sea pen


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sea pen,

long, slender colonial organism of the same phylum as the jellyfish. Sea pen colonies are formed by several genera of the order Pennatulacea. The colony consists of a stalk formed by an organism called a primary polyp (see polyp and medusapolyp and medusa,
names for the two body forms, one nonmotile and one typically free swimming, found in the aquatic invertebrate phylum Cnidaria (the coelenterates). Some animals of this group are always polyps, some are always medusae, and some exhibit both a polyp and a medusa
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) and short branches formed by secondary polyps. The stalk, embedded in sand or mud, holds the colony upright. Sea pens differ from the closely related sea pansiessea pansy,
fleshy, leaf-shaped colony of marine organisms belonging to the genus Renilla in the same phylum as the jellyfish. The colony consists of a stalk formed by a large organism called a primary polyp (see polyp and medusa) that is thrust into soft bottom material;
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 and sea feathers by the form of the colony. Sea pens are marine organisms; they are found on Atlantic and Pacific coasts in shallow to moderately deep water. Some reach a length of 2 ft (61 cm) or more. They belong in the phylum CnidariaCnidaria
or Coelenterata
, phylum of invertebrate animals comprising the sea anemones, corals, jellyfish, and hydroids. Cnidarians are radially symmetrical (see symmetry, biological).
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, class Anthozoa, order Pennatulacea.

sea pen

[′sē ‚pen]
(invertebrate zoology)
The common name for cnidarians constituting the order Pennatulacea.
References in periodicals archive ?
The most abundant benthic macroinvertebrates that we observed were sea whips and orange sea pens (Ptilosarcus gurneyi) at the two northern sites and sea whips and heart urchins (Brisaster spp.) at the two southern sites (Table 2).
Our observations of bite-strikes on the sea pen Ptilosarcus gurneyi are similar to reports of feeding on Virgularia sp.
The first step is to get them into a natural sea pen, where they can experience the natural rhythms of the sea, the tides, the currents, and that's how the healing begins.
From there, a military helicopter waited to chauffeur the dolphins to a natural sea pen on the coast of Nicaragua's Corn Island, where marine mammal specialist Ric O'Barry began their rehabilitation.
In Canada she was put in another sea pen and released when her original pod swam by.
"Sea floors that have not been dredged or trawled tend to be covered with a dense reef of living creatures: oysters, fan mussels and many other shelly species, soft corals, sea pens, sea fans, sponges, coralline seaweeds, peacock worms and anenomes.
The most commonly used grow-out systems for sea cucumbers are earthen ponds, sea pens, sea cages, and release into delimited areas of seabed (i.e., sea ranching) (Chen 2004, Renbo & Yuan 2004, Yaqing et al.
Until now, scientists had long believed the rocks were made up of ocean sediments and that Dickinsonia and other primeval creatures fossilized in the outcroppings were sea dwellers similar to jellyfish or sea pens that lived just before the Cambrian explosion began about 540 million years ago, when all the major animal groups suddenly appeared.
These (http://sanfrancisco.ibtimes.com/articles/169718/20110626/philippines-discovers-300-new-species-california-academy-science-amazing-rare-photos.htm) new species include insects, spiders, corals, sea pens, sea urchins, sea stars, "colorful" sea slugs, and more.
It is estimated the Irish salmon swim an incredible 8,000 miles during their two years in the sea pens.
Corals and anemones are part of this group, as are critters known as sea fans and sea pens. Like jellyfish, most Cnidarians have a tubular body with a mouth on one end surrounded by tentacles.
They grow in many different forms, including branching sea fans and sea pens. From a distance they look like bushes or trees, sometimes reaching two meters tall.