Elimia potosiensis (Lea, 1841)

A-C. Color Variations. Length, 19 mm. Franklin Co., Meramec River at Meramec State Park, 4 mi. SE of Sullivan, on gravel in shallow water. Frieda Schilling. D. Color variation and carinate form. Length 15 mm. Washington Co., Big River south of Potosi, on gravel in shallow water. Frieda Schilling. E. Dwarfed, Ozark cold spring variety. Length, 9 mm. Phelps Co., Meramec Spring at St. James, on rocks in ice cold, swift moving water. Frieda Schilling.