Eels have spines

It's funny how when you spot a glitch in a presentation it can take on horrible proportions. Watching back my neuroscience explanantion for the Kavli prize I note that I say that eels don't have spines. I think I must have meant legs, but who knows? An old professor of mine at Cambridge was always keen to point out the difference between an error and a slip. I think the distinction is about what might reasonably have been in your head as opposed to your mouth.