tf&4 THE CHICAGO ACADEMY OF SCIENCES. 



20-24. Galba obrussa (Say). Abandoned quarry, Lemont, Ills. (23967). 

 25. Galba obrussa (Say). Joliet, Ills. (Ferriss coll.). 

 26-31. Galba obrussa (Say). Joliet, Ills. (23197). 

 32. Galba obrussa (Say). Boulder, Colo. (23201). 

 33-34. Galba obrussa (Say). Owasco Lake, N. Y. (23195). 

 35-37. Galba obrussa (Say). Clear Lake, La Porte, Ind. Immature. 

 (23257). 

 All figures enlarged about two diameters. 



PLATE XXXII. 



Figures 1-6. Galba obrussa peninsulas (Walker). Types (Walker Coll. 24269). 

 7-9, 13. Galba obrussa exigua (Lea). Aroostook Co. (23293). 

 10-12. Galba obrussa exigua (Lea). Near Des Moines, Iowa (23973). 



14. Galba obrussa exigua (Lea). Near Charlotte, N. Y. (23972). 



15. Galba obrussa decampi (Streng). Brooks Lake, Mich. Cotype 



(Walker Coll., 10847). 

 16-21. Galba obrussa decampi (Streng). Caribou, Maine (23307). 

 22. Galba obrussa decampi (Streng). Ann Arbor, Mich. (23303). 

 23-24. Galba galbana (Say). Alpena, Mich. (23310). 

 25-27. Galba galbana (Say). White Pond, N. J. (23311). 

 28-36. Galba galbana (Say). Squaw Island, Niagara River, N. Y. 



(23313). 



All figures enlarged about two diameters. 



PLATE XXXIII. 



Figure 1. Galba palustris (Muller). Braddock'.s Bay, N. Y. (Long-spired 

 specimen, 23612). 

 2-7. Galba palustris (Muller). Owasco Lake, N. Y. (23425). 

 8-10. Galba palustris (Muller). Owasco Lake, N. Y. (23518). 

 11. Galba palustris (Muller). Seattle, Wash. (23345). 

 12-13. Galba palustris (Muller). Madison Lake, Mont. (23387). 

 14-18. Galba palustris (Muller). Florissant, Colo-. (23511). 



19. Galba palustris (Muller). Goshen, Colo. (Pathologic, 23453). 



20. Galba palustris (Muller). Near Ward, Colo. (Immature, 23655). 



21. Galba palustris (Muller). North Platte City, Neb. (23388). 



22. Galba nuttalliana (Lea) =palustris (Muller). California (23518). 



23. Galba nuttalliana (Lea) =palustris (Muller). Brigham City, Utah. 



(Coll. Hemphill). 



24. Galba nuttalliana (Lea) =palustris (Muller). California (23350). 



25. Galba haydeni (Lea) =palustris (Muller). California (Coll. Hemp- 



hill). 



26-30. Galba palustris alpenensis Baker. Thunder Bay Island, Alpena, 

 Mich. (Types, 23486). 



31. Galba palustris alpenensis Baker. Whitefish Point, Alpena, Mich. 



(23492). 

 32-33. Galba palustris alpenensis Baker. Long Island, Alpena, Mich. 



(23491). 



