FIGURE 6.

Arion vulgaris, histochemistry of the ventral pedal integument. (a) Strong positive periodic acid‐Schiff reaction (PAS) of the ventral gland types, as indicated by the dark pink staining (black arrowheads). (b) With Alcian blue staining (pH 2.5), a positive staining (dark blue) of the gland types is noted (white arrowheads). (c) Lipids (Sudan black B staining) could be confirmed (blue staining) in the isolated ventral mucus, while (d) Alizarin red S staining showing the presence of calcium (black arrowhead) in the subepithelial layer on the ventral side of the animal . Scale bars in all images = 100 μm