Hi Lucas,
 
I agree with G's ID of your snail. I've collected them in several widely
scattered lakes in Minnesota...at one location they were over 2" in length and
of an olive green color with very few growth marks, and no hint of brown. At
another, they were all smaller, and mostly brown, very much resembling your
images, although slighty eroded.
 
Hey G, has the specific name "chinensis" been officially dropped? Everything
in my library calls it C. chinensis malleatus.
 
Ken Zentzis
Wichita, Kansas
 
G Thomas Watters wrote:
>
> At 12:54 PM 5/6/99 -0700, you wrote:
> >I found this snail shell in the flood bank of a pond near the DesPlaines
> >River in River Forest, IL near Thatcher and Washington.
> >
> >Can you suggest what species it might be? Or point me to a web site where I
> >might be able to find it's classification?
> >
>
> Looks like Cinpangopaludina malleatus (Reeve, 1863), an exotic viviparid
> that is widespread in the US. Could be a little greener, but it seems too
> big and lacks the bands of our native viviparids. It certainly occurs in