OF NORTH AMERICA. 519 



PLATE XXI. 



Figure 1. Lymncea stagnalis higleyi BAKER. Michipicoten Island, Lake Superior. 

 TYPE (23050). 



2. Lymncea stagnalis higleyi BAKER. Michipicoten Island, Lake Superior. 



(23052). 



3. Lymncea stagnalis higleyi BAKER. Michipicoten Island, Lake Superior. 



COTYPE (Coll. Ferriss). 



4-5. Lymncea stagnalis sanctcemarice WALKER. Siskowit Lake, Isle Roy- 

 ale, Mich. (23927). 



6-7. Lymncea stagnalis sanctcemarice WALKER. Specimens showing 

 thickening of columella by callus, thus obscuring the gyrate 

 character of the axis. Figure 7 shows the formation of the 

 callus, while figure 6 shows the typical condition. The latter is 

 a younger shell. (23926.) 

 8-9. Lymncea stagnalis lilliance BAKER. Lake Harriett, Minneapolis, 



Minn. (23049). 

 10-12. Lymncea stagnalis lilliance BAKER. Tomahawk Lake, Wisconsin. 



TYPES (24554). 

 Figures 4 to 7, slightly reduced; figure 2, enlarged; balance natural size. 



PLATE XXII. 



Figures 1-2. Lymncea stagnalis appressa SAY. Nautilus, VI, pi. 1, figs. 2-3. 

 % nat. diam. 



3. Lymncea stagnalis appressa SAY. Distortion. Nautilus, VI, pi. 1, fig. 



1. % nat. diam. 



4. Lymncea stagnalis appressa SAY. Variety. Dredged from depth of 10 



meters in Lake Michigan, at High Island Harbor, Beaver 

 Island. (Photo by Walker.) 



5. Lymncea stagnalis perampla WALKER. Nautilus, VI, pi. 1, fig. 6. % 



nat. diam. 



6. Lymncea stagnalis lilliance BAKER. Minnehaha River, Minn. (Coll. 



Hemphill). 

 7-8. Lymncea stagnalis sanctcemarice WALKER. TYPES. Nautilus, VI, 



pi. 1, figs. 4-5. % nat. diam. 

 9-11. Galba utahensis (CALL). Bull. U. S. Geol. Surv., II, pi. 6, figs. 



7-9 (x2). 

 12-15. Radix auricularia (LINNE). .Greenhouse, Lincoln Park, Chicago 



(23087). Slightly enlarged. 



PLATE XXIII. 



Figures 1-3. Lymncea stagnalis sanctcemarice WALKER. Sault Ste. Mariae, Mich. 



(23051). 



4-5. \Lymncea stagnalis occidentals HEMPHILL. Lake Whatcom, Wash- 

 ington. TYPES (Coll. Hemphill). 



6-7. Lymncea lepida GOULD. Tryon's Continuation Haldeman's Mono- 

 graph, pi. 16, figs. 12-13. 



8. Pseudosuccinea columella (SAY). Pennsylvania (23061). 



9. Pseudosuccinea columella (SAY). Greenwood, S. C. (23060). 

 10-12. Pseudosuccinea columella (SAY). Bradford, Conn. (23063). Figure 



11 is a typical macrostoma SAY. 



