#rhynchohyalus

Glasshead Barreleye (Rhynchohyalus natalensis) "[F]ound in the oceanic 'twilight zone', [this species] has bi-directed eyes capable of seeing above and below. The barreleye has a conventional refractive lens on top of its head to see predators and prey that are silhouetted against the dim light filtering down from above. It also has a curved mirror-like lens and retina that sees the flashes of bioluminescence from fishes and invertebrates to the side and below. The red arrows in the lower right figure indicate the notch in the cornea of the 'second eye.'"