Wikipedia provides detailed information on echinoderms, or a phylum of marine animals including star fish and sea urchins. Website includes image, chart of scientific classification, and many hyperlinked terms.

Site provides a general overview of echinoderms from the perspective of the marine aquarium enthusiast. Content includes a focus on physical characteristics, individual classes, and acquarium maintenance.

This site from the University of Arizona provides a very thorough information on chrinoidea, including diagrams and pictures.

Resource provides a brief overview of echinoderms. Includes pictures and links for more information.