5. =A. spermatica interna= (_h_).--This rises from the aorta on each side at about the level of the caudal ends of the kidneys, and passes laterad (or it may arise from the renal). In male specimens the artery turns caudad, along with the corresponding vein (_u_), and passes to the inguinal canal. Thence it passes along with the vas deferens and the vein (forming all together the spermatic cord) to the testes and the other structures in the scrotum. In females (Fig. 112, 2, page 265) the artery is larger and passes more nearly directly laterad, being much convoluted. It passes to the ovary, being now called the =ovarian artery=. It sends branches into the ovary (_c_) and to the cranial end of the uterus (_f_); the latter anastomosing with branches of the uterine artery (3). 6. =A. mesenterica inferior= (Fig. 126, _i_).--The inferior mesenteric artery has its origin from the aorta at about the level of the last lumbar vertebra. It passes toward the large intestine, and near it divides into two branches, the =colica sinistra=, which passes craniad along the descending colon, anastomosing with the colica media, and the =superior hemorrhoidal=, which passes caudad along the descending colon and rectum and anastomoses with the middle hemorrhoidal (page 308). 7. =A. iliolumbalis= (Fig. 126, _j_).--The iliolumbar arteries arise from the aorta about two centimeters caudad of the inferior mesenteric and pass laterad over the ventral surface of the psoas minor and iliopsoas muscles. Each divides into two main branches, one passing caudad and the other craniad; these supply the muscles of this region. The cranial branch anastomoses with branches of the adrenolumbalis (_e_). The caudal branch sends an artery through the abdominal wall to appear at the cranial edge of the thigh; it passes onto the lateral surface of M. sartorius and extends here some distance distad. 8. =A. lumbalis.=--There are usually seven pairs of lumbar arteries, passing almost directly dorsad from the dorsal surface of the aorta; the first pair arising just craniad of the diaphragm, the last at the same level as the origin of the external iliac. The two arteries of a pair usually arise from the aorta one behind the other, or they may arise by a common trunk. They correspond to the intercostal arteries. They pass between the centra of the vertebræ and the muscles of the dorsal region, and send one main branch laterad, the other dorsad; both supply the dorsal muscles. From the dorsal branch small arteries pass into the vertebral canal to join the anterior spinal artery.