Size of Theropods

[endocrin@desktop.com.au (Peter Mark)]

Just a follow up to Scott Horton's post - it would seem that in the past
there was at least a tendency, perhaps not scientifically rigorous, to lump
large theropods into carnosauria and small ones into coelurosauria. Now that
coelurosaurs have got pretty big with the inclusion of tyrannosaurs, just
what is an acceptable definition of the differences between the two?
Graeme Worth