Clams are marine mollusks and belong to the bivalve class, with body structures similar to cockles, oysters, and clams.However, their two outer shells connect along the back but also fuse slightly at the rear end, forming a clear drainage hole in the back.On the posterior margin of the mantle, many branched tentacles grow.Water flows through the body of the clam from these tentacle-bearing mantles into the mantle cavity, then passes through the gills to the back and is discharged through the drainage hole.Clams use flowing seawater for respiration and circulation, and they also feed on tiny organisms carried in by the water flow.
