Ischadium

Ischadium is a monotypic genus of mussels in the family Mytilidae. The sole species is Ischadium recurvum, known as the hooked mussel or bent mussel. It can be found along the Atlantic coast of North America, ranging from Cape Cod to the West Indies. They are often found growing on eastern oysters, either intertidally (south of the Chesapeake Bay, where exposed oysters can survive the winter) or subtidally. They also attach to other hard substrates, including artificial reefs and dead shells of the brackish water clam Rangia cuneata.