| Found along with the cephalopods are gastropods, pelecypods, echinoderms, and vertebrate bones. |
| We chordates are deuterostomes, as are echinoderms, some marine worms called hemichordates, and the urochordates, or sea squirts. |
| The water vascular system, found in all echinoderms, accommodates the elongated body of the holothurians. |
| Marine invertebrates include ammonites, echinoderms, bivalves and crustaceans, but infaunal elements are rare. |
| As an initial matter, the echinoderms and chordate phyla have been arranged in almost every possible phylogenetic order. |
| Most radially symmetric animals are sessile, however, echinoderms are able to move. |
