the excretory organ serving as the adult kidney of fishes and amphibians and as the embryonic kidney of higher vertebrates: the mesonephros and its duct develop into the epididymis and vas deferens in higher vertebrates
Origin:
ModL < meso-, meso- + Gr nephros, kidney: see nephro-
The second of the three excretory organs that develop in a vertebrate embryo, becoming the functioning kidney in fish and amphibians but replaced by the metanephros in higher vertebrates. Also called Wolffian body.