''Aplexa'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of small, left-handed or sinistral, air-breathing freshwater snails, aquatic pulmonate gastropod

mollusk Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is e ...

s in the family Physidae.

Shell description

These small snails are quite distinctive, because they have shells that are sinistral, which means that if you hold the shell such that the spire is pointing up, then the aperture is on the left-hand side. The shells of ''Aplexa'' species have a long and large

aperture In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. An ...

, a relatively high and pointed

spire A spire is a tall, slender, pointed structure on top of a roof of a building or tower, especially at the summit of church steeples. A spire may have a square, circular, or polygonal plan, with a roughly conical or pyramidal shape. Spires a ...

, and no operculum. The shells are thin and corneous and rather transparent.

Species

Species in the genus ''Aplexa'' include: * '' Aplexa atava'' White, 1877 * '' Aplexa brevispirata'' (Cossmann, 1913) * '' Aplexa disjuncta'' (White, 1879) * '' Aplexa elongata'' (Say, 1821) - the lance aplexa * '' Aplexa gigantea'' (Michaud, 1837) * '' Aplexa grasseti'' (Matheron, 1878) * '' Aplexa heberti'' (Deshayes, 1863) * ''

Aplexa hypnorum ''Aplexa hypnorum'', or by the common name, the moss bladder snail, is a species of small air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Physidae, a family which are sometimes known as the bladder snails ...

'' (Linnaeus, 1758) - the moss bladder snail * '' Aplexa jaimei'' (Hermite, 1879) * '' Aplexa kasekikabe'' (Isaji, 2010) * '' Aplexa macerata'' (Russell, 1937) * '' Aplexa militaria'' (Yen & Reeside, 1946) * '' Aplexa morrisonana'' (Yen & Reeside, 1946) * '' Aplexa praelonga'' (Matheron ex Heer, 1861) * '' Aplexa primigenia'' (Deshayes, 1863) * '' Aplexa prisca'' (Noulet, 1854) * '' Aplexa pseudogigantea'' (F. Sandberger, 1870) * '' Aplexa pulchella'' (A. d'Orbigny, 1850) * '' Aplexa ricei'' (Russell, 1957) * '' Aplexa rivalis'' (Maton & Rackett, 1807) * '' Aplexa subelongata'' (Meek & Hayden, 1856) * '' Aplexa subhypnorum'' (Gottschick, 1920)

Shell description

Species

References

Further reading