THE COD. ic; 



the anus. Take a second incision passing verti- 

 cally dorsalwards from the anterior end of the 

 first, and a third sloping obliquely backwards and 

 upwards from its posterior end : carefully lift up 

 the flap of muscle as you make these cuts so as to 

 be sure that none of the internal organs are 

 injured. Extend both cuts upwards until the 

 body cavity is well exposed ; then fasten back or 

 remove the flap of muscle. Observe the following 

 points without further dissection : — 

 100. The abdominal cavity, enclosed by the muscular 

 walls of the body, ending in front at about the level of the 

 shoulder girdle, and extending posteriorly for a short distance 

 behind the anus, 



loi. The peritoneum (parietal layer), a pigmented mem- 

 brane lining the abdominal cavity. The visceral layer of 

 the peritoneum is reflected over the viscera (see § no). 



102. The liver (Fig. 31, Ir), a large brown-coloured 

 organ, with its broad attached end at the anterior boundary 

 of the abdomen and its long left (/r3) and short right (/;-') 

 and middle (Ir'') lobes extending backwards towards the 

 posterior end of the cavity. 



103. The stomach (Fig. 31, st), a wide thick-walled tube, 

 passing from the front wall of the abdomen, backwards to 

 within a short distance of the anus, where it becomes bent 

 forwards upon itself: in the undisturbed position of the 

 parts it is largely covered by the liver. 



104. The intestine (Fig. 31, dm., il., rd), a coiled tube, 

 connected anteriorly with the recurved portion of the 

 stomach, and ending behind in the anus (see § 119). 



105. The pyloric caeca (Fig. 31, py.c) numerous small 

 blind tubes, arranged in bunches around the small intestine 

 at its junction with the stomach. 



