  OBSERVATIONS of galaxies to very faint magnitudes have revealed a population
of blue galaxies at intermediate redshift$^{1-5}$. These galaxies represent a
significant excess over the expectation of standard cosmological models for
reasonable amounts of evolution of the locally observed galaxy population.
However, the surveys which define the local galaxy population are strongly
biased against objects of low surface brightness$^{6-9}$. Low surface
brightness galaxies have properties very similar to those of the excess blue
population$^{10,11}$, and recent work suggests that they are comparable in
abundance to the more readily detected normal galaxies$^{9,12}$. I show that
the very deep surveys which reveal the excess population can easily detect low
surface brightness galaxies to large redshifts, but that local surveys will
miss them because they are not comparably sensitive. This suggests that the
excess faint galaxies {\it are\/} low surface brightness galaxies. No
alteration of standard cosmology is required, but it is necessary to reconsider
the way in which the galaxy distribution function is specified.
