Dear friends:

        A friend of mine brought me an interesting shell from his trip to
the Okanvango Delta, in Bostwana. It is sinistral, about 45 mm big, greenish
in colour, and silky in appearance. It was collected inside the water, so it
seems to be a fresh water species, rather than a land or tree snail. Do you
know what species is it? I have no experience nor references for this sort
of shells.
        Thank you, and greetings from southern Spain

                                Manuel Jimenez Tenorio