A member of the Halle choir has contributed this to Usenet:

   It's "Pluto, the renewer".  You may be interested to know, also,
   that the tempo indication is "prestissimo scorrevole" and the time
   signature is 5/4.  I haven't heard it yet, but will do so at a
   rehearsal on Tuesday (I'm singing in Thursday's performance - the
   offstage female chorus has a part in "Pluto", which we only got a
   few days ago).  From the cues in my copy it *looks* as if Matthews
   has used many of the thematic ideas from the other Planets movements.

   Jocelyn Lavin                 "Big Issue?" "Yes! It is!"
   The Halle Choir home page: http://www.wardle.demon.co.uk

Tony Duggan, England.
Mahler survey:
http://www.musicweb.force9.co.uk/music/Mahler/