: Adult size from 4.75 to 7.25 inches. Shape
: Elliptical; L:H ratio close to, or exceeding, 2.0. Dorsal posterior margin may be compressed and formed into slight wing, but this trait is variable. Valves laterally inflated, thin, and fragile. Beaks
: Low; rarely project above the hinge line. Periostracum
: Yellowish, yellowish-brown, brown, or black. Some specimens may have a tinge of green. Periostracum is usually shiny, and growth lines are usually evident. Hinge Teeth
: None. Nacre:
White or bluish-white, sometimes pinkish toward the central portion of the nacre and iridescent toward the posterior end.
For a discussion on Anodonta
taxomony, please refer to the original publication, The Freshwater Mussels of the Pacific Northwest.