LIVER OF AMERICAN OPOSSUM 



(DIDELPHIS MARSUPIALIS.) 



Here important differences as regards the mesial 

 lobe are noted when compared with Trichosurus. 



On the Diaphragmatic aspect we notice three pri- 

 mary divisions of the liver, viz., mesial, small right, and 

 large left lobes. These are separated by well defined 

 complete fissures, viz.. right and left lateral fissures, 

 (page 100. ) The mesial or cystic lobe is usually the largest 

 of the three, and the ventral cleft or fissure, about 1.5 cm. 

 long, for the gall bladder, forms on this aspect its separa- 

 tion into right and left mesial or cystic lobes. On the 

 dorsal aspect of the mesial lobe, to the left of the gall 

 bladder fissure or cleft, is the suspensory ligament, which 

 does not come forward to the ventral edge. On this edge, 

 however, to the left of the gall bladder cleft, a small fis- 

 sure, about .5 cm. long, may be met with. Prolonged dor- 

 sally this would reach the suspensory ligament, but there 

 is no depression between the two. I have, however, seen 

 a distinct line, almost a depression (faint), from the liga- 

 ment to the ventral edge, which latter, however, was not 

 fissured. Here we see an early indication of the forma- 

 tion of the cystic or mesial fissure leading to the tripartite 

 cystic lobe. It is not an instance where fusion of the inter- 

 mediate and left cystic lobes has taken place, for in those 

 instances the suspensory ligt. has corresponded to the 

 gall bladder fissure, while here it is distinctly to the left. 



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