The scrotum contains the external spermatic fascia, testes, epididymis, and ductus deferens. The accumulation of sperm increases pressure in the vas deferens and epididymis. An epididymal cyst is a cyst of the epididymis containing serous liquid. It carries the spermatozoa from the epididymis to ejaculatory duct. Sperm are produced in the testes and stored in the attached epididymis. An inflammation of the epididymis is called epididymitis. Opossum spermatozoa exhibit sperm-pairing, forming conjugate pairs in the epididymis. In men, inflammation of the epididymis, prostate gland, and urethra can result from untreated gonorrhea. While in the epididymis the spermatozoa gain motility and become capable of fertilization. Spermatoceles can originate as diverticulum from the tubules found in the head of the epididymis. The sperm that are produced in the seminiferous tubules flow into the epididymis. The bacteria in the urethra back-track through the urinary and reproductive structures to the epididymis. Sperm is matured in the epididymis for about a month before leaving the testicles. The stereocilia in the epididymis are non-motile. The epididymis is covered by a two layered pseudostratified epithelium.