mesonephros In the development of an amniote embryo, the part of each kidney that at first is concerned with excretion. In later development that role is assumed by the metanephros, the mesonephros degenerating in females and in males becoming connected to the testes and associated with reproduction.

mesonephros (Wolffian body) (mes-oh-nef-ross) n. kidney tissue that is functional only in the embryo. Its duct – the Wolffian (or mesonephric) duct – persists in males as the epididymis and vas deferens.
—mesonephric adj.