HISTOLOGY 



123 



poorly developed in the colon and well developed in the rectum. The mus- 

 cularis externa and the serous membrane are like those of the small intes- 

 tine. Taeniae are absent (56). 





Epithelium 



Goblet cell 



Intestinal gland 



Lamina propria 



Muscularis mucosae 



Solitary follicle 



ibmucosa 



-Muscularis externa 



Fig. 57. — Colon, longiludinal section. (X200.) 



Solitary lymph follicles are present in varying numbers. They extend 

 into the submucous layer. Peyer's patches are also found. The ascending 

 part of the colon contains several (about fourteen) parallel transverse folds, 

 which are made up of the mucous membrane (Fig. 57). In the descending 

 colon and rectum the fecal material is pellet-shaped. Where pellets are 

 found the lumen is slightly distended and smooth, while between them 

 longitudinal folds (colic ridges) are present (55). The first part of the 



