MODE OF LIFE OF THE MIDDLE CAMBRIAN ELDONIOID LOPHOPHORATE ROTADISCUS

The discs of the alleged 'medusoids' Rotadiscus from the recently disc overed Mid Cambrian soft-bodied Kaili fauna in South China are commonl y overgrown by shelled epizoans of unknown affinities. Most are attach ed to the convex side of the disc, near its margin. Towards the disc c entre only small shells occur usually, which suggests that their growt h was inhibited by an anoxic environment under the disc. The eldonioid s were thus sedentary animals, analogous to Recent deep-water thecocya thid corals, with the discs passively lying on the mud surface with th e convex side of the disc orientated downward.