Assertion: aperture | /r/MadeOf | a thickened
Facets:
Source sentences:
text: The shells of juveniles in some species (especially some families of land snails) have a simple aperture with a sharp edge, but after reaching adult size the aperture of the shell finally acquires adult characters, consisting of a thickened, reflected, inflected or lipped edge, which is sometimes more or less contracted by inflected calcareous projections known as teeth.