Family: Body long, flat, with beak-like anterior rostrum; oral area in long ventral groove behind rostrum Müllerian vesicles in endoplasm. Genus: Oral area round, behind rostrum, leads into tubular cavity (Illustrated Guide, 1985). Species (magnus Stokes): Extended about 700 μm long; dark brown; twelve to twenty or more Müllerian vesicles in a row along dorsal border (Kudo, 1966).