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ABRU'PT. (abruptus, Lat.) Broken ; 

 craggy ; steep ; precipitous. In botany, 

 applied to leaves ; when the extremity of 

 the leaf is, as it were, cut off by a trans- 

 verse line. 



ABRTJ'PTLY PIN'NATE. Applied to pinnate 

 leaves, terminated neither with a leaflet 

 nor a tendril. 



ABRUPTNESS. Cragginess ; steepness ; 

 roughness ; precipitousness. 



A'BSONOUS. (absonus, Lat.) Without 

 sound ; ill-sounding ; untunable. 



ABSO'RBENT. (from absorbeo, Lat.) 



1. Any substance possessing the pro- 

 perty of absorbing, or sucking up, fluids, 

 or neutralizing acids ; as the earths, alu- 

 mina, magnesia, &c. 



2. In anatomy, the absorbents are small 

 pellucid tubes, which have been dis- 

 covered in most parts of the body, and 

 are supposed to exist in all. The ab- 

 sorbents begin by numberless open 

 mouths, too minute to be visible to the 

 naked eye ; by the assistance, however, 

 of glasses, the orifices of the lacteals 

 have been seen in the human body, and 

 those of the lymphatics in certain fishes. 



ABSO'RBENT SYSTEM. This consists of 

 the absorbent vessels and conglobate 

 glands ; the former are divided into 

 lymphatics and lacteals, and the thoracic 

 duct, or common trunk, in which they 

 terminate. 



ABSTE'RGENT. (from alstergeo, Lat. ab- 

 stergent, Fr.) Having a cleansing pro- 

 perty ; which not only wash off adhering 

 substances, but possess a power of 

 loosening their cohesion. 



ABSTE'RSIVE. (abstersif,r. astersivo^t.) 

 That has the property of cleansing. 



ABU'TTAL. A head-land ; a bounding of 

 land. 



ACA'LEPHA. (d/caX^j;, Gr.) A class of 

 zoophytes found swimming in the waters 

 of the ocean. The acalepha are divided 

 into orders, namely, the A. simplicia, and 

 A. hydrostatica. The latter, or hydro- 

 statica, are recognized by one or more 

 bladders commonly filled with air, by the 

 aid of which they suspend themselves in 

 their watery element. "In all parts of 

 the ocean," says Professor Grant, "are 

 numerous gelatinous animals, for the most 

 part of a simple and transparent texture, 

 such as the Medusa and Portuguese man- 

 of-war, and numerous other genera. 

 For the most part, those soft gelatinous 

 animals (which are entirely aquatic, and 

 all of them marine) possess a property 

 by which they excite inflammation, when 

 they touch the surface of the skin, like 

 nettles. The word whence they derive 

 their name is a Greek term expressive of 

 nettles. The Acalepha scarcely possess a 

 trace of a nervous system, and are all 



aquatic. They float, for the most part, 

 by the action of their own muscular 

 power, or by air-sacs, or by cilia. They 

 feed upon animals of extreme minute- 

 ness for the most part, on the microscopic 

 crustaceous animals, which abound in 

 the ocean as in other waters." Cuvier 

 places the Acalepha in the third class of 

 the fourth great division of the animal 

 kingdom, or Radiata. Linnaeus placed 

 them in the class Zoophyta, order Gela- 

 tinous zoophytes. 



ACALY'CINOUS. A term applied to plants 

 which want a calyx. 



ACANA'CEOUS. (from UKCIVOG, Gr.) Armed 

 with spines or prickles. 



ACA'NTHA. (dicavQa, Gr.) 



1. In botany, the spine or prickle of a 

 plant. 



2. In zoology, a term for the prickly 

 fins of fishes. 



3. In anatomy, the spinous process of a 

 vertebra. 



ACANTHA'CEOUS. (acanthace, Fr.) Pos- 

 sessing spines or prickles. 



ACANTHOPTERY'GIOUS. (from dicavOa and 

 Trrlpu?, Gr.) A term applied to those 

 fishes whose back fins arc osseous and 

 prickly. The acanthoptcrygii form the 

 first, and by far the most numerous divi- 

 sion of ordinary fishes. 



ACANTHOCE'PHALA. (from aicavQa. and 

 KtQaXij, Gr.) An intestinal worm, be- 

 longing to the order Parenchymata, class 

 Entozoa. 



ACAN'TICONE. A sub-species of prismatoi- 

 dal augite, occurring principally in primi- 

 tive rocks, such as mica-slate, gneiss, &c. 

 Known also as pistacite and epidote. 



A'CARUS. (aKopi, Gr. animal minutissi- 

 mum.) The tick or mite. A genus of 

 insects belonging to the order Aptera. 

 The Acarus has eight legs, two eyes, and 

 two jointed tentacula. The female is ovi- 

 parous, and excessively prolific. Authors 

 estimate the number of species variously ; 

 Linnaeus enumerates 35, and Gmelin 82 

 species. Most of these are very small and 

 almost microscopical. Some are parasi- 

 tical, living in the skin of animals : some 

 of the coleoptera are found covered with 

 them. 



ACAU'LIS. ) (from a, priv. and *arA6c, 



ACAU'LOUS. $ Gr.) A term applied to 

 plants, the flowers of which have no 

 pedicle or stalk. 



ACCENDIBI'LITY. Capability of being kin- 

 dled or ignited. 



ACCI'PITRES. (Lat. from accipiendo.} Ra- 

 pacious birds ; the first order of birds in 

 the Linnsean system of ornithology. The 

 Accipitres are known by their hooked 

 beak and talons ; they feed upon other 

 birds, as well as upon the weaker quadru- 

 peds, and reptiles. They have been di- 



