 Alternatively these animals are considered related to echinoderms, as the shell (or test) is similar in structure and composition to the tests of echinoderms.However, stylophorans are asymmetric organisms that lack either the radial symmetry typical of most echinoderms, or the bilateral symmetry of the chordates.The body of "Cothurnocystis" consists of a chalice (or theca) and a stem (tail or foot).