148 



ANATOMY OF 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. 





FIG. 36. 



A. Section of the duodenum of the fowl, i, Villus. 2, Gland. 3, Mass of 

 lymphoid tissue. 4, Muscularis mucosa. 5, Longitudinal layer. 6, Circular 

 muscular layer. 7, Serous layer. 



B. A section from A at a. i, The striated free border of the cells. 2, Goblet 

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



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 numerous long, 

 thin projecting mill. The villi (Fig. 36, A) are concerned in the 

 absorption of the digested food, absorbing principally the emulsified 

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

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



