148 



ANATOMY OP THE DOMESTIC FOWL 



intestine, only the first, the duodenum, can be distinguished. There 

 is no demarcation between the jejunum and the ileum. The je- 

 junum and the ileum or that part which represents these sections, 

 are in coils suspended from the free border of the mesentery the 

 other border of which is, in turn, attached to the dorsal wall (Fig. 

 64). The length of the small intestine in a hen of average size is 

 about 61.7 inches. 



iif^tt 



Fig. 36. 



A. Section of the duodenum of the fowl, i, Villus. 2, Gland, 

 lymphoid tissue. 4, Muscularis mucosa. 5, Longitudinal layer, 

 muscular layer. 7, Serous layer. 



B. A section from A a.t a. i, The striated free border of the cells, 

 cell. 3, Columnar cell. 4, Nucleus of cell. 



3, Mass of 

 ), Circular 



2, Goblet 



The wall of the small intestine is provided with four coats, as 

 follows: a mucous, submucous, muscular coat made up of two layers 

 — the outer, longitudinal and the inner circular layer, and an 

 external serous. 



The mucous membrane which lines the intestine is thick, soft, and 

 highly vascular. It has a velvety appearance, due to niunerous long, '. 

 thin projecting villi. The villi (Fig. 36, A) are concerned in th^ 

 absorption of the digested food, absorbing principally the e mulsifi ed 

 fats. Each villus is covered with a single layer of high columnar' 

 epithehal cells. Some of these, the so-called goblet cells, provide 



