40 NOMENCLATURE. 



Venter seu Corpus. Belly or Body; the 

 lowest whorl, the last circumvolution of 

 the shell, which is the most tumid. 



Vertex. Vertex; in the Patella signifies the 

 supereminent point of the shell, 



submarginalis. Submarginal ; placed near the 

 posterior margin. 



Umbilicus. Umbilicus ', the base of the colu- 

 mella visible underneath. 



perforatus. Perforate ; having a hollow duct or 

 opening through the centre to the very 

 apex. 



suloltechis seu Rima umhilicalis. Umbilical 

 cleft ; where the lip is reflected over the 

 hollow, and only the margin of the open- 

 ing is apparent. 



Margo columiiaris. Columnar Margin ; when 

 the margin of the columella forms the in- 

 terior wall of the aperture. 



