THE SPLEEN IX MARSUPIALS. 



mobile than the superior angle. It is to be noted that the 

 gastro-splenic omentum does not extend to the tip of 

 either extremity. 



(c) The left extremity corresponds to the left process 

 seen in other Marsupials and in the Monotremes, and is 

 related to the outer margin of the left kidney about the 

 middle. 



Margins. — (a) Right (anterior of human) lies be- 

 tween the superior and right extremities along the great 

 curve of the stomach. It is thin, usually concave, fre- 

 quently notched below, and formed by the body and right 

 ventral process. 



(b) The left margin extends between the right ventral 

 and the left extremities. It is usually thin, is the longest 

 of the three, and presents a well-defined notch about its 

 middle or towards the left, so that the left process or 

 extremity becomes differentiated off. It is free and 

 comes into relation with the distal colon and the left por- 

 tion of the stomach. 



(c) The renal or dorsal margin extends between the 

 superior and left extremities, being formed by the body 

 and left posterior process. It is thicker and more dorsal 

 than the others and is curved — being in relation with the 

 outer convex margin of the left kidney. 



Surfaces. — (a) The outer or left surface is usually 

 smooth, slightly convex, corresponding to 8, 9, 10, 11, and 

 12 ribs. It is related to the diaphragm and the mesial or 

 visceral surface of the left lobe of the liver. 



(b) Inner, right or visceral surface is more complex 

 and presents, as in the human spleen, certain very definite 

 areas, viz. right, gastric, or upper; left, lower, or colic; 

 dorsal or renal. The attachment of the gastro-splenic 

 omentum extends on the gastric surface close to the pos- 



147 



