Figure 2.

The structures around the pneumostome opening positive to anti-rhodopsin antibody. A) Lymnaea during breathing through the pneumostome. B) An image of the structures around pneumostome opening positive to anti-rhodopsin antibody. C) Negative control image without antibody staining. D) Enlarged image of the rectangular area in B), obtained through a double staining experiment using an antibody and nuclear staining. The cells with a single nucleus, comprising numerous granular clusters located at 10 to 100 μm beneath the surface, with cell bodies of 5 to 20 μm in diameter, as indicated with arrows.