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The shells of sea snails are often found washed up on beaches. Because many are attractive and durable, they have been used to make necklaces and other jewelry since prehistoric times. The shells of a few species of large sea snails within the Vetigastropoda have a thick layer of nacre and have been used as a source of mother of pearl.
Freshwater snails are gastropod mollusks that live in fresh water. 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
Snails can be found in a very wide range of environments, including ditches, deserts, and the abyssal depths of the sea. Although land snails may be more familiar to laymen, marine snails constitute the majority of snail species, and have much greater diversity and a greater biomass. Numerous kinds of snail can also be found in fresh water.
The snails are a unique part of the neuston, organisms which live on or near the surface of the water, because of their relatively large size. They have veliger , or free swimming larvae, but the adults do not swim, and cannot create their rafts, except at the surface where air bubbles are available.
Gastropods with protective shells are referred to as snails , whereas gastropods without protective shells are referred to as slugs . Gastropods are by far the most numerous molluscs in terms of classified species, accounting for 80% of the total. [25]
The shell height can reach up to 65 millimetres (2.6 in). [5] Cipangopaludina chinensis has a width to height ratio of 0.74–0.82. [5] The aperture is ovoid with a simple outer lip and inner lip. [7] In juveniles, the last shell whorl displays a distinct carina, and the shell contains grooves with 20 striae/mm between each groove. [5]
Empty shells have been found in depths of up to 97 metres (318 ft). [12] [27] These snails are often found in association with the offshore Atlantic calico scallop beds, probably attracted by the abundant food. [16] Shipwrecks also seem to provide a good habitat for this species. [16]
The largest living species is the Giant African Snail or Ghana Tiger Snail (Achatina achatina; Family Achatinidae), which can measure up to 30 cm. [13] [14] The largest land snails of non-tropical Eurasia are endemic Caucasian snails Helix buchi and Helix goderdziana from the south-eastern Black Sea area in Georgia and Turkey; diameter of the ...