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Shell of marine snail Lunella torquata with the calcareous operculum in place Gastropod shell of the freshwater snail Viviparus contectus with corneous operculum in place. The operculum (Latin for 'cover, covering'; pl. opercula or operculums) is a corneous or calcareous anatomical structure like a trapdoor that exists in many (but not all) groups of sea snails and freshwater snails, and also ...
An operculum (gastropod), a single lid that (in its most complete form) closes the aperture of the shell when the animal is retracted, and thus protects the internal soft parts of the animal that are not completely covered by the shell. The operculum lies on the top rear part of the foot.
Turbo marmoratus, known as the green turban, the marbled turban or great green turban, is a large species of marine gastropod with a thick calcareous operculum in the family Turbinidae, the turban snails. [1] The shells of these large sea snails have a very thick layer of nacre; this species has been commercially fished as a source of mother of ...
Turbo is a genus of large sea snails with gills and an operculum, marine gastropod molluscs in the family Turbinidae, the turban snails. [ 2 ] Turbo is the type genus of the family.
Gastropods have the greatest numbers of named mollusk species. However, estimates of the total number of gastropod species vary widely, depending on cited sources. The number of gastropod species can be ascertained from estimates of the number of described species of Mollusca with accepted names: about 85,000 (minimum 50,000, maximum 120,000). [9]
Turbinidae have a strong, thick calcareous operculum readily distinguishing them from the somewhat similar Trochidae or top snails, which have a corneous operculum. This strong operculum serves as a passive defensive structure against predators that try to enter by way of the aperture or that would break the shell at the outer lip.
Viviparidae, sometimes known as the river snails or mystery snails, are a family of large aquatic gastropod mollusks, being some of the most widely distributed operculate freshwater snails. This family is classified in the informal group Architaenioglossa according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005 .
Viviparus viviparus is a species of large freshwater snail with a gill and an operculum, an aquatic gastropod mollusk in the family Viviparidae, the river snails. This species is a viviparous (ovoviviparous) snail.