Last week I wrote in the New York Times about a fascinating new paper in which scientists described a lamp shell embryo that is, in effect, a swimming eyeball. The paper itself, however, comes in two parts. Along with the part on the swimming eyeball, the scientists also described a later stage of the lamp shell embryo in which it developed simple eyes connected to neurons. It's primitive version of our own eyes that reveals some interesting things about evolution--particularly about the different photoreceptors that evolved over half a billion years ago for sensing light. At the time, I was struck by the fact that this one paper had two newsworthy insights. So I was glad to see PZ Myer takes up the other half of the story in excellent detail over at Pharyngula. Check it out.