Fig. 3

Representative photomicrographs of sections of the left valve of zebra mussels exposed to radial extracorporeal shock waves as shown in Fig. 2a produced with 0 (a), 2.0 (b), 2.5 (c), 3.0 (d), 3.5 (e) and 4.0 (f) bar. In order to correctly identify the individual layers of the valves, the brightness of the images was greatly increased as shown in Panels a' to f'. Abbreviations: out, outside surface of the mussel shell; P, periostracum; O, ostracum; H, hypostracum; in, inside surface of the mussel shell. The scale bar in f' represents 300 µm in a–f