The small (2.2–2.8 mm.) shell is oval in shape and thin and fragile. It is broad and flattened (laterally compressed) with flattened umbos near the midpoint. The colour is yellowish-white and the periostracum (surface) is silky with fine, concentric striation.
Ecology
P. conventus is a relict of colder climatic periods found only in deep, cold, upland lakes.