Stylosmilia Milne Edwards 1848

Phaceloid corallum with cylindrical corallites. Costae potentially covered by a thin epitheca. Extracalicular increase that preserves the axial symmetry of the septal apparatus of the mother corallite that generally keeps its growth trajectory. Radial elements compact, unequal, rather straight, bicuneiform. Only first cycle septa may join the columella according to a periodic vertical pattern. Distal edge smooth, inner edge with koutaliform auriculae, lateral faces with rare acute granules poorly organised in distribution. Microstructure stylinid. Axial symmetry very stable (hexameral in the type species), bilateral symmetry sometimes visible through the elongation of the styliform columella. Endotheca made of horizontal tabulae, columella styliform, often elongated. No synapticula. No palus. Wall made by external enlargement of septa and addition of thickening deposits.