Fig. 3

SEM images of the L. fortunei gills. a View in perspective of a set of filaments [f], showing ciliary discs [cd], lateral cilia [lc], laterofrontal cirri [lfc] and frontal cilia [fc]. The outlined arrowheads indicate likely mucus-strings on the frontal tract. The outlined and filled open arrowheads indicate larger particles on the frontal and lateral tract, respectively. Images (b) and (c, d) show in detail a cd, the lc and lfc, respectively. Microvilli [mv] are present below the lc and around the cd. Several spherical particles of about 200-300 nm and one of nearly 4-5 μm size were observed attached to the lfc. e View in perspective of one filament showing its lateral aspect and the detailed lfc at the top frontal margin. f Higher magnification image of the region marked with the rectangle in (e). Each individual cilia of the laterofrontal cirrus bent at the top, thus having a shape of a comb