214 VERTEBRATE ZOOLOGY 



body, and the narrow posterior portion, which bends sharply for- 

 ward and lies near the median plane. Its anterior end, where the 

 oesophagus joins it, is called the cardiac end; the posterior end, 

 where it passes into the intestine, is called the pyloric end. Its con- 

 vex left side is called the greater curvature, and the concave right 

 side the lesser curvature. The portion of the greater curvature 

 that extends farthest to the left is called the fundus of the stomach. 



Study the course of the intestine. This portion of the digestive 

 tract is made up of two divisions : an interior division, the small 

 intestine, and a posterior division, the large intestine. 



The small intestine is further divided into three parts: the 

 duodenum, the jejunum, and the ileum. The duodenum is that 

 portion immediately posterior to the stomach. Note the sharp 

 turn it makes as it leaves the pyloric end of that organ. It is 

 five or six inches in length and U-shaped, and between its two 

 limbs lies a portion of the light-red pancreas. Turn the intestine 

 to the left and the course of the duodenum will be seen. No 

 definite boundary separates the duodenum from the jejunum ; this 

 division and the ileum each form about half the remaining part 

 of the small intestine. Lift them up and note the mesentery which 

 joins them with the dorsal body wall, but do not cut it. The 

 hinder end of the ileum will be seen to lie on the right side of the 

 body, where it joins the large intestine. 



The large intestine is divided into the colon and the rectum. 

 The colon, the anterior division, is a thick tube, which lies back 

 of the liver and stomach against the dorsal body wall. The ileum 

 does not join the colon at the anterior end of the latter, but a short 

 distance from it, and the blind sac thus formed is called the caecum. 

 This pouch is a rudiment of a division of the intestine which in 

 many vegetarian animals, as the rabbit, is very long ; in man the 

 hinder portion of it is the vermiform appendix. The colon may 

 be divided into three parts: the ascending colon, the short ante- 

 rior portion, which lies on the right side of the animal and extends 

 forward ; the transverse colon, which extends transversely to the 

 left ; and the descending colon, which extends back to the rectum. 

 This last-named portion of the large intestine extends along the 

 mid-dorsal line of the body cavity to the anus. Its anterior end 



