The clausilium is a calcareous structure, tongue-shaped or spoon-shaped, which can close the aperture of the snail shell and thus protect the soft parts against predation by animals such as carnivorous beetle larvae.
The clausilium is a calcareous structure, which can be tongue-shaped, spoon-shaped or spatula-shaped. The wide flat end of the clausilium can close the aperture of the snail shell, and thus protect the soft parts against predation by animals such as carnivorous beetle larvae.