>the Roman toilets were probably elevated to raise them above open sewers, rather than for sitting.

However in the image http://en.wikipedia.org/wiki/File:Ostia-Toilets.JPG accompanying one can see that this would mean that the Romans were wasting a lot of well prepared stone building the toilets twice as high as needed (note the extra stone below the opening).

One thought was that this could be an economy of parts, the "seat" and front pieces appear same-dimensioned - but then I noticed that the bottom part has a corner that the top part didn't and so in this instance that theory appears unsound.

Given the Romans amazing engineering prowess I can't see them wasting materials like this in order to make the toilets harder to use.

http://books.google.com/books?id=RIRlPwAACAAJ&printsec=f... appears to be the major ref on Wikipedia and is widely cited in scientific papers but unfortunately I can't find a place to read it online (and don't have a copy!).

Edit: http://www.amazon.com/gp/product/0715638505?ie=UTF8&tag=... "Latrinae Et Foricae: Toilets in the Roman World" clearly, to me, shows a Roman toilet as a seat on the front (my posterior would fit but my feet wouldn't fit either side of the hole to squat). Review - http://bloggingpompeii.blogspot.com/2009/12/latrinae-et-fori...

Perhaps the Romans started out squatting, and later changed to sitting. I predict this is the point in time when the rise of the Romans stopped and their fall began. (Tongue-in-cheek.)