MAY, 1921. AMERICAN MARSUPIAL, C^NOLESTES OSGOOD. 73 



The short colon combined with the small caecum in Ccenolestes 

 is contrary to the usual condition in marsupials and is most nearly 

 met in certain of the dasyures. Although the short colon is perhaps 

 primitive, the small caecum is obviously a secondary condition. 



GLANDS. 



Liver. The liver is relatively large in size. It has three primary 

 divisions, the left lateral, the right central and the right lateral, the last 

 being subdivided into right lateral proper, caudate and spighelian 

 (PI. VII, Fig. 2). The largest lobe is the left lateral, although the right 

 central or cystic lobe almost equals it and the combined bulk of the three 

 subdivisions of the right lateral is nearly or quite as great as either of the 

 other primary divisions. In a male specimen hardened by preservative, 

 the right central lobe is 18 mm. wide; the left lateral has practically the 

 same width but is slightly more bulky. 



The large left lateral is entire without trace of a division, although a 

 slight projection of its dorsal part is somewhat separated to curve around 

 the oesophagus. In Didelphis and Marmosa there is at least one cleft 

 in its lateral boundary partially dividing it into left lateral and left 

 central. 



The right central is entire except for one fissure extending about 

 halfway to its base and inclosing the gall bladder in a wholly concealed 

 position similar to that in some other marsupials but unlike that of 

 Didelfhis in which it is exposed and in contact with the diaphragm. 



The right lateral proper lies next to the right central and is regular in 

 shape although its dorsal border has a slight cleft. It is about half as 

 large as the right central and its dorso-caudal border is in contact with 

 the kidney. Although for the most part separate from it by a deep fis- 

 sure, it is united at its base to the caudate. 



The caudate is in ventral position and incloses a considerable part 

 of the right kidney. It has an anterior projection and two posterior ones 

 through the inner of which the vena cava passes. 



The spighelian lobe arises from the base of the caudate and divides 

 into two lobes almost at right angles to each other, one appressed to the 

 left lateral and the other hanging free caudad of it and ventrad of the 

 caudate lobe. Its peduncle attaches it to the caudate but the portal 

 vein and the ductus choledochus pass between the free surfaces of the 

 caudate and the spighelian. The pancreatic duct and the ductus choledo- 

 chus unite just before entering the duodenum. 



The liver of Canolestes differs from that of Didelphis and at least 

 some other polyprotodonts in its large bipartite spighelian lobe, in its 



