10 CATECHISM OF CONCHOLOGY, 



Q. Describe the different parts of which Mul- 

 tivalves consist. 



A. 1st. Basis ; in the Chiton and Lepas, that 

 part of shell which is affixed to extraneous 

 bodies, either with or without a peduncle, or 

 stem. In the Pholas, the part of the margin 

 opposite to the summit of the beaks. 



2dly. Ligamentum, Cartilage, the membrane 

 which connects the valves. 



3d. Limbus ; Border, the marginal membrane 

 of the Chiton. 



4th. Operculum ; Operculum, in Lepas, the 

 lid which closes the vertical aperture of the shell, 

 consisting usually of four triangular valves. 

 . 5th. Pedunculus ; Peduncle, the tabular sup- 

 port of certain Lepades* 



