The specific feature is given by these « distinct undulating transverse striae » – J. G. Jeffreys: “On the marine Testacea of the Piedmontese coast”, Annals and Magazine of Natural History ser.2, vol.17, London 1856, p.186. – Playa de las Higuericas, Pilar de la Horadada, Alicante Province, SE. Spain. 1,3mm. Original pictures provided by M. Zonneveld for iNaturalist – (CC BY).

Jeffreys: « I took two live specimens of this very distinct shell by dredging in about 10 fathoms at Spezia. » – Same spot. 1mm. Original pictures provided by M. Zonneveld for iNaturalist – (CC BY).