Originally Posted by Andrew R Stewart

I believe this LH crank arm has a cap which also acts as the extractor surface. So as the retaining bolt is loosened it presses against the cap's inside and pushes the arm off the axle. the axle/RH arm should be able to be pulled out the bearings, sometimes a wooden whack device helps. The bearing "cups" need a wrench (like a Park BBT-9) and will unthread with some initial effort to loosen. The drive side has LH threads and the other side has RH threads. Andy.