  A new class of singlet superconductors with a gap function $\Delta(\bk,
\omega_n)$ which is {\it odd} in both momentum and Matsubara frequency is
considered. Some of the physical properties of this superconductivity are
discussed and it is argued that: i) the electron-phonon interaction can produce
this kind of pairing, ii) in many cases there is no gap in the quasiparticle
spectrum, iii) these superconductors will exhibit a Meissner effect.
