Transvaal Money Box

I found this money bank at a suburban auction where there were alot of other cast iron banks and mechanical banks dispersed throughout the various items. When trying to unscrew the back screw the screw snapped due to corrosion on the inside. The inside has surface rust but nothing serious except the screw need to be removed from the front to be replaced with a new one. The inscription on the back is underlined like this : ------o------.