No. 465.] GENITALIA OF LYMNAA. 671 
Lymnea reflexa Say. 
The genitalia of this species seem to agree in all essential 
characteristics with those of palustris. The penis-sac has but 
one retractor muscle while the penis has the long retractor 
inserted in this muscle as in palustris. 
Lymnea emarginata Say. (Figs. 6, 7.) 
Male Organs.— Penis and penis-sac as in palustris and reflexa. 
A single penis-sac retractor muscle in which the penis retractor 

Fic. 6.— Genitalia of Lymnea emarginata. 
is inserted. Prostate cylindrical, of large diameter, with a 
somewhat bulbous proximal extremity, which narrows behind 
and then enlarges, to contract again before connecting with the 
ovisperm duct. 
Female Organs.— The vagina is rather short and of large 
