Epididymis, light micrograph. The epididymal duct is a long coiled tube (6-7 meters) that appears as many sections in the micrograph. This is a section of the head epididymis, showing a very dilated epididymal duct filled with spermatozoa, which appear as blue plugs in the lumen. Along the bottom border of the section are the efferent ducts (which connect the rete testis with the initial section of the epididymis) with their typical irregular wall and a lymphoid nodule.