WOMBAT. 



portal interval it is a pointed extremity, i.e., is atrophy- 

 ing. Although apparently so primitive, yet this liver 

 would approach the human type if the left cystic and 

 left lateral lobes were linked up. 



(D) Here the greatest width of the right mesial or 

 cvstic lobe was 3.5 cm., and of left 1.5 cm. The dorsal 

 extremity of the left part was only l-3rd cm. wide, and did 

 not reach the portal interval, i.e., the fissure for the cystic 

 duct and the longitudinal fissure are being merged, since 

 the dorsal portion of the left cystic is disappearing. Thus 

 we see how the lobus quadratus becomes defined dorsally. 



Gall Bladder. — This is a somewhat broad sac, meas- 

 uring, in a large specimen, 4-5 cm. dorso-ventrally, and 

 about 3 cm. laterally. In one male specimen the gall blad- 

 der was unusually small, only measuring 2 cm. dorso- 

 ventrally, and 1 cm. laterally. It usually projects beyond 

 the ventral border of the liver, and is lodged in the broad 

 cleft or interval between the right and left portions of 

 the mesial or cystic lobe (corresponding to the right and 

 intermediate of the tripartite mesial lobe), and is seen 

 both on the dorsal and ventral surfaces. It is mobile, 

 being invested by peritoneum completely for the ventral 

 4-5ths, the dorsal l-5th being invested on the upper and 

 under surfaces, but bound laterally to the margins of the 

 cleft. 



Cystic Duct. — This passes back in the groove on the 

 under surface of the cystic or median lobe, between its 

 right and left divisions, though dorsally portion of the 

 left lateral lobe may take part in its boundary. It ex- 

 tends from the cleft for the gall bladder to the portal 

 interval, and is invested by peritoneum on the under sur- 

 face and sides being attached above. It measures 4.5 cm. 

 to 6.5 em. long, and is joined by the hepatic ducts, and 

 becomes the common bile duct. 



53 



