IocrinusIocrinus is an extinct genus of crinoid. It is an early form of crinoid, from the Ordovician rock of North America, England, and Gilwern [Hill, Powys] in Wales.Selected species Iocrinus brithdirensis Iocrinus crassus Iocrinus pauli Iocrinus shelvensis Iocrinus similis Iocrinus subcrassus Iocrinus trentonensis ''Iocrinus whitteryi''