Living by Light

Jellyfish aren't reknowned for specialized organs; they lack brains, guts, hearts, and lungs. But some of them have eyes in spades. Mo writes on Neurophilosophy that box jellyfish have "24 eyes contained within a club-shaped sensory apparatus called a rhopalium, one of which is suspended from each side of the cube-shaped umbrella by a flexible, muscular stalk." A crystal called a stratolith weighs down each of the four rhopalia and ensures that the "upper lens eyes remain in a strictly upright position, regardless of body orientation." For the first time, researchers have shown that the four upper lens eyes can detect terrestrial landmarks above the surface of the water, helping lagoon-dwelling jellyfish to keep their bearings. And on Oscillator, Christina Agapakis takes a peek at the future, when light-sensitive proteins delivered to the retina by a virus could help blind people to see.

• Box jellyfish stable-eyes vision to hunt prey on Neurophilosophy
• Future Vision on Oscillator