292 The MoUuscan Family Plauorhidae 



PLATE 28 



Helisoma 



1-5. Helisoma oregoncnse (Tryon). From Tooele Co., Utah; collected by J. Hen- 

 derson. 



1. Penial complex showing long penial gland duct. 



2. Genitalia dissected and organs separated. 



3. Cross section of prostate near middle of gland. 



4. Penial gland viewed from above. 



5. Section through penial gland. 



6-14. Helisoma scalare (Jaj'). From Lake Butler, Florida; received from Dr. E. A. 

 Andrews. 



6. Entrance of penial gland duct into vergic sac. 



7. Section through penial gland. 



8. Pseudobranch and pneumostome. 



9. Penial complex with preputium pushed upward. 



10. Penial complex in normal position, the penial gland duct extended. 



11. Penial complex in section to show relationship of organs. 



12. Section through prostate near middle. 



13. Section through ovotestis near anterior end. 



14. Genitalia dissected and organs separated. 



Line near figure indicates 1 mm. in length 



