262 THE CHICAGO ACADEMY OF SCIENCES. 



on the upper outer edge of the reflection; the outer marginals 

 have all the cusps placed at the distal end and the margins are 

 simple (Fig. 83). 



Genitalia: Not examined. 



Distribution: New England to Iowa, Canada to Georgia; 

 Tepic, New Mexico.* 



Geological distribution : Pleistocene; Loess. 



Habitat: Found abundantly in small ponds and creeks 



FIG. 83. 



Radula of LIMN^A COLUMELLA Say. (Original.) c, central tooth; 

 1, first lateral; 10, first marginal; 12, 13, 16, typical marginals; 25, 30, 35, 

 outer marginals. 



where the water is more or less stagnant. Particularly fond 

 of a locality where lily pads are in abundance. 



Remarks: This species is very variable in the shape of its 

 aperture, and several distinct species have been made from 

 these variations, which will stand simply as varieties. It is 

 very frequently taken for & Sue cine a, and the shell bears a 

 very strong resemblance to that genus. The animal, however, 

 is quite different, and shows that it is a genuine Limncea. The 

 raised spiral lines are very beautiful and resemble those found 

 on many land shells. So far as known it has only been col- 

 lected in the greenhouses and lily ponds in Lincoln Park. 



*Vide J. G. Cooper, Proc. Cal. Acad. Sci., 2nd Ser., Vol. V, pt. i, p. 167, 1895. 



