670 THE AMERICAN NATURALIST. [Vor. XXXIX. 
lum seminis very large and globular, its duct very fine, enlarging 
somewhat at the point of insertion near the opening of the 
vagina. Ovotestis and nerves as in stagnalis. 
The colors of the organs are: albuminiparous gland and 
uterus bright yellow, receptaculum seminis and prostate yellow- 

Fic. um Genitalia of Lynn P MES TA ARS d 

ish, penis-sac blackish, muscles, 
whitish or flesh-colored. 
Palustris differs from stagnalis in the greater length of the 
penis, has a larger receptaculum seminis, a more pear-shaped 
uterus, and the proximal end of the prostate is pyriform, not 
bulbous, 
penis, vas deferens, and nerves 
