Terebratulide
in zoölogy, a family of Brachiopoda. Woodward enumerates five genera, to which Tate adds two others. Shell minutely punctate; usually round or oval, smooth or striated; ventral valve with a prominent beak and two curved hinge-teeth; dorsal valve with depressed umbo, a prominent cardinal process between the dental sockets, and a slender shelly loop. Animal attached by a pedicle, or by the ventral valves; oral arms united by a membrane, variously folded, sometimes spiral at their extremities. The family is numerous and widely distributed in time and space. The generic and sub-generic forms are usually classified according to the modifications of the loop or calcified support for the respiratory and alimentary organs, the simplest and highest type of this loop being found in Terebratula.
The family was represented in Silurian seas, and reached its maximum about the dawn of the Tertiary epoch, since when many of its representatives have become extinct.