Archaeocyatha

The  Archaeocyatha are organisms, presently extinguished, who lived in the Cambrian seas. These animals are of conical shape, consisting of two concentric porous walls joined by vertical separating membranes and horizontal slates. In the central part of the organism there was a cavity comparable to the pseudo gastric cavity of sponges.

The Archaeocyatha  lived stable in the seabed, in shallow water close to the shoreline. They were classified both in coelenterates, for the presence of radial vertical separating membranes, and in sponges, for the central cavity. Today they are considered a completely separate category. The oldest Italian fossils belong to Archaeocyatha and were found in the Cambrian soils of Sardinia.