receptaculitidæ

Century Dictionary and Cyclopedia

1. A family of fossil organisms, typified by the genus Receptaculites, of a very doubtful nature. They have been referred by many to the silicious sponges; but the skeleton was originally calcareous, and the silicious examples are the result of fossilization. They are of a spherical or pyriform shape, with a central closed cavity and an upper and lower pole, and the wall is composed of pillar-like spicules at right angles to the surface and expanded at their outer ends into rhomboidal summit-plates forming a mosaic-like outer layer. The species lived in the seas of the Silurian and Devonian epochs. Also called Receptaculidæ.