218 FRANKLIN PARADISE JOHNSON 



From table 1 it would appear that the earlier longitudinal 

 folds which develop before the 120 mm. stage are lost. Later 

 oblique folds are formed which, owing to their course, position, 

 and constancy, must be the plicae semilunares coli. These 

 folds, however, are not present in portions of the large intestine 

 which are distended, although the opposite view is held by some 

 regarding those of the adult. 



THE VERMIFORM PROCESS 



Early development 



The history of the mucosa of the vermiform process in the 

 human embryo is quite similar to that of the colon. One finds 

 first an epithelial tube with smooth walls and a round lumen. 

 Later as the tube grows in size, folds appear. The folds give 

 place to villi and glands develop. With the development of 

 glands the villi disappear. Unlike the glands of the colon, 

 however, those of the vermiform process oftentimes develop into 

 cysts, which degenerate, and thus cause a decrease in the num- 

 ber of glands. In the following brief description, numerous 

 references are made to the already described conditions of the 

 large intestine. 



The early development of the vermiform process has been 

 described in connection with the early stages of the colon. In 

 the last-described stage (42 mm.) it is a simple tube of epithe- 

 lium of about two to four cell nuclei in thickness, and presents 

 on its inner surface three or four slight ridges. x\t 55 nnn. the 

 epithelial tube is decidedly large near its base (0.60 mm.), but 

 rapidly becomes smaller when followed towards its tip. The 

 epithelium of the basal portion is thrown into ridges which resem- 

 ble very much those of the ascending colon of the same embryo. 

 A few vacuoles are present in some of the higher ridges. In 

 the base of the vermiform process of an embryo of 58 nnn. (diam- 

 eter only 0.40 mm.) the epithelial ridges are more numerous 

 They continue distalward for a short distance and gradually 

 fade out. 



