GENERAL HISTOLOGY

Detailed explanation-1: -The term ‘Echinos’ means spiny and ‘dermos’ means skin. These animals have a mesodermal endoskeleton of calcareous ossicles and hence they are called echinoderms or spiny skinned animals.

Detailed explanation-2: -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-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.