  A fourth-order theory of gravity is considered which in terms of dynamics has
the same degrees of freedom and number of constraints as those of scalar-tensor
theories. In addition it admits a canonical point-like Lagrangian description.
We study the critical points of the theory and we show that it can describe the
matter epoch of the universe and that two accelerated phases can be recovered
one of which describes a de Sitter universe. Finally for some models exact
solutions are presented.
