That's the great Michael Henderson on bass. From Wikipedia:
Davis saw the young Henderson performing [with Stevie Wonder] at the Copacabana in New York City in early 1970 and reportedly said to Wonder simply "I'm takin' your bass player."
And I sense another 70's Miles Groove o' the Day coming up...
A couple of other versions after the break:
From Panthalassa, Bill Laswell's album of Miles remixes:
From Agharta (remember, this is from Miles's pandering commercial phase, according to some people):
I can't find my favorite version, from Miles Davis in Concert, but you can buy the CD, or better yet find it on LP at your local used record store.