Unusual Cased Antique Silver S&P Shakers

A very unusual and strange little set of silver salt and pepper shakers (or muffineers or castors) with three ball-shaped feet. Almost reminds me of UFO-style from mid-century but from what I've been told these are much older. They come in a little blue velvet and light blue green satin lined box, the inner lid of which states: "Robert Jones & Sons Goldsmiths & Silversmiths Liverpool" (as far as I can tell, they operated during the nineteenth century and the very beginning of the twentieth).