ii6 C O N C H O L O G Y. 



The mouth or aperture (apertura) needs^ 

 no explanation. See PI. I. fig. 3, 6. e e. 



A full or round mouth. Plate III. fig. 12. 

 A timilunar mouth. Plate IIL fig. 14. 



- The lip (hiblum) fimply, is the meer 

 •outer contour of the mouth or aperture ; 

 but the inner, or columella lip, (labium 

 interius vel columellae) is the polifhed or 

 fmooth part oppofite to the lip, and is al- 

 ways fpread on the columella. Sec PI. I. 



The beak (roftrum) is that prolonged 

 furrowed part, extended ftreight upwards 

 from the top of the aperture like a horn, 

 more or lefs in the different families. It 

 is by fome authors called the tongue or 

 bore, efpecially when fpoken of the Pur- 

 puras: as it is imagined they bore the Shells 

 of the fiih they feed on, with it. See PI. I. 



fig- 



