Pterioida
bivalve order
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annotated classification
- In bivalve: Annotated classification
Order Pterioida (pearl oysters and fan shells) Shell equivalve, variably shaped; anisomyarian but often monomyarian; shell structure of outer simple calcitic prisms and inner nacre; ctenidia pseudolamellibranch, often plicate (deeply folded); mantle margin lacking fusions; foot reduced; marine; endobyssate or epibyssate. About 100 species.
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