Gastropoda

Gastropods have a unique body characteristic, known as torsion that occurs during the veliger larval stage (Encyclopedia of Life, 2012).  This occurs when the visceral mass rotates, putting the anus and mantle cavity near the head gills (Encyclopedia of Life, 2012).  Most gastropods also have a coiled shell that protects the body and encloses the visceral mass; however, the shell has been lost in a few groups, such as slugs (Encyclopedia of Life, 2012).  Some species go through a process known as detorsion, in which torsion is reversed (Hickman, et al., 2009).  Fumonelix jonesiana is classified in Class Gastropoda because it has torsion and a coiled shell.

To learn more, go back to classification, or continue on to Stylommatophora.