Information from Nothing? The Flatworm's Tale

We've talked a lot about roundworms here recently, but there is another phylum of worms that is not round but flat. The only flatworms most of us know are the planaria we cut up in biology class, watching them grow two "heads" or other grotesque forms. Actually, these members of the phylum Platyhelminthes are complex organisms, important for the study of parasitism, evolution, and especially regeneration. Littlewood and Waeschenbach provide an overview in Current Biology:

Linnaeus had little...