I am looking for references on some creature/animal that has only a few nerve
cells in its whole nervous system, and whose full nervous system has been
completely understood, and hence whose behavior is completely understood. If
there is no such animal, are there any that are close to being fully
Ideally, the references would be either authoritative to experts, or readable
to a larger audience.
I don't know if years ago someone or some article said that the horseshoe crab
has nine nerve cells total, the nerves are very large and easy to study, and
that the whole interaction of these nine nerves had been fully analyzed and
characterized (and hence also the behavior of the crab).
In searching libraries and the Internet, I have not found much at all on the
horseshoe crab (or on Chelicerata/Merostomata). Grzimek's "Encyclopedia of
Animal Life" seemed to have the most material but it still did not have much.
These crabs are very ancient, going back to well before dinosaurs.
Through a children's book on them I discovered that they have eyes with about a
thousand facets. The eye has been studied for line etc detection. This would
seem to imply that there are many more than nine nerves in the creature. Unless
there is something like a visual array that is not considered part of the
nervous system, an array that processes for e.g. lines etc..
Thanks for any refs, or for leads, sources, or places to check or query for
refs and information.