Holostomata

See HOLOCHLAMYDA. IMG:content-0622.png:[graphic] Holostomous. Having the shell aperture entire or IMG:content-0623.jpg:[graphic] Holothuroidea. slug-shaped or worm-like bodies, with leathery skin containing scattered spicules, and the ambulacral areas indistinctly marked into a dorsal (bivial) and a ventral (trivial) surface. The mouth is at one end, surrounded by branched tentacles; the anus is at the other. The sexes are usually distinct. Some have large respiratory trees. They are divided into the Apoda and Pedata , or the Apneumona , Dip neum on a , and Tetrapneu mona . See also ELASIPODA.