OF CONCHOLOGY. 13 



genera, to make the student ac- 

 quainted with the terms used in Tes- 

 taceology, as far as regards the dif- 

 erent parts of shells. 



EXPLANATION 



PARTS OF SHELLS. 



MULTIVALTE. 



Operculum is four small valves on 

 the summit of the iepas, which how- 

 ever is in a certain degree stationarj^ ; 

 and different from the operculum of 

 univalve shells, which will hereafter be 

 described. See plate 1st, fig. 1st, A. 



£ase is that part of the shell by 

 which it is fixed to rocks and other 

 bodies ; plate 1st, figures 1st and 2d, 

 B B B. — H is a piece of stone to which 



