CARP, the typical fish of a large family (Cyprimdae) of Ostariophysi, as they have been called by M. Sagemehl, in which the air-bladder is connected with the ear by a chain of small bones (so-called Weberian ossicles). The mouth is usually more or less protractile and always toothless; the lower pharyngeal bones, which are large and falciform, subparallel to the branchial arches, are provided with teeth, often large and highly specialized, in one, two or three series (pharyngeal teeth), usually working against a horny plate attached to a vertical process of the basioccipital bone produced under the anterior vertebrae, mastication being performed in the gullet. These teeth, adapted to various requirements, vary according to the genus, being conical, hooked, spoon-shaped, molariform, etc.
The species are extremely numerous, about 1400 being known, nearly entirely confined to fresh water, and feeding on vegetable substances or small animals. They are dispersed over the whole world with the exception of South America, Madagascar, Papuasia, and Australasia. Remains of several of the existing genera have been found in Oligocene and later beds of Europe, Sumatra and North America. One member of the Cyprinidae is at present known to be viviparous, but no observations have as yet been made on its habits. It is a small barbel discovered in Natal by Max Weber, and described by him under the name Barbus viviparus.
The Cyprinidae  are divided into four subfamilies: - Catostominae (mostly from North America, with a few species from China and eastern Siberia), in which the maxillary bones take a share in the border of the mouth, and the pharyngeal teeth are very numerous and form a single, comb-like series; Cyprininae, the great bulk of the family, more or less conforming to the type of the carp; Cobitinae, or loaches (Europe, Asia, Abyssinia), which are dealt with in a separate article (see Loach); and the Homalopterinae (China and south-eastern Asia), mountain forms allied to the loaches, with a quite rudimentary air-bladder.
For descriptions of other Cyprinids than the carp, see Goldfish, Barbel, Gudgeon, Rudd, Roach, Chub, Dace, Minnow, Tench, Bream, Bleak, Bitterling, Mahseer.
The Common Carp.
The carp itself, Cyprinus carpio, has a very wide distribution, having spread, through the agency of man, over nearly the whole of Europe and a part of North America, where it lives in lakes, ponds, canals, and slow-running rivers with plenty of vegetation. The carp appears to be a native of temperate Asia and perhaps also of south-eastern Europe, and to have been introduced into other parts in the 12th and 13th century; it was first mentioned in England in 1496. The acclimatization of the carp in America has been a great success, especially in the northern waters, where, the growth continuing throughout the entire year, the fish soon attains a remarkable size. The presence of carp in Indo-China and the Malay Archipelago is probably also to be ascribed to human agency. In the British Isles the carp seldom reaches a length of 2 ft., and a weight of 20 lb, whilst examples of that size are quite frequent on the continent, and others measuring 4 ft. and weighing 60 lb or more are on record. The fish is characterized by its large scales (34 to 40 in the lateral line), its long dorsal fin, the first ray of which is stiff and serrated, and the presence of two small barbels on each side of the mouth. But it varies much in form and scaling, and some most aberrant varieties have been fixed by artificial selection, the principal being the king-carp or mirror-carp, in which the scales are enlarged and reduced in number, forming more or less regular longitudinal series on the sides, and the leather-carp, in which the scales have all but disappeared, the fish being covered with a thick, leathery skin. Deformed examples are not of rare occurrence.
Although partly feeding on worms and other small forms of animal life, the carp is principally a vegetarian, and the great development of its pharyngeal apparatus renders it particularly adapted to a graminivorous régime. The longevity of the fish has probably been much exaggerated, and the statements of carp of 200 years living in the ponds of Pont-Chartrain and other places in France and elsewhere do not rest on satisfactory evidence.
A close ally of the carp is the Crucian carp, Cyprinus carassius, chiefly distinguished by the absence of barbels. It inhabits Europe and northern and temperate Asia, and is doubtfully indigenous to Great Britain. It is a small fish, rarely exceeding a length of 8 or 9 in. It has many varieties. One of these, remarkable for its very short, thick head and deep body, is the so-called Prussian carp, C. gibelio, often imported into English ponds, whilst the best known is the goldfish (q.v.), C. auralus, first produced in China.
(G. A. B.)
 The name of the fishes of the genus Cyprinus is derived from the island of Cyprus, the ancient sanctuary of Venus; this name is supposed to have arisen from observations of the fecundity and vivacity of carp during the spawning period.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)