Va Sa, (from defero, to convey). Immediately beneath the tunica albuginea are lodged the testicles, the tubuli of which run on to form the epididymis. They then become larger, unite, and form the vasa deferentia, which ascend in the spermatic cord behind the blood vessels; and having got through the abdominal rings, are reflected downwards, and passing on the back of the bladder, between that and the ureter, go on the inside of the vesicula seminalis, to its anterior end, where they unite with the vesicula; and, from the union of these with the vesiculae seminales, two ducts are formed and continued, which gradually approaching each other, become contiguous at the notch, in the basis of the prostate gland, and terminate in a small duct on each side of the caput gallinaginis, in the urethra. At a distance from the vesiculae seminales, the vas deferens is hardly capable of admitting an hog's bristle; but, as it approaches the vesicula, it grows larger both externally and internally, and becomes cellular and tortuous. The use of these vessels is to contain the sperm secreted from the blood, and to carry it into the spermatic vessels.