1. (phylum Brachiopoda) A class of brachiopods, existing from the Lower Cambrian to the present day, in which the shell is calcareous and comprises valves hinged by teeth in one valve and sockets in the other. The pedicle is of a horny material. Their main radiation was in the early Ordovician; of the seven orders present in the Palaeozoic, three are still extant.

2. (sea lilies) (subphylum Crinozoa, class Crinoidea) Subclass of sea lilies (crinoids) in which the basal plates are small or strongly reduced. Articulation between the radial and brachial plates, and in the majority of brachials, is muscular, with a well-developed fulcral ridge. The arms are always uniserial. All post-Palaeozoic crinoids belong to the Articulata.