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 the pancreatic secretion 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 Acipen- 
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 arterta caliaco-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 centimetre 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. 
A 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 backwards, to open beside the bile duct into 
the mid-gut near the pyloric valve. 
