The position of the echinoderms, in particular, has been a matter of doubt and controversy in the studies of the vertebrate ancestors. Embryological, anatomical and biochemical evidence seem now to indicate that the first one is wrong: echinoderms, as proposed Kampmeier (ref1), are more likely to have been the ancestors of the invertebrates than the annelids. An essential point appears to be the fact that echinoderms are deuterostomia, like the vertebrates, while annelids are protostomia, like arthropods and mollusks.