Echinoderms - Echinodermata

Characteristics:

The name Echinodermata originates from Greek and means spiny skin. Not all have spines in their skin, although it is quite common. An outer layer of calcareous material is typical. It may form a shell as in the sea urchins, or plates connected by a flexible material, as in the sea stars. Most echinoderms live their adult lives on the bottom, clinging to the ground with hydraulic suckers. Hydraulic liquid, sea water, is also used to transport nutrition around the body. Sperm and eggs are released in the water. When the larvae are hatched, they live their first phase in the water before they attach themselves to the seabed.

Taxonomy:

The Echinoderms are exclusively marine species, including familiar classes like the sea stars, brittle stars, feather-stars, sea urchins and sea cucumbers.