A DICTIONARY OF TERMS. 



liii 



Compressed. 



concamerated. 

 Contour. - - 



CoRCELET. 



CoRDIFORME. 



Coriaceous. 

 Crenated. 



Crest. 



Nearly flat. Several of the Tellens are com- 

 pressed shells. 



The same as chambered. 



The exterior surface, and round the edge of 

 a shell. The Tuns are round in their contour ; 

 the Murex is angular. 



The part near the hinge in bivalve shells, to 

 which the ligament is attached. It is remark- 

 able in the shells of the genus Venus, and 

 received one of those names from Linnzeus, 

 which disgrace the pages of his Systema 

 Natura. 



Heart-shaped. The Cockles and some other 

 shells are cordiforme. 



Hard and fibrous ; of a substance between 

 horn and skin. 



Having blunt teeth. The margins of many 

 bivalve shells are crenated. 



Crested like the comb of a cock. Some oysters 

 are crested. 



D. 



Decussated. - Striated crossways. 



Dentated. - - Toothed. The margin of most Cockles are 

 dentated. 



Diaphonous. - Transparent when held to the light. 



Digitated. - - Made in the shape of fingers. The lips of 

 some shells of the genus S trombus are digi- 

 tated. 



Diverging. - - Separating from a point. The teeth in the 

 Anomia placenta diverge. 



Dorsal. - - - Belonging to the back. 



E. 



Ears. - - - - External projections, nearly triangular, which 

 are seen at the base of Pectens. 



