Just a note to the group from one who generally lurks:
 
  I was fortunate to have caught Scientific American Frontiers (copyright
1996)  on PBS tonight.  Among five segments, they had a 15 minute one with
Gary Vermeij discussing the evolution of the defensive function of shells, and
another showing that the octopus may be able to learn by seeing and following
an example.  These subject matters were not mentioned in the channel guide
write-ups.  It would be worthwhile to catch this if it has not aired yet at
your location.
 
Martin