Also found in: Dictionary, Thesaurus, Wikipedia.
Related to Ectoprocta: Brachiopoda, Entoprocta, Phoronida, Bryozoans


(ĕk'təprŏk`tə), phylum of sessile, colonial aquatic animals (commonly known as moss animals or oryonzoans). The zooids, or individual members of a colony, are microscopic, but colonies may grow up to 1 ft (30 cm) or more in diameter. Some colonies are erect and branching; others are thin, flat encrustations on rocks, seaweed, or water plants. The body wall of each zooid forms a tubular or boxlike case from which a circular or U-shaped crown of ciliated tentacles, the lophophore, is extended for feeding. Tentacle cilia generate water currents that sweep small organisms and organic particles toward the mouth, located within the lophophore. They reproduce sexually via a planktonic larval stage which settles and attaches to start a new colony. They also reproduce asexually by fission, fragmentation, or encapsulated resting stages. They were formerly placed in the phylum Bryozoa along with the EntoproctaEntoprocta
, animal phylum consisting of small marine organisms living in shallow coastal waters. The entoprocts are either colonial or solitary. The body is vase-shaped, with the upper edge covered by ciliated tentacles that direct microscopic animals and debris into the
..... Click the link for more information.
, which they superficially resemble. Ectoprocts are a large and ancient group (dating from the Ordovician). There are about 5,000 living species.

Class Phylactolaemata

Exclusively freshwater animals having chitinous or gelatinous zooids with circular or horseshoe-shaped lophophores and well-developed body wall musculature. They produce characteristic resting bodies called statoblasts, which can survive cold and drying and germinate to found a new colony.

Class Stenolaemata

Fossil and recent marine animals that have tubular zooids, calcified walls, and circular orifices. Protrusion of the circular lophophore does not depend on muscular deformation of body walls. They reproduce sexually by embryonic fission (polyembrony).

Class Gymnolaemata

Fossil and recent primarily marine animals with cylindrical or boxlike chitinous or calcified zooids. Their colonies are often polymorphic, with zooids specialized for feeding, defense, support, and reproduction. The lophophore is circular and protrusion depends on body wall deformation.

The Columbia Electronic Encyclopedia™ Copyright © 2013, Columbia University Press. Licensed from Columbia University Press. All rights reserved.


(invertebrate zoology)
A subphylum of colonial bryozoans having eucoelomate visceral cavities and the anus opening outside the circlet of tentacles.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Although bryozoans (Ectoprocta and Entoprocta) are widely distributed in epibenthic and littoral communities (Rogick 1934, 1957; Bushnell et al.
Twelve of them are in the Phylum Ectoprocta and follow the classification scheme outlined by Wood (2001), while a single species, Urnatella gracilis, is in the Phylum Entoprocta.
On the taxonomy and distribution of freshwater Ectoprocta in Michigan.
Fresh-water Ectoprocta: Distribution and ecology of five species in south-eastern Louisiana.
Taxonomy, distribution, and ecology of the freshwater bryozoans (Ectoprocta) of eastern Canada.
As a prominent example, the tentacle-bearing Entoprocta and Ectoprocta have for decades been considered sister groups and were united in the clade "Bryozoa" within the Spiralia (Nielsen, 1971.
- - 4 serotonergic (chordoid larva only) NEMERTEA 2 - - PLATHELMINTHES 2-8 - (between 0 - - PHORONIDA and 2 lateral nerve cords/giant fibers) ECTOPROCTA 2 - - BRACHIOPODA 2 - - Character (larval) Taxon Nerve ring Apical organ Reference underlying ciliated larval swimming organ ANNELIDA + + (simple) Voronezhskaya et ai.
18S rRNA suggests that Entoprocta are protostomes, unrelated to Ectoprocta. J.
Function of lateral cilia in suspension feeding lophophorates (Brachiopoda, Phoronida, Ectoprocta).
Estimates of nomenclatorial and taxonomic diversity among Recent Entoprocta and Ectoprocta. Abstracts of the 9th International Conference on Bryozoa, Swansea 1992: 25.
The Invertebrates: Smaller Coelomate Groups, Chaetognatha, Hemichordata, Pogonophora, Phoronida, Ectoprocta, Brachiopoda, Sipunculida, the Coelomate Bilateria, Vol.