Globular Cluster Populations: Results Including S$^4$G Late-Type
  Galaxies
  Using 3.6 and 4.5$\mu$m images of 73 late-type, edge-on galaxies from the
S$^4$G survey, we compare the richness of the globular cluster populations of
these galaxies to those of early type galaxies that we measured previously. In
general, the galaxies presented here fill in the distribution for galaxies with
lower stellar mass, M$_*$, specifically $\log({\rm M}_*/{\rm M}_\odot) < 10$,
overlap the results for early-type galaxies of similar masses, and, by doing
so, strengthen the case for a dependence of the number of globular clusters per
$10^9\ {\rm M}_\odot$ of galaxy stellar mass, T$_{\rm N}$, on M$_*$. For $8.5 <
\log ({\rm M}_*/{\rm M}_\odot) < 10.5$ we find the relationship can be
satisfactorily described as T$_{\rm N} = ({\rm M}_*/10^{6.7})^{-0.56}$ when
M$_*$ is expressed in solar masses. The functional form of the relationship is
only weakly constrained and extrapolation outside this range is not advised.
Our late-type galaxies, in contrast to our early-types, do not show the
tendency for low mass galaxies to split into two T$_{\rm N}$ families. Using
these results and a galaxy stellar mass function from the literature, we
calculate that in a volume limited, local Universe sample, clusters are most
likely to be found around fairly massive galaxies (M$_* \sim 10^{10.8}$
M$_\odot$) and present a fitting function for the volume number density of
clusters as a function of parent galaxy stellar mass. We find no correlation
between T$_{\rm N}$ and large-scale environment, but do find a tendency for
galaxies of fixed M$_*$ to have larger T$_{\rm N}$ if they have converted a
larger proportion of their baryons into stars.
