  We study the {\it arc and curve} complex $AC(S)$ of an oriented connected
surface $S$ of finite type with punctures. We show that if the surface is not a
sphere with one, two or three punctures nor a torus with one puncture, then the
simplicial automorphism group of $AC(S)$ coincides with the natural image of
the extended mapping class group of $S$ in that group. We also show that for
any vertex of $AC(S)$, the combinatorial structure of the link of that vertex
characterizes the type of a curve or of an arc in $S$ that represents that
vertex. We also give a proof of the fact if $S$ is not a sphere with at most
three punctures, then the natural embedding of the curve complex of $S$ in
$AC(S)$ is a quasi-isometry. The last result, at least under some slightly more
restrictive conditions on $S$, was already known. As a corollary, $AC(S)$ is
Gromov-hyperbolic.
