Armless, mostly unattached echinoderms, with a tough leathery body wall containing strongly developed radial and longitudinal muscles, lacking articulated test. The body is typically cylindroid, elongated orally-aborally, with a mouth located at or near extremity defined as oral encircled by altered podia, and the anus at or near opposite end.
Holothurians are marine, generally benthic invertibrates
that crawl over the substrate or vegetation or burrow in sea-bottom mud.
They are sluggish swimmers and may be pelagic. They are found living at
all depths but are most abundant in warm shallow waters.