Dorsal aorta

Each primitive aorta receives anteriorly a vein—the vitelline vein—from the yolk-sac, and is prolonged backward on the lateral aspect of the notochord under the name of the dorsal aorta. The paired dorsal aortae arise from aortic arches that in turn arise from the aortic sac.

The dorsal aortae give branches to the yolk-sac, and are continued backward through the body-stalk as the umbilical arteries to the villi of the chorion.

The two dorsal aortae combine to become the descending aorta in later development.