On the genus Typhlopolycystis Karling, 1956 (Platyhelminthes, Kalyptorhynchia, Polycystididae), with data on the five known species and the description of eleven new species Author Schockaert, Ernest R. Author Moons, Patricia Author Janssen, Toon Author Tessens, Bart S. Author Reygel, Patrick C. Author Revis, Nathalie Author Jouk, Philippe E. H. Author Willems, Wim R. Author Artois, Tom J. text Zootaxa 2019 2019-05-08 4603 1 81 104 journal article 26901 10.11646/zootaxa.4603.1.4 1fa78a19-6a9c-498b-89b5-a0d6ceb58080 1175-5326 2673305 9539EFE1-7676-4015-946B-9F1A2782AB38 Typhlopolycystis riegeri n. sp. Artois & Schockaert. ( Figs 12 A–C) Diagnosis . Colourless species of Typhlopolycystis of about 1 mm with a proboscis 1/6 to 1/5 of the body length and with eyes. The prostate stylet is rather broad (18 and 14 µm , 14 µm in the holotype ), 99 (in the holotype ) and 104 µm long, almost straight in the proximal 2/3 of its length, then bent over 90° and tapering to a blunt end. The accessory stylet starts at the convex end of the main stylet; after a short turn over 180° it is straight and pointed, 104 and 91 µm long. The proximal diameter is 26–29 µm . The prostate vesicle seems reduced. The seminal receptacle is pear-shaped. Occurrence. Tanzania : Mbweni (Zanzibar Island), beach behind the Mbweni Ruins Hotel, south of the creek, in a higher part of the tidal sand flat, with relatively coarse sand (by Artois & Schockaert, 11 August 1995 ; Type Locality). Same locality but north of the creek, in a small pool with sea-grass ( Thallasia spec.), all at low tide. Material examined . A whole mount from the type locality, indicated as holotype . (SMNH nr 8917). A second whole mount from the second habitat (HU nr III.1.47). Etymology . We dedicate this species in honour and friendship of the late Prof. Dr. R. Rieger (Innsbruck, Austria ).