332 The Molluscan Family Planorhidae 



PLATE 48 



Digestive System of Planorbidae 



1. Helisoma trivolvis (Say). Entire digestive system except liver. From above. 



2. Helisoma trivolvis (Say). Region of the stomach from below. 



3. Carinifex ponsonbyi E. A. Smith. Region of stomach from below. 



4. Promenetus exacuous (Say). Region of stomach from above. 



5. Promenetus exacuous (Say). Region of stomach from below. 



6. Planorbis planorbis (Linn.). Region of stomach from above. 



7. Planorbis planorbis (Linn.). Region of stomach from below. 



8. Bathyomphalus contortus (Linn.). Portion of digestive system from above. 



9. Atistrnlorbis glabratns (Say). Region of stomach from above. 

 10. AuMralorbis glabratus (Say). Region of stomach from below. 



IL Drepanotrema hicidum (Pfeiffer). Region of stomach from above. 



12. Hippeutis complanatus (Linn.). Region of stomach from above. 



13. Gyraulus albus (Miiller). Region of stomach from above. 



14. Gyraulus parvus (Say). Region of stomach from above. 



15. Armiger crista (Linn.). Region of stomach from above. 



16. Segmentina nitida (Miiller). Region of stomach from above. 



17. Helisoma anceps (Menke). Nerves and blood vessels to penial complex. Nerve 



from left cerebral ganglion. 



18. Nerve ring of Helisoma trivolvis (Say), from above. 



Line near figure indicates 1 mm. in length 



