Hi ProteusUnbound - since I am the one responsible for these fine works (
), let me give you a bit more of an explanation than what the ScienceDaily blurb reports.
In coleoids (octopus, cuttlefish, squid), the brain contains several lobes that have been shown previously to be necessary for either (or both) the formation or storage of long term memory. These are the vertical lobes (VL) and frontal lobes (FL), which in coleoids sit right on top of the supraoesophageal nerve cord.
Nautilus brains are very different to coleoid brains. Their supraeospohageal nerve cord is just that - a ~2mm thick cord of primarily axonal tracts, with very little in the way of cell bodies. The VL and FL are completely absent from the nautilus brain. So we know that memory must be made and stored somewhere else in the nautilus brain, the question is where, and is this region (wherever it might be) somehow antecedent and homologous to the VL/FL in coleoids.
We still don't know this. The studies done on the papers D posted are behavioural, and there has been only one attempt to record LTP (a cellular signature of learning and memory) in Nautilus brains (we didn't find it, and this work is not published).
So whatever the learning and memory areas are in Nautilus (assuming they are indeed localised and not diffuse), we do not know where they are, what they look like or what they are homologous to in the coleoid brain. It's not so much that we 'misidentified' them - since we know they can't be the same as coleoids, we don't know what they are at all.
Here is the citation of the paper that the ScienceDaily article describes:
http://jeb.biologists.org/content/211/12/1992.short