280 The Molluscan Family Plauorbidae 



PLATE 22 



Indoplanorbis and Helisoma 



5-9. Indoplanorbis exustus (Deshayes). Continued from plate 21. 



5. Retractor muscle of verge showing branching to vergic sac. Also nerve 



connection. 



6. Cross section of preputium in extended condition as .-^hown in fig. 7. 



7. Penial complex of specimen in breeding condition with preputium extended 



from male opening in neck. Compare with fig. 1 on plate 21. 



8. Section of vergic sac through bulbous termination of verge. 



9. Section of vergic sac through verge. 



Line near figure indicates 1 mm. in length. Figure 5 is enlarged. Figure 6 



has same magnification as fig. 7. These figures 



were published in Jour. Morph. 



1. Helisoma anccps latchfordi (Pilsbry). 



1. Verge. Also enlarged portion of vas deferens (epiphallus). 



2-4,11. Helisoma anccps pcrcarinatiDii (Walker). 



2-4. A'ariation in form of muscles and in position of verge in preputium. Greatly 

 enlarged. 



11. Penial gland with cup turned back to show folds in inner cup. 



10, 12. Helisoma anccps (Menke). 



10. End of verge .showing papilla and sperm canal outlet. 



12. Prostate showing attachment of prostate duct to sperm duct. 



Line near figure indicates 1 mm. in length 



