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). 
Genitaha: 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 
1% 413 16 
[/P [- Lui 
25 go ie 
Fie. 83. 
Radula of LIMN2ZA 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 variablein 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 a Swccginea, and the shell bears a 
very strong resemblance to that genus. The animal, however, 
is quite different, and shows that it is a genuine Limnea. 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. 1, p. 167, 1895, 
yo De 
rE ig he Ting 
