Among all of the unsupported assertions about the golden ratio one of the most puzzling is that the golden rectangle determines the proportions of the Nautilus shell, because it is demonstrably false. Given the flood of misinformation to be found on the internet it is probably inevitable that different versions of the idea are current, and some of them are not so obviously wrong, but it is surprising that it could have arisen in the first place. It is possible to trace its origins back into the nineteenth century, encountering some interesting methods of approximate construction along the way, but the mistake seems to be surprisingly modern.