EXPLANATION OF PLATE XXXII. 

 Figure 1. LIMN/EA PALUSTRIS Muller. 



" 2. LlMN^EA PALUSTRIS EXPANSA Lea. (SUFFLATUS Calkins). 



" 3. LlMNiEA REFLEXA EXILIS Lea. 



" 4. LlMN^EA REFLEXA JOLIETENSIS Baker. 



" 5. LIMN^EA PALUSTRIS MiCHiGANENSis Walker. Large va- 

 riety. 



" 6. LIMN^A REFLEXA Say. 



" 7. PLANORBIS TRIVOLVIS Say. Age variation. 



" 8. PLANORBIS TRIVOLVIS Say. 



" 9. PLANORBIS TRIVOLVIS Say. 



" 10. PLANORBIS TRIVOLVIS Say. (DISTORTUS Calkins). 



" 11. PLANORBIS CAMPANULATUS Say. 



" 12. PLANORBIS BICARINATUS Say. 



" 13. PHYSA SAYII Tappan. Short spired variety. 



" 14. VALVATA TRICARINATA Say. Enlarged. 



" 15. VALVATA SINCERA Say. Enlarged. 



" 16. APLEXA HYPNORUM Linne. 



All figures natural diameter except where otherwise mentioned. 



