the world > animals > invertebrates > phylum Arthropoda > class Crustacea > [noun] > subclass Entomostraca > order Cirripedia > member of > parts of > flap or lid of shell (3)
operculum1681
Zoology. The calcareous, horny, or fibrous plate secreted by some gastropod molluscs, esp. prosobranchs, which serves to close the aperture of…