A snail is, in loose terms, a shelled gastropod. The name is most often applied to land snails, terrestrial pulmonate gastropod molluscs. However, the common name snail is also used for most of the members of the molluscan class Gastropoda that have a coiled shell that is large enough for the animal to retract completely into. When the word "snail" is used in this most general sense, it includes not just land snails but also numerous species of sea snails and freshwater snails. Gastropods that naturally lack a shell, or have only an internal shell, are mostly called slugs, and land snails that have only a very small shell are often called semi-slugs.
A seashell or sea shell, also known simply as a shell, is a hard, protective outer layer created by an animal that lives in the sea. The shell is part of the body of the animal. Empty seashells are often found washed up on beaches by beachcombers. The shells are empty because the animal has died and the soft parts have been eaten by another animal or have decomposed.
The gastropods, more commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca, called Gastropoda. This class comprises snails and slugs from saltwater, from freshwater, and from the land. There are many thousands of species of sea snails and slugs, as well as freshwater snails, freshwater limpets, and land snails and slugs.
Sea slug is a common name for some marine invertebrates with varying levels of resemblance to terrestrial slugs. Most creatures known as sea slugs are actually gastropods, i.e. they are sea snails that over evolutionary time have either completely lost their shells, or have seemingly lost their shells due to having a greatly reduced or internal shell. The name "sea slug" is most often applied to nudibranchs, as well as to a paraphyletic set of other marine gastropods without obvious shells.
Whelk is a common name that is applied to various kinds of sea snail. Although a number of whelks are relatively large and are in the family Buccinidae, the word whelk is also applied to some other marine gastropod species within several families of sea snails that are not very closely related.
The operculum, meaning little lid, is a corneous or calcareous anatomical structure like a trapdoor which exists in many groups of sea snails and freshwater snails, and also in a few groups of land snails; the structure is found in some marine and freshwater gastropods, and in a minority of terrestrial gastropods, including the families Helicinidae, Cyclophoridae, Aciculidae, Maizaniidae, Pomatiidae, etc.
Captain Frederick Wollaston Hutton, FRS, was an English-New Zealand scientist who applied the theory of natural selection to explain the origins and nature of the natural history of New Zealand. An army officer in early life, he then had an academic career in geology and biology. He became one of the most able and prolific nineteenth century naturalists of New Zealand.
Amphibola crenata is a species of air breathing snail with an operculum, a pulmonate gastropod mollusc which lives in a habitat that is intermediate between the land and the sea, not entirely terrestrial and not entirely marine.
Cypraeoidea, the cowries and cowry allies, is a superfamily of sea snails, marine gastropods included in the clade Littorinimorpha. This superfamily had been called Cypraeacea and was named by Rafinesque in 1815.
Cone snails, cone shells, or cones are common names for a large group of small to large-sized extremely venomous predatory sea snails, marine gastropod molluscs.
Chorus giganteus is a species of sea snail in the family Muricidae. It is endemic to the coast of Chile, where it occurs from Antofagasta (23° S) to the south of the country at depths of 8–30 metres (26–98 ft). It is a benthic predator that lives on rocks in temperate waters. It has been overexploited by local fishermen in much of its range.
Janthina janthina, common name the violet sea-snail or common violet snail, is a species of holoplanktonic sea snail, a marine gastropod mollusk in the family Janthinidae, the violet snails or purple storm snails.
Vanikoroidea is a superfamily of sea snails, marine gastropod molluscs in the clade Littorinimorpha. The superfamily Eulimoidea is a synonym of Vanikoroidea.
Costellariidae sometimes called the "ribbed miters" is a taxonomic family of minute to medium-sized predatory sea snails, marine gastropod mollusks. This family of snails is also sometimes referred to as Vexillum miters. The main family of miter shells however is Mitridae, a closely related group.
Freshwater snails are gastropod mollusks which live in freshwater. There are many different families. They are found throughout the world in various habitats, ranging from ephemeral pools to the largest lakes, and from small seeps and springs to major rivers. The great majority of freshwater gastropods have a shell, with very few exceptions. Some groups of snails that live in freshwater respire using gills, whereas other groups need to reach the surface to breathe air. In addition, some are amphibious and have both gills and a lung. Most feed on algae, but many are detritivors and some are filter feeders.
Typhina is a genus of sea snails, marine gastropod mollusks in the family Muricidae, the murex snails or rock snails.
Calyptraea chinensis, common name the Chinese hat snail or Chinese hat shell, is a species of small sea snail, a marine gastropod mollusk in the family Calyptraeidae, the slipper snails or slipper limpets, cup-and-saucer snails, and Chinese hat snails.
Neverita didyma, common name the bladder moon snail or moon shell, is a species of predatory sea snail, a marine gastropod mollusk in the family Naticidae, the moon snails.
Terrestrial molluscs or land molluscs (mollusks) are ecological group that includes all molluscs that lives on land in contrast to freshwater and marine molluscs.
