526 THE CHICAGO ACADEMY OF SCIENCES. 



PLATE XXXVI. 



Figures 1-6. Galba reHexa (SAY). Rock Run, Joliet, Ills. (23546). Pathologic 



forms. 



7-11. Galba crystalensis (BAKER). Crystal Lake, Ills. (TYPES, 23634) 

 =reHexa, immature. 



12. Galba reilexa walkeri (BAKER). Calumet River, Ills. (23572). 



13. Galba reilexa walkeri (BAKER). Calumet Lake, Ills. (23570). 



14. Galba reilexa walkeri (BAKER). Joliet, Ills. (23569). 



15-16. Galba reilexa walkeri (BAKER). Wolf Lake, Ills. (23571). 



17. Galba reilexa walkeri (BAKER). Silver Lake, Ills. (23527). 



18. Galba reilexa walkeri (BAKER). Silver Lake, Ills. (23578). A form 



with spire resembling that of exilis. 

 19-20. Galba reilexa hemphilliana (BAKER). Lake Albert Lea, Minn. 



TYPES (Coll. Bryant Walker, 14037). 

 21-22. Galba exilis (LEA). Calumet River, Ills. (23577). 

 Figures 11 and 13 are enlarged \ l / 2 diameters; the other figures are about 



natural size. 



PLATE XXXVII. 



Figure 1. Galba exilis (LEA). Berry Lake, Chicago, Ills. (23583). 



2. Galba exilis (LEA). Antrim Co., Mich. (23591). 



3. Galba-cxilis (LEA). Winnebago Co., Ills. (23580). 

 4-6. Galba-exilis (LEA). Mercer Co., Ills. (23582). 

 7-10. Galba exilis (LEA). Des Moines, la. (23585). 



11. Galba exilis (LEA). Des Moines, la. (23595). 



12-13. Galba kirtlandiana (LEA). Crystal Lake, Ills. (23607). 



14-16. Galba kirtlandiana (LEA).' Mud Lake, Grand Crossing, Chicago, 



Ills. (23610). 



17-18. Galba lanceata ( GOULD). Carp Lake, Emmet Co., Mich. (23593). 

 19-22. Galba lanceata (GOULD). Tomahawk Lake, Wis. (23590). 

 23-24. Galba attenuata (SAY). Near City of Mexico (Coll. Walker). 

 Figure 4, enlarged about \ l / 2 diameters; figures 1-3, 11-24, slightly enlarged; 

 figures 5-10, natural size. 



PLATE XXXVIII. 



Figures 1-2. Galba danielsi (BAKER). Lake Maxinkuckee, Ind. (TYPES, 



23622). 



3. Galba danielsi (BAKER). Lake Maxinkuckee, Ind. Pathologic speci- 

 men. (Coll. Bartsch). 



4-8. Galba danielsi (BAKER). Lake Maxinkuckee, Ind. (23624). 

 9-11. Galba proxima (LEA). San Francisco, Cal. (23642). 



12. Galba proxima (LEA). San Mateo, Cal. (23641). 



13. Galba calif ornica (SOWERBY) =. proxima (LEA). Specimen com- 



pared with Sowerby's type in British Museum (Walker coll.). 



14. Galba proxima rowellii (TRYON). San Francisco, Cal. (Coll. Hemp- 



hill). 



15-18. Galba proxima rowellii (TRYON). San Francisco, Cal. (23659). 

 Showing variation toward proxima. 



