266 The Molluscan Family Planorbidae 



PLATE 15 



Gyraulus 



1-7. Gyraulus hirsutus (Gould). From Bass Creek, Lake Nipissing, Ontario, Canada; 

 received from A. LaRocqiie. 



1. Genitalia dissected and organs separated. A portion of the intestine is shown 



beneath the albumen gland. 



2. Penial complex, external view. 



3. Fore end of body showing pseudobranch, pneumostome, rectum, etc. 



4. Distal end of genitalia showing connection of various ducts. From right side. 



5. Same as fig. 4, from left side. 



6. A single diverticuhun of the prostate with duct separate from the sperm duct. 



7. Two diverticula of the ovotestis. 



8-10. Gyraulus vcrmicularis (Gould). From Stone Lake, Golden Gate Park, San 

 Francisco, California; from Dr. G. D. Hanna. 



8. Fore end of body showing pseudobranch. 



9. Distal end of genitalia showing relationship of ducts. 

 10. Genitalia dissected and organs separated. 



Line near figure indicates 1 mm. in length. Line in upper left 

 corner of plate is for figs. 4, 5, 6, and 7. 



