 The white nucleus is nearly smooth, but under a lens, with rows of small pits.The subsequent 4 violet whorls contain 3 spirals, crossed by numerous ribs, beaded where they cross each other, leaving square interspaces.The lower whorls contain conspicuously beaded spirals, of which there are 6 larger on each whorl, and in the interstices a much smaller thread, more or less beaded.