Shell minute to small, equivalve, inequilateral, polished, with weak growth-marks. Inside nacreous. Chevron-shaped cardinal plate with numerous teeth.
 

Shell minute, with no or very weak radial sculpture. Beaks prosogyrate. Ventral margin smooth outside as inside.
 

« The distinguishing characters indicated [in Iredale, 1931] were the notably oblique chondrophore (ligament pit) with the lessened teeth not notably angulate to the posterior row; the denticulations of the inner margin of the shell are generally obsolete. » – T. Iredale: “Mollusca part I”, Scientific Reports / Great Barrier Reef Expedition 1928-29 vol.V, London 1935-1950 (1939), p.235.
 

The « angle of opposition of the two rows of teeth is scarcely marked » (Iredale, 1931); pallial margin denticulate.