Fig. 6. Franc2d lateral model, a 2-D model of the y–z plane of the 3-D experiments. (A) The displaced finite element mesh from model 2 (378 Pa pharynx stress, 92 Pa, linearly decreasing to 60 Pa, body stress) is shown as solid lines, and the original geometry with the crack is shown by dotted lines. (B) The displaced mesh shows the shape of the worm in gelatin and the head region (boxed area in A) enlarged below. The surface of the displaced mesh is slightly raised, a result of the displacements along the crack walls. Scale bar, 5 mm; magnification factor, 1.