Cancellate Semele

Shell size to 20 mm; shell ovate, thin, strong. Sculpture of concentric ridges and radial ribs, stronger anteriorly and posteriorly, giving cancellate aspect to shell surface in these regions. Umbones just slightly posterior. Ligament internal. Color cream or yellowish-white with reddish markings, or grayish-purple. Internally cream, white, or reddish.