STARFISH ,SEA URCHINS, AND OTHER ,relatives (including feather star,basket star, sea daisies, sea lilies,and sea cucumbers) make up the phylum Echinoderm. A unique feature of the Echinoderms is the water vascular system, which consists of a series of water filled canals from which protrude thousands of tiny tube feet . The tube feet may be used for movement, feeding, or respiration.Other features include pentaradiate symmetry that is the body can be divided into five parts radiating from the cent re ); no head ; diffuse ;decentralized nervous system that lacks a brain ; and no excretory organs.Typically echinoderms also have an en do skeleton(internal skeleton ) consisting of a hard calcite ossicles embedded in the body wall and often bearing protruding spines or tubercles .The ossicles may fit together form a test (as in sea urchins) or remain separate ( as in sea cucumbers)
STAR FISH AND SEA URCHINES
STAR FISH AND SEA URCHINES
Comments
Post a Comment