Do you think a feature of early embryology, such as the fate of the blastopore, is a good basis for classifying animals? Explain your answer. Although they are the most abundant class of echinoderms, comparatively little is known about ophiuroids, Why do you suppose that is the case? In which class of cnidarians is Aristotle's Lantern present? What is its function? How do hemichordates differ from chordates? How is feeding similar in urochordates and cephalochordates? How is it different?