\centerline{\structure{
\atom{C}\epin{H$_3$}\nnwsingle\atom{C}\wpin{H$_2$}
\nnesingle\atom{C}\epin{H$_2$}\nnwsingle\atom{C}\wpin{H$_2$}
\nnesingle\atom{C}\epin{H$_2$}\nnwsingle\atom{C}\wpin{H$_2$}
\nnesingle\atom{C}\epin{H$_2$}\nnwsingle\atom{C}\wpin{H$_2$}
\nnesingle\atom{C}\epin{H$_2$}\nnwsingle\atom{C}\wpin{H$_2$}
\nnesingle\atom{C}\epin{H$_2$}\nnwsingle\atom{C}\wpin{H$_2$}
\nnesingle\atom{C}\epin{H$_2$}\nnwsingle\atom{C}\wpin{H$_2$}
\nnesingle\atom{C}\epin{H$_2$}\nnwsingle\atom{C}
\side{\wdouble\atom{O}}
\nnesingle\atom{O}\nesingle\atom{C}\epin{H$_2$}
\nnesingle\firstbicycloatom{C}\side{\wsingle\atom{H}}
\nnwsingle\atom{C}\wpin{H$_2$}\nnesingle\atom{O}
\side{\nsingle\atom{P}\side{\esingle\atom{O$^\ominus$}}
\side{\ndouble\atom{O}}
\side{\wsingle\atom{O}\swsingle\atom{CH$_2$}\nwsingle
\atom{~~H$_3$C---N$^\oplus$---CH$_2$}
\side{\nsingle\atom{C}\epin{H$_3$}}
\side{\ssingle\atom{C}\epin{H$_3$}}}}
\ephantom\phantatom{OOO}\ephantom\ssephantom\phantatom{O}
\sswphantom\secondbicycloatom{O}\sesingle\atom{C}
\side{\nedouble\atom{O}}
\ssesingle\atom{C}\epin{H$_2$}\sswsingle\atom{C}\wpin{H$_2$}
\ssesingle\atom{C}\epin{H$_2$}\sswsingle\atom{C}\wpin{H$_2$}
\ssesingle\atom{C}\epin{H$_2$}\sswsingle\atom{C}\wpin{H$_2$}
\ssesingle\atom{C}\epin{H$_2$}\sswsingle\atom{C}
\side{\wsingle\atom{H}}\ssedouble\atom{C}
\side{\swsingle\atom{H}}
\sesingle\atom{C}\epin{H$_2$}\ssesingle\atom{C}\wpin{H$_2$}
\sesingle\atom{C}\epin{H$_2$}\ssesingle\atom{C}\wpin{H$_2$}
\sesingle\atom{C}\epin{H$_2$}\ssesingle\atom{C}\wpin{H$_2$}
\sesingle\atom{C}\epin{H$_2$}\ssesingle\atom{C}\epin{H$_3$}}}
\medskip 
\centerline{\bf Figure~12. \rm  
1-Palmitoyl-2-oleoyl-3-{\it sn\/}-glycerophosphocholin.}