Wikimedia
Wikipedia: Echinoderm
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.
Tree of Life Project
The Tree of Life Web Project: Crinoidea
This site from the University of Arizona provides a very thorough information on chrinoidea, including diagrams and pictures.
Other
Wet Web Media: Spiny Skinned Animals & Echinodermata
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.
California Academy of Sciences
California Academy of Sciences: Echinoderm Webpage
Resource provides a brief overview of echinoderms. Includes pictures and links for more information.