326 THE CHICAGO ACADEMY OF SCIENCES. 



Iowa : Missouri River, in the vicinity of Council Bluffs, Pottawattamie 

 Co. (Say). 



Michigan: Grand Rapids, Kent Co. (Currier; McNeil); Stoney Creek, 

 Monroe Co. (Sister Mary Katherine) ; East Saginaw, Saginaw Co. (Lathrop) ; 

 Ecorse and Greenfield, Wayne Co. ; Higgins River, Roscommon Co. (Walker) ; 

 Galien River, New Buffalo, Berrien Co. (Webster). 



Minnesota: Ponds, southern Minnesota (Shimek). 



New Jersey: White Pond, Sussex Co. (Pilsbry and Rhoads). 



New York: South Ogden Street pond, Buffalo, Erie Co. (Letson) ; Chip- 

 pewa Creek, Erie Co. (Letson; Miss Walker); Sacketts Harbor, Jefferson Co., 

 Lake Ontario (Phil. Acad) ; Canandaigua Lake, Ontario Co. (Say) ; Litchfield, 

 Herkimer Co. (Walker). 



Ohio: Shore of Johnson's Island, near Sandusky, Erie Co.; pool at 

 Linndale, near Cleveland, Cuyahoga Co. (J. A. Allen) ; Cincinnati, Hamilton 

 Co. (Anthony; Shaffer) ; Toledo, Lucas Co. (F. A. Bossard) ; Columbus, Frank- 

 lin Co. ( H. Moores) ; Miami Canal, Lockland, Hamilton Co. (Walker). 



South Dakota: Brookings Co. (P. C. Truman). 



Wisconsin : In pool, Johnson's woods, near National Soldiers' Home, 

 Milwaukee, Milwaukee Co. (C. E. Brown) ; Lake Mendota, Dane Co. (C. 

 Judey) ; Madison, Dane Co.; Kenosha, Kenosha Co. (Mrs. Wiswall). 



BRITISH AMERICA. 



Ontario: Rainy Lake and Seine River, Rainy River Dist. (Say). 



Geological Range : Xot differentiated by authors from that of 

 palustris. 



Ecology : Inhabits ponds and sloughs which become more or less 

 dry in summer. 



Remarks : Elodcs differs from palustris in having more loosely 

 coiled whorls and in being narrower and more attenuated, with more 

 fiat-sided whorls. The spire is very narrow and considerably longer 

 than the aperture. In narrow specimens of both species, clodes is seen 

 to have a longer and more compressed body whorl and a narrower 

 and longer aperture. In the majority of cases elodes is easily sepa- 

 rable from palustris, the whorls of elodes being comparably longer than 

 in palustris, though not as long as in reflexa. 



This is the form which is frequently confounded with reflexa and 

 which has caused the statement to be so frequently made by writers 

 that "palustris runs into reflexa:" In reflexa the body-whorl and the 

 penultimate whorl are normally very long in comparison with their 

 height; they are usually (in the typical form) flatly rounded and 

 oblique ; the first to the fourth whorls are very small and regularly 

 increase, while the fifth to seventh whorls increase disproportionately 

 in size ; in elodes all of the whorls have usually a regular increase. 

 The upper whorls of reflexa also have a puffy appearance, while those 

 of elodes are more evenly rounded. The aperture in reflexa is very 

 different, being strongly reflexed and "bayed" just below the columellar 



