BRACHIANO. 396 BRACHT. BRACHIANO, bra-cha'nfi, DuKE OP. The name of a cliaiacter in the tragedy TJlc "White Devil, by John Webster (1612). BRACHIOPODA, brak'i-up'o-da (Gk., arm- footed, from Ppaxtav , hrarliiOii, arm + irovs pous, foot). A L-lass of peculiar animals, having bivalve shells, but differing in important points from the vast majority of recent raollusks with bivalve shells. The mantle or pallium (seeJIoi.- LLSK) in the brachiopods consists of two broad expansions or lobes, covered by the two valves of the shell, which are dorsal and ventral, and in- closing all the other soft parts of the animal; while the chief function of these folds is unques- tionably the formation of the two-shell valves, it is possible that the,v are supplied with blood lacima- or vessels, and may serve as the principal organs of respiration. The circulatory system is not satisfactorily known, but there is probably a vascular system present, with a heart placed above tlie intestine. The nervous system is weak- ly developed, but includes a small brain and a ANATO.MY OP BEACHIOPODA. Structure of Terrbratula. A, The shell viewed from be- hind, showinj; the dorsal valve, and the iiei-forated summit of the ventral valve above it. B, Inner view of the dorsal valve, showiuff the shell.v loop (i) which supports the spiral arms. C, Inner view of the ventral valve, showing the fora- men or apert ure( f)m the beak, through which {d) the muscu- lar stalk of attachment passftx. I), Longitudinal and verti- cal section of the animal, showing the spiral arms (a), the Ktomarli («). and the liver (A). At f is the opening in the beak, with the stalk of attachment (p) passing through it. (.fter Davidson and Owen.) larger infra-a'sophageal ganglion, with two prin- ci|)al trunks running backward from it. There are no special sensory organs of any kind. The organs by which food is procured are also re- markablfr— two long arms arising from the sides of the mouth, and disposed wholly or partly in spiral curves, when not extended to seek or seize prey. These arms are usually furnished with numerous vibratory filaments, which are sup- jiosed not only to aid in the capture of prey, bvit in the maintenance of the current necessary for respiration. The arms are often supported by a special calcareous skeleton, attached to the dorsal valve. Excretion takes place by means of nejihridia, of which one or two pairs are present; these also serve as ducts for the transmission of the sexual products. They open into the mantle- cavity on each side of the mouth. The Brachio- poda are attached to solid bodies either by a footstalk or by one of the valves of the shell. When the stalk is present it emerges either be- tween the valves or through a hole in the pos- terior upward bulging of the larger ventral valve. The Brachio])oda are most notable because of the fact that in the earliest geological times they were a domiijant type ; but since the close of the Paleozoic Age they have been steadily decreasing in number, ilore than 4000 species are known, btit more than 95 per cent, are extinct and exist only as fossils. !Most of the living brachiopods are small, less than an inch across, but some of the extinct forms were six inches across. All living species are marine, and there is every reason to believe the same is true of the extinct species. Existing species are found in water of moderate depth, sometimes down to 2.50 fath- oms. They are generally grouped in two orders: the Articulata, or Testicardines, in which the shell-valves are hinged, and the hiariiculata, or Ecardines, without hinge. Examples of Brachio- pods are shown on the plate: 1, Crania Bordeni; 2, Spirifer cameratus; 3, Bilobites biloba; 4, Tropidoleptus occidens; 5. Pentamerus oblongus; l5. Uncites gryphus ; 7, Derbva Bennetti ; 8, Orthis tricenaria; 9, Athyris spiriferoides; 10, Orthis pectinella (interior) ; ll,lvhipidomella Jlichelini; 12, Stropheodouta deuiissa; 13, Cauiarota?chia eongregata. BRACHIOSPONGIA, brak'i-6-sp6n'ji-a (Gk. (3pax'w, hruchion, arm + (r7ro77ia, spongia, sponge). A curious genus of hexaetinellid sponges. This sponge has a form somewhat like that of the earth-star ])U(l'hall {(Irosler) , and consists of a central dcjircsscd hollow portion from which radiate several cylindrical arms that are bent downward toward the ocean-floor iipon which the sponge lived. Into these arms extend prolongations of the central gastral cavity. The aperture of the gastral cavity is large and often elevated above the plane of the arms. These sponges have been found chiefly in the Ordovi- cian rocks of Franklin County, Ky., where they occur as hard, stony masses. The stony nature is due in part to a compact skeleton of delicate siliceous spictiles that gave rigiditj- to the sponge mass when alive, and also to mineral matter that has been deposited in the cavities of the skele- ton during the progress of petrifaction. Consult Beecher, "BrachiospongidiC," Alcinoirs of the Pea- hoiltj Museum of Yale Vnim-rxil;/, vol. ii., pt. i. (New Haven, 1889). See also general article on .Sro-(n;. BRACHISTOCHRONE, bni-kls'tA-kron (Gk. ppdxicTos, brachistos, shortest + XP^'"^-, chronos, time), or the curve of quickest descent. See Cycloid. BRACHT, braKt, Felix Prosper Eugen ( 1842 — ). A German painter, born at Morges (Lake Geneva, Switzerland). He was a pujiil of Friseh and Seeger in Darmstadt, of the Karlsriihe Art School, and of Gude in Diisscldorf. In 1882 he became a professor in the Berlin Academy. He has painted chielly landscapes, drawing his motives from the Liineburg Heath, the island of Biigcn, Syria, and Palestine. In 188!) he received the gold medal of the Berlin Exhibition. lie is extremely skillful in interi)reting by a few sig- nificant strokes the local moods of various di- verse regions, . iong his w<uks are "Giant's Grave on (he Liineburg Heath," "Stormy Even- ing on Rilgen," "Sheidicrd on the Heath," ".Moon-
