Colonies form multiserial encrusting sheets originating from an ancestrular complex of six radially arranged zooids. The aragonitic mineralogy of the skeleton means that specimens are often chalky and easily crumble, and are lost in those parts of the Coralline Crag leached of aragonite.
Autozooids are about 0.4-0.5 mm long by 0.25-0.3 mm wide, and typically elongate rhomboidal in outline shape. The frontal shield is relatively flat, minutely granular, bordered by numerous conspicuous areolar pores but lacking pseudopores. An ascopore is present immediately below the adventitious avicularium. The orifice is ovoidal to hemielliptical, wider than long, and without oral spines.
Polymorphic brooding zooids (gonozooids) are present. These are slightly larger than the autozooids, lack an adventitious avicularium and have a crescent shaped orifice and a large ascopore. The outline shape of the gonozooid is constricted between the level of the ascopore and the proximal edge of the orifice.
Adventitious avicularia are located on the frontal shields of the autozooids. They are large and oriented obliquely such that the pointed distal end is adjacent to one of the proximolateral corners of the autozooidal orifice. The pivotal bar is not calcified.
Small tubular kenozooids may be present at triple junctions between neighbouring zooids.