\def\layoutcaption{\def\caption@dir{Z}\captionwidth\z@
\def\caption@posa{Z}\def\caption@posb{Z}%
\@ifnextchar<\X@layoutcaption{%
\def\layoutcaption{\def\caption@dir{Z}\captionwidth\z@
\def\caption@posa{Z}\def\caption@posb{Z}%
\@ifnextchar<\X@layoutcaption{%