Brachiopods belong to the large category of animals
without backbones, the invertebrates. They have two
shells or valves that are often composed of the mineral
calcite (calcium carbonate). Brachiopods have a coiled
feeding organ called a lophophore that is protected by its
valves.
There are two major divisions (Classes) of brachiopods:
the inarticulate brachiopods and the articulate brachiopod