THE SPLEEN IN MARSUPIALS. 



splenic), a peritoneal band stretches across the omentum 

 between the stomach and spleen. The body varies from 

 7 to 8 cm. in length, and greatest width is 1.75 cm. 



(2) The right ventral process is also in relation with 

 the lesser sac, being swung freely on the great omentum. 

 It varies from 4 to 5 cm. long and is about 1.75 cm. wide. 

 This portion forms almost a right angle with the body. 



(3) The left dorsal process, 2.5 cm. long and 2 cm. 

 wide, is outside the lesser sac and gives attachment to the 

 left lateral fold. This membrane is somewhat triangular 

 in shape and measures 9 to 10 cm. long, and over it the 

 main pancreatic tissue diffuses itself, but it never extends 

 nearer than 2 cm. to the dorsal attachment. The basal 

 portion of the membrane (5 to 6 cm. long) extends from 

 the root of the mesentery out along the lower part of 

 the lesser sac to the left dorsal process of the spleen. Its 

 left margin is free. The right margin is not continuous 

 dorsally with the mesocolon of the large intestine, but 

 with the peritoneum slightly to its left. The left lateral 

 fold, as in the Platypus and Kangaroo, is free from dorsal 

 wall and ventrum of the left kidnev. 



Koala (Phascolarctus cinereus). 



The spleen is suspended in the great omentum, being 

 contained in the lesser sac, and is characterised by the 

 relative shortness of the left dorsal process and the 

 absence (this being the only instance among Marsupials 

 and Monotr ernes) of the left lateral or lieno-mesocolic 

 fold. The shape of the spleen varies slightly in different 

 animals. In all there is an elongated right ventral pro- 

 cess varying from 7 cm. to 12.5 cm. long. It is usually 

 constricted and fissured where it joins the main splenic 

 mass. The remainder of the spleen or body may approach 



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