274 PROCEEDINGS OF THE CANADIAN INSTITUTE. 



mouth of the large duct of the organ from the chyme as it escapes 

 from the stomach, and which contains traces of pepsin. Trypsin 

 may gain an entrance also, as th e pancreatic seci-etion is poured into 

 the canal nearly opposite the opening of the appendage. Without 

 taking the precaution of removing the matter present, traces of all 

 the enzymes named were found in the extracts of the appendage. 

 Krukenberg came to a different result with Acipenser ruthenus, 

 having found the enzymes normally present in the organ. 



A pancreas is present in the three genera. This organ in Acipeii.- 

 ser is disseminated through the right half of the peritoneal cavity in 

 the liver, and between it and the valvate portion of the mid-gut. 

 The distribution of the pancreatic tubules seems to follow wholly the 

 course of the branches of the arteria cceliaco-mesenterica, about which 

 they entwine. The duct of the organ opens on the same papilla on 

 the inner wall of the intestine with the bile duct. This papilla is 

 placed about a centimetie from the tip of the pyloric valve. The 

 tubules of the pancreas are much similar to those observed in other 

 fishes, except that structures analogous to the centro-acinar cells of 

 Langerhans have been observed in them. 



k. pancreas has been described by Balfour and Parker as occurring 

 in young Lepidostei in the form of a rounded organ, situated on the 

 posterior face of the pyloric portion of the mid-gut. I find the 

 pancreas in Lepidosteus to be much more extended, its tubules 

 being partly imbedded in the dorsal face of the posterior two-thirds 

 of the liver, and partly entwined about the portal vein, as far back 

 as the posterior border of the pyloric appendage. The organ which 

 was considered by Balfour and Parker to be the pancreas, seems to 

 be an accessory spleen for the greater part, with a few pancreatic 

 tubules in it. The duct of the pancreas opens in common with the 

 bile duct into the intestine, the junction of the two taking place 

 immediately outside the intestinal wall. 



A pancreas has not hitherto been found in Amia. The reason is 

 that it is imbedded to a large extent in the liver, forming the greater 

 part of the bridge between the right and left lobes. The tubules are 

 arranged about the larger interlobular branches of the portal vein. 

 The duct passes straight backwai'ds, to open beside the bile duct into 

 the mid-gut near the pyloric valve. 



