124 UNIVALVES. 



and ending in two or three spiral turns ; it is 

 usually covered with a rough epidermis which 

 projects beyond the margin and forms a ciliated* 

 border : beneath, the colour is reddish, the in- 

 side glassy white, or flesh colour ; the base, which 

 is nearly circular, varies from one to two inches 

 in diameter ; the shell is rather more than half 

 as high. 



This species, so remarkable for its elegant 

 form, is found on the western shores of Britain, 

 but is not common. 



GENUS. DENTALIUM.f 



TOOTH OR TUSK SHELL 



Generic character. Shell univalve, resembling 

 a tooth, straight or slightly curved, without any 

 internal partition, open at both ends, and very 

 gradually tapering. 



OBSERVATIONS ON THE SHELL AND ITS 

 INHABITANT. 



The shells of this genus are easily known by 

 their very simple construction ; they all more or 

 less resemble a miniature tusk, and 4 the name 



* Ciliated, bordered with a fringe like eye-lashes, from the Latin 

 cilia, an eye-lash. 

 f Plate VI. figure 6 



