Shell is thick anteriorly to thin posteriorly; rounded to squared-off moderately inflated shell with 2 poorly defined rows of elongated knobs diverging from the umbo to the ventral margin. Umbo is rounded and raised high above the hinge line. Epidermis is generally yellowish to light brown, becoming darker with age. Inside shell beak cavity deep; pseudocardinal teeth large, grooved and roughened; lateral teeth moderately long, grooved and slightly curved; nacre (lining) white, iridescent posteriorly.
Similar species: Pimplebacks are similar but have randomly distributed small knobs and may have a green ray from umbo to halfway down shell. Monkeyface has a distinct groove.