THE EMBRYO. 



1201 



of the duodenum and lying just below the greater curvature of the stomach ; 

 within this arch the coils of the small intestine are disposed (Fig. 765). Some- 



Trachea.--\ 



I 

 (Esophagus. -- 



Stomach. -- 

 Bile duct 



V-shaped loop 

 of mid-ijut. 



Vitello-intestinal duct. 



Cloaca 



*---Lung. 



-Trachea. 



t-Pancreas. 



Bile duct. 

 Pancreas. 



~Lung. 

 (Esophagus. 



ir- Stomach. 



\. Csecum. 

 -Cloaca. 



FIG. 761. Front view of two successive stages in the development of the alimentary canal. (His.) 



times the downward progress of the caecum is arrested, so that in the adult it 

 may be found lying immediately below the liver instead of in the right iliac 

 region. 



Further changes take place in the bursa omentalis and in the common mesen- 

 tery, and give rise to the peritoneal re- 

 lations seen in the adult. The bursa 

 omentalis, which at first reaches only 

 as far as the greater curvature of the 



Right 



suprarenal 

 capsule 



Liver 



Right 



suprarenal 



capsule 



Left 



suprarenal 

 capsule 



Liver 



FIG. 762. Schematic and enlarged cross-section 

 through the body of a human embryo in the region 

 of the mesogastrium. Beginning of third month. 



(Toldt.) 



Left 



suprarenal 

 capsule , 



Liver 



FIG. 763. Same section as in Fig. 762, at end 

 of third month. (Toldt.) 



stomach, grows downward to form the great omentum, and this downward extension 

 lies in front of the transverse colon and the coils of the small intestine. The 

 anterior layer of the transverse mesocolon is at first quite distinct from the posterior 

 wall of the bursa omentalis, but ultimately the two blend, and hence the great omen- 

 tum appears as if attached to the transverse colon (Figs. 768, 769, and 770). The 



76 



