Abstract
Cymodoce truncata (Leach, 1814), the type species of the genus, C. zanzibarensis (Stebbing, 1910) and C. richardsoniae (Nobili, 1906) are redescribed based on type specimens or topotypic material, and a neotype is designated for Cymodoce richardsoniae. A revised generic diagnosis and description is provided for the genus Cymodoce. Cymodoce delvarii sp. nov. is described from the subtidal zone of the Iranian coasts of the Persian Gulf.