YES! Findthee Swing! Phew... Thank you for that! I'd be going crazy here trying to remember the name till I got home from work so I could check! My mind is like a sieve. Really. Can't remember anything! (So I guess it's a good thing I'm donatin for Alzheimer's research early. I'll cash on it in a few years time ;D)
I did know it because I studied Latin in school! 8)
Except that Errol isn't in Night Watch! I think he's just a swamp dragon. If you look at the Rembrandt painting that this is based on, there's some sort of animal where the dragon is - a dog or possibly a large cat.
Ahh, so it's based off a Rembrandt painting? That explains a lot, I often wondered why they chose that particular cover rather than something like a scene in the novel, that would explain it.
And yes, I've actually just noticed that Findthee is carrying his cane in the picture, so it must be him