Pisidium nitidum
Pisidium nitidum, the shining pea clam, is a species of minute freshwater clam, an aquatic bivalve mollusc in the family Sphaeriidae, the pea clams and fingernail clams. Description. The 3 – 4 mm. shell is slightly tumid (swollen). In shape it is regular-oval with low umbos slightly behind the midpoint. The umbonal area is demarcated by three concentric furrows. The surface (periostracum) is very glossy, with prominent irregularly spaced concentric striae. The colour is yellowish. Distribution. Its native distribution is Holarctic.