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THE NATURAL HISTORY SURVEY. 285 
Geological distribution : Pleistocene; Loess. 
Habitat: Found generally in stagnant spots of ponds and 
rivers about decaying vegetation. Rotting fruit or vegetables 
floating in the water will be found a good habitat for this spe- 
cies. Dredged from a depth of ten meters at High Island 
Harbor, Lake Michigah. (Vide Bryant Walker.) 
Remarks: This is our largest and finest Limnea, easily 
distinguished by its great size, pointed spire and ample aper- 
ture. It varies to a great extent, principally in the form and 
size of the aperture, which is normally about the same length 
as the spire, but may be twice its length; it may also be elon- 
gately rounded or spreading and flaring. With all its variation, 
A3 
Fic. 93. 
Radula of LIMN#A STAGNALIS Linné. (Original.) c, central tooth 
(abnormal); 1, first lateral; 2, second lateral; 14, fourteenth lateral or first 
intermediate tooth; 19, 25, marginal teeth. 
however, it is easily identified and cannot be mistaken for any © 
other shell. This species may be classed with /alustris, under 
the remarks on the latter species, in regard to its food. It has 
been seen about dead carcasses of a number of animals. So 
far as known it is confined to the southern and western regions. 
Mr. Bryant Walker has called the writer’s attention to the 
fact that the typical stagnalis of Europe is not found in Amer- 
ica. Astudy of numerous specimens has convinced the writer 
