AND MYOLOGY OF THE MARSUPIALIA. 865 



one csecum. The latter is Lusiform, but is devoid of longitudinal 

 bands, sacculi, and a vermiform appendage, and the superior 

 mesenteric artery does not occupy the free edge of its mesentery. 

 At the point where the ileum enters the colon there is a trans- 

 verse vein. At a point two inches proximal to the ileo-csecal 

 jvmction there is a single Peyer's Patch measuring one and a 

 quai'ter inches in length. 



No trace of a second csecum was found in my pouch specimens 

 of Macropus benneUi, Macropios giganteus, Onychogale lunata, and 

 Bettongia penicillata. 



I have refrained from giving a detailed list of the measure- 

 ments of the different parts of the intestinal tract in my speci- 

 mens as they had been preserved for varying periods. The data, 

 if given, would be of little value in consequence. 



The Pancreas, 



In all Marsupials examined except Phascohuxtos cinereus, I 

 found the pancreas much subdivided and dendritic, but the 

 arrangements of the subdivisions varied considerably. In Afeta- 

 chirus opossum the}"" are aggregated to form a compact mass in the 

 posterior part of the duodenal loop, and a long, narrow part 

 stretches across the abdomen to the spleen. Small branches are 

 given off from the body. The duct opens into the duodenum 

 along with the couimon bile-duct. Perameles ohesula also pos- 

 sesses a long, narrow body with lateral processes, and the duodenal 

 loop contains an almost complete ring of pancreatic tissue such as 

 is found in some Rodents and Oarnivora. 



In Petaurus sciureus, P. hreviceps, and P. breviceps pajyuanus the 

 pancreas consists of long strips and small isolated pieces arranged 

 along the course of the mesenteric vessels. It is difficult to detect 

 the ducts of the small lobules, and it is impossible to do so when 

 there is much fat in the omentum and mesentery. The same 

 dendritic arrangement is seen in Dendrolagus ursinus, in which 

 the pancreatic and common bile-ducts open separately into the 

 duodenum. In Macropus, on the other hand, the ducts are 

 confluent (Owen). 



Osgood describes a dendritic pancreas in Goenolestes ohscurus (9), 

 so its condition is no more highly evolved than that of Perameles 

 ohesula. 



It is evident, therefore, that the pancreas of Phascolarctos 

 cinereus is of a higher type than the dendritic, more or less 

 diffuse, organ of other forms. * 



The Organs of Circulation,. 

 The Pericardium adheres to the diaphragm in all Marsupials 

 except Trichosurths vulpecula, and it adheres to a variable extent 

 to the sternum and ribs. In Dendrolagus ursinus and pouch 

 specimens of Macropms (/iganteus and M. hennetti the lungs were 

 seen to overlap the base of the heart, and the preconlia, or 

 uncovered part, was adherent to the sternum and ribs. 



