GENERAL HISTOLOGY

Detailed explanation-1: -Definitions of Holothuroidea. class of echinoderms including the sea cucumbers. synonyms: class Holothuroidea. type of: class. (biology) a taxonomic group containing one or more orders.

Detailed explanation-2: -Holothurians generally look long and worm-like, but retain the pentaradial symmetry characteristic of the Echinodermata. Some may be spherical in body shape. The mouth and anus are located on opposite poles, and five rows of tube feet run from the mouth to the anus along the cylindrical body.

Detailed explanation-3: -Description: The holothuroideans, commonly called sea cucumbers, are a very unique group of echinoderms. They are the only class that is soft bodied rather than hard with well-developed circular and longitudinal muscles. Their axis of symmetry is horizontal unlike other echinoderms.

Detailed explanation-4: -External morphology of holothurians The body is formed like a short or long cylinder, with the mouth (at the anterior end) encircled by tentacles, and the anus (at the posterior end) often edged by papillae. The pentamerous symmetry is sometimes recognizable by the presence of 5 meridional ambulacra bearing podia.