Efferent ductules

At the upper end of the mediastinum, the vessels of the rete testis terminate in from twelve to fifteen or twenty ducts, the ductuli efferentes; they perforate the tunica albuginea, and carry the seminal fluid from the testis to the epididymis. 

Their course is at first straight; they then become enlarged, and exceedingly convoluted, and form a series of conical masses, the coni vasculosi, which together constitute the head of the epididymis. Each cone consists of a single convoluted duct, from 15 to 20 cm. in length, the diameter of which gradually decreases from the testis to the epididymis. Opposite the bases of the cones the efferent vessels open at narrow intervals into a single duct, which constitutes, by its complex convolutions, the body and tail of the epididymis. When the convolutions of this tube are unravelled, it measures upward of 6 meters in length; it increases in diameter and thickness as it approaches the ductus deferens. The convolutions are held together by fine areolar tissue, and by bands of fibrous tissue.

The ductuli efferentes and the tube of the epididymis have walls of considerable thickness, on account of the presence in them of muscular tissue, which is principally arranged in a circular manner. These tubes are lined by columnar ciliated epithelium