A new genus and 8 new species belonging to the family Tornidae (=Vitrinellidae) (Caenogastropoda: Truncatelloidea) are described. The species studied are from the southeastern tropical Pacific and were collected in New Caledonia, the Marquesas Islands and the Philippines, mainly during the Tropical Deep-Sea Benthos expeditions conducted by IRD and MNHN. The new genus Monodosus is based on unique morphological features that are present in the eight new species described; their systematic position is discussed and the new genus is compared with others genera presenting similar morphological characters. Each species is illustrated by scanning electron microscope photographs; their specific variability is discussed and information about their habitat, geographical distribution and bathymetric range is provided.