  We explore the relationship between the mass function of CDM halos and
dynamical probes of the mass function such as the distribution of gravitational
lens separations and the local velocity function. The compression of galactic
halos by the cooling baryons, a standard component of modern models, leads to a
feature in the distribution of lens separations near 3 arcsec or in the
velocity function near 400 km/s. The two probes of the mass function, lens
separations and the local velocity function, are mutually consistent. Producing
the observed velocity function of galaxies or the separation distribution using
standard adiabatic compression models requires more cold baryons, an equivalent
cosmological density of Omega_b=0.02 compared to a total cosmological
Omega_b=0.04, than are observed in standard accountings of the baryonic content
of galaxies, Omega_b=0.006$, or our Galaxy, Omega_b<0.015. The requirement for
a higher cold baryon density than is usually assigned to galaxies appears to be
generic to models which use the standard adiabatic compression models for the
transformation of the CDM halo by the cooling baryons. If real, this dynamical
baryon discrepancy suggests either that we are neglecting half of the cold
baryonic mass in standard galactic models (e.g. a MACHO, cold molecular or warm
gas component), or that there is a problem with standard adiabatic compression
models.
