Opisthoproctus soleatus (Vaillant 1888; 10.4cm) is an extant barrel-eye, a deep sea fish with a transparent head and telescope eyes perpetually looking dorsally. Here it nests with Santatanichthys (above). Note the tiny mouth and the quadrate in front of the orbit. Many of the fragile bones are transparent or nearly so.

Chanos salmoneus (Vaillant 1888; 10.4cm) is an extant barrel-eye, a deep sea fish with a transparent head and telescope eyes perpetually looking dorsally. Here it nests with Santatanichthys (above). Note the tiny mouth and the quadrate in front of the orbit. Many of the fragile bones are transparent or nearly so.

Albula vulpes (Linneaus 1758; 105cm in length) is the extant bonefish. It feeds on deep seafloor and tidal invertebrates. Note the floating cheekbone, dorsal nares, open rostrum, shark-like premaxilla, and large frontal. The large number of pre-sacral vertebrae is a primitive trait.