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Aplexa Prisca
''Aplexa'' is a genus of small, left-handed or sinistral, air-breathing freshwater snails, Aquatic animal, aquatic pulmonate gastropod mollusks in the family Physidae. Shell description These small snails are quite distinctive, because they have gastropod shell, 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 (mollusc), aperture, a relatively high and pointed Spire (mollusc), spire, and no Operculum (gastropod), 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gastropod Shell
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 (mollusc), 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. Shell layers The gastropod shell has three major layers secreted by the Mantle (mollusc), mantle. The calcareous central layer, ostracum, is typically made of calcium carbonate (CaCO3) precipitated into an organic matrix ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
