  The main purpose of this article is to supplement the authors' results on
degenerate principal series representations of real symplectic groups with the
analogous results for metaplectic groups. The basic theme, as in the previous
case, is that their structures are anticipated by certain natural
subrepresentations constructed from Howe correspondence. This supplement is
necessary as these representations play a key role in understanding the basic
structure of Howe correspondence (and its complications in the archimedean
case), and their global counterparts play an equally essential part in the
proof of Siegel-Weil formula and its generalizations (work of Kudla-Rallis).
The full results in the metaplectic case also shed light on the seeming
peculiarities, when the results in the symplectic case are viewed in their
isolation.
