I just heard a talk that discussed the molecular control of the development of left-vs-right differences in gastropods that was interesting. I think it's unpublished work, so I'm not going to mention details, but I think it's safe to say that the mechanism for determining left-handed or right-handed spirals in snail shells is controlled by a mechanism more like the one in vertebrates than like the one in arthropods, which is interesting. Naturally, I was interested in how this may apply to cephalopods. Modern shelled cephs seem to have bilaterally symmetric shells, but certainly some ammonoids are "dextral" (clockwise when looking down at the point) or "sinistral" (the other way), and I'm not sure about nautiloids. All(?) modern cephs have sexual dimorphism in a left-or-right sense, except maybe the squids that have an internal penis instead of a hectocotylus. I can't remember if there are asymmetrical internal organs, though... I don't see any in Wells' book, but he tends to show the two halves of the animal at different stages of dissection to show more with one picture. The funnel is also weird, in that in octopus, it's off-center, but I think the development, and maybe even the muscles, form it symmetrically. All octos can switch the funnel to either side, right?