124 COWRY. 



Lam. Fam. Balanidea, Bl. — Descr. Six radiated valves, joined 

 side by side in a circle, forming a depressed cone ; internal struc- 

 ture of the valves, porous or chambered; thickened at the base; 

 operculum consisting of four valves in pairs; imbedded horizon- 

 tally in a cartilaginous substance. — Obs. The shells composing 

 this genus are found partly imbedded in the skin of whales, and 

 the shells of tortoises, and are therefore destitute of the shelly 

 foundation on which the Balani and other Coronular Multivalves 

 are supported. C. Testudinaria, (Chelonobia, Leach,) fig. 15. 

 C. Baleenarum, (Cetopirus, Ranz.) fig. 16. C. Diadema, (Dia- 

 dema, Ranz.) fig. 17. 



CORONULAR MULTIVALVES are those which have their pa- 

 rietal valves joined together side by side in a circle, surrounding 

 the body of the animal, so as to form a sort of coronet. This is 

 the characteristic of the Sessile Cirripedes of Lamarck's system, 

 the Balanidea of De Blainville. 



CORRODED. (Corrodo, eat away, consume.) The umbones, apices, 

 and other thick parts of shells, are frequently worn away or 

 consumed by the action of the element in which they exist. As 

 the thickest parts of some shells are the most subject to this 

 operation; it appears to the author to arise from the outer surface 

 of the shell, being less under the influence of the animal juices 

 than the other parts; and therefore, more exposed to the influ- 

 ence of the surrounding element. This, however, is not the 

 case with respect to the Nayades and other fresh-water shells ; 

 with these, corrosion does not take place until after the thick 

 epidermis which covers them, becomes wounded by some means 

 or other, and then the animal thickens its shell within as fast as 

 it is corroded without. 



CORTALUS. Montf. (Conch. Syst. 1. 115.) A genus of mi- 

 croscopic Foraminifera, placed by De Blainville in a division of 

 the genus Rotalites. 



COSTATED. Ribbed, as Cardium Angulatum, fig. 123. 



COSTELLARTA. A sub-genus of the genus Tiara, Sw. (Mitra.) 

 C. rigida. Swainson, Zool. 111. 1st series, pi 29. 



COWRY. A common name for shells of the genus Cypraea. 



