Family Hemithyrididae Rzhonsnitskaya, 1965
Ribbed or radially striped shells with short flat brachial supports (crura). Outer hinge plates are very small or absent. There are two pairs of coelomoducts.
Ribbed or radially striped shells with short flat brachial supports (crura). Outer hinge plates are very small or absent. There are two pairs of coelomoducts.