94 LIMN^A. 



general form appears to approach my L. Gahhil. 

 The latter, however, is rather more robust, 

 and has no umbilical opening. 



Subgenus BULIMNEA, Haldeman. 



8. LIMN^A MEGASOMA, Say. 

 Hald., p. 13, t. 3, figs. 1, 3. 



Inhabits from Lake Champlain westward in 

 the great lakes to Michigan. 



Subgenus LIMNOPHYSA, Fitzinger. 



'^ Shell large, narrow, with elevated sphx. 

 9. LIMN^A REFLEXA, Say, 



Hald., Monog., 26, t. 8. 



L. umbrosa, Say, Hald. Monog. 24, t. 7, figs. 1, 2, 3, 6, 7, b. 



L. zebra, Tryon, Plate 16, fig. 14. 



I have concluded, after careful study of a 

 large series of specimens, that my L. zebra 

 (68) 



