Biological Sunglasses in a Deep-Sea Squid: Pigment Migration in the Retina of .

The outward migration of ommin pigment granules from the bases to the tips of the photoreceptors in response to light has been reported in the retina of several (mostly coastal) squid species. Following exposure to light and then dark conditions, we collected and processed retinal tissue from juvenile specimens of a deep-sea oegopsid squid, . We aimed to determine whether the ommin pigment returns to baseline, and to investigate the presence of glutamate neurotransmitter signaling under both dark and light conditions.