502 Intestinal Folds and Villi in Vertebrates 



PLATE VI. 



Figures of sections and wax reconstructions from the intestine of 

 embryo white rats, to show the development of folds and villi. 



Fig. 71. Cross section of white rat's intestine; length of embryo 

 3.3 cm. X 56 diameters. 



Fig 72. Same as Fig. 61 near the pylorus. X 56 diameters. 



Fig. 73. Section of intestine from white rat of 3.4 cm. Villi partly 

 formed. X 56 diameters. 



Figs. 74 and 75. Sections of different stages from a white rat of 

 2.3 cm. in length. X 56 diameters. 



Fig. 76. Eeconstruction of a single fold removed from near the 

 pylorus of a young embryo of white rat. Thick end of fold is taken 

 nearest the pylorus. X 100 diameters. 



Fiff. 77. Eeconstruction of the rest of the intestine from which the 

 above was taken. The pyloric end of the piece is away from the ob- 

 server and has one more fold than the end towards the observer. X 100 

 diameters. 



Fig. 78. Portion of white rat's intestine after the folds are beginning 

 to break up into smaller parts. X 133 diameters. 



Figs. 79 and 80. Different views of reconstructions showing folds 

 iartjolv divided into ^-illi. X 100 diameters. 



