Chthamalidae

The Chthamalidae are a family of chthamaloid barnacles, living entirely in intertidal/subtidal habitats, characterized by a primary shell wall of eight, six, or four plates, lacking imbricating plate whorls, and either membraneous or more rarely calcareous basis. They are not found below immediate subtidal habitats, and more likely are found in the highest tier of shallow-water barnacle fauna. They can be found in the most rigorous wave-washed locations, and some species are found in the surf zone above high tide mark, only receiving water from wave action at high tide. The family includes at least 56 recognized species.

== Definition and discussion == 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 four 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.