Body whorl

The term is also sometimes used in a similar way to describe the shell of a cephalopod mollusk.

The opposite tendency can sometimes create a high spire with very little whorl increase per revolution.

In these instances, e.g. in the shell of Turritella species, both the body whorl and the aperture are relatively small.

In mollusc shells where there is no elevation at all to the spire, and only moderate whorl expansion, the body whorl can sometimes still represent a large part of the shell, e.g. in some species in the family Planorbidae, such as the genus Segmentina.

[2] The body of the animal occupies the living chamber, apart from the siphuncle which extends through the rest of the septa (the phragmocone) to provide buoyancy.