\begin{table}%t1
  \caption{Feature identifications, with surface areas (pixels
    and  square   arcseconds),  and   minimum  and  maximum   radial  velocities
    (km~s$^{-1}$).  The  last column  gives  [\ion{He}{i}]/[Br$\gamma$] for  the
    different      structures,     relative      to      the     mean      value
    $\langle$[\ion{He}{i}]/[Br$\gamma$]$\rangle$.  The  Minicavity  is  separated  from  the
    \object{Northern Arm}, as it warrants special attention. \label{tablesurf}}
%\centerline
{
      \begin{tabular}{clrrrrc}
\hline\hline
ID & Feature name & $S$ (pix) & $S$ (arcsec$^2$) & $V$min & $V$max & [\ion{He}{i}]/[Br$\gamma$]$^a$\\
\hline
a&\object{Northern Arm} & 2414 & 300.8 & --290 & 186 & 0.74$^b$ \\
& \object{Minicavity} &&&&& 0.85 \\
b&\object{Bar} & 1389 & 173.1 & --214 & 194 & 0.99 \\
c&\object{Ribbon} & 833 & 103.8 & 130 & 240 & 0.78 \\
d&\object{Eastern Bridge} & 670 & 83.5 & 32 & 180 & 1.09 \\
e&\object{Western Arc} & 471 & 58.7 & --40 & 72 & 0.52 \\
f&\object{Western Bridge} & 327 & 40.7 & --124 & 98 & 1.73 \\
g&\object{Tip} & 207 & 25.8 & 220 & 336 & 2.64 \\
h&\object{Northern Arm Chunk} & 185 & 23.1 & 12 & 72 & -- \\
i&\object{Bar Overlay} & 136 & 16.9 & --270 & --10 & 1.81 \\
\hline
\end{tabular}}
\medskip
$^a$  Normalized to its mean value. \\
$^b$  Except \object{Minicavity}.
\end{table}