THE ANATOMY OF TEN TO TWELVE MM. PIG EMBRYOS 



127 



Esophagus and Stomach. The esophagus extends as a narrow tube caudal 

 to the lungs, where it dilates into the stomach. The stomach is wide from its 

 greater to its lesser curvature and shows a cardiac diverticulum (Lewis). The 

 pyloric end of the stomach has rotated more to the right, where it opens into the 

 duodenum, from which division of the intestine develop the liver and pancreas. 



The liver, with its four lobes, fills in the space between the heart, stomach 

 and duodenum (Fig. 117). Extending from the right side of the duodenum along 



Lat. nasal process 

 Lacrymal groove 



Maxillary process 

 Mandibular process 



Cervical sinus 

 Trachea 



Tracheal lung bud 



Upper limb bud 



Septum transtiersum 



Hepatic diverticulum 



Yolk-sac 



Yolk-stalk 



Allantois 

 R. umbilical artery 



Olfactory pit 



Eye 



Median nasal process 



Br. arch 2 

 Br. arch j 

 Br. arch 4 



L. lung 



Esophagus 



Stomach 



Mesonephric duct 

 Ventral pancreas 

 Mesonephros 

 Cephalic limb of intestine 



Caudal limb of intestine 



Rectum 



Metanephros 





Lower limb bud' 



Mesonephric duct / Spinal cord 

 Rectum 



FIG. 119. Ventral dissection of a 9 mm. pig embryo. The head is represented as bent dorsally. 



the dorsal and caudal surface of the liver is the hepatic diverticulum. It lies to 

 the right of the midline and its extremity is saccular. This saccular portion 

 becomes the gall bladder. Several ducts connect the diverticulum with the liver 

 cords. One of these persists as the hepatic duct which joins the cystic duct of the 

 gall bladder. The proximal portion of the diverticulum becomes the common 

 bile duct, or ductus choledochus. The ventral pancreas arises from the common 

 bile duct near its point of origin (Fig. 118). It is directed dorsad and caudad to 

 the right of the duodenum. The dorsal pancreas arises more caudally from the 



