  The WFPC2 Camera on board HST has been used to obtain high-resolution images
of NGC 3610, a dynamically young elliptical galaxy. These observations
supersede shorter, undithered HST observations where an intermediate-age
population of globular clusters was first discovered. The new observations show
the bimodal color distribution of globular clusters more clearly, with peaks at
(V-I)o = 0.95 and 1.17. The luminosity function (LF) of the blue, metal-poor
population of clusters in NGC 3610 turns over, consistent with a Gaussian
distribution with a peak Mv ~= -7.0, similar to old globular-cluster
populations in ellipticals. The red, metal-rich population of clusters has a LF
that is more extended toward both the bright and faint ends, as expected for a
cluster population of inter-mediate age. It is well fit by a power law with an
exponent of alpha = -1.78 +-0.05, or -1.90+-0.07 when corrected for
observational scatter. A Kolmogorov-Smirnov test confirms the significant
difference between the LFs of the red and blue clusters, with a probability of
less than 0.1% that they come from the same population. A comparison with the
Fall & Zhang cluster disruption models shows marginal agreement with the
observed LF, although there are differences in detail. In particular, there is
no clear evidence of the predicted turnover at the faint end. A by-product of
the analysis is the demonstration that, at any given metallicity, the peak of
the LF should remain nearly constant from 1.5 Gyr to 12 Gyr, since the effect
of the disruption of faint clusters is almost perfectly balanced by the fading
of the clusters. This may help explain the apparent universality of the peak of
the globular cluster luminosity function. (Abridged)
