The structure and surface morphology of gill filaments in the brown musselPerna perna

The morphology of the gills of adult Perna perna were examined by stereo li ght-microscopy and scanning electron microscopy. While the surface morpholo gy of each filament was similar to that previously described for Mytilus ed ulis, there were some subtle inter-generic differences. In M. edulis, inter -lamellar connections are reported to connect the inner and outer lamellae over the entire ventral to dorsal surface. In P. perna, the inter-lamellar connections are restricted to between the third and sixth row of cilial dis ks from the marginal groove. All cilia emanating from the epithelial cells of NI. edulis are reportedly longer than those of their counterparts in P. perna. Further, laterofrontal cirri in M. edulis comprises 22-30 pairs of c ilia, whereas in P. perna there are only 18-23 pairs. This report complemen ts an earlier fine-structural study and completes the description of gill f ilaments in P. perna. These data serve as a morphological baseline for futu re local pollution impact studies.