Love the jug, the pink inner glaze is really typical of traditional majolica such as Minton. I don't think it's Oriental, though I may be way off base here, but there is a 'Mojin' in Slovakia and the jug looks more European. Shame it isn't Minton though, you'd have your hands on a valuable little piece!
Are there no marks at all on the shell (pretty in its own right and looks to be very well modelled, but not my cup of tea)? Often Portuguese ceramics have an impressed 'P' followed by a mold number, but these can be very small and quite faint, especially on thickly glazed pieces.
