Help a novice please!!!

The problem is that I am trying to create a half hollow sphere that has some thickness to it (like a tennis ball cut in half). I don't know much about Cinema 4D (version 7), but I reckon a lathe is the way to go? I tried this and nearly got the result I wanted. Only trouble is is that at the 'pole' of the half sphere it isn't smooth. There is like a 'pinch point'. I tried editing the b-spline, but can't for the life of me get it to be perfectly smooth?

I bet there is an easy solution!!?

Marty.