GYM 



[ 125 ] C Y B, 



CY'MOPHANE. A name given by Haiiy 

 to the chrysoberyl, which see. 



CYMO'S^. Plants whose inflorescence 

 is disposed in the form of a cyme ; 

 the sixty-third natural order of 

 Linnaeus. 



CYPB^A. (The cowry.) Animal a 

 slug; shell univalve, oval, or oblong, 

 involute, smooth, obtuse at each 

 end ; aperture long, narrow, ex- 

 tending 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 consists of beau- 

 tifully 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 testaceae 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. 



CYPKI'FEBOTJS. Containing shells of 

 the genus Cypris. Entire layers of 

 stone are sometimes composed of 

 the consolidated remains of the 

 cypris; these shells occur in the 

 Hastings sand and sandstone, in 

 the Sussex marble, and in the 

 Purbeck limestone. The cypris 

 contains -many species of a genus 

 of crustaceous animalcules formerly 

 called monoculus, from its single 

 eye. 



CY'PEIS. A genus of animals, en- 

 closed within two flat valves, like 

 those of a bivalve shell, inhabiting 

 the waters of lakes and marshes. 

 The cypris throws off its integu- 

 ments every year, which the con- 

 chiferous molluscs do not. This 



circumstance serves to explain the 

 presence in certain places of the 

 countless myriads of the shells of 

 the cypris. The cypris is a micro- 

 scopic crustacean, with which cer- 

 tain clay beds of the Wealden are 

 so abundantly charged, that the 

 surfaces 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. 



The cypris has two antennae ter- 

 minated by a pencil of hairs ; one 

 eye and four legs ; the head con- 

 cealed, and the tail small. It 

 inhabits fresh-water only. Three 

 or four species of cypris have been 

 discovered in the Wealden group, 

 but the cypris taba is the most 

 abundant. 



CY'PETNA. Anequivalve, inequilateral, 

 sub-orbicular, marine bivalve; liv- 

 ing in sandy mud. Fossil species 

 occur in the tertiary deposits. 



CY'PBINE. Cupreous idocrase. See 

 Idocrase and Vesuvian. 



CYPEICA'BDIA. A genus of bivalve 

 shells belong to the family Cardi- 

 acea of Lamarck. Fourteen species 

 are established as occuring in our 

 English deposits, namely, five in 

 the Silurian, three in the Devonian, 

 four in the carboniferous, one in 

 the oolitic, and one in the tertiary 

 system. 



CYBE'NA. A genus of small bivalve 

 fluviatile shells, eight species of 

 which are recorded as found in the 

 tertiary series of rocks. 



CYETO'CEEAS. (from Kvp-ros, carved, 

 and Kepas, a horn, Gr.) A genus of 

 fossil chambered shells established 

 by Goldfuss, the form is bent, 

 arched or partially convoluted, the 

 free end being sometimes elongated 

 and straight, the siphuncle is sub- 

 dorsal or marginal, the aperture 

 nearly orbicular. Cyrtoceras has 

 been found only in the Silurian 

 and Devonian systems of rocks; 13 



