Mesentery. The radial muscular plate which occurs in the Anthozoa (q.v.). They support the digestive tube and the reproductive organs: they divide the body-cavity into a number of chambers or loculi. In the human body the abdominal contents are enveloped in the folds of the great serous membrane known as the peritoneum. The folds of peritoneum which envelop the small intestine pass backwards to become continuous with the rest of the peritoneum in the neighbourhood of the spinal column, and the two layers of serous membrane contain the blood-vessels, nerves, and lymph vessels, which are transmitted to the small intestines. The whole connecting structure serves as a kind of ligament which tethers the intestines to the vertebral column, and is called the mesentery.