DOLIUM. 



a thickened, reflected and crenated edge. A thin, h6rny 

 epidermis generally covers the outside of the shell. 



The species of this Genus are not numerous, nor are 

 they rare ; some of them grow to an enormous size, and 

 they are then handsome ornamental shells. Fossil species 

 are very uncommon, nor can we with certainty assert 

 their existence. There is in the chalk a shell having 

 nearly the general form of a Dolium, but its characters 

 are not sufficiently developed in the specimens we have 

 seen to enable us to judge with certainty. 



