ESOPHAGUS, STOMACH AND INTESTINE 



179 



vagus nerves of the adult organ, the left nerve supplying the ventral wall of the 

 stomach, originally the left wall, while the right vagus supplies the dorsal wall, 

 originally the right. 



Gastric pits are indicated in 16 mm. embryos and at 100 mm. gland cells of the gastric 

 glands are differentiated. These undoubtedly arise from the gastric epithelium, according to 



Tongue 



Rathke's 

 pouch 



Yolk-stalk 



Allantoic 



stalk 



Cloaca 



Metan- 

 ephros 



Meson- 



ephric 



duct 



Laryngo- 



tracheal 



groove 



L. lung 



Stomach 



Liver 



Dorsal 

 pancreas 



Allantois 



FIG. 171 B. Reconstruction of a 5 mm. human embryo showing the entodermal canal and its 

 derivatives (His in Kollmann's Handatlas). 



Lewis. The cardiac glands are developed early (91 mm. embryos) and, according to Lewis, 

 there is no " evidence in favor of Bensley's conclusion that the cardiac glands are decadent . . . 

 fundus glands." 



At 10 mm. the stomach wall is composed of three layers, entodermal epithelium, a thick 

 mesenchymal layer and the peritoneal mesothelium. At 16 mm. the circular muscle layer is 

 indicated by condensed mesenchyma. The tunica propria forms a dense layer at 55 mm. 



