  In a recent paper we presented a general perturbation result for generators
of $C_0$-semigroups. The aim of the present paper is to replace, in case the
unperturbed semigroup is analytic, the various conditions appearing in this
result by simpler assumptions on the domain and range of the operators
involved. The power of our result to treat classes of PDE's systematically is
illustrated by considering a generic example, a degenerate differential
operator with generalized Wentzell boundary conditions and a reaction diffusion
equation subject to Neumann boundary conditions with distributed unbounded
delay.
