holothurian

echinoderm

Also known as: Holothuria

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Last updated

June 29, 2026

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Holothurians, commonly known as sea cucumbers, are marine invertebrates belonging to the class Holothuroidea within the phylum Echinodermata. These soft-bodied creatures, ranging from about 0.75 inches to 6.5 feet in length, typically have a dull, warty appearance resembling a cucumber. They possess five rows of tube feet and retractile tentacles around their mouths used for feeding on sediment or small aquatic animals.1

Sea cucumbers are found in all oceans and can expel their internal organs to escape predators or for physiological reasons. Some species also release toxins harmful to small animals. They are commercially harvested for various products, with dried sea cucumber, known as b\u00eache-de-mer, being a delicacy in Asia. Overfishing has significantly impacted many sea cucumber populations.1

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circulatory system
Echinodermata
…most highly developed in the holothurians (sea cucumbers), in which it consists of an anterior hemal ring and radial hemal sinuses. The most prominent features are the dorsal and ventral sinuses, which accompany the intestine and supply it through numerous smaller channels. The dorsal sinus is contractile, and fluid is…
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…most highly developed in the holothurians (sea cucumbers), in which it consists of an anterior hemal ring and radial hemal sinuses. The most prominent features are the dorsal and ventral sinuses, which accompany the intestine and supply it through numerous smaller channels. The dorsal sinus is contractile, and fluid is…
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sea cucumber
…sea cucumbers of the genus Holothuria are especially abundant on coral reefs. Most species of Holothuria are deposit feeders similar to earthworms: they ingest sediment to extract the organic constituents.
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…sea cucumbers of the genus Holothuria are especially abundant on coral reefs. Most species of Holothuria are deposit feeders similar to earthworms: they ingest sediment to extract the organic constituents.
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