The shell wall consists of eight wall plates, which reduce to six, and four in some species. Plate reduction is accomplished by fusion of rostrolatera with adjacent laterals, or initially by suppression of carinolatus II, reducing plate number from eight to six. Unlike the superfamilies Coronuloidea and Balanoidea, the rostrum rarely fuses with rostrolatus. In soft parts, caudal appendages are rare, and the mandible usually has three or our teeth, rarely five, and frequently bears fine bristles. Cirri I and II, sometimes III, bear specialized setae to comb net-forming cirri for food particles. These are termed comb setae, which are thin spines bearing fine bristles, and card setae (also known as grapple setae). Card setae are grapple-like or wool carder-like in appearance.