its speed. Cheetahs’ sprints have been measured at a maximum of 114 km (71 miles) per hour, and they routinely reach velocities of 80–100 km per hour while pursuing prey. Nearly all the cheetahs remaining

Ezekiel Cheever was a leading schoolmaster in colonial British America. Cheever was the son of a weaver and was educated at Christ’s Hospital in London and in the classics at the University of Cambridge. Cheever came to America in 1637 as a Puritan in search of religious freedom. In 1638 he settled

John Cheever was an American short-story writer and novelist whose work describes, often through fantasy and ironic comedy, the life, manners, and morals of middle-class suburban America. Cheever has been called “the Chekhov of the suburbs” for his ability to capture the drama and sadness of the

cheesesteak: Cheez Whiz—a product that Kraft Foods launched in the early 1950s to imitate the sauce used in Welsh rarebit—is the traditional choice for cheese in Philadelphia, but American cheese and provolone are common as well.

Jon Favreau: Marvel blockbusters and Disney movies: … (2011) and wrote and directed Chef (2014), in which he also starred, alongside Downey and Scarlett Johansson. He directed and served as a voice actor in The Jungle Book (2016)—which took home an Oscar for visual effects—and directed another animated Disney movie, The Lion King (2019).

cooking: The professionalization of cooking: …produced a class of professional chefs, whose main job was cooking for others. Tomb paintings, sculptures, and archaeological remains from more than 5,000 years ago clearly show that ancient Egypt already had many different food-related jobs, including butchery, baking, brewing, and winemaking. Beer brewing may have been initiated much earlier…

Lenny Henry: …star in the situation comedy Chef! (1993–96). He was given the Radio and Television Industry Club Award for BBC Personality of the Year in 1993. He took on a purely dramatic role in the BBC production Hope and Glory (1999–2000), which helped lead to varied small parts in films such…

toque: The typical white baker’s cap, traditionally worn by chefs, is a form of toque.

Chefchaouene, town, northern Morocco, situated in the Rif mountain range. Founded as a holy city in 1471 by the warrior Abū Youma and later moved by Sīdī ʿAlī ibn Rashīd to its present site at the base of Mount El-Chaouene, it became a refuge for Moors expelled from Spain. A site long closed to

Yantai, port city, northeastern Shandong sheng (province), northeast-central China. It is located on the northern coast of the Shandong Peninsula on the Yellow Sea, about 45 miles (70 km) west of Weihai. The city was traditionally known as Zhifu (Chefoo), which was the name of the island that

unequal treaty: The Chefoo Convention, negotiated at Yantai (Chefoo) with Britain in 1876 (although not ratified by Britain until 1885) following the murder of a British explorer by Chinese nationals, resulted in more Chinese concessions and the opening of several new ports. By the Treaty of Beijing (November…

Chegutu, town, central Zimbabwe. Named originally for Henry Hartley, who discovered gold in the vicinity, it was founded in 1891 on the Umfuli River but about 1900 was moved 18 miles (29 km) west. A town-management board was constituted in 1942. On the main road and railway line from Harare

Fuad Chehab was a Lebanese army officer and statesman who served as president of Lebanon in 1958–64. Noted for his honesty and integrity, he brought a measure of stability to the government and to the nation. Chehab received a military education in Syria and France and served with French mandatory

raï: …of female Muslim singers called cheikhas, who rejected the refined, classical poetry of traditional Algerian music. Instead, to the accompaniment of pottery drums and end-blown flutes, they sang about the adversity of urban life in a raw, gritty, sometimes vulgar, and inevitably controversial language that appealed especially to the socially…

Shehu Ahmadu Lobbo was a Fulani Muslim leader in western Africa who established a theocratic state in the Macina region of what is now Mali. Influenced by the teachings of the Islamic reformer Usman dan Fodio, he began a holy war (jihad) in 1818 or possibly as early as 1810. He defeated the forces

Shehu Ahmadu Lobbo was a Fulani Muslim leader in western Africa who established a theocratic state in the Macina region of what is now Mali. Influenced by the teachings of the Islamic reformer Usman dan Fodio, he began a holy war (jihad) in 1818 or possibly as early as 1810. He defeated the forces

lip fern, (genus Cheilanthes), any of about 150 species of ferns of the genus Cheilanthes (family Pteridaceae), found in tropical and temperate regions around the world. Lip ferns are often found in dry or seasonally dry climates, and many can tolerate open rocky areas in full Sun. A few are

Pteridaceae: Cheilanthoid clade: The Cheilanthoid clade includes 20 genera and about 400 species. The major genera include Pellaea (cliff brakes) and Cheilanthes (lip ferns), both of which tend to grow on rock cliffs or ledges. Many of the species in this clade occur in arid or…

flying fish: …enlarged; others, such as the California flying fish (Cheilopogon), are four-winged, with both the pectoral and pelvic (posterior) fins enlarged.

riboflavin: …corners of the mouth (cheilosis); inflammation of the tongue (glossitis); ocular disturbances, such as vascularization of the eyeball with eyestrain and abnormal intolerance of light; and a greasy, scaly inflammation of the skin. Some disagreement persists as to the characteristic syndrome of riboflavin deficiency in humans because it tends…

Cheilostomata, major group of calcified bryozoans (small, colonial, aquatic invertebrate animals) that first appeared during the Jurassic period (200 to 146 million years ago). Individual members of the cheilostome colony are small (usually less than 1 mm [0.04 inch]) and protected by a calcareous

Cheilostomata, major group of calcified bryozoans (small, colonial, aquatic invertebrate animals) that first appeared during the Jurassic period (200 to 146 million years ago). Individual members of the cheilostome colony are small (usually less than 1 mm [0.04 inch]) and protected by a calcareous

perciform: Annotated classification: Family Cheimarrhichthyidae (torrent fish) Small, resembling a cottid or sculpin (family Cottidae); eyes on top of head and close together; 1 species; freshwater streams of New Zealand; young in brackish water. Family Trachinidae (weever fishes) Eocene to present. Body elongated, compressed, deep at head end, tapering to…

tetra: The cardinal tetra (Cheirodon axelrodi) of Brazil is similar but with more red on its body.

lemur: Lemur diversity: …lemurs, make up the family Cheirogaleidae, which in many respects are the most primitive living lemurs. Dwarf lemurs store fat in their tails and are dormant (estivate) during dry periods; they live in monogamous pairs. Mouse lemurs, which eat insects and fruit, are the smallest living primates. Fork-crowned lemurs inhabit…

primate: Classification: Subfamily Cheirogaleinae (dwarf and mouse lemurs) Subfamily Phanerinae (fork-crowned lemurs) Family Lemuridae (“true” lemurs) 5 genera, about 18 species from Madagascar. 1 Holocene fossil genus.

lemur: Lemur diversity: The dwarf lemurs (Cheirogaleus), along with the mouse (Microcebus), Coquerel’s (Mirza), hairy-eared (Allocebus), and fork-crowned (Phaner) lemurs, make up the family Cheirogaleidae, which in many respects are the most primitive living lemurs. Dwarf lemurs store fat in their tails and are dormant (estivate) during dry periods;…

conifer: Annotated classification: †Family Cheirolepidiaceae Mesozoic; scales shed from the cone together with the seeds; large bracts remain attached to the axis in a semblance of a complete cone; distinctive pollen, called Classopollis; foliage resembles that found in the modern Cupressaceae; great variety of lifestyles. Family Pinaceae Largest and…

Cheirolepis, extinct genus of primitive fishes whose fossils are found in European and North American rocks of the Devonian period (408 to 360 million years ago). The genus Cheirolepis is representative of the paleoniscoids, a group of primitive ray-finned fishes, and may represent the common