concava = hollow
Shell much depressed; suborbicular, horn colour, or whitish, immaculate; volutions five, irregularly wrinkled across, more convex beneath; suture distinctly impressed; umbilicus very large exhibiting all the volutions to the summit distinctly; aperture large, shirt; labrum towards the base very slightly and inconspicuosly reflected.
Inhabits Illinois and Missouri.
Greatest width 7-10 of an inch.
Found in moist places near the Mississippi river, on the Missouri as high council bluff, and on the sea islands of Georgia. It is a much depressed shell.
Original Description Citation:
Say, T. (1821). Description of univalve shells of the United States. Journal of the Academy of Natural Sciences of Philadelphia. 2(1): 149-179.
Nature Serve Conservation Status: