Figure 6
From: Regulation of red fluorescent light emission in a cryptic marine fish
Guanine crystal platelets from the iris of T. delaisi under light microscopy. A: phase contrast. B: fluorescence. Note the weak blue-green fluorescence of the regular guanine crystal at the bottom right, which lacks red fluorescent pigment present in the others. Shapes vary a lot in these crystals, but do not seem to differ systematically between fluorescent or non-fluorescent forms.