Echinoderms
Echinoderms ( e-ky'-no-derms ) are sea bottom animals that have external calcite skeletons.
Echinoderms have a five fold symmetry and an internal fluid-filled system that supports respiration, movement, and feeding.
A special characteristic of some is their use of tube feet.
The best known echinoderm fossils are the cystoids, blastoids, and crinoids – all of which are favorites among collectors.
Other well known echinoderms, which are not common in my home area, are starfish (Asteroids) and sea urchins (Echinoids). These animals arose during Ordovician time, about 490 million years ago, and continue to the present.
Here's what you can now find in the sea.
Copyright ©2009 John W. Kimball. All rights reserved.
For information about Cystoids, click here.
For Blastoids, click here, and for Crinoids, go here.s |
