Of Barrel and Escape Bars

I was asked about the difference between the Barrel and Escape Bars on my Chinese movements and why is it that I say that the bars have been modified from the original. OK here goes, hope I got the terminology right.

The modified barrel bar and Escape bars on the Chinese movement. The bars have been modified into 3 different bars. The barrel bar has been divided into 2 bars. From the photograph below, the bar on the left is the barrel bar. However the other half of the bar has been 'merged' with the escape bar, which is now the center piece. The escape bar has also been divided into two. The third bar (on the right) on this movement would be the escape bar.

The barrel bar has been further modified to show part of the barrel.

This is another view of the 3 bars.

The photograph below shows the normal layout of the barrel and escape bars. The bar on the left is the escape bar and the one on the right (the big one) is the barrel bar.

The barrel bar, unmodified, thus we can just see the barrel (6 o'clock position).

Another view of the bars.