212 FRANKLIN PARADISE JOHNSON 



Diameter of ('jjillu'lial tube 3.5 mm. 



Perimeter, measured at bases of glands 1 1 . 1 mm. 



Thickness of mucosa 0.40 mm. 



Tliickness of outer layers 0.27 mm. 



Number of glands touching muscularis mucosae 75.0 



Number of glands per running millimeter 6.7 



In the iliac colon of the same embryo, a slight distention is 

 present as is indicated by the thickness of both the mucosa 

 (0.32 mm.) and the outer layers (0.18 mm.). Although the 

 preservation of the embryo is poor, enough can be made out 

 from it to see that both villi and glands are shorter and broader 

 than in the transverse colon. 



In an embryo of 240 mm. the transverse colon shows some 

 distention, but not so much as was seen in this portion of the 

 large intestine at 190 mm. This is made evident by compar- 

 ing the thicknesses of the mucosa and the outer coats. As seen 

 in a model (not figured), made at double the magnification of 

 the former model, the mucous membrane presents on its lumen 

 surface a number of large irregular anastomosing folds. Be- 

 tween the folds are clefts, which in some places appear to be 

 the glands themselves; in other places they are merely crypts 

 into which the glands open. The glands are, for the greater 

 part, of the simple tubular type, but some show bifurcations 

 into two or three portions. The epithelium, which varies in 

 thickness from 0.020 to 0.034 mm., is made up of the typical 

 simple columnar cells found in the adult intestine, and contains 

 large numbers of goblet cells. The following list of measure- 

 ments is given for comparison with the other stages: 



Total diameter of epithelial tube 4.6 mm. 



Perimeter, measured at the bases of the glands 14,8 mm. 



Thickness of mucosa 0.36 mm. 



Thickness of outer coats 0.22 mm. 



Number of glands touching muscularis mucosae 114.0 



Number of glands per running millimeter 7.7 



In an embryo of 320 nun. a piece of transverse colon which 

 was greatly distended with meconium was examined. The large 

 folds of the nmcosa have all disappeared and the intestinal wall 



