SEM micrographs of the reflector layer and the photogenic layer in the light organ.

A) Light organ (LO), located at the abdominal tissue section (the 6^th body segment), is a slab-like tissue with a thickness about 240 µm. B) The photogenic layer (P) located at the ventral light organ is a 40 µm thick tissue, and shows a morphology distinct from that of the reflector layer (R). C) In the reflector layer (R), densely packed spherical granules are found, and some of them had become hollowed (indicated as arrows). DO: Dorsal organ.