In this coral the calicle is divided into quadrants by four principal septa, the main septum, counter septum, and two alar septa. |
The septa, radial plates of calcite reaching from the periphery nearly or quite to the centre of the coral-cup or calicle. |
Tabulae are stout horizontal partitions traversing the centre of the calicle and dividing it into as many superimposed chambers. |