GENERAL HISTOLOGY

Detailed explanation-1: -Echinoderm, any of a variety of invertebrate marine animals belonging to the phylum Echinodermata, characterized by a hard, spiny covering or skin.

Detailed explanation-2: -Echinoderm means spiny skin. If we break the word down echino = spiny and derm= skin, so these animals are spiny-skinned. Sea stars and their cousins are part of a group of spiny-skinned animals. Sea Stars: Most sea stars have five arms.

Detailed explanation-3: -Echinoderms are named for the spines or bumps covering the outer surface of the bodies of many of them (Greek root word echino-meaning spiny; Latin root word-derm meaning skin). Examples of echinoderms include sea stars, sea urchins, sea cucumbers, brittle stars, and feather stars (Fig. 3.83).

Detailed explanation-4: -Spiny skinned animals are placed in Echinodermata. The spines on the skin in echinoderms are part of the endoskeleton. The endoskeleton is made up of calcium carbonate plates called ossicles that bear spines which project outside.

Detailed explanation-5: -In addition to radial symmetry, echinoderms have a water-vascular system. True. True or False? The hard, spiny skin of an echinoderm is called an exoskeleton.