The<unk>  (Latin for "middle kidney") is one of three excretory organs that develop in vertebrates. It serves as the main excretory organ of aquatic vertebrates and as a temporary kidney in higher vertebrates. The<unk>  is included in the Wolffian body after Caspar Friedrich Wolff who described it in 1759. (The Wolffian body is composed of :<unk>  + paramesonephrotic blastema)
Mesonephros
Yolk sac
Metanephric blastema
Urachus
Amniotic sac
Spermatic cord
Callus
Fallopian tube