  Identifying the progenitors of Type Ib and Type Ic supernovae requires
knowing, among other things, whether SNe Ib eject hydrogen, and whether SNe Ic
eject helium, and perhaps even hydrogen. Recently it has become clear that some
SNe Ib do eject hydrogen, and it may be that all SNe Ib do. Two arguments that
have been made in the past that SNe Ic eject helium are difficult to confirm,
but I discuss other possible evidence that SNe Ic eject helium, as well as
hydrogen. If so, these elements extend to lower ejection velocities than in SNe
Ib. The spectroscopic differences between SNe Ib and SNe Ic may depend on the
radial distributions of the helium and hydrogen as well as on the ejected
masses of helium and hydrogen. We should consider the possibility that SNe Ic
are more mixed up.
