Our original Sea Urchin Embryology site, designed in the 1990's, provides extensive background information on sea urchins and how to use them in the classroom.
One sea urchin, the purple urchin Strongylocentrotus purpuratus, has a fully sequenced genome, with others on the way.
Sea urchins have an extensive fossil record, and the University of California Museum of Paleontology at UC Berkeley has an excellent background site.
Sea urchins are members of the phylum Echinodermata, which also includes sea stars, sea cucumbers, and others. The Tree of Life web project has information about echinoderms, their evolutionary tree, and how they are related to other animals.
Dr. John B. Morrill has produced a beautiful atlas of sea urchin development on CD, using the sea urchin Lytechinus variegatus from Florida. Several of the photos from this CD are featured on our site.