paired ducts of the embryo that run down the lateral sides of the urogenital ridge and terminate at the mullerian eminence in the primitive urogenital sinus. In the female, they will develop to form the fallopian tubes, uterus, and the upper portion of the vagina; in the male, they are lost. These ducts are made of tissue of mesodermal origin[WP]. develops either by lengthwise splitting of the archinephric duct (in chondrichthyans and some amphibians) or by a elongated invagination of the coelomic epithelium (other vertebrates) In males, the oviducts regress. The cranial end of the oviduct maintains an opening into the coelom (which primitively may have been the anteriormost coelomic funnels connecting the nephrocoel with the coelom). This opening is the ostium tubae[USM]. [ http://amigo.geneontology.org/amigo/term/GO:0061205 http://www.usm.maine.edu/bio/courses/bio205/bio205_26_sex.html http://en.wikipedia.org/wiki/Paramesonephric_duct ]