Isomeria tamsiana (Dunker, 1847) comb. nov.

Labyrinthus tamsiana (Dunker, 1847), whose anatomy was described by Baker (1926) and Wurtz (1955), shows more anatomical similarities closer to Isomeria than to Labyrinthus . The presence of a vaginal swelling called ring of vaginal knobs, and the presence of a flagellar pilaster with a terminal papilla through which the vas deferens opens (Wurtz 1955), are characters known to occur in both I. awa (this study) and I. globosa (Solem 1966), the only species of the genus with described anatomies. Shells of L. tamsiana illustrated by Solem (1966) shows that the aperture has a typical subquadrate form with few teeth and lamella, characteristic also of the Isomeria species. For these reasons we reclassify L. tamsiana within the genus Isomeria .