See text Dallina is a genus of small to average size lampshells (maximum 35 millimetres or 1.4 inches long).

Small to large, triangular to subquadrangular in outline; rectimarginate to paraplicate; beak erect, without beak ridges; foramen small to large, mesothyrid, attrite, symphytium concave.

Hinge teeth small, weak; pedicle collar very short.

Cardinalia lamellar with excavate inner and outer hinge plates separated by narrow crural bases; inner hinge plates converging on median septum to form V-shaped septalium; cardinal process not differentiated; median septum low anteriorly, extending beyond midvalve; adult loop teloform.

Nine extant species are recognized (though one has recently been synonymized),[3] these are listed below: