Anatomy of <i>Plicadomus sulcatus </i>and taxonomical structure of Mauritian Gibbinae (Gastropoda, Pulmonata, Streptaxidae)

Gibbinae subfamily in the Mauritius Island is represented by four taxa of generic rank. The anatomy of the type species of three of them has been known previously. The description of the reproductive tract of the fourth - Plicadomus sulcatus (Müller, 1774) is presented. It is shown that under striking conchological differences the anatomy of members of all four taxa is very similar and differs in quantitative characters only (the ratio of the length of the separate elements: the vagina / free oviduct and the relative length of the penis.). On the basis of this fact it was concluded that Mauritian Gibbinae is represented by a single genus Gibbus Montfort, 1810 with four subgenera ( Gonospira Swainson, 1840, Plicadomus Swainson 1840, Gonidomus Swainson, 1840, and Gibbus s. str.).