Thank you.  That was it.  IN answer to another query, as to why not symlink, I cannot point to a particular behavior, but I have found that symlinks do not behave in all situations like real hardlinks.  What I want it something like a hardlink to a directory.

I think this may be possible with bind mounting. 

One major problem with nautilus or any other GUI file manager---in fact many, many GUI programs that rely on mouse input primarily---has been the loss of subtler capabilities like hard link.  I've been looking at using hardlinks to organize my literature collection.  A single paper may belong equally in several categories.  Or for photos, to go beyond, say, catalogs in gthumbs: catalogs are possibly lost in an upgrade or minor accident.

 I'd be interested in seeing particular examples of the use of bind mounts for the purposes I propose.  Reiterating:

   - mounting a directory from another tree with a full status in all respects as a directory on the current tree. 
   - mounting a directory in several places.   (A subdirectory of microscopical images and another subdirectory of notes can be linked together in the same directory under the specific project or organism under study).

Perhaps a more skilled approach to the use of symlinks would serve the same purpose more directly?

Thank you again for the input.

Alan