They draw in seawater through a porous spot called a madreporite located on the top surface of the body.

There are five prominent mouth-shields and a separate madreporite on the ventral surface.

Sir R. Murchison, whose much more close and extensive acquaintance with fossils enabled him to assign to the deposit its true place, was struck, however, with the general resemblance of its polypifers to "those of the Madreporite Limestone of the Carboniferous series."