_c._ =A. hemorrhoidalis media= (Fig. 126, _r_).--The middle hemorrhoidal passes ventrad from the hypogastric, onto the lateral surface of the rectum. It passes caudad near the ventral side of the rectum as far as the anus. A short distance from the origin it gives off a branch which passes almost directly ventrad toward the beginning of the urethra. In the male this branch is small, sending twigs to the urethra and the prostate. In the female it is much larger, forming =A. uterina= (Fig. 112, 3, page 265). The uterine artery turns craniad onto the uterus, which it supplies, passing to the cranial end of the uterine cornu and anastomosing with the ovarian artery. The middle hemorrhoidal gives off in the female branches to the vagina (Fig. 112, _m_) and neck of the bladder (_k_), and a large branch to the urogenital sinus (_n_); it then supplies the anal glands and other structures about the anus, and anastomoses with the terminal branches of the hemorrhoidalis superior. In the male branchlets are given to the urethra, to the bulbourethral (or Cowper’s) gland, and to the penis. The =A. dorsalis penis= is a small branch which passes along the median dorsal groove of the penis to the glans. The middle hemorrhoidal then supplies the structures about the anus and anastomoses with the superior hemorrhoidal, as in the female. _d._ =A. glutea inferior= (Fig. 126, _q_).--This is the terminal portion of the hypogastric. It passes along with the great sciatic nerve to the great sciatic notch, and reaches the medial surface of M. pyriformis. It divides into branches which supply the gluteus and pyriformis muscles, while a small branch accompanies the great sciatic nerve. A small branch also passes onto the lateral surface of the tail, extending caudad along its side. 11. =A. sacralis media= (Fig. 126, _o_).--This is the continuation of the aorta into the sacral and caudal regions. It extends to near the end of the tail, lying in the ventral middle line against the sacral and caudal vertebræ. In the caudal region it passes through the hæmal arches, covered by the chevron bones. Between the vertebræ it gives off side branches comparable to the intercostal and lumbar arteries of the aorta. Branches of the sacralis media: _a._ =A. sacralis lateralis.=--Behind the first sacral vertebra a large branch, the lateral sacral, is given off on each side. This enters the first anterior sacral foramen, gives a branch to the structures in the sacral canal, and sends a dorsal branch out through the posterior sacral foramen to the muscles on the dorsal side of the sacrum. Similar but smaller branches are given off between the succeeding vertebræ, sacral and caudal. _The External Iliac and its Branches._--The origin of the external iliac (Fig. 126, _k_) is described above (page 307). It gives off the following branches: