  We study several integrable Hamiltonian systems on the moduli spaces of
meromorphic functions on Riemann surfaces (the Riemann sphere, a cylinder and a
torus). The action-angle variables and the separated variables (in Sklyanin's
sense) are related via a canonical transformation, the generating function of
which is the Abel-Jacobi type integral of the Seiberg-Witten differential over
the spectral curve.
