Subfamily MEGATREMAOTINAE Holthuis, 1982

Bosciinae Newman & Ross, 1976: 59.

Megatrematinae Holthuis, 1982: 319.

Diagnosis.

Wall of four plates wholly concrescent; opercular valves normal; tergum with weakly developed lateral depressor muscle crests or crests lacking; when shell concrescent, sheath with paired sulci.

Type genus.

Megatrema Sowerby, 1823, by original designation (Holthuis 1982).