GENERAL HISTOLOGY

Detailed explanation-1: -Echinoderms are named for their “spiny skin.” However, the spines aren’t on their skin. They are part of the endoskeleton. The endoskeleton consists of calcium carbonate plates and spines, covered by a thin layer of skin. Adult echinoderms have radial symmetry.

Detailed explanation-2: -The class Echinoidea includes the sea urchins, heart urchins, cake urchins and familiar sand dollars. The sea urchins are well known to most people, having a large number of sharp spines pointing out in all directions. These spines offer protection from many would-be predators.

Detailed explanation-3: -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-4: -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.

Detailed explanation-5: -In fact, the name, Echinodermata, means spiny skin, a reference to the occurrence of spines on sea urchins, and to a lesser extent, on sea stars and brittle stars.