Corallum an irregular mass, upper surface produced into prominent hillocks; badly attacked by crustacean, annelid and molluscan borers. Living portion limited to upper 3-6 cm.
Corallites closely set, especially in valleys where walls are in contact. On top and sides of hillocks they are 0.5-1.5 mm apart. Calice a little over 1.5 mm diameter at most, smaller in valleys; circular or oval. Wall usually projecting around 0.5 mm above perithecal areas; fairly thick.
Septa narrow so fossa relatively wide, open. Primaries very prominently exsert over mural border, (0.5 mm or more); exsert arch subtruncate or rounded; inner border with prominent teeth, longer ones near columella so that they cover the latter in some calices; surface with abundant fine, sharp spines. Secondaries barely touching columella or short from it, only slightly less prominently exsert than primaries; edge and surface resembling those of primaries but slightly narrower. Tertiaries very thin and very narrow but also dentate at the edge, slightly exsert over wall. All septa conspicuously inflated over wall.
Costae thicker than septa; tertiary costae hardly recognizable in most corallites.
Columella a reticulum usually obscured by approximating lower septal dentation; sometimes a single central tubercle visible.
Perithecal areas where corallites not in contact covered with heavy conical spines with sharp tips, oversized bases and granulous sides. Vesicles hardly recognizable.
