and their Relation to the Peritoneum. 



479 



spleen in the greater, the artery in question may be grasped. Recent 

 works on anatomy {e.g., " Quain's Anatomy," Ninth Edition, 1882, 

 vol. ii, p. 729, fig. 621, &c.) delineate the peritoneum in accordance 

 with the above description. The process of development which has 

 been described seems to afford an explanation of the very complicated 

 relations of this artery, both to the peritoneum and to its greater and 

 lesser cavities. 



Diagram 3. 



S. Stomach. MG. Mesogastrium. 



The arteria vasa brevia and gastro-epiploica sinistra are 

 naturally the next to demand attention. It has been pointed out 

 already that the gastro-splenic omentum is simply that part of the 

 mesogastrium which lies between the spleen and the stomach. Blood- 

 vessels are present in the mesentery of the stomach long before the 

 appearance of the spleen, but it does not seem possible to say whether 

 the vasa brevia are the representatives of these, or whether, as was 

 remarked before, they might have been developed in connexion with 

 the spleen itself. Similar doubts appear to exist when the epiploic 

 arteries are in question; how far they are prolongations of the 

 original arteries of the mesogastrium, or to what extent they are 

 developed in the mesoblast which surrounds the stomach. A solution 

 of this point would in no way affect what has been said about the 

 course and relations of the splenic artery itself. This vessel is 

 exceedingly like the gastric, for it has a similar origin and similar 

 course through the mesogastrium. 



The arteries in the vicinity of the pylorus are the next to demand 

 notice. The development of the liver and lesser omentum has a pro- 

 found influence upon these, and therefore requires ample considera- 

 tion. Owing to difficulties which have been mentioned before their 

 development will be studied in the chick. The very earliest stages of 

 the development of the liver determine its arterial supply. A trans* 



