The layers of its wall are much more fully differentiated than in the more anterior regions of the enteron.
The first indication of the formation of the enteron is seen in the very early embryo shown, from the dorsal aspect, in figure 1.
The cells lining the Wolffian ducts are smaller than those lining the enteron.
Because of the lack of properly fixed tissue no sections of the enteron of this stage were made.
In A the shell-gland and the mouth and the rudiment of the enteron are shown; primitive mesoderm cells.
A reconstruction, plotted from transverse sections, of the enteron of an embryo of about the age of the one shown in figure 6.
The openings of the Wolffian ducts, wdo, are seen at the lower end of the section of the enteron.
An outline drawing, from the ventral aspect, of the enteron of an embryo of 20 cm.
This structure as has been noted above, is quite distinct from the other parts of the enteron.
The endoderm, on the other hand, gives rise to the lining of the enteron, and of the glands which open into it.
enteron en·ter·on (ěn'tə-rŏn')
The alimentary canal; the intestines.