Acantha′ceæ, or Acanthads, a nat. ord. of dicotyledonous herbaceous plants or shrubs, with opposite leaves and monopetalous corolla, mostly tropical; species about 1400. See Acanthus.
Acanthop′teri, Acanthopterygii (Gr. akantha, a spine, pterygion, a fin), a group of fishes, distinguished by the fact that at least the first rays in each fin exist in the form of stiff spines; it includes the perch, mullet, mackerel, gurnard, wrasse, &c.
Acanth′us, a genus of herbaceous plants or shrubs, order Acanthaceæ, mostly tropical, two species of which, A. mollis and A. spinōsus (the bear's-breech or brankursine), are characterized by large white flowers and deeply-indented shining leaves. They are favourite ornamental plants in British gardens.—In architecture the name is given to a kind of foliage decoration said to have been suggested by this plant, and much employed in Greek, Roman, and later styles.
Acapul′co, a seaport of Mexico, on the Pacific, with a capacious, well-sheltered harbour; a coaling station for steamers, but with no great trade. Pop. 5950.
Acar′ida, a division of the Arachnida, including the mites, ticks, and water-mites. See Mite.
Acarna′nia, the most westerly portion of Northern Greece, together with Ætolia now forming a nomarchy with a pop. of 188,597. The Acarnanians of ancient times were behind the other Greeks in civilization, living by robbery and piracy.
Ac′arus, the genus to which the mite belongs.
Acca′dians (Akkad), the primitive inhabitants of Northern Babylonia (Akkad), who had descended from the mountainous region of Elam on the east, and to whom the Assyrians ascribed the origin of Chaldean civilization and writing. This race is believed to have belonged to the Turanian family, or to have been at any rate non-Semitic. What is known of them has been learned from the cuneiform inscriptions. See Babylonia and Summerians.