Page:The New International Encyclopædia 1st ed. v. 01.djvu/98

ACAMAPICTLI. and built many stone edifices in his capital of Tenochtitlan.

AC'ANTHA'CEÆ (for derivation see ). An order of dicotyledonous plants embracing about 130 genera and 1600 species. It is found chiefly in the tropics, but also occurs in the south of Europe and the United States. The species are mostly herbs and shrubs, although a few become trees. Plants of this order frequent almost every situation, from marshes to the driest of conditions where plants are able to survive. The leaves are usually thin and entire. The flower parts in fours or fives, stamens often two and styles two. The fruit is a two-celled capsule, upon the explosion of which the seeds are thrown out, aided by peculiar outgrowths from the base of their stalks. The chief genera are Nelsonia, Thunbergia, Strobilanthus, Ruellia, Blepharis, Acanthus, and Justicia.

ACAN'THITE (Gk. άκανθα, akantha, thorn). A silver sulphide that crystallizes in the orthorhombic system. It is iron-black in color, and has a metallic lustre. It occurs with argentite and stephanite at various localities near Freiberg in Saxony, and is named from the peculiar shape of its crystals.

ACAN'THOCEPH'ALA (Gk. ἄκανθα, akantha, thorn, prickle + κεφαλή, kephalē, head). An order of round parasitic worms distinguished by an elongated cylindrical body and a proboscis armed with horny hooks. The order contains three families, viz., Gigantorhynchidæ, Neorhynchidæ, and Echinorhynchidæ. Echinorhynchus gigas is parasitic in the small intestine of swine. Other species are found in ducks and other aquatic birds. The Acanthocephala belong to the class Nemathelminthes, which includes also the Gordiacæ and the Nematodes.

ACANTHOPTERYGII, ak'an-thop-ter-ij'i-i (Gk. ἄκανθα, thorn + πτερυγιον, pterygion, wing; plural. fins). One of the primary divisions of the osseous fishes (Teleostei). It includes many families, among which are largely the most specialized forms of fishes. They are characterized by the possession of spines in the anterior portion of the dorsal fin or in the first dorsal when two are present, and by the usual absence of a pneumatic duct connecting the air-bladder with the œsophagus. The ventral fins are generally thoracic, i.e., fastened to the shoulder. The acanthopterygian fishes include the perch, bass, mackerel, and similar forms.

ACAN'THUS (Lat., from Gk. ἄκανθος, akanthos, brankursine). A name given by the Greeks and Romans to certain plants of the natural order Acanthaceæ, which order contains nearly 134 genera and 1600 species. The plants of the order are herbs or shrubs, rarely trees, chiefly tropical, a few occurring in the Mediter- ranean region, in the United States, and in Australia. The greater number are mere weeds, but the genera Justicia, Aphelandra, and Ruellia contain some of our finest hothouse flowers. In cultivation the Acanthus is only semi-hardy, and needs protection in England and in the United States north of Virginia. Of a dozen varieties of the genus Acanthus two only were anciently common in Mediterranean lands: the wild Acanthus (Acnnthua .ipinosuf:). a short prickly plant with curly leaves: and the cultivated Acanthus [Acanthus mollis), with larger, thick- er, smooth leaves without thorns. See Plate of Acanthus, etc.

In Architecture. The leaves of both of the.se varieties have been copied in architectural deco- ration. Those of Acanthus spinosus only were conventionalized by the Greeks in the Corinthian capital (q.v.), whose characteristic decorations they formed, as well as in other details, such as the acroterion (q.v.) of temples, monuments.

ACANTHUS. or sepulchral columns, etc. In all these Grecian decorations the acanthus leaves are straight and pointed. Etruscan and early Roman works show a form of acanthus with curling, split leaves of quite different aspect. The typical Greek three-lobed acanthus was introduced into Roman architecture before the close of the Repub- lic, but the Roman artists of the time of the Empire were not satisfied with its simple forms; they conventionalized it, adopted in preference the form of the more luxuriant Acanthus mollis, and combined with it the forms of other trees and plants, especially the olive, laurel, and parsley. The result was an extremely rich dec- oration of capitals, friezes, consoles, moldings, and cornices quite unknown to Greek art. The acanthus came into use also in other forms of decoration: in fresco painting, in the ornamen- tation of table feet, of vases, candelabra, furni- ture, goldsmith work, and embroideries. It naturally passed into post-classical ornament, together with the Corinthian capital, which was the favorite form, and we find it in early Chris- tian, Byzantine, and Romanesque art. In cer- tain parts of Italy it preserved its purity until the Renaissance — especially in central and southern Italy — and in southern and central France it was superseded only by Gothic foliage. See.

A CAPELLA, a ka-pel'Ia (Ital., in the church style), Music for voices without accompani- ment, like the early church compositions. The term is also used when the accompaniment is octaves or unison. As an indication of time it is equivalent to alla breve (q.v.).

A CAPRICCIO, a ka-pre'cho (Ital.). At the caprice or pleasure of the performer, regarding both time and expression. A musical term.

ACAPULCO, a'ka-pool'k6 (a corrupted abbreviation of the Latin name [Portus] Acquæ Pulchræ. [Port of] beautiful water). A town on the Pacific coast, in Guerrero, Mexico, 231 miles southwest of the City of Mexico, of which it was formerly the Pacific port, on account of the excellence of its harbor (Map: Mexico, J 9). It was the chief centre of commerce with the Philippine Islands, as well as China and India, until the railroad between the City of Mexico and San Blas robbed it of most of its trade. Population, about 4000.