Crystallographic arrangement of cerioid and phaceloid corals

Upper part of image shows a schematic representation of the shared wall of halysitid corallites of Pleurosiphonella sp. and the variation of c-axis orientation around the contact area by the stretching of polyps. Lower part of image shows the variation of morphologies and c-axis orientation of granules and fibres by the folding up of polyps in a cerioid taxon similar to Roemeripora sp.