CRY 



CRY 



those of the oyster, scallop, cockle. See 

 CANCKB. 



CRUSTS, in chemistry. By crusts we 

 understand those bony coverings of which 

 the whole external surface of crabs, lob- 

 sters, and other similar sea animals, are 

 composed. Mr. Hatchett found them 

 composed of three ingredients: 1. A car- 

 tilaginous substance possessing the pro- 

 perties of coagulated albumen. 2. Carbo- 

 nate of lime. 3. Phosphate of lime. By 

 the presence of this last substance they 

 are essentially distinguished from shells, 

 and by the great excess of carbonate of 

 lime above the phosphate they are equally 

 distinguishedfrom bones. Thus the crusts 

 lie intermediate between bones and shells, 

 partaking of the properties and constitu- 

 tion of each. The shells of the eggs of 

 fowls must be referred likewise to,, the 

 class of crusts, since they contain both 

 phosphate and carbonate of lime. The 

 animal cement in them, however, is much 

 smaller in quantity. From experiments 

 it is extremely probable that the shells 

 of snails are composed likewise of the 

 same ingredients, phosphate of lime hav- 

 ing been detected in them by these che- 

 mists. 



Mr. Hatchett examined the crusts of 

 crabs, lobsters, prawns, and crayfish. 

 When immersed in diluted nitric acids 

 these crusts effervesced a little, and gra- 

 dually assumed the form of a yellowish- 

 white soft elastic cartilage, retaining the 

 form of the crust. The solution yielded 

 a precipitate to acetate of lead, and am- 

 monia threw down phosphate of lime. 

 Carbonate of ammonia threw down a 

 much more copious precipitate of carbo- 

 nate of lime. . 



On examining the crust which covers 

 different species of echini, Mr. Hatchett 

 found it to correspond with the other 

 crusts in its composition. Some species 

 of starfish yieldeth phosphate of lime, 

 others none : hence the covering of that 

 genus of animals seems to be intermedi- 

 ate between shell and crust. 



CRUZITA, in botany, a genus of the 

 Tetrandria Digynia class and order. Atri- 

 plices, Jussieu. Essential character : in- 

 ner calyx four- leaved; outer three-leaved; 

 corolla none ; seeds one. One species, 

 viz. C. 1 lisp union, a native of South Ame- 

 rica. 



CRYPS1S, in botany, a genus of the 

 Diandria Digynia class and order. Natu- 

 ral order of Grasses. Essential charac- 

 ter : calyx glume two valved, one-flow- 

 ered ; corolla glume two-valved, awnless. 

 One species, viz. C. aculeate, prickly 



crypsis. This grass is a native of the Soutfi 

 of Europe and Siberia ; it is common also 

 in Barbary. 



CRYPTOCEPHALUS, in natural his- 

 tory, a genus of insects of the Coleoptera 

 order. Characterised by filiform antennae ; 

 four feelers ; thorax margined ; shells im- 

 marginate ; body somewhat cylindrical. 

 This is a very extensive genus, nearly 

 300 species have been enumerated. They 

 are divided into two sections. A. feelers 

 equal, filiform ; B. feelers unequal; fore- 

 ones hatchet-shaped. A. is subdivided 

 into a, jaw, one-toothed ; 1. lip entire, 

 cylindrical ; 2. lip entire, palpigerous at 

 the tip ; 3. lip bifid ; body oblong ; b, jaw 

 bifid ; body oblong. In B. there are some 

 of the genera that have horny lips; others 

 with lip membranaceous, entire ; and 

 some whose lip is membranaceous, widely 

 emarginate. 



CRYPTOGAMIA, in botany, the name 

 of the twenty-fourth class of Linnseus's 

 Sexual Method, consisting of plants, in 

 which the parts of fructification are, ei- 

 ther from their minuteness or their situa- 

 tion, entirely concealed or imperfectly 

 visible. 



CRYPTOSTOMUM, in botany, a genus 

 of the Pentandria Monogynia class and 

 order. Essential character : calyx ven- 

 tricose, five-cleft ; tube of the corolla 

 inserted into the throat of the calyx, 

 border five-cleft; nectary five-toothed, 

 closing the mouth of the corolla ; berry ; 

 seeds scarred. There is but one spe- 

 cies, viz. C. Guianense, Guiana cryptos- 

 tomum. 



CRYSTALLINE humour, in anatomy, a 

 thick, compact humour, in form of a nat- 

 tish convex lens, situated in the middle 

 of the eye, serving to make that refrac- 

 tion of the rays of light, necessary to 

 make them meet in the retina, and form 

 an image thereon, whereby vision may 

 be performed. See EYE. 



CRYSTALLIZATION. When the at- 

 traction of aggregation has been weak- 

 ened, either by the application of heat, or 

 of a chemical affinity, and is suffered to 

 resume its force more slowly or equally, 

 the particles are not united indiscrimi- 

 nately, but in uniting assume a particular 

 arrangement ; and thus form masses of 

 regular figures, bounded by plain sur- 

 faces and determinate angles. When 

 aggregation is exerted in this manner, 

 and with this result, the operation is 

 named crystallization, and the regularly 

 figured masses are denominated crys- 

 tals. 



