entoproct

/en"teuh prokt'/, n. Zool.
1. any of various sessile, chiefly marine, mosslike animals of the phylum Entoprocta (formerly a subphylum of Bryophyta), occasionally solitary polyps but usually forming branching colonies, each individual polyp having an almost closed ring of tentacles within which lie the mouth and anus.
adj.
2. belonging or pertaining to the phylum Entoprocta. Also called endoproct. Cf. ectoproct.
[1935-40; see ENTOPROCTA]

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      any member of the phylum Entoprocta, a group of aquatic invertebrate animals composed of about 150 species. Entoprocts occur throughout the world, primarily in marine habitats, although one genus, Urnatella, is a freshwater form. Entoprocts may either exist singly or form colonies of communicating members, called zooids, by budding. The zooids measure only about 0.4 to 5 mm (0.016 to 0.2 inch) in height. Each of them has a stalk (peduncle), which may be jointed, that attaches to shells, seaweed, or to other animals, such as sponges, bryozoans, hydroids, and segmented worms.

      The entoproct body consists of a globular head (calyx) that houses a U-shaped gut and the nervous, excretory, and reproductive systems. A crown of ciliated tentacles creates a water current that draws food particles toward a central mouth. The anus lies within this tentacular ring. The calyx often is discarded and then regenerated in colonial species. The solitary species develop daughter buds, which detach themselves when mature. Entoprocts also produce free-swimming larvae that disperse and then metamorphose into new colonies or individuals. The larva and the pattern of its early development indicate that the entoprocts may be linked remotely with the annelids and other protostome phyla, but precise evolutionary relationships with other phyla are not yet clear. All entoproct species that have been studied are simultaneous hermaphrodites (that is, each individual possesses both male and female sexual organs).

      First described in 1774, entoprocts were classified with the moss animals (bryozoans), in which filter-feeding, tentaculated zooids also are present. The similarities between the two groups, however, are probably superficial. The patterns of water flow across their tentacles, for example, differ fundamentally, as do their developmental patterns; in addition, among bryozoan zooids the anus opens outside the tentacles. The name Entoprocta was introduced in 1869, and the group was first recognized as a phylum in 1888. Alternative names (Calyssozoa and Kamptozoa) were proposed in 1921 and 1929.

      The phylum Entoprocta has no known fossil members and is subdivided into four families.

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Universalium. 2010.

Look at other dictionaries:

  • entoproct — [en′təpräkt΄] n. [ ENTO + Gr prōktos, anus] any of a phylum (Entoprocta) of small, mosslike aquatic invertebrates with a complete digestive tract and an anus opening near the mouth and within the circlet of oral tentacles …   English World dictionary

  • entoproct — noun Etymology: ultimately from ent + Greek prōktos anus Date: 1940 any of a phylum (Entoprocta) of chiefly marine animals that are very similar to bryozoans but lack a true coelom and have the anus located near the mouth inside a crown of… …   New Collegiate Dictionary

  • entoproct — en·to·proct …   English syllables

  • entoproct — noun any of various moss like aquatic animals usually forming branching colonies; each polyp having a both mouth and anus within a closed ring of tentacles • Hypernyms: ↑invertebrate • Member Holonyms: ↑Entoprocta, ↑phylum Entoprocta, ↑Endoprocta …   Useful english dictionary

  • endoproct — ˈendəˌpräkt noun or adjective Etymology: New Latin Endoprocta : entoproct * * * /en deuh prokt /, n. entoproct …   Useful english dictionary

  • Bryozoa — Temporal range: Upper Cambrian–Recent[1] …   Wikipedia

  • Nemertea — For the Romanian village that bears this name, see Gura Teghii. Nemertea …   Wikipedia

  • Dinomischus — Temporal range: Chengjiang–Burgess shale …   Wikipedia

  • Entoprocta — Kelchwürmer Barentsa discreta Systematik Unterreich: Vielzellige Tiere (Metazoa) …   Deutsch Wikipedia

  • Kamptozoa — Kelchwürmer Barentsa discreta Systematik Unterreich: Vielzellige Tiere (Metazoa) …   Deutsch Wikipedia

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