THE SPLEEN IX MAESUPIALS. 



tion pancreas, left process of spleen, kidney, and meso- 

 colon, only the shortened remains of the lieno-mesocolic 

 fold intervening. In these two varieties of Phalanger 

 important light is thrown on the combination of corre- 

 lated factors necessary to produce the close relationship 

 of spleen, pancreas, and colon in the left human hypo- 

 chondrium. 



Wombat (Phascolomys) , 



The spleen is placed in the left hypochondrimn in rela- 

 tion with the left part of the stomach and upper portion 

 of the left kidney. It may be described as triangular in 

 shape, presenting three margins: (1) dorsal or renal; 

 (2) right, gastric, or ventral: (3) left, lower, or colic. 



We also note three extremities or angles, viz., an 

 oesophageal or upper, a right ventral, and a left ex- 

 tremity. In addition, two main surfaces, viz., outer, 

 lateral or left, and inner, mesial, visceral, or right. its 

 greatest length is 12 cm. and breadth 11 cm. 



Extremities. — (a) The oesophageal or superior ex- 

 tremity is most dorsal and frequently the most pointed, 

 and lies 3 to 4 cm. from the sesophagus. It is in relation 

 with the great curvature of the stomach, to which it is 

 connected by gastro-splenic omentum, i.e. upper part of 

 the great omentum, and which is thickened in this region, 

 with a width of only 1 cm. Frequently, as in the human, 

 it bends towards the inner surface so as to give a rounded 

 shape to the upper end of the spleen. This is probably 

 an accommodation effect for a well-developed left hepatic 

 lobe, with the lower and inner part of which it is related. 



(b) The ventral or right extremity is usually rounder! 

 and corresponds to the right ventral process seen in the 

 Monotremes and other Marsupials. It is connected to the 

 great curve of the stomach by the gastro-splenic (great) 

 omentum, the width of which is 4 cm., so that it is moro 



14G 



