290 The Molluscan Family Planorbidae 



PLATE 27 



Helisoma campamdatum (Say) 

 From Oneida Lake, New York, near Brewerton; collected by F. C. Baker. 



1. Section through penial gland. 



2. Albumen gland from below. 



3. Section through diaphragm showing relationship of penial gland duct to vergic 



sac. 



4. Section through ovotestis near anterior end. 



5-7. Penial complex of Helisoma campayiulatum sniithi (F. C. Baker), from 

 Douglas Lake, Michigan, showing variation in form, especially the preputium. 



-14. Helisoma campaiudatinn canadense F. C. Baker. From Sturgeon Lake, Ontario, 

 Canada; collected by Dr. A. R. Cahn. 



8. Penial complex. 



9. Penial complex showing penial gland duct coiled between preputium and 



vergic sac. Also variation in muscles. 



10. Section of penial complex showing relationship of penial gland to verge. 



11. Penial complex with penial gland duct uncoiled to show length. 



12. Section through prostate near middle of gland. 



13. Pseudobranch, pneumostome, and rectum. 



14. Genitalia dissected and organs separated. 



Line near figure indicates 1 mm. in length 



