205 
two parts of the inner circular muscular coat unite on either side of 
the common bile-duct to form the complete inner circular muscular 
wt 
IN 
| 
I 
ln! 
Fig. 5. Cross-section somewhat removed from the orifice of the duodenal portion 
of the common bile-duet of dog. > 30. 
litte, 
SW; 
SOL BOOS 
i ae 
) 7% 
\ N i Os 7, ( 4 
TOLLE Sg 
Se G50? 
7 2 »/ 
Fig. 6. Cross-section near the middle of the duodenal portion of the common bile- 
duct of dog. X 30. 
coat again, muscle fibres can be seen running from the upper to the 
lower part. This occurs on both sides, and there is, therefore, a com- 
