288 



STUDY OF PIG EMBRYOS. 



large trunk of the vena cava inferior, V.C.I, on its way past the right dorsal lobe 

 of the liver. Near the aorta on the left is the mesogastrium, Om.maj, or future 

 great omentum, by which the stomach is suspended from the median dorsal wall 

 of the abdomen. The stomach, St, is entirely upon the left side of the body and 

 is directly connected with the liver by means of the anlage of the lesser omen- 

 tum, Om.min. The walls of the stomach are constituted by the splanchnopleure, 

 and, therefore, comprise a layer of thickened entoderm, which bounds the cavity 

 of the organ, and a relatively thick layer of mesoderm which forms the greater 



& f*** 



0G> e<%r <= 

 - ' 



Hep 



Mes 



Ves.ep 



Msth 



FIG. 199. SECTION OF GALL-BLADDER OF A 14.0.1. PIG. FRONTAL SERIES 67, SECTION 171. - 

 Hep, Hepatic cells. Mes, Mesenchyma. Msth, Mesothelium. Ves.ep, Epithelium of gall-bladder. 



t ,.ui' JL the wall, and the very thin superficial mesothelium. The entoderm is a 

 smooth layer of moderate thickness composed of elongated epithelial cells. It 

 :orms no folds and shows no trace of differentiation into gastric glands. In the 

 nesenchyma there are some capillary blood-vessels. The mesothelium is thicker 

 .han over the liver and somatopleure, and contains crowded, more or less nearly 

 >pherical nuclei. The liver, Li, is by far the largesT organ of the body. It 

 .ip nearly half the section. It is divided into four main lobes, the two dorsal -and 



:ral; two on the right and two on the leu. The reference line. Li, : 

 ie left dorsal lobe. The liver consists of a complicated network of n 



