24 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; a hole in the base of 



the columella visible underneath. 

 perforatus. Perforate ; having a hollow duct or 



opening through the centre to the very 



apex. 

 subobtectus seu Rima umbilicalis. Umbilical 



cleft; where the lip is reflected over the 



hollow, and only the margin of the opening 



is apparent. 

 Mar go columnaris. Columnar Margin ; when the 



margin of the columella forms the interior 



wall of the aperture. 



