498 Intestinal Folds and Villi in Vertebrates 



PLATE IV. 



Drawings from sections of embryo cbick's intestines. 



Fig. 50. (a) Transection of the small intestine of an 11-day chick. 

 X 60 diameters, (b) Longitudinal section through folds from the duo- 

 denum of an 11-day chick. X 60 diameters. 



Fig. 51. Transection of the small intestine of a 13-day chick. X 60 

 diameters. 



Fig. 52. Longitudinal section through a single fold of a 13-day 

 chick's intestine. X 60 diameters. 



Fig. 53. Longitudinal section of the small intestine of a 11-day chick 

 where villi are partly formed. X 60 diameters. 



Fig. 51. Longitudinal section of a single fold from a 14-day chick. 

 The larger part of the fold is where the section has cut deepest into the 

 base, and the smaller end is where the top of the fold is cut through at 

 the place where villi are beginning to be formed. X 60 diameters. 



Fig. 55. Longitudinal section of the cfecum of a 13-day chick. X 60 

 diameters. 



Fig. 56. A'illi from the c?ecum of a 16-day chick. X 60 diameters. 



Fig. 57. Villus bud from the small intestine of a 3-5-day white rat. 

 X 300 diameters. 



Fig. 58. Section of large intestine of a 14-day chick. X 2 TO diame- 

 ters. 



Fig. 59. Epithelial projection or villus bud from the large intestine 

 of an embryo white rat. X 417 diameters. 



