504 Intestinal Folds and Villi in Vertebrates 



PLATE VII. 



Figures illustrating the development of the crypts of Lieberkiihn and 

 the disappearance of villi from the large intestine of* young white rats. 



Fig. 81. Surface views of villi and crypts from the small intestine 

 of a 3-day white rat. V=villus, encrypt. X 50 diameters. 



Fig. 82. Sections from the large intestines of several white rats to 

 show the disappearance of villi. All the figures X 58 diameters. 



(a) Five days after birth. 



(b) Six days after birth. 



(c) Eight days after birth. 



(d) Eight days after birth, more advanced stage. 



(e) Eleven days after birth. 



Fig. 83. Villi and beginning crypts from a 3-5-day white rat (after 

 birth). C=crypts. X 300 diameters. 



Figs. 8-1 and 85. Beginning crypts from the small intestine of a 

 white rat 3-4 days after birth. X 300 diameters. 



Fig. 86. Crypt of Lieberkiihn from the intestine of a 4-day white 

 rat. X 300 diameter^,. 



Fig. 87. Lieberkiihn crypt from the small intestine of a white rat, 

 36 days after birth. X 300 diameters. V = parts of villi, c ^ crypt 

 and s = surface of the intestine between villi. 



