Planispiral
Planispiral is a condition in which a tubicolous shell is coiled in a single horizontal plane and the diameter increases away from the axis of coiling. This term is usually used for describing gastropod shells. Many cephalopods and tubeworm A tubeworm is any worm-like sessile invertebrate that anchors its tail to an underwater surface and secretes around its body a mineral tube, into which it can withdraw its entire body. Tubeworms are found among the following taxa: * Annelida, the ...s can also have a planispiral shell (Allaby and Allaby, 1999). References * External links {{Gastropod anatomy Mollusc shells ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Gastropod
The gastropods (), 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 land. There are many thousands of species of sea snails and slugs, as well as freshwater snails, freshwater limpets, and land snails and slugs. The class Gastropoda contains a vast total of named species, second only to the insects in overall number. The fossil history of this class goes back to the Late Cambrian. , 721 families of gastropods are known, of which 245 are extinct and appear only in the fossil record, while 476 are currently extant with or without a fossil record. Gastropoda (previously known as univalves and sometimes spelled "Gasteropoda") are a major part of the phylum Mollusca, and are the most highly diversified class in the phylum, with 65,000 to 80,000 living snail and slug species. The anatomy, behavior, feeding, and re ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Anisus Septegyrus1pl
''Anisus'' is a genus of small air-breathing freshwater snails, aquatic pulmonate gastropod mollusks in the subfamily Planorbinae of the family Planorbidae, the ramshorn snails and their allies.Rosenberg, G.; Bouchet, P. (2014). Anisus. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=716342 on 2014-11-23 Species The genus contains the following species: ;Subgenus ''Anisus'' * '' Anisus calculiformis'' (Sandberger, 1874) * † '' Anisus komarovae'' Prysjazhnjuk, 1974 * † '' Anisus krambergeri'' (Halaváts, 1903) * † '' Anisus laskarevi'' Milošević, 1976 * ''Anisus leucostoma'' (Millet, 1813) * † '' Anisus septemgyratiformis'' (Gottschick, 1911) * '' Anisus septemgyratus'' (Rossmässler, 1835) * ''Anisus spirorbis'' (Linnaeus, 1758) - the type species of the genusGlöer, P. 2002 ''Die Süßwassergastropoden Nord- und Mitteleuropas''. Die Tierwelt Deutschlands, ConchBooks, Hackenheim, 326 pp., , page 254-263 ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Cephalopod
A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles (muscular hydrostats) modified from the primitive molluscan foot. Fishers sometimes call cephalopods "inkfish", referring to their common ability to squirt ink. The study of cephalopods is a branch of malacology known as teuthology. Cephalopods became dominant during the Ordovician period, represented by primitive nautiloids. The class now contains two, only distantly related, extant subclasses: Coleoidea, which includes octopuses, squid, and cuttlefish; and Nautiloidea, represented by ''Nautilus'' and ''Allonautilus''. In the Coleoidea, the molluscan shell has been internalized or is absent, whereas in the Nautiloidea, the external shell remains. About 800 living species of cephalopods have been ident ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Tubeworm
A tubeworm is any worm-like sessile invertebrate that anchors its tail to an underwater surface and secretes around its body a mineral tube, into which it can withdraw its entire body. Tubeworms are found among the following taxa: * Annelida, the phylum containing segmented worms ** Polychaetea, the class containing bristle worms *** Canalipalpata, the order containing bristle-footed annelids or fan-head worms **** Siboglinidae, the family of beard worms ***** ''Riftia pachyptila'', a species known as giant tube worms ***** Lamellibrachia, a genus **** Serpulidae, a family **** Sabellidae, the family containing feather duster worms * Phoronida, the phylum containing horseshoe worms * Microconchida, an order of extinct tubeworms * ''Kuphus polythalamia ''Kuphus polythalamius'' is a species of shipworm, a marine bivalve mollusc in the family Teredinidae. Description The tube of ''Kuphus polythalamius'' is known as a crypt and is a calcareous secretion designed to enable the an ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |