450 



DR. P. CHALMERS MITCHELL ON THE 



that in Dromicia closely, with the peculiarity, to which I shall call attention later, that 



the distal end of Meckel's tract is inserted at an acute angle into the junction of the 



csecum and hind-gut, so disposed as to suggest the former existence of a pair of caeca 



(fig. 47, II, p. 518). 



Fis. 6. 



Intestinal Tract of Phalangista vulpina. 

 Letters as in fie. 5. 



In Bettongia penicillata (fig. 7) there is no specialised duodenum. Meckel's tract is 

 relatively short and with slight minor loops ; it enters the conjoined very wide, rather 

 long caecum and hind-gut at an acute angle, with the same suggestion as in Petaurus. 

 The hind-gut shows a marked differentiation into an enlarged colon and a straight 

 rectum. The portal system is diagrammatically simple, the vessel to the colon being 

 distinct from the posterior mesenteric or rectal branch. 



