 The duodenum forms a large loop, the descending part of which first is directed downwards towards the gastralia and then runs to the back.There in a sharp bend, the folds of which are clearly visible, it turns to the front, proceeding as an ascending tract, its visible part ending near the stomach.At this point the tract is directed to the left of the body, perpendicular to the fossil slab, and its course can thus no longer be followed.