250 The Molluscan Family Planorbidae 



PLATE 7 



Anisus leucostomus and Ainsus septemgyratus 



1-5. Anisus leucostomus (Millet). From small pond in Bielany Park, Warsaw. Poland; 

 collected by A. Jankowski. 



1. Foot, pseudobranch, and pneumostome. 



2. Genitalia dissected and the organs separated. Figure under seminal vesicle 



shows this organ stretched out. 



3. Muscular ring or diaphragm in upper part of preputiimi showing papilla with 



stylet protruding. 



4. End of oviduct and vas deferens showing where ovisperm duct joins the ovi- 



duct and vas deferens. 



5. Stylet. 



6. Anisus septemgyratus (Ziegler). From turfy meadow in Drewnica, 4 km. northwest 

 of Warsaw, Poland; collected by A. Jankowski. 



6. Outline of genitalia exclusive of the penial complex. 



Line near figure indicates 1 mm. in length. Line at left of 

 fig. 5 is only for .size of figs. 3 and 4. 



