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CYMO'PHANE. A name given by Haiiy to 

 the chrysoberyl, which see. 



CYMO'S^E. Plants whose inflorescence is 

 disposed in the form of a cyme ; the 

 sixty-third natural order of Linnaeus. 



CYPERA'CE^. A tribe of plants answering 

 to the English sedges ; they are distin- 

 guished from grasses by their stems being 

 solid and generally triangular, instead of 

 being hollow and round. Together with 

 gramineae, they constitute what writers 

 on botanical geography often call glu- 

 maceae. Lyell, Principles of Geology. 



CYPR^E'A. (The cowry.) Animal a slug ; 

 shell univalve, oval, or oblong, involute, 

 smooth, obtuse at each end ; aperture 

 long, narrow, extending the whole length 

 of the shell, and dentated on each side. 

 The mantle sufficiently ample to fold 

 over and envelope the shell, which at 

 a certain age it covers with a layer of 

 another colour. The genus cypraea con- 

 sists of beautifully coloured shells very 

 highly polished. They live in sand at 

 the bottom of the ocean ; the animal is 

 provided with a membrane, which it 

 throws over its shell, which not only 

 preserves the fine polish, but prevents 

 testacese from fixing on it. One hundred 

 and twenty species have been described, 

 one only of which belongs to our seas ; the 

 rest are all tropical. In some parts the 

 shell of this animal is used in the place of 

 money, and passes current. By some it 

 is thought that the cyprsea casts its shell 

 annually. 



CYPRI'FEROUS. Containing shells of the 

 genus Cypris. Entire layers of stone 

 are sometimes composed of the consoli- 

 dated remains of the cypris ; these shells 

 occur in the Hastings sand and sand- 

 stone, in the Sussex marble, and in the 

 Purbeck limestone. 



CY'PRIS. A genus of animals, enclosed 

 within two flat valves, like those of a 

 bivalve shell, inhabiting the waters of 

 lakes and marshes. The cypris throws 

 off its integuments every year. The 

 cypris is a microscopic crustacean, with 

 which certain clay beds of the Wealden 

 are so abundantly charged, that the sur- 

 faces of many laminae into which this 

 clay is easily divided, are often entirely 

 covered with them as with small seeds. 

 The Sussex marble abounds in the shells 

 of the cypris. 



CY'PRINA. An equivalve, inequilateral, 

 sub-orbicular, marine bivalve ; living in 

 sandy mud. Fossil species occur in the 

 tertiary deposits. 



CYTHER^E'A. A marine bivalve ; equivalve, 

 lenticular, oval ; hinge with two cardinal 

 teeth ; one anterior lateral tooth in each 

 valve, which distinguishes this genus from 

 Venus. It is found in depths of the 

 ocean varying to fifty fathoms, in mud 

 and coarse sands. Several species have 

 been found fossil in the tertiary deposits. 

 Cytheraea nitidula is mentioned by Dr. 

 Mantell as occurring in the London clay, 

 and cytheraea convexa in the Plactic clay. 



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DA'OURITE. The siberite of Lermina. A 

 variety of the red schorl of Siberia, called 

 also rubellite. This stone is found in 

 Siberia mixed with white quartz. It is 

 composed of silica 56, alumina 36, with 

 some oxide of manganese, and oxide of 

 iron. 



DASY'PUS. (daavTTovs, from SO.CTVG and 

 TTOVC, Gr.) The armadillo, which see. 



DASYU'RUS. An animal of the marsupial 

 order. The dasyurus is said to be the 

 largest of the carnivorous marsupial ani- 

 mals. The head of a species of dasyurus 

 has been discovered in the Eocene fresh- 

 water limestone of Auvergne. 



DA'THOLITE. ) The Dystom-spath of Mohs. 



DA'TOLITE. > A. sort of spar- stone ; the 

 siliceous borate of lime. According to 

 Menil, it is a combination of silica 38-50, 

 lime 35-60, boracic acid 21-30, water 

 4-60. Its varieties are named Botryolite, 

 Earthy Botryoidal Datolite, and Com- 

 mon Datolite. It has been found prin- 



cipally in Norway, in beds of magnetic 

 iron-ore. 



DEBA'CLE. (Debacle, Fr. Amas de gla^ons 

 qui arrivent avec impetuosite, dans un 

 degel subit, apres qu'une riviere a ete 

 prise long-temps.) A violent torrent or 

 rush of waters, which, overcoming all 

 opposing barriers, carries with it stones, 

 rocks, and other fragments, spreading 

 them in all directions. 



DEBOU'CHE. (debouche, Fr. Uextremite 

 d'un defile, d'un col de montagnes.} The 

 outlet of a narrow pass. 



DEBRI'S. (debris, Fr.) The fragments of 

 rocks ; the ruins of strata ; the rubbish, 

 sand, grit, &c., brought down by tor- 

 rents. 



DECAHE'DRAL. (from <S!ica, and efya, Gr.) 

 Having ten sides. 



DECAHE'DRON. A figure which hath ten 

 sides. 



DECA'NDRIA. (from <fgca, and avrjp, Gr.) 

 A class of plants characterized by having 



