Behind, it passes by the neurenteric canal into the primitive gut or primitive groove.

These enclose a digestive cavity, the primitive gut, with an opening, the primitive mouth.

The primitive gut (d) opens above at the primitive mouth (m).

This is the primitive gut-cavity or the gastric cavity of the gastrula, progaster or archenteron.

In reality, the whole body of the gastrula is merely a " primitive gut."

Civilisation and basic civility are knocked down with hate, fear, xenophobia and primitive gut nationalism.

The central primitive gut-cavity (d) is full of entodermic cells.

Naturally, the primitive gut and mouth change very considerably afterwards in the various classes of animals.

The simple hollow of the cup, the primitive gut (g), has a narrow opening (o).

N primitive gut cavity (progaster or Rusconian alimentary cavity).

In both the gut consists of a muscular gullet (s) and a glandular primitive gut (d).

C gastrula, with complete primitive gut: the embryonic cavity has almost disappeared in consequence of invagination.)

Thus the human alimentary canal is as simple as the primitive gut of the gastrula in its original structure.

In consequence of these important folding-processes in the primitive gut, the simple entodermic tube divides into four different sections:-

The elaborate alimentary canal of the higher animals develops ontogenetically from the same simple primitive gut of the gastrula.

The chorda may have been originally a digestive glandular groove in the dorsal middle line of the primitive gut.