On T. nitida teeth within the outer (palatal) lip are quite evenly sized (1), sometimes one is a bit higher. Jeffreys (1867) stated of his Essex specimens, “inner [columellar/parietal] lip  – – never tuberculated”, but some Adriatic T. nitida  have tubercles/teeth on the inner lip (2).

Croatia, Adriatic. September 2016. © A. Petani.