The corallum grows in the form of plates a centimeter thick. or somewhat more, or as an irregularly nodose mass.
The calices are small, and although distinctly delimited, occur in rather definite rows, which roughly parallel the growing edge. The calices in one row are separated by narrow walls; adjoining rows are separated by that collines. The distance between calicinal centers in the same row is about 1.5 millimeters.; between opposite centers across a
colline, about 2 millimeters. The collines are as has been said, flattened, there  are no erests, and are crossed
by the septa-costa, whcih are crowded and reoulurly alternate in height. The usual number of septa for  each calice is twelve, two cycles, of which the six primaries are decidedly the larger and more prominent, and join the columella by
their inner ends. In some calices two. or even more, of the secondaries may reach the columella; where this condition prevails septa of the third cycle are present. The edges of the septo-costal portions of (lie septa lie in a plane, and are microscopically denticulate; the inner margins fall al)rui)tly to the bottom of the calicular fossa and appear to be entire. The faces of the septsi and of the septo-costae are minutely granulated. Roth synapticula, which are rather scarce, and thin dissepiments, which are abundant, occur in the interseptal loculi. Tlie texture of the corallum is light.
The columella is compressed, often lamellate, and situated in the bottom of a narrow, rather deep calicular fossa.