Mesenteron \Mes*en"te*ron\, n. [NL. See {Meso-}, and {Enteron}.]
(Anat.)
All that part of the alimentary canal which is developed from
the primitive enteron and is lined with hypoblast. It is
distinguished from the stomodaeum, a part at the anterior end
of the canal, including the cavity of the mouth, and the
proctodaeum, a part at the posterior end, which are formed by
invagination and are lined with epiblast.
[1913 Webster]