Colonies are free-living (lunulitiform), attached to a minute substrate that is often totally overgrown. They are disc shaped with a convex frontal surface on which the autozooids and vibracula open, and a concave underside. Rectangular kenozooidal sectors on the underside each contain 4-10 pores. More than one layer of basal kenozooids is present, producing a thickened colony base. The diameter of colonies is up to 12 mm. In colonies originating by sexual reproduction, a triad of zooids constitutes an ancestrular complex from which subsequently budded zooids are arranged radially in alternating series. Colonies that formed from asexual reproduction through fragmentation followed by reparative growth generally lack these early generational zooids and tend to be somewhat less symmetrical in shape. The growing edge at the perimeter of the colony is stepped.
Autozooids are ovoidal to rhombic, longer than wide, on average about 0.52-0.58 mm long by 0.36-0.43 mm wide (fide Cadée 1979, table 3). Gymnocyst and spines are lacking. The cryptocyst is narrow, granular, slopes steeply inwards and lacks denticles. Most of the frontal surface of the autozooids is occupied by the longitudinally elongate opesia. Ovicells are lacking.
Vibracula are present distally of each autozooid. They are smaller than the autozooids, and have ear-shaped opesia and asymmetrical condyles. The rostrum is directed proximally, deflected either to the left or right of the associated autozooid. Vicarious vibracula rarely replace autozooids.