Arching when starter cranks engages and now no crank at all

Just as I stated in addition it was periodically not cranking, no response when turning the key. But most of the time would work fine. Also the arching was intermitent?
Finally, when turning the key now nothing. I am thinking of course starter and Bendix, more specifically. Never in my life have I experienced the crackling-arching sound when starting. Very odd!