The =anterior mesenteric artery= (Fig. 63, No. 5; Fig. 64, No. 26) originates from the posterior aorta near the generative glands. It is directed downward, and divides into many branches which pass in the mesentery toward the intestines. Recurrent branches (Fig. 64, No. 27) are given off, which anastomose, forming mesenteric arches. From these arches are given off branches which supply the intestinal walls. The anterior mesenteric artery gives off the _recurrent ilio-celiacus_ (Fig. 64, No. 28) which is distributed to the cæca; other of its branches are distributed to the small intestine. The anterior mesenteric artery extends along the small intestine and ends in the _recurrent superior hemorrhoidal arteries_ (Fig. 64, No. 29) which anastomoses on the surface of the rectum with a branch of the posterior mesenteric artery. Branches from the anterior mesenteric artery also anastomose with branches of the celiac axis. The =posterior mesenteric artery= (Fig. 64, No. 30) is given off from the posterior aorta posterior to the origin of the anterior mesenteric and near the arteries of the thigh and is distributed to the lesser mesentery supplying the large intestine. Branches of the superior hemorrhoidal arteries anastomose with branches of the posterior mesenteric artery. Branches from this source are called the _median hemorrhoidal_ (Fig. 63, No. 6). The posterior mesenteric artery (Fig. 64, No. 30) also gives off a long branch to the cæca. Branches of the posterior mesenteric artery anastomose with branches of the anterior mesenteric. The =crural arteries= (Fig. 64, No. 31) are given off in a pair from the posterior aorta. They pass through the mass of the lobes of the kidneys, at about the median region, and extend out of the pelvic cavity in front of the spine and ilio-pubic ligament. [Illustration: FIG. 65.—Blood-vessels and nerves of the hind extremity. Inside view of leg. 1, Ischiadic nerve. 2, Ischiadic artery. 3, Posterior tibial vein. 4, Vena metatarsa dorsalis interna. 5, Vena metatarsalis plantaris profunda. 6, Vena cruralis. 7, Vena metatarsalis interna, vena magna. 8, Vena tibialis postica. 9, Vena metatarsa magna. 10, Nerves of the toes. 11, Vena metatarsalis dorsalis profunda. ] The crural, or the external iliac artery, is divided into three branches as follows: First, the _internal pelvic_, or _umbilical artery_, is given off just as the cruralis leaves the pelvic cavity. It passes, as a long vessel, on the inner surface of the lumbo-sacral bones and supplies the obturator internus muscle and extends into the umbilical region. It gives off branches to the abdominal muscles, and, in the female, a branch is distributed to the ligament of the oviduct. Second, the _arteria circumflex femoris_, which passes between the sartorius and vastus internus and extends dorsalward, supplies the sartorius muscle, the vasti muscles, and the ilio-trochanteric region.