NOMENCLATURE, 19 



Labium. Lip ; the internal or columellar mar- 



inlerius. gin of the aperture. 



In the Patelte this name is given to a 

 testaceous membrane in tlieir concavity 

 calledyor?^/caZevvhen under the vertex, and 

 laterale when it constitutes a chamber in 

 the side. 



£Xterius, Labrum. The outer margin of the aper- 

 ture. 



anticum. Anterior part ; next the spire. 



posticum. Posterior; that nearest the rostrum. 



coar datum. Coarctate ; drawn back to the base. 



digitatum. Digitate ; divided into attenuated di- 

 verging lobes. 



solutum. Disengaged; separated from the whorls 



by a sinus or gutter. 

 Jlsmm. Cloven ; almost divided in the middle by 

 a linear sinus. 



mucronatum. Mucronate ; projecting in one sin- 

 gle sharp point. 



Operculum. Lid ; a plate or door with which 

 some species close the aperture of their 

 sliells : it is either of a horny, testaceous, 

 c 2 



