Barreleye fish shows a transparent head..

The barreleye (Macropinna microstoma) has extremely light-sensitive eyes that can rotate within a transparent, fluid-filled shield on its head. The fish’s tubular eyes are capped by bright green lenses. The eyes point upward (as shown here) when the fish is looking for food overhead. They point forward when the fish is feeding. The two spots above the fish’s mouth are are olfactory organs called nares, which are analogous to human nostrils. Image: © 2004 MBARI