Plain pocketbook mussels spend the first part of their lives in the gills of bass and other host fish. How do they get into the fish's gills? Pregnant female mussels wiggle a fleshy part of their body that looks like a small fish. When a bass tries to eat the "fish" it gets a mouthful of mussel larvae. The larvae attach to the fish’s gills, transform into juvenile mussels, and then drop to the river bottom to begin life on their own.
Pollution and silt drove these mussels from the Illinois River by 1930, but they may be returning. A live specimen was recently found in the upper Illinois River near Morris.
Native Americans used plain pocketbook shells to make spoons with elaborately carved handles.