bluesky,
Hopefully BigGuy has it right and you have a reverse cut tiller. As he said, that's an option for some manufacturers.
On the other hand, I thought I remember reading somewhere that some of the early Kubota had a PTO that rotated opposite to today's standard. If that's is in fact true, you might have a tiller designed for one of those machines.
If that's the case, I think I also remember someone saying that a reversing kit or adapter is available.
~Rick