A swimming eyeball?

Here's one of the weirder things I've come across in biology. When lamp shells are just tiny 36-hour-old embryos--just a clump of a few hundred cells--they can see. Many cells on their outer surface express a photoreceptor gene, and they show evidence of being able to swim towards light. In other words, these lamp shells are swimming eyeballs. Aside from the surrealism, this discovery is also cool because it might be a model for how our own eyes evolved. Perhaps they started out in a similar way. For more details, check out my story in today's New York Times.[Image: Coreldraw]