Light-insulating apparatus of the camera-like eye of the terrestrial gastropod mollusk Arion rufus (Heterobranchia, Stylommatophora)

The cellular composition, the morphology of the components, and the screening function and evolutionary changes of the light-insulating apparatus of the camera-like eye of the terrestrial gastropod pulmonate mollusk Arion rufus were studied and evaluated using light and electron microscopy. According to all the considered characteristics, the light-insulating apparatus of A. rufus is typical for terrestrial pulmonate mollusks. Evolutionary transformations of the light-insulating apparatus, caused by the change in the mollusks' environment, are insignificant and affect the cellular composition, the morphology of pigmented cells and the isolation of the light-sensitive parts of photoreceptor cells from each other.