174 



NORMAL HISTOLOGY. 



columns, the mucous membrane is replaced by the skin lining the lower 

 segment of the anal canal. The surface of the rectal mucosa is punctated 

 with minute tubular depressions, the rectal pits of Cunningham, at the 



Lumen of 



caecun 



Orifice of 



appendix 







Circular muscle 



Lymph-nodul 



Mucous 



Groups of 

 fat-cells 



FIG. 216. Longitudinal section through junction of vermiform appendix and caecum. X 10. 



bottom of each of which is an accumulation of lymphoid tissue resembling a 

 lymph-nodule. The submucous coat is lax and contains the extensive hemor- 



Circular muscle 



Lymph-nodule - 



Submucous 

 coat 



FIG. 217. Transverse section of vermiform appendix. X 10. 



rhoidal plexus of veins. In addition to the temporary folds, the rectal 

 mucous membrane presents usually three crescentic shelf-like projections, 

 the rectal valves, that are ineffaceable. These plicae are formed by the 



