We analyze a functor from cyclic operads to chain complexes first
considered by Getzler and Kapranov and also by Markl. This functor is
a generalization of the graph homology considered by Kontsevich, which
was defined for the three operads ${\mathrm{Comm}}$, $\mathrm{Assoc}$, and ${\mathrm{Lie}}$. More
specifically we show that these chain complexes have a rich algebraic
structure in the form of families of operations defined by
\emph{fusion} and \emph{fission}. These operations fit together to
form uncountably many $\mathrm{Lie}_\infty$ and $\mathrm{co}$-$\mathrm{Lie}_\infty$ structures.
In particular, the chain complexes have a bracket and cobracket which
are compatible in the {Lie} bialgebra sense on a certain natural
subcomplex.