Comparative analysis of the structure and crystallin composition of the lenses of freshwater fish and gastropods with respect to their vision.

The structural organisations of the lenses of the pikeperch Sander lucioperca and the whitefish Coregonus lavaretus as well as of the pond snail Lymnaea stagnalis and the apple gold snail Pomacea canaliculata were studied by phase contrast microscopy, scanning electron microscopy and Raman spectroscopy. All microscopical examinations were based on 70 um thick lens sections, whereas spectral measurements were performed on whole crystalline lens. The lenses of S.