2,5-Methano-2H-s-indaceno[8,1-bc]furan-2,- 5a,7,8c(2aH,6H)-tetrol,octahydro-2a,5,8- trimethyl-3-(1-methylethyl)-,(2S,2aS,3S,4aS,- 5R,5aR,7S,8S,8aS,8bR,8cS)-