50 THE STRUCTURE OF THE FOWL 



dorsal wall of the abdomen by a thin mem- 

 brane, the mesentery. The duodenum, on the 

 contrary, is very readily recognised (Figs. 12, 

 15, and 22). Beginning at the right side of the 

 muscular stomach it forms a long loop, con- 

 sisting of descending and ascending limbs, 

 extending as far as the entrance to the pelvis, 

 and sloping somewhat obliquely from right 

 to left. 



The large intestine is very short, and does 

 not differ very markedly from the small 

 intestine in its calibre. It runs in an approxi- 

 mately straight line ventral to the vertebrae 

 and ends in the cloaca (Fig. 12). Though 

 unnecessary, it is sometimes the practice to 

 describe the tube as consisting of two parts, 

 the colon and the rectum, the latter name being 

 then applied to the terminal part of the gut. 



At the junction of small and large intestines 

 are two cceca — long tubes, with somewhat wider 

 blind extremities directed towards the liver 

 (Fig. 23). The caeca always contain a larger 

 or smaller amount of material, often of a dark 

 colour. 



Inasmuch as it is in the intestines that 

 much of digestion and the whole of absorption 

 take place, their structure is of importance. 



