\begin{table}%t1
\par
%%\centering
\par
\caption{Mean colours of Seyfert galaxies from Clavel et~al. (\cite{Clavel01})
  and ULIRGs from Klaas et~al. (\cite{Klaas01}). $N$ gives the number of objects
  used for deriving the two colours, respectively.
\label{msxxxx_table_colours}
}
\begin{tabular}{lcrcr}
\hline\hline
              &  $H - K_{\rm s}$    &$N$   &    $K_{\rm s} - LW2$  &$N$ \\
\hline				       		   		 	  
Sy~1 ($<$1.8)  &  0.59  $\pm$   0.18 &25  &      2.8   $\pm$  0.6 &25\\
Sy~2 ($\ge$1.8)&  0.39  $\pm$   0.18 &23  &      2.7   $\pm$  0.8 &23\\
\par
SBs-ULIRGs    &  0.49  $\pm$   0.17 &21  &      3.9   $\pm$  0.5 & 7\\
AGN-ULIRGs    &  0.94  $\pm$   0.35 & 5  &      3.9   $\pm$  0.4 & 5\\
\hline
\end{tabular}
\end{table}