Dipleurula is a hypothetical larva of the Echinoderms. It represents the type of basis of all larva forms of the Eleutherozoa, to which the sea-stars, sea-hedgehog, sea-rollers and sand stars belong. The Dipleurula is a bilaterally symmetrical, ciliated echinoderm larva. Dipleurula represents an ancestral form for these primitive deuterostomes. We...