242 The Molluscan Family Planorhidae 



PLATE 3 



Segmentina and Bathyo))iphalus 



1-4. Segmentina nitida (Miiller). From meadow near Warsaw, Poland; from A. Jan- 

 kowski. 



1. External view of penial complex. 



2. Hermaphrodite complex. 



3. Cross section of prostate and ducts of prostate and vas deferens. 



4. Head showing position and form of pseudobranch. 



5-10. Bathyomphalus contortus (Linn.). From Drewnica, a turfy ground 4 km. north- 

 east of Warsaw, Poland; collected by A. Jankowski. 



5. Head showing position and form of pseudobranch. 



6. Pseudobranch showing position of rectum. 



7. Cross section of ovotestis. 



8. Cross section of prostate showing prostate duct sei)arate from sperm duct. 



9. Penial complex from the outside. 



10. Hermaphrodite complex dissected and spread out. 



Line near figure indicates 1 mm. in length. Line at left of fig. 7 also repre- 

 sents size of figs. 3 and 8. Figure 9 is same magnification as fig. 10. 



