Well now here’s a turn up for the books. I’m in this week’s New Scientist. Each week in the Back Pages, they print a couple of questions sent in by (named) readers, and answers (or at least ideas of answers) from other readers to earlier questions. And this week they’ve printed a question I sent in a while ago.

The question is printed as:

Some worms regenerate when cut in half laterally, but what would happen if they were cut in half longitudinally?
Keith Marshall, London, UK

Hmmm … I’m not sure this is quite what I meant because “worms” is going to get interpreted as “earthworms” by too many people, especially as the online version has an image of earthworms. Maybe the question is appropriate for “earthworms” and not just the “flatworms” I had intended – I don’t know.

But space is limited, so the question as printed is a cut down version of the question I submitted:

There’s a recent report in Scientific American, https://www.scientificamerican.com/article/regenerating-deep-sea-worms-harness-live-in-algae-as-they-split-into-three/, of acoel flatworms regenerating when cut in half laterally. The head grows a new tail, but the tail grows two heads and then divides. But what would happen if the worm was cut longitudinally, with each half containing some head and some tail? Would this be viable, or is the presence of (say) a brain a binary requirement?

Nonetheless I shall be very interested to see what the readers come up with over the next few weeks. I’ll try to remember to report back.