SEXUAL DUCT VESTIGES. “In males, the Wolffian duct becomes the efferent or deferent duct (including the epididymis, vas deferens, and seminal vesicle) that stores and transports sperm and seminal fluids. In females, the Wolffian duct degenerates and remains solely as a withered rudiment.”
https://evolution-outreach.springeropen.com/articles/10.1186/s12052-014-0012-5