The space between external and internal shells of the main dome was filled with hollow clay resonators.
The small internal shell of the species is however quite a familiar object to many beachcombers.
The internal shell in general thin, slightly convex, ovate and white.
While most seashells are external, some cephalopods have internal shells.
It has an internal shell which is small (about 1 in or 24 mm) but very light and buoyant.
An internal shell is present in the Limacidae and Parmacellidae.
Cephalopods only have small internal shells, with the exception of the Nautiloidea.
They have two fins on the head and a small internal shell.
This spoon-shaped "door" is supported by, and slides in, a series of internal shell folds, see the image below.
In addition to its internal shell, it also supports running image files of games and software originally intended to start without any operating system.
