Operculum (gastropod) in the context of "Land snail"

Marisa cornuarietis, common name the Colombian ramshorn apple snail, is a species of large freshwater snail with an operculum, an aquatic gastropod mollusc in the family Ampullariidae, the apple snail family.

These snails are popular in aquariums, and are also used in the wild as a biological control agent.

The gastropod shell is part of the body of many gastropods, including snails, a kind of mollusc. The shell is an exoskeleton, which protects from predators, mechanical damage, and dehydration, but also serves for muscle attachment and calcium storage. Some gastropods appear shell-less (slugs) but may have a remnant within the mantle, or in some cases the shell is reduced such that the body cannot be retracted within it (semi-slug).

Some snails also possess an operculum that seals the opening of the shell, known as the aperture, which provides further protection. The study of mollusc shells is known as conchology. The biological study of gastropods, and other molluscs in general, is malacology. Shell morphology terms vary by species group.

The common periwinkle or winkle (Littorina littorea) is a species of small edible whelk or sea snail, a marine gastropod mollusc that has gills and an operculum, and is classified within the family Littorinidae, the periwinkles.

This is a robust intertidal species with a dark and sometimes banded shell. It is native to the rocky shores of the northeastern, and introduced to the northwestern, Atlantic Ocean.

Neritidae, common name the nerites, is a family of small to medium-sized saltwater and freshwater snails which have a gill and a distinctive operculum.The family Neritidae includes marine genera such as Nerita, marine and freshwater genera such as Neritina, and freshwater and brackish water genera such as Theodoxus.

The common name "nerite" as well as the family name Neritidae and the genus name Nerita, are derived from the name of Nerites, who was a sea god in Greek mythology.

Bithynia tentaculata, common names the mud bithynia or common bithynia, or faucet snail is a relatively small species of freshwater snail with gills and an operculum, an aquatic prosobranch gastropod mollusk in the family Bithyniidae.

Bithyniidae is a family of small freshwater snails with an operculum, aquatic gastropod molluscs in the clade Littorinimorpha.

Their minute shell is often colored. They are characterized by a calcareous operculum, a lobe on the upper surface of the neck. The ctenidium, the respiratory gill-comb, is very broad. They have a ciliary feeding habit. The kidney has a large extension towards the mantle.

Pomacea maculata is a species of large freshwater snail with an operculum, an aquatic gastropod mollusk in the family Ampullariidae, the apple snails.

The common name of its synonymous name Pomacea insularum is the island apple snail.

Ampullariidae, whose members are commonly known as apple snails, is a family of large freshwater snails that includes the mystery snail species. They are aquatic gastropod mollusks with a gill and an operculum. These snails simultaneously have a gill and a lung as functional respiratory structures, which are separated by a division of the mantle cavity. This adaptation allows these animals to be amphibious. Species in this family are considered gonochoristic, meaning that each individual organism is either male or female.