English: Unio sp. lives on the silted and sandy bottom of rivers, lakes and ponds. This inactive animal feeds passively. Toothless food is suspended in water particles of detritus (the smallest remains of plants and animals). The mollusk filters them out of the water passing through the mantle cavity. In the posterior part, both shell valves and mantle folds do not adhere tightly to one another; between them there are two holes - siphons. The lower, inlet, siphon serves to introduce water into the mantle cavity. A continuous directed flow of water is carried out due to the movement of numerous cilia. Water washes the gills and provides gas exchange; it also contains food particles. Through the upper, outlet, siphon, the used water together with excrement is discharged outside

English: Unio sp. in the natural environment. Sumy region, the river Sejm