Novocrania anomala (Müller, 1776)

Dorsal valve exterior smooth to hummocky with concentric growth lamellae, dorsal valve interior with adductor muscle scars flush with valve surface or slightly raised, small anterior muscles commonly attached to a tiny anterior septum, ventral valve sometimes organic, commonly partly calcitic/partly organic or completely calcitic, ventral valve punctate (when calcitic), rostellum organic, ventral posterior adductor muscle scars organic, in dead shells ventral muscle scars and rostellum latent.