Globular clusters at the distance of M31 have
apparent angular sizes of a few arcseconds.
While many M31 GCs have been detected and studied from
ground-based images, the high spatial resolution of HST
allows much more robust detection and characterization of
star cluster properties. We present the results of a search
of 157 HST/WFPC2 images of M31. We found 82 previously-cataloged
globular cluster candidates as well as 32 new
globular cluster candidates and 20 open cluster candidates.
We present images of the new candidates and photometry
for all clusters. We assess existing cluster catalogs' completeness
and use the results to estimate the total
number of GCs in M31 as 460 ± 70. The specific frequency is
SN = 1.2 ± 0.2and the mass specific frequency T = 2.4 ± 0.4;
these values are at the upper end of the range seen for spiral galaxies.