Thecidiidae

Thecidiidae, a family of Brachiopoda ranging from the Carboniferous period to the present. The members of it are fixed by the beak to some body, while the margin of the shell is much thickened; it thus assumes a form very different to those of most Brachiopoda. One of the most remarkable genera included in 1he family is the genus Oldhamina from the Carboniferous rocks of India.