An Operculum is an AnatomicalConcept It is a bulge of tissue joining two Gyri or Pars and separating two Sulci It may be involved in 0 or more Delimitation relations by a Sulcus
Bony covering over the gill slits of fish; or, in gastropod molluscs, the calcareous plate over the shell opening that protects the body when the animal withdraws into the shell