AMP 



ANA 



hornblende : for particulars see Horn- 

 blende. 

 AMPHI'BOLITE. Any rock whose basis is 



amphibole or hornblende. 

 A'MPHIGENE. (from a/w0i and ysvo, Gr.) 

 Trapezoidal zeolite, or leucite. This 

 mineral, also called Vesuvian, occurs in 

 imbedded grains or crystals, in the more 

 ancient lavas, and is found mixed with 

 garnet, hornblende, quartz, &c. in the 

 ejected masses of old volcanoes. 

 A'MPHISB^ENA. (from ap,<piQ and (3aiva>, 

 Gr. to walk both ways.) The name given 

 to a genus of serpents, natives of South 

 America. 

 AMPHITRI'TE. A genus of Tubicola, of the 



division Articulata. 



A'MPHORA. A vessel used by the ancients, 

 containing about seven gallons, and thus 

 named from its having two handles. 

 AMPLEXICAU'LENT. (from amplexus and 

 caulis, Lat.) Stem clasping ; embracing 

 the stem. 



AMPLE'XUS. A singularly formed fossil, 

 resembling a coral or madrepore, found 

 in the Dublin limestone : it is described 

 as being nearly cylindrical, divided into 

 chambers by numerous transverse septa, 

 which embrace each other with reflected 

 margins. Sowerly. 



AMPULLA'RIA. (from ampulla, Lat.) A 

 ventricose, subglobose, univalve, with an 

 umbilicated base ; the opening oblong 

 and entire, with no thickening on the left 

 lip. The ampullaria is a river shell of 

 warm climates. Its spire, which always 

 slightly projects, distinguishes this genus 

 from Planorbis ; and there being no 

 thickening on the left lip marks it from 

 Natica. Parkinson. Lamarck places 

 the genus in the family Peristomata 

 order Trachellipoda. There are many 

 species, as the Ampullaria patula, Ampul- 

 laria Sigaretina, &c. 



AMY'GDALOID. (afivyddXr], an almond 

 Gr. amygdala ide, Fr.) A volcanic, or 

 igneous, rock of any composition, con- 

 taining nodules of minerals, scatterec 

 through its base, of a roundish shape 

 cellular volcanic rock, having its cells, 01 

 cavities, occupied with nodules of a dis 

 similar substance. 



AMYGDALOI'DAL. Containing rounded, o 

 kernel-shaped, cavities, filled with mi 

 neral matter of a different character fron 

 the substance generally. 

 AMY'GDALYTE. Almond-stone. 

 A'NAL. Pertaining to the anus ; the fin 



between the vent and the tail. 

 ANA'LCIME. A simple mineral, a variet 

 of zeolite, with which it was formerl 

 confounded ; it is also called eubizite 

 It occurs regularly crystallised ; in an 

 gulo -granular concretions, and massive 

 Specific gravity above 2. When rubbee 



it acquires only a small degree of electri- 

 city, and with difficulty. It is composed 

 of silica 55-07, alumina 20-22, soda 

 14 71, moisture 8'28. It is found, in 

 secondary greenstone rocks, in various 

 parts of Scotland, more especially near 

 Edinburgh. This mineral, also called 

 Cubizite, has been regarded by mineralo- 

 gists as having the cube for its primitive 

 form. Analcime has certainly no cleav- 

 age planes, and it must be regarded at 

 present as forming in this respect as 

 great an anomaly in crystallography as it 

 does in optics by its extraordinary optical 

 phenomena. The most common form of 

 analcime is the solid, called the icositetra- 

 hedron. which is bounded by twenty-four 

 equal and similar trapezia ; and we may 

 regard it as derived from the cube, by 

 cutting off each of its angles by three 

 planes equally inclined to the three faces 

 which contain the solid angle. The Abbe 

 Haiiy first observed in this mineral its 

 property of yielding no electricity by fric- 

 tion, and derived the name of analcime 

 from its want of this property. 

 ANA'LOGOUS. (from ava and Xoyo, Gr. 

 analogue, Fr. analogo, It.) Having ana- 

 logy ; bearing some resemblance. 

 A'NALOGUE. (analogue, Fr. On le fait 

 quelquefois substantif. Ce sont deux 

 analogues.) Any body which corresponds 

 with, or bears great resemblance to, some 

 other body. A recent shell of the same 

 species with a fossil shell, is an Analogue 

 of the latter. Lyell. 



ANANCHY'TES. A helmet -shaped echinus, 

 a fossil of the chalk formation. Bake- 

 welL It approaches near to the form of 

 Spatangus globosus. 



ANASTOMO'SIS. (anastomose, Fr. anasto- 

 mbso, It. from ava and errojua, Gr. ) The 

 running of vessels one into another, or 

 communication by inosculation, as of the 

 arteries into the veins. 

 ANASTOMO'SING. Communicating by anas- 

 tomosis. Applied to vessels, threads or 

 fibres, which by meeting or touching in 

 separate points only, form a sort of net- 

 work, or reticulation. 



ANATA'SE. (avardaiQ, Gr. extension.) 

 Pyramidal titanium ; this mineral is 

 nearly of the same nature as titanite. It 

 is found in Dauphiny, Bavaria, Norway, 

 Switzerland, Spain, and Brazil. It is a 

 pure octahedral oxyde of titanium. Its 

 colours are brown and blue ; structure 

 lamellar; lustre splendent and adaman- 

 tine ; it scratches glass. Specific gravity 

 3-80. 



ANA'TIFA. A cuneiform multi valve, com- 

 posed of several unequal valves, five or 

 more, united together at the extremity of 

 a cartilaginous tube, fixed at its base. 

 The opening without an operculum. 



