His huge long tail wound up in hundred folds,
  Does overspread his long brass-scaly back,
  Whose wreathed boughts when ever he unfolds,
  And thick entangled knots adown does slack.
  Bespotted all with shields of red and black,
   It sweepeth all the land behind him far,
  And of three furlongs does but little lack;
  And at the point two stings in-fixed are,
Both deadly sharp, that sharpest steel exceeden far.

Book I, Canto XI