« The shell is ovate-conic, slender, and has three moderately inflated whorls with narrowly spaced spiral striae. There is no umbilicus. The aperture is rather circular and detached from the last whorl. The colour is mostly light brown or corneous, but white and dark brown specimens occur as well. » – J.  van der Linden: “A new marine Gastropod species from S. Europe, Nodulus spiralis spec. nov.”, Basteria 50 (4/6) 1986, p.189.