C R U 



[117] 



CRY 



ing every year, whereas the testa- 

 ceous animals retain theirs as long 

 as they exist. The shells of crus- 

 taceous animals appear to grow all 

 at once, whereas those of testaceous 

 animals are evidently formed by 

 the animal adding gradually to 

 them, either annually or periodi- 

 cally, and they are all composed of 

 layers. 



Fossil crustaceans are by no means 

 rare both in the most recent, as 

 well as in the most ancient strata, 

 but they are rarely found in a state 

 of complete preservation. Crustacea 

 constituted the fourth class of the 

 sub-kingdom Annulosa, and is 

 divided into nine orders, two of 

 which, Trilobita and Eurypterida, 

 are found fossil only. 



CRTTSTA'CEAN. } (crmtacee, Fr. crust- 



CRUST A'CEOUS. ) aceo, It.) Shelly, 

 with joints. The crustaceous ani- 

 mals possess a hard shelly covering 

 divided into parts by joints, while 

 the testaceous have a continued un- 

 interrupted shell. The crustaceous 

 animals are the spiders of the sea. 



CRUST ACITE. The name given by 

 some authors to any fossil crusta- 

 cean. 



CRY'OLITE. (from Kpvo? and \jOos, 

 Gr.) Ice-stone. A rare mineral 

 of a white, brown, or red colour, 

 hitherto found only in Greenland, 

 at the arm of the sea named Arksut, 

 where it occurs in gneiss, associated 

 with iron-pyrites and galena. It 

 consists of fluoric acid 44, soda 32, 

 alumina 24. 



CRYPTOGA'MIA. (from K/JVTTTO?, con- 

 cealed, and rya/to<?, nuptials, Gr.) 

 The 24th class of plants in the 

 LinnaBan artificial system, com- 

 prehending those whose fructifica- 

 tions are concealed, either through 

 minuteness, or within the fruit. 

 According to more modern classifi- 

 cation, the cryptogamia include the 

 thalogens, the anogens, and the 

 acrogens. The carboniferous era 

 abounded in the vascular crypto- 



gamia to a degree unexampled at 

 the present time ; the plants belong 

 to species and genera now extinct, 

 but allied to existing types by 

 common principles of organization. 

 The numerical preponderance of 

 the cryptogamia in the coal is 

 such, that while in the present 

 order of nature they are to the 

 whole number of known plants as 

 one to thirty, at that epoch they 

 were in the proportion of twenty- 

 five to thirty. In the saliferous 

 system, about fifty species have 

 been ascertained, some of which 

 differ from any observed in the 

 coal measures. The class crypto- 

 gamia contains the ferns, mosses, 

 funguses, and sea- weeds : in all of 

 which the parts of the flowers are 

 either little known, or too minute 

 to be evident. 



CRYPTOGA'MIC. } A term applied to 

 CRYPTOGA'MOUS. ) plants not bearing 

 flowers with stamens and ovarium 

 visible; belonging to the class 

 Cryptogamia. Ferns, mosses, fungi, 

 &c., are cryptogamic plants. In 

 the transition rocks, about thirteen 

 species of cryptogamic plants, four 

 of which are alga3, and the re- 

 mainder ferns, comprise all that is 

 known of the vegetable kingdom, 

 anterior to the carboniferous system. 

 CRY'STAL. (from KpvaraXXos, Gr. 

 crystallus, Lat. crystal, Fr. cristallo, 

 It. kry stall, Germ.) A crystal 

 may be defined as a more or less 

 symmetrical, geometrical solid, com- 

 monly bounded by plane surfaces, 

 which, in mineralogical language, 

 are termed planes, or faces. There 

 are many mineral, or inorganic, 

 substances, which assume certain 

 regular forms when becoming solid 

 from a fluid state, or when, after 

 being dissolved in a fluid, this 

 fluid is evaporated. These regular 

 figures are termed crystals. The 

 cause of a body's possessing this 

 power, or property, is unknown, but 

 it is supposed to be connected with 



