GENERAL HISTOLOGY

Detailed explanation-1: -As well as the starfish, the echinoderms include sea urchins, sand dollars, brittle and basket stars, sea cucumbers and crinoids.

Detailed explanation-2: -They are in a phylum of animals called echinoderms. Sea stars are one class of echinoderm, Asteroidea. Other classes include sea urchins (Echinoidea), sea cucumbers (Holothuroidea), and a huge range of living and extinct creatures.

Detailed explanation-3: -Fast Facts. The echinoderms (Greek for spiny skin) include sea stars, sea urchins, feather stars, brittle stars and sea cucumbers. All are found in the marine environment in a range of habitats from intertidal surf beaches to the deepest oceans.

Detailed explanation-4: -Examples of echinoderms include sea stars, sea urchins, sea cucumbers, brittle stars, and feather stars (Fig. 3.83). Although they may appear very different, echinoderms all have two major defining characteristics that set them apart from all other animals: a water vascular system and five-sided radial symmetry.

Detailed explanation-5: -Echinodermata is a phylum of about 7000 living species distributed among five classes: Echinoidea (sea urchins and sand dollars), Holothuroidea (sea cucumbers), Ophiuroidea (brittle stars), Asteroidea (sea stars), and Crinoidea (feather stars and sea lilies).