Pirate XIX 
Fig.1 Viviparus unicolor (Olivier). Lake Kabamba. 
Fig. 2. Neothauma tanganyicense var. bridouxianum Giraud. lLuvu Bay, 
Lake Tanganyika. 
Fig. 3. Neothawma tanganyicense E. A. Smith. Lake Tanganyika. 
Fig. 4. Neothawma tanganyicense var. bicarinatum Bourguignat. Off Kalemb- 
we, Lake Tanganyika. 
Fig. 5. Neothauma tanganyicense E. A. Smith. Moliro, 20m., Lake Tan- 
ganyika. 
Fig. 6. Viviparus mweruensis EH. A. Smith. Pweto, Lake Moero. 
Fig. 7. Viviparus mweruensis pagodiformis E. A. Smith. Kilwa, Lake Moero. 
Figs. 8-9. Pila congoensis Pilsbry and Bequaert. Opercula of adult and young 
individuals Stanleyville. 
Fig. 10. Pzrla congoensis amplior Pilsbry and Bequaert. Operculum. 
