294 The MoUuscan Family Planorbidae 



PLATE 29 



Helisoma 



1-6. Helisoma trivolvis pseudotrivoivis (F. C. Baker) ^ lentum Say. From St. Joseph, 

 Champaign Co., Illinois; collected by F. C. Baker. 



1. Penial complex with penial gland duct spread out to show length. 



2. Penial complex in section showing penial gland m natural position in pre- 



putium. 



3. Penial complex with penial gland duct coiled on preputium. 



4. Penial gland in section. 



5. Penial complex in section showing preputium pushed upward and penial gland 



duct vmcoiled. From Illinois River, Peoria, Illinois. 



6. Neck of animal showing penial gland everted. From Reelfoot Lake, Tennessee. 



7-13. Helisoma trivolvis lentum (Say). From Xew Orleans, Louisiana; collected by 

 E. C. Faust. 



7. Penial complex with penial gland everted. 



8. Penial complex with penial gland duct uncoiled. 



9. Verge fully extended with sections in two places as indicated. 



10. End of verge showing exit of sperm canal with small, lip-like processes sur- 



rounding the opening. 



11. Head and neck of animal showing penial gland and verge everted. 



12. Penial complex with penial gland and verge everted. 



13. Verge in fig. 12 removed from penial complex. 



14-16. Helisoma trivolvis macrostomum (Whiteaves). 



14. Penial complex. From Bayfield, Wisconsin; collected by F. C. Baker. 



15. Penial complex with preputium pushed upward. Same locality as fig. 14. 



16. Penial complex with penial gland duct uncoiled. From Lake Gauvreau, 



Canada; collected by A. LaRocque. 



17,18. Helisoma trivolvis fallax (Haldeman). From Cambridge, Massachusetts; col- 

 lected by W. J. Clench. 



17. Penial complex showing large size of preputium. 



18. Exterior view of penial gland. 



19-22. Helisoma chautauquense F. C. Baker. From Chautauqua Lake, New York; 

 collected by F. C. Baker. 



19. Penial complex of immature specimen. 



20. Exterior view of penial gland. 



21. Verge much retracted. 



22. Penial complex of adult .specimen in normal condition. 



Line near figure indicates 1 mm. in length. In fig. 10 line equals 0.5 mm. 



