EXPLANATION OF PLATE L 



The figures are from photographs which have been retouched. The 

 photographs were taken with millimeter cross-section paper for a back- 

 ground and the scale can be obtained from this. Figure 1 is less en- 

 larged than figures 2 and 3, 



Figures 1, 2 and 3. Gastrodonta imperforata new species. 



Figures 4, 5 and 6. Pyramidula viascallensis new species. 



Figures 7, 8 and 9. Polygyra expansa new species. 



Figures 10, 11 and 12. Polygyra inartini new species. 



(12) 



