THE SPLEEN IN MARSUPIALS. 



formed by the left dorsal and right anterior processes. 

 On examining the inner or visceral surface (page 154) of 

 the spleen we are struck with the resemblance borne to 

 that of Man and the Wombat. We note a well-defined 

 renal surface, concave, formed bv the body and left 

 process; a gastric surface formed by the body and right 

 process, with the gastro-splenic omentum (great omen- 

 tum) attached along a groove extending from the ex- 

 tremity of the body to the extremity of the anterior pro- 

 cess. This surface is separated dorsally by a distinct 

 raised edge from the renal surface, but unless there is a 

 defined concavity this is not marked. From the gastro- 

 splenic omentun, running down the left dorsal process, 

 we see the attachment of the left lateral fold (lieno- 

 mesocolic). This, with the anterior part of the gastro- 

 splenic omentum, separates off the lower left or colic 

 surface. Below the attachment of these two membranes 

 we have a ridge simply the result of the impressions of the 

 colon and stomach, just as the posterior ridge separating 

 the renal from the gastric surface is the result of the renal 

 impression. The lieno-mesocolic (left lateral fold), 

 instead of being free as in the preceding specimens from 

 the short left splenic process to the mesocolon of the distal 

 colon, has, in addition, become attached to the ventrum 

 and outer surface of the lower half of the left kidney. 

 The result is that the spleen and left portion of the 

 pancreas which is supported on the fold are brought into 

 relation with the kidney, and so we have defined the 

 concave renal surface of the spleen related to the upper 

 and outer convex portion of the kidney — the pancreas 

 lying ventral to that organ. Thus we see that we have a 

 definitely formed lieno-renal fold which is really the 

 upper part of the lieno-mesocolic fold, and the lower part 

 of the fold is really now reno-mesocolic. A peritoneal 

 hand is noted in both Trichosurus and Pseudochirus from 



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