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1 (phylum Brachiopoda) A class of brachiopods in which the calcareous valves are impunctate, punctate, or pseudo-punctate. The fibrous or prismatic secondary layer and non-fibrous primary layer are well differentiated. Hinge teeth and dental sockets are developed. Lophophore support is formed from modifications of socket ridges to give crura, loops, or spires. The alimentary canal ends blindly. Articulate brachiopods first appeared in the Early Cambrian. There are six orders, with 37 superfamilies.

2 (subphylum Crinozoa, class Crinoidea) A subclass containing all living, stalked crinoids, plus the feather stars, which are identified by the arrangement of the skeletal plates forming the calyx. 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.

Subjects: Zoology and Animal Sciences — Earth Sciences and Geography.

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