A pilot reported a near miss at 300 FT approaching X50 after a Citabria pilot failed to communicate on CTAF and was maneuvering on the runway and over the airport before departing.

Narrative

During a go around noted a Citabria holding short Runway 36. Continued with normal upwind. After turning cross-wind observed Citabria back taxing Runway 36 however I did not hear a radio transmission. A Mooney departed 20 minutes earlier from X50 and I communicated with him on CTAF. Abeam the numbers for Runway 36 I reduced the power as normal but noticed Citabria was stopped at the end of Runway 36 facing north. I announced on CTAF I was abeam the numbers and continued for a normal descent. Before turning base I lost visual contact with the Citabria and continued to turn base and saw him depart and appear to turn cross wind. On final I saw the Citabria again but it initially appeared he was heading 360. I then realized he was flying parallel to Runway 36 over the taxiway heading 180 at me. His altitude was likely not more than 500 FT. I continued to descend since he appeared to be climbing and I was at 300 FT and was on very short final. I continued to fly over Runway 36 at approximately 100 FT until the fuel farm to ensure I was clear of the Citabria and then executed a normal go around. On downwind I observed the Citabria heading directly toward the beach below 1;000 MSL/AGL. Citabria did not communicate on CTAF at all.