 It consisted of a calyx (or body) on a long, thin stalk, surrounded by a whorl of 18 short "petals", which enclosed both openings of its U-shaped gut.The presence of this gut identified it as a metazoan, and the stem implied that it lived permanently attached to the sea floor by a small holdfast.The twenty or so "petals" borne by each organism were solid, plate-like structures, about two thirds the length of the calyx.