312 THE ANATOMY OF THE HORSE. 



descend, one on each side of the branches of that artery, until they 

 reach the intestine. At the concave edge of the bowel the two layers 

 separate ; and, after encircling the tube as visceral peritoneum, they 

 meet and become continuous at its convex or free border. Where the 

 mesentery suspends the first part of the jejunum it is continuous with 

 the peritoneal frsenum of the duodenum ; and at its opposite extremity, 

 where it envelopes the termination of the ileum, it passes on to the 

 caecum. At the latter point it will be observed that the two layers of 

 mesentery do not become continuous around the convex border of the 

 ileum, but are prolonged beyond that, so that the terminal portion of 

 the small intestine is included in the mesentery some distance from its 

 free edge. 



The Colic Mesentery. — This is the membrane that suspends the single 

 or floating colon. It is composed of two layers of peritoneum, which 

 leave the roof of the abdomen along a line extending from the root of 

 the anterior mesenteric artery to the inlet of the pelvis. These two 

 layers include between them the posterior mesenteric artery and its 

 branches ; and, after enveloping the single colon, they become continuous 

 at its free edge. At its anterior extremity the colic mesentery is con- 

 tinuous with the great omentum and with the great mesentery, and at 

 the pelvic inlet it is continuous with the meso rectum. 



The Uterine Broad Ligaments. — These are the double peritoneal folds 

 that suspend the uterus, ovaries, and Fallopian tubes. Each ligament 

 leaves the roof of the abdomen in the lumbar region, and descends to 

 the concave edge of the cornu, and to the side of the upper face of the 

 body, of the uterus. At these points the layers of the ligament sepa- 

 rate, and pass on to the uterus as its visceral covering. The ligaments 

 are widely apart in front ; but as they are traced backwards they become 

 narrower and nearer to each other. The Fallopian tube is sustained 

 between the two layers of each ligament at its anterior edge, and here 

 the fimbriated extremity of the tube opens into the sac of the peri- 

 toneum. In the female, therefore, the peritoneum does not form a closed 

 sac. Stretching between the ovary and the uterine cornu is a cord of 

 non-striped muscular tissue — the ligament of the ovary — which forms 

 the free edge of a small secondary fold of peritoneum. This forms with 

 the adjacent part of the broad ligament a pocket-like cavity. On the 

 outer side of the broad ligament another secondary fold extends as far 

 as the internal abdominal ring, and contains a layer of non-striped 

 muscular tissue corresponding to the round ligament of the human 

 uterus. Besides some scattered fibres of non-striped muscle, the layers 

 of the broad ligament include between them the uterine and ovarian 

 vessels and nerves. 



The other peritoneal ligaments will be described in connection with 

 the organs to which they belong. 



