Assertion: oyster's valve | /r/CapableOf | estuarine hard surfaces
Facets:
Source sentences:
text: This form has allowed the close attachment of one valve to a hard surface, and although some groups still retain byssal attachment (family Anomiidae), others have forsaken this for cementation, as in the true oysters (family Ostreidae), where the left valve is cemented to estuarine hard surfaces.