Twenty penis from normal boars were injected with various media at known reservoir pressures and examined by radiography, dissection, maceration, clearing and sectioning. Injections into the corpus spongiosum penis (csp) produced dorsal deviation and clockwise spiral twisting. The ccp was traversed by a system of large longitudinal cavernous spaces. The csp consisted of one large vascular space, its walls joined by trabeculae which were close together ventrally and further apart dorsally. The corpus spongiosum glandis (csg) was a vascular network within the penile integument communicating with the csp by fine vascular spaces around the urethral orifice. The penile arteries and veins were supplied and drained by the internal pudendal vessels. The ccp was drained from its crura by the v profunda penis but no venous drainage of this cavernous body was demonstrated within the body of the penis. The csp was drained from its bulb by the v bulbi penis; its distal extremity was drained by two large veins which ran proximally enclosed by the tunica albuginea of the csp. The right vein was always much larger than the left vein and at the sigmoid flexure the two united to form the right tributary of the v dorsalis penis. The csg and the entire penile integument were drained by the left tributary of the v dorsalis penis; the csg was also drained by one or both of the ventral veins of the csp. Blood from the scrotum was drained by the v circumflexa perinealis and v perinealis ventralis into the v dorsalis penis and v penis. A large dorsal lymphatic vessel drained lymph from the body of the penis into the pelvic lymph nodes. No connections with the superficial inguinal lyphocentres were identified.