DESCRIPTION OF THE PLATES. 



Plate I. 



1,2. Neritina fluviatilis 1 



."}. Neritina fluviatilis, the 



operculum 2 



4,5. Paludiua vivipara ."} 



(), 7. Paludina achatina 4 



8,9. Paludiua impura 4 



10, 11. Paludina ventricosa ... 5 



12, 13. Assiminia Grayana 



14, 15. Valvata piscinalis fi 



16, 17. Valvata piscinalis, var. 7 



18,19. Valvata cristata 7 



20. Valvata cristata, young ... 7 



21,22. Lymnsea stagnalis 8 



23, 24. Lymnsea stagnalis, var. 8 



25. Lymnsea stagnalis, young.. 8 



26,27. Lymnsea minuta 9 



Plate II. 



1,2. Lymnsea palustris 9 



3, 4, .5, 6, 7, 8, 9, 10. Lymntea 



palustris, different varieties 9 



11, 12, 13, 14. Lymnsea auri- 



cularia 11 



1.5, 16, 18, 19. Lymnsea peregra 11 

 17, 20, 21, 22, 23, 24, 25. Lym- 

 nsea peregra, different 



varieties - 12 



27. Lymnsea involuta 13 



Plate III. 



1, 2, 3, 4. Lymnsea elongata. 10 



5,6. Amphipeplea lacustris... 14 



7,8. Amphipeplea glutiuosa.. 13 



9,10. Physa acuta 16 



1!, 12. Physa fontinalis, var. 1 15 



Flu. PAGE 



13, 14. Physa fontinalis 15 



15, 16. Physa fontinalis, var. 2 15 



17, 18. Physa hypnorum 16 



19, 20. Planorhis spirorhis 23 



21, 22, 23. Planorhis corneus . 17 



24, 25. Planorhis coutortus 24 



26,27,28. Planorhis marginatus 20 

 29. Planorhis marginatus, a 



litsus natiirce 21 



30,31. Planorhis alhus 18 



32,33. Planorhis vorte.x 22 



34, 35, 30. Planorhis cariuatus. 20 



37,38,39. Planorhis Isevis .... 18 



40, 41. Planorhis imhricatus ... 19 



42,43. Planorhis imhricatus, var. 19 



Plate IV. 



1,2. Planorhis nitidus 23 



3,4. Segmentina lineata 25 



5, 6. Planorhis marginatus, 



young 21 



7. Planorhis carinatus, var. ... 20 



8, 9. Carychium minimum ... 28 

 10, 11. Cyclostoma elegans ... 26 



12. Bulimus luhricus 34 



13, 14. Cyclostoma marmorea. 27 



15. Acme fusca 28 



16. Acme minuta 29 



17. 18. Bulimus montanus 34 



19. Succinea ohlouga 31 



20,21. Succinea amphihia 30 



22, 23. Succinea gracilis, var. 31 



24,24.* Bulimus ohscurus 33 



26, 27. Succinea gracilis 30 



28,29. Achatina Acicula 32 



30. Baltea fragilis 36 



