The Chthamaloidea are a subdivision of Balanomorpha proposed by Newman and Ross to include barnacles with shell wall composed of rostrum, carina, and one to three pairs of latera, rarely supplemented with one or more whorls of basal imbricating plates. The rostrolatus enters the sheath, but rarely fuses with the rostrum, as in the three higher superfamilies. Shell plates are simple in construction, solid, and incorporate organic chitin between carbonate layers.