Pimple-back, Quadrula pustulata (Lea) a; Purple pimple-back, Quadrula granifera (Lea), from Mississippi River, b & c; Three-horned warty-back, Obliquaria reflexa (Rafinesque), d; pimple-back, Quadrula cooperiana (Lea) from Cumberland River, e; Purple pimp

Freshwater and Marine Image Bank, University of Washington Libraries Digital Collections