The nephridial organs of flatworms are called metanephridia.

Nephridial Organs

Excretory organs found in many invertebrates, functioning similarly to kidneys in removing metabolic wastes from the organism’s body.

Metanephridia

Excretory organs in many invertebrates, such as annelids, that filter body fluid directly from the coelom.

Flatworms

A group of simple, soft-bodied invertebrate animals that include planarians, tapeworms, and flukes, known for their flat bodies.