518 THE CHICAGO ACADEMY OF SCIENCES. 



11. Lymnaa maxima STEARNS. Univ. Cal. Pub., Geol., V, p. 69, fig. l. 



Type. 



12. Lymnaa contracosta J. G. COOPER. Proc. Cal. Acad. Sci., ii, IV, pi. 



14, fig. 12. Type. 



13. Lymn&a scudderi COCKERELL. Bull. Am. Mus. N. H., XXII, p. 461, 



fig. 4, a. Type;, b, narrow variety of scudderi; x l / 2 . 



14. Lymn&a sieverti COCKERELL. L. c., fig. 3. Showing interior of shell 



and outside. of a portion near the mouth; X 4. 



PLATE XVIII. 

 Section of shells to show axis. 

 Figure 1. Acella haldemani ('DESK/ BINNEY). 23936. 



2. Galba bulimoides cocker elli (PiLS. & FERR.). 23940. 



3. Galba obrussa (SAY). 24506. 



4. Galba palustris (MULLER). 23987. 



5. Pseudosuccinea columella (SAY). 23931. 



6. Galba randolphi (BAKER). 23675. Young. 



7. Lymncea stagnalis appressa SAY. 23925. 



8. Bulimnea megasoma (SAY). 23097. 



9. Radi-x auricularia (LINNE). 23934. 

 10. Galba reftexa (SAY). 23988. 



Figures Enlarged. 



PLATE XIX. 



Figures 1, 2. Lymncea stagnalis LINNE. Baden, Germany (23008). 



3. Lymnaa stagnalis LINNE. Elba River, Germany (Coll. Walker). 



4. Lymnaa stagnalis appressa SAY. Braddocks Bay, Lake Ontario, N. 



Y. (23035). 



5-6. Lymnaa stagnalis appressa SAY. Round Bay, Lake Ontario, N. Y. 

 (23006). 



7. Lymn&a stagnalis appressa SAY. Calumet Lake, Ills. (Coll. Ferriss). 



8. Lymnaa stagnalis appressa SAY. Pigeon Lake, Ontario (23046). 



9. Lymncea stagnalis appressa SAY. Calumet River, Ills. (8113). 

 10. Lymn&a stagnalis appressa SAY. Romeo, Ills. (23009). 



Figures Natural Size. 



PLATE XX. 



Figures 1, 2, 3. Lymncea stagnalis appressa SAY. Squaw Island, Niagara River, 

 N. Y. (Coll. Walker). 



4. Lymn&a stagnalis appressa SAY. Calumet Lake near Pullman, Ills. 



(19584). 



5. Lymncea stagnalis appressa SAY. Bear Lake, Mich. (23014). 



6. Lymnaa stagnalis appressa SAY. Batavia, N. Y. (23015). 



7. Lymnaza stagnalis perampla WALKER. Houghton Lake, Mich. CO- 



TYPE (23924). 



8. 9. Lymncea stagnalis perampla WALKER. Douglas Lake, Mich. (Coll. 



Ferriss). 

 10-12. Lymncea stagnalis wasatchensis HEMPHILL. Near Ogden, Utah. 



TYPES (Coll. Hemphill). 

 Figure 6, enlarged 1 1/3 ; figure 5, enlarged 2 diameters ; balance natural size. 



