44 



PUOCEKDINGS OF TlIK MA I.ACnLOGICAL SOCIETV. 



Fk;. 



4. 



f). 



6. 



7. 



S. 



9. 

 10. 

 11. 

 1-2. 

 13. 

 14. 

 1.5. 

 16.) 

 17./ 

 IS. 

 19. 

 '20. 

 21. 

 22. 

 23. 



HeUcella Heripcnsis (Mab. 



Eastbourne, East Sussex. 



Stoner Hill, near Petersfiekl, South Hants. 



Laleham, Middlesex. 



Cambridge. 



liingstead, Nortliants. 



Market Harborough, Leicestershire. 



Brough, near Hull, South-East Yorks. 



Oakley, Northants. 



Devil's Dyke, near Brighton, West Sussex. 



Bignor, West Sussex. 



]3uckden, Hunts. 



Horn Head, West Donegal. 



Stradbally, Dingle Peninsula, South Kerry. 



Marshes near Lewes, East Sussex. 



Marshes near Lewes, East Sussex. 



Marshes near Eastbourne, East Sussex. 



Marshes near Lewes, East Sussex. 

 Planorbis vorticulus, Troschel. Marshes near Lewes, East Sussex. 

 P. vortex (Linn.). Marshes near Lewes, East Sussex. 



The uppermost of the four specimens shown in Fig. 10 is an immature shell, 

 which has the somewhat sharp peripheral keel characteristic of juvenile 

 examples of H. Hcripensis. 



Figs. 15, 16, and 17 I'epresent the large Western Irish form of H. caperatn. 



The lowest examples given in Figs. 19 and 21 are juveniles, which may be 

 comj)ared with specimens of V. cristata of equal diameter. The shells shown 

 in Figs. 18, 19, and 21 were all taken in the same habitat. 



Yah 



caper ata (Mont.) 



ata cristata, Miill. 



V. macrostoma, Steenbuch. 

 T'. piscinalis, Miill. 



