PLATYPUS AND ECHIDNA. 



forms an angle and is traced upwards and to the left 

 above the duod-intest. junction. It lies in the wall of the 

 lesser sac, which it leaves as the spleen is approached, and 

 then curves downwards towards the pelvis on the lieno- 

 mesocolic fold. Thus we can describe three portions, viz., 

 descending, oblique and ascending, and descending, and 

 as the length of each portion is about 7 cm. the total length 

 is 21 cm. 



Pancreas in Platypus. — The pancreas in Platypus, 

 though abundant, is more diffuse and mobile than in the 

 Echidna, in which we have a relative compactness and 

 Immobility. In the Platypus the most compact portion 

 is as a rule to be found on the extreme left in relation 

 with the lesser process of the spleen and descending part 

 of the left colon. A knowledge of the relationship of the 

 pancreas necessitates a brief knowledge also of the rela- 

 tionship of the spleen, stomach, and duodenum, as well as 

 left colon. The stomach is a small tubular sac succeeded 

 by a somewhat horseshoe-shaped duodenum about 18 cm. 

 long. The colon, which is swung on the common mesen- 

 tery, comes into relationship with mesoduodenum which 

 suspends the duodenum making it freely mobile, and fol- 

 lows the curve of the latter as in diagram. It then de- 

 scends swung on its own mesocolon into the pelvis. The 

 great omentum is attached above to stomach and duo- 

 denum, extending as far to right as, or even beyond, the 

 bile duct entrance. It does not include the colon but in 

 the region of the duodeno-jej. flexure is in relation with 

 its superior margin for about 2-4cm. Suspended in the 

 great omentum we have the body and greater process of 

 the spleen — the smaller process is outside the lesser sac, 

 being related to the descending part of the colon by a 

 fold, the left lateral or lieno-mesocolic fold. The pan- 

 creas diffuses itself in the duodenal loop between the 



1.7 c 



