55 



main body cavity in the median plane the stomach curves downwards, endino- at 

 the pylorus at the ventro-posterior angle of the body cavity. Then commences the 

 intestine, the first part of which may, as usual, be called the duodenum. At its 

 commencement this is but little narrower than the stomach, but it rapidly narrows, 

 and, passing forwards to the antero-ventral angle of the body cavity, bends at an acute 

 angle and runs backwards and upwards along the border of the right fold of the liver, 

 crossing the stomach on the right side to enter the right lateral body cavity alonw the 

 dorsal part of which it runs to a little distance from its posterior end. The duodenum, 

 like the stomach, is white, and has thick muscular walls, but towards the posterior 

 end of the right lateral cavity it commences to get thinner walled and wider, and also 

 darker from the contents seen through the walls. It now bends completely on itself, 

 becoming considerably wider, and so passes into what may be called the ileum, which has 

 extremely thin walls. This passes forwards along the ventral side of the right cavity 

 in contact ventrally with the right ovary till it reaches to about the middle of the 

 main body cavity where, lying on the right side of the duodenum, it again bends on 

 itself and passes into the next length, which may be called the colon. At the bend, 

 and about a centimetre on either side of it, the walls are again white, thick, and 

 muscular, and the diameter of the tube is much reduced at this portion, which forms 

 a kind of ileo-colonic valve, but internally there are no transverse folds of the wall, 

 only longitudinal folds. After the bend the tube again dilates, this time suddenly, 

 and the colon, with thin flaccid walls, passes back again into the right lateral 

 cavity dorsal to the ileum, to a point about 2 cm. anterior to the end of the 

 duodenum. At this point the colon, without any change of character, passes into the 

 rectum, which passes forwards again on the dorsal side of and partially covering 

 the colon, to the antero-ventral angle of the main body cavity, wliei'e it opens at the 

 anus. 



The spleen lies anterior to the stomach, between it and the liver, and a portion of it 

 is sometimes visible on removing the right body wall, between the duodenum and the 

 rectum. There is no pancreas, and no pyloric cteca. All the parts of the intestine 

 and the liver and spleen are connected together by the branches of the splanchnic 

 artery and portal vein : these are especially conspicuous between the duodenum and 

 the liver, where they run from one to the other across the spleen. 



The gall duct runs downwards from the gall bladder and opens into the duodenum 

 a little behind the pylorus on the anterior side. The hepatic duct leaves the liver iu 

 the anofle between the two folds and joins the gall duct about 1 cm. from the gall 

 bladder. 



Cutting through the CEsophagus and the terminal part of the rectum we now 

 remove the whole of the intestine, liver, and spleen, and examine the kidne\-s auc? 

 ovaries. 



The two ovaries extend, as has been said, along the ventral border of the right 

 and left body cavities respectively. They are both about the same length, but the 



