Assertion: gastropod's shell | /r/HasProperty | secreted along outer lip of the aperture
Facets:
value: by secretion of inner thickening layers
type: MANNER
Source sentences:
text: The shell is secreted along the outer lip of the aperture by the fleshy part of the animal called the mantle, first by outward additions to the shell lip and then by secretion of inner thickening layers.