318 The Molluscan Family Planorbidae 



PLATE 41 



Promenetus exacuous (Say) 

 From Winnebago Lake, near Oshkosh, Wisconsin; collected by F. C. Baker. 



L Penial complex. Swollen gland causing bulge in preputium. 



2. Penial complex, external view, showing a single retractor muscle. 



3. Penial complex opened to show verge and penial gland. 



4. Cross section of ovotestis about midway of its length. 



5. Cross section of prostate near anterior end. 



6. Ovotestis viewed from left side of animal, showing diverticula. 



7. Albumen gland from the side. 



8. Head and neck of animal showing pseudobranch. 



9. Head of animal showing verge and jienial gland ]>rojecting from the male genital 



opening. 

 10. Genitalia dissected and organs separated. 



Line near figure indicates 1 mm. in length. Line at left of figs. 4 and 5 is for 

 both of these figures. Figure 7 has the same magnification as fig. 10. 



