This is most unusual and is described as a capacitor tube. The construction consists of a triode section with a screen on the outer side and the grid open on the inside and facing the curved plate that is the capacitor element. The cage with side holes is the anode.
The information sheet that the valve was wrapped in.
The screen is on the left the capacitor plate is in the centre and the anode is on the right with the three side holes.
This looks like a conventional anode but in this valve is the screen.
Just visible to the right of the anode ar the horizontal wires of the control grid.
Here the anode is on the left with the screen on the right and the curved capacitor plate in the middle.
The thin glass tube envelope is 21 mm in diameter, and excluding the B9A base pins is 61 mm tall.