Alimentary canal; digestive tract (7)
I believe the answer is:
enteron
I believe this clue is a double definition.
'alimentary canal' is the first definition.
(enteron is a kind of alimentary canal)
'digestive tract' is the second definition.
(I know that enteron is a type of digestive tract)
(Other definitions for enteron that I've seen before include "gut" , "Begin; engage in" , "Open" , "element of guts" .)