The individuals of the colony inhabit one side of the branches in two parallel rows, that can be recognized as small rimmed pores (or apertures), and in well-preserved specimens are closed by centrally perforated lids.
The individuals of the colony (or zooids) inhabit one side of the branches in two parallel rows or two at the branche base and three or more rows further up. Zooids can be recognized as small rimmed pores (or apertures), and in well-preserved specimens the apertures are closed by centrally perforated lids.