<prompt> Lower 13 of vagina is formed byMesonephric ductParamesonephric ductSinovaginal bulbMesoderm of mullerian duct  <response>: Lower 23rd of vagina formed from sinovaginal bulb which comes from endoderm of urogenital sinus. Upper 13rd of vagina is derived from fused paramesonephric duct. Mesonephric duct forms the collecting pa or ductular pa of male reproductive system. Mesoderm of Mullerian duct is basically paramesonephric duct. 